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  • Font serialization in vb.net

    - by jovany
    Hello all, as the title says , I need to serialize my font. I have tried the following approach unfortunately to no avail. This is what I have and what happens; I have a drawing application and certain variables and properties need to be serialized. (So , Xml.Serialization has been used.) Now this has already been done in a huge portion and I've created some other attributes which needed to be serialized and it works. There is one base class and classes such as drawablestar, drawableeclipse ,etc. all inherit from this class. As does my drawabletextboxclass. The base class is Serializable as can be seen in the sample below. It looks like this... Imports System.Xml.Serialization <Serializable()> _ Public MustInherit Class Drawable ' Drawing characteristics. 'Font characteristics <XmlIgnore()> Public FontFamily As String <XmlIgnore()> Public FontSize As Integer <XmlIgnore()> Public FontType As Integer <XmlIgnore()> Public ForeColor As Color <XmlIgnore()> Public FillColor As Color <XmlAttributeAttribute()> Public LineWidth As Integer = 0 <XmlAttributeAttribute()> Public X1 As Integer <XmlAttributeAttribute()> Public Y1 As Integer <XmlAttributeAttribute()> Public X2 As Integer <XmlAttributeAttribute()> Public Y2 As Integer ' attributes for size textbox <XmlAttributeAttribute()> Public widthLabel As Integer <XmlAttributeAttribute()> Public heightLabel As Integer '<XmlTextAttribute()> Public FontFamily As String '<XmlAttributeAttribute()> Public FontSize As Integer 'this should actually not be here.. <XmlAttributeAttribute()> Public s_InsertLabel As String ' Indicates whether we should draw as selected. <XmlIgnore()> Public IsSelected As Boolean = False ' Constructors. Public Sub New() ForeColor = Color.Black FillColor = Color.White 'FontFamily = "Impact" 'FontSize = 12 End Sub Friend WriteOnly Property _Label() As String Set(ByVal Value As String) s_InsertLabel = Value End Set End Property Public Sub New(ByVal fore_color As Color, ByVal fill_color As Color, Optional ByVal line_width As Integer = 0) LineWidth = line_width ForeColor = fore_color FillColor = fill_color ' FontFamily = Font_Family ' FontSize = Font_Size End Sub ' Property procedures to serialize and ' deserialize ForeColor and FillColor. <XmlAttributeAttribute("ForeColor")> _ Public Property ForeColorArgb() As Integer Get Return ForeColor.ToArgb() End Get Set(ByVal Value As Integer) ForeColor = Color.FromArgb(Value) End Set End Property <XmlAttributeAttribute("BackColor")> _ Public Property FillColorArgb() As Integer Get Return FillColor.ToArgb() End Get Set(ByVal Value As Integer) FillColor = Color.FromArgb(Value) End Set End Property 'Property procedures to serialize and 'deserialize Font <XmlAttributeAttribute("InsertLabel")> _ Public Property InsertLabel_() As String Get Return s_InsertLabel End Get Set(ByVal value As String) s_InsertLabel = value End Set End Property <XmlAttributeAttribute("FontSize")> _ Public Property FontSizeGet() As Integer Get Return FontSize End Get Set(ByVal value As Integer) FontSize = value End Set End Property <XmlAttributeAttribute("FontFamily")> _ Public Property FontFamilyGet() As String Get Return FontFamily End Get Set(ByVal value As String) FontFamily = value End Set End Property <XmlAttributeAttribute("FontType")> _ Public Property FontType_() As Integer Get Return FontType End Get Set(ByVal value As Integer) FontType = value End Set End Property #Region "Methods to override" Public MustOverride Sub Draw(ByVal gr As Graphics) ' Return the object's bounding rectangle. Public MustOverride Function GetBounds() As Rectangle ...... ........ ..... End Class [/code] My textbox class which looks like this , is the one that needs to save it's font. Imports System.Math Imports System.Xml.Serialization Imports System.Windows.Forms <Serializable()> _ Public Class DrawableTextBox Inherits Drawable Private i_StringLength As Integer Private i_StringWidth As Integer Private drawFont As Font = New Font(FontFamily, 12, FontStyle.Regular) Private brsTextColor As Brush = Brushes.Black Private s_insertLabelTextbox As String = "label" ' Constructors. Public Sub New() End Sub Public Sub New(ByVal objCanvas As PictureBox, ByVal fore_color As Color, ByVal fill_color As Color, Optional ByVal line_width As Integer = 0, Optional ByVal new_x1 As Integer = 0, Optional ByVal new_y1 As Integer = 0, Optional ByVal new_x2 As Integer = 1, Optional ByVal new_y2 As Integer = 1) MyBase.New(fore_color, fill_color, line_width) Dim objGraphics As Graphics = objCanvas.CreateGraphics() X1 = new_x1 Y1 = new_y1 'Only rectangles ,circles and stars can resize for now b_Movement b_Movement = True Dim frm As New frmTextbox frm.MyFont = drawFont frm.ShowDialog() If frm.DialogResult = DialogResult.OK Then FontFamily = frm.MyFont.FontFamily.Name FontSize = frm.MyFont.Size FontType = frm.MyFont.Style 'drawFont = frm.MyFont drawFont = New Font(FontFamily, FontSize) drawFont = FontAttributes() brsTextColor = New SolidBrush(frm.txtLabel.ForeColor) s_InsertLabel = frm.txtLabel.Text i_StringLength = s_InsertLabel.Length 'gefixtf Dim objSizeF As SizeF = objGraphics.MeasureString(s_InsertLabel, drawFont, New PointF(X2 - X1, Y2 - Y1), New StringFormat(StringFormatFlags.NoClip)) Dim objPoint As Point = objCanvas.PointToClient(New Point(X1 + objSizeF.Width, Y1 + objSizeF.Height)) widthLabel = objSizeF.Width heightLabel = objSizeF.Height X2 = X1 + widthLabel Y2 = Y1 + heightLabel Else Throw New ApplicationException() End If End Sub ' Draw the object on this Graphics surface. Public Overrides Sub Draw(ByVal gr As System.Drawing.Graphics) ' Make a Rectangle representing this rectangle. Dim rectString As Rectangle rectString = New Rectangle(X1, Y1, widthLabel, heightLabel) rectString = GetBounds() ' See if we're selected. If IsSelected Then gr.DrawString(s_InsertLabel, drawFont, brsTextColor, X1, Y1) 'gr.DrawRectangle(Pens.Black, rect) ' Pens.Transparent gr.DrawRectangle(Pens.Black, rectString) ' Draw grab handles. DrawGrabHandle(gr, X1, Y1) DrawGrabHandle(gr, X1, Y2) DrawGrabHandle(gr, X2, Y2) DrawGrabHandle(gr, X2, Y1) Else gr.DrawString(s_InsertLabel, drawFont, brsTextColor, X1, Y1) 'gr.DrawRectangle(Pens.Black, rect) ' Pens.Transparent gr.DrawRectangle(Pens.Black, rectString) End If End Sub 'get fontattributes Public Function FontAttributes() As Font Return New Font(FontFamily, 12, FontStyle.Regular) End Function ' Return the object's bounding rectangle. Public Overrides Function GetBounds() As System.Drawing.Rectangle Return New Rectangle( _ Min(X1, X1), _ Min(Y1, Y1), _ Abs(widthLabel), _ Abs(heightLabel)) End Function ' Return True if this point is on the object. Public Overrides Function IsAt(ByVal x As Integer, ByVal y As Integer) As Boolean Return (x >= Min(X1, X2)) AndAlso _ (x <= Max(X1, X2)) AndAlso _ (y >= Min(Y1, Y2)) AndAlso _ (y <= Max(Y1, Y2)) End Function ' Move the second point. Public Overrides Sub NewPoint(ByVal x As Integer, ByVal y As Integer) X2 = x Y2 = y End Sub ' Return True if the object is empty (e.g. a zero-length line). Public Overrides Function IsEmpty() As Boolean Return (X1 = X2) AndAlso (Y1 = Y2) End Function End Class The coordinates ( X1 ,X2,Y1, Y2 ) are needed to draw a circle , rectangle etc. ( in the other classes ).This all works. If I load my saved file it shows me the correct location and correct size of drawn objects. If I open my xml file I can see all values are correctly saved ( including my FontFamily ). Also the color which can be adjusted is saved and then properly displayed when I load a previously saved drawing. Of course because the coordinates work, if I insert a textField ,the location where it is being displayed is correct. However here comes the problem , my fontSize and fontfamily don't work. As you can see I created them in the base class, However this does not work. Is my approach completely off? What can I do ? Before saving img14.imageshack.us/i/beforeos.jpg/ After loading the Font jumps back to Sans serif and size 12. I could really use some help here.. Edit: I've been using the sample from this website http://www.vb-helper.com/howto_net_drawing_framework.html

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  • Floats will not align, stay staggered, can't find a solution?

    - by Sarah Proper
    What I am trying to do is build a multi column layout. The main two sections are divided 2/3 to 1/3 and inside the 2/3 column is divided 2/3 1/3 as well. My problem is that my floats will not align nicely with each other, choosing instead to stagger like stairs. I have tried declaring the widths smaller, floating them individually, including in the float sections display:block,inline, or inline-block and nothing seems to be working. I am getting really frustrated and would appreciate any help! Thanks! <div class="wrapper"> <div class="width50" style="float:left;"> <h1>Our Mission:</h1> <p> Bacon ipsum dolor sit amet swine spare ribs pork meatloaf pancetta filet mignon. Rump frankfurter pork belly prosciutto beef boudin andouille pig pork chop meatball ham drumstick filet mignon. Strip steak flank shank pig, tongue tri-tip jowl leberkas sirloin brisket t-bone. Ground round spare ribs salami capicola filet mignon. Capicola turkey t-bone corned beef sausage ham hock. Corned beef capicola leberkas pork chop, swine pastrami drumstick. Frankfurter fatback bacon jowl short loin, jerky pancetta bresaola corned beef shoulder drumstick ball tip tri-tip.</p> <div class="width50 float-left"> <img src="@Url.StaticContent(Links.Content.images.map_homepage_png)" alt="Map" /> </div> <div class="width33 float-right"> <img src="@Url.StaticContent(Links.Content.images.address_line_text_png)" alt="addressline" /> <br /> <h3>address</h3> <b>405 Empire Boulevard<br /> Rochester, NY 14609 </b> </div> </div> <div class="width33" style="float:right;"> <h1>Events</h1> <ul class="events"> <li> <h2>Fall Volunteer Festival</h2> <p> <b>october 6<br /> 10 am to 3pm </b> </p> <p> come to our town location for some fun activities for family and friends! </p> </li> <li> <h2>Fall Volunteer Festival</h2> <p> <b>october 6<br /> 10 am to 3pm </b> </p> <p> come to our town location for some fun activities for family and friends! </p> </li> <li> <h2>Fall Volunteer Festival</h2> <p> <b>october 6<br /> 10 am to 3pm </b> </p> <p> come to our town location for some fun activities for family and friends! </p> </li> </ul> </div> </div> </div> and the css: .clearfix:before, .clearfix:after, .grid-block:before, .grid-block:after, .deepest:before, .deepest:after { content: ""; display: table; } .clearfix:after, .grid-block:after, .deepest:after { clear: both; } .grid-box { float: left; } /* Grid Units */ .width16 { width: 16.666%; } .width20 { width: 20%; } .width25 { width: 25%; } .width33 { width: 39.333%; } .width40 { width: 40%; } .width50 { width: 50%; } .width60 { width: 60%; } .width66 { width: 66.666%; } .width75 { width: 75%; } .width80 { width: 80%; } .width100 { width: 100%; } .width16, .width20, .width25, .width33, .width40, .width50, .width60, .width66, .width75, .width80, .width100 { -moz-box-sizing: border-box; -webkit-box-sizing: border-box; box-sizing: border-box; padding: 5px 10px 5px 10px; } /* Create new Block Formatting Contexts */ .bfc-o { overflow: hidden; } .bfc-f { -moz-box-sizing: border-box; -webkit-box-sizing: border-box; box-sizing: border-box; width: 100%; float: left; } /* Align Boxes */ .float-left { float: left; } .float-right { float: right; } /* Grid Gutter */ .grid-gutter.grid-block { margin: 0 -15px; } .grid-gutter > .grid-box > * { margin: 0 15px; } .grid-gutter > .grid-box > * > :first-child { margin-top: 0; } .grid-gutter > .grid-box > * > :last-child { margin-bottom: 0; } /* Layout Defaults --------------------------------------------------------------------------------------- -------------*/ /* Center Page */ .wrapper { -moz-box-sizing: border-box; -webkit-box-sizing: border-box; box-sizing: border-box; margin: auto; } /* Header */ #header { position: relative; padding-top: 10px; } #toolbar .float-left .module, #toolbar .float-left > time { margin: 0 15px 0 0; float: left; } #toolbar .float-right .module { margin: 0 0 0 15px; float: right; } #headerbar .module { max-width: 300px; margin-right: 0; float: right; } #logo, #logo > img, #menu { float: left; } #search { float: right; } #banner { position: absolute; top: 0; right: -200px; } /* Footer */ #footer { position: relative; text-align: center; } /* Absolute */ #absolute { position: absolute; z-index: 15; width: 100%; }

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  • Non recursive way to position a genogram in 2D points for x axis. Descendant are below

    - by Nassign
    I currently was tasked to make a genogram for a family consisting of siblings, parents with aunts and uncles with grandparents and greatgrandparents for only blood relatives. My current algorithm is using recursion. but I am wondering how to do it in non recursive way to make it more efficient. it is programmed in c# using graphics to draw on a bitmap. Current algorithm for calculating x position, the y position is by getting the generation number. public void StartCalculatePosition() { // Search the start node (The only node with targetFlg set to true) Person start = null; foreach (Person p in PersonDic.Values) { if (start == null) start = p; if (p.Targetflg) { start = p; break; } } CalcPositionRecurse(start); // Normalize the position (shift all values to positive value) // Get the minimum value (must be negative) // Then offset the position of all marriage and person with that to make it start from zero float minPosition = float.MaxValue; foreach (Person p in PersonDic.Values) { if (minPosition > p.Position) { minPosition = p.Position; } } if (minPosition < 0) { foreach (Person p in PersonDic.Values) { p.Position -= minPosition; } foreach (Marriage m in MarriageList) { m.ParentsPosition -= minPosition; m.ChildrenPosition -= minPosition; } } } /// <summary> /// Calculate position of genogram using recursion /// </summary> /// <param name="psn"></param> private void CalcPositionRecurse(Person psn) { // End the recursion if (psn.BirthMarriage == null || psn.BirthMarriage.Parents.Count == 0) { psn.Position = 0.0f; if (psn.BirthMarriage != null) { psn.BirthMarriage.ParentsPosition = 0.0f; psn.BirthMarriage.ChildrenPosition = 0.0f; } CalculateSiblingPosition(psn); return; } // Left recurse if (psn.Father != null) { CalcPositionRecurse(psn.Father); } // Right recurse if (psn.Mother != null) { CalcPositionRecurse(psn.Mother); } // Merge Position if (psn.Father != null && psn.Mother != null) { AdjustConflict(psn.Father, psn.Mother); // Position person in center of parent psn.Position = (psn.Father.Position + psn.Mother.Position) / 2; psn.BirthMarriage.ParentsPosition = psn.Position; psn.BirthMarriage.ChildrenPosition = psn.Position; } else { // Single mom or single dad if (psn.Father != null) { psn.Position = psn.Father.Position; psn.BirthMarriage.ParentsPosition = psn.Position; psn.BirthMarriage.ChildrenPosition = psn.Position; } else if (psn.Mother != null) { psn.Position = psn.Mother.Position; psn.BirthMarriage.ParentsPosition = psn.Position; psn.BirthMarriage.ChildrenPosition = psn.Position; } else { // Should not happen, checking in start of function } } // Arrange the siblings base on my position (left younger, right older) CalculateSiblingPosition(psn); } private float GetRightBoundaryAncestor(Person psn) { float rPos = psn.Position; // Get the rightmost position among siblings foreach (Person sibling in psn.Siblings) { if (sibling.Position > rPos) { rPos = sibling.Position; } } if (psn.Father != null) { float rFatherPos = GetRightBoundaryAncestor(psn.Father); if (rFatherPos > rPos) { rPos = rFatherPos; } } if (psn.Mother != null) { float rMotherPos = GetRightBoundaryAncestor(psn.Mother); if (rMotherPos > rPos) { rPos = rMotherPos; } } return rPos; } private float GetLeftBoundaryAncestor(Person psn) { float rPos = psn.Position; // Get the rightmost position among siblings foreach (Person sibling in psn.Siblings) { if (sibling.Position < rPos) { rPos = sibling.Position; } } if (psn.Father != null) { float rFatherPos = GetLeftBoundaryAncestor(psn.Father); if (rFatherPos < rPos) { rPos = rFatherPos; } } if (psn.Mother != null) { float rMotherPos = GetLeftBoundaryAncestor(psn.Mother); if (rMotherPos < rPos) { rPos = rMotherPos; } } return rPos; } /// <summary> /// Check if two parent group has conflict and compensate on the conflict /// </summary> /// <param name="leftGroup"></param> /// <param name="rightGroup"></param> public void AdjustConflict(Person leftGroup, Person rightGroup) { float leftMax = GetRightBoundaryAncestor(leftGroup); leftMax += 0.5f; float rightMin = GetLeftBoundaryAncestor(rightGroup); rightMin -= 0.5f; float diff = leftMax - rightMin; if (diff > 0.0f) { float moveHalf = Math.Abs(diff) / 2; RecurseMoveAncestor(leftGroup, 0 - moveHalf); RecurseMoveAncestor(rightGroup, moveHalf); } } /// <summary> /// Recursively move a person and all his/her ancestor /// </summary> /// <param name="psn"></param> /// <param name="moveUnit"></param> public void RecurseMoveAncestor(Person psn, float moveUnit) { psn.Position += moveUnit; foreach (Person siblings in psn.Siblings) { if (siblings.Id != psn.Id) { siblings.Position += moveUnit; } } if (psn.BirthMarriage != null) { psn.BirthMarriage.ChildrenPosition += moveUnit; psn.BirthMarriage.ParentsPosition += moveUnit; } if (psn.Father != null) { RecurseMoveAncestor(psn.Father, moveUnit); } if (psn.Mother != null) { RecurseMoveAncestor(psn.Mother, moveUnit); } } /// <summary> /// Calculate the position of the siblings /// </summary> /// <param name="psn"></param> /// <param name="anchor"></param> public void CalculateSiblingPosition(Person psn) { if (psn.Siblings.Count == 0) { return; } List<Person> sibling = psn.Siblings; int argidx; for (argidx = 0; argidx < sibling.Count; argidx++) { if (sibling[argidx].Id == psn.Id) { break; } } // Compute position for each brother that is younger that person int idx; for (idx = argidx - 1; idx >= 0; idx--) { sibling[idx].Position = sibling[idx + 1].Position - 1; } for (idx = argidx + 1; idx < sibling.Count; idx++) { sibling[idx].Position = sibling[idx - 1].Position + 1; } }

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  • Maze not generating properly. Out of bounds exception. need quick fix

    - by Dan Joseph Porcioncula
    My maze generator seems to have a problem. I am trying to generate something like the maze from http://mazeworks.com/mazegen/mazetut/index.htm . My program displays this http://a1.sphotos.ak.fbcdn.net/hphotos-ak-snc7/s320x320/374060_426350204045347_100000111130260_1880768_1572427285_n.jpg and the error Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1 at Grid.genRand(Grid.java:73) at Grid.main(Grid.java:35) How do I fix my generator program? import java.awt.*; import java.awt.Color; import java.awt.Component; import java.awt.Graphics; import javax.swing.*; import java.util.ArrayList; public class Grid extends Canvas { Cell[][] maze; int size; int pathSize; double width, height; ArrayList<int[]> coordinates = new ArrayList<int[]>(); public Grid(int size, int h, int w) { this.size = size; maze = new Cell[size][size]; for(int i = 0; i<size; i++){ for(int a =0; a<size; a++){ maze[i][a] = new Cell(); } } setPreferredSize(new Dimension(h, w)); } public static void main(String[] args) { JFrame y = new JFrame(); y.setLayout(new BorderLayout()); Grid f = new Grid(25, 400, 400); y.add(f, BorderLayout.CENTER); y.setSize(450, 450); y.setVisible(true); y.setDefaultCloseOperation(y.EXIT_ON_CLOSE); f.genRand(); f.repaint(); } public void push(int[] xy) { coordinates.add(xy); int i = coordinates.size(); coordinates.ensureCapacity(i++); } public int[] pop() { int[] x = coordinates.get((coordinates.size())-1); coordinates.remove((coordinates.size())-1); return x; } public int[] top() { return coordinates.get((coordinates.size())-1); } public void genRand(){ // create a CellStack (LIFO) to hold a list of cell locations [x] // set TotalCells = number of cells in grid int TotalCells = size*size; // choose a cell at random and call it CurrentCell int m = randomInt(size); int n = randomInt(size); Cell curCel = maze[m][n]; // set VisitedCells = 1 int visCel = 1,d=0; int[] q; int h,o = 0,p = 0; // while VisitedCells < TotalCells while( visCel < TotalCells){ // find all neighbors of CurrentCell with all walls intact if(maze[m-1][n].countWalls() == 4){d++;} if(maze[m+1][n].countWalls() == 4){d++;} if(maze[m][n-1].countWalls() == 4){d++;} if(maze[m][n+1].countWalls() == 4){d++;} // if one or more found if(d!=0){ Point[] ls = new Point[4]; ls[0] = new Point(m-1,n); ls[1] = new Point(m+1,n); ls[2] = new Point(m,n-1); ls[3] = new Point(m,n+1); // knock down the wall between it and CurrentCell h = randomInt(3); switch(h){ case 0: o = (int)(ls[0].getX()); p = (int)(ls[0].getY()); curCel.destroyWall(2); maze[o][p].destroyWall(1); break; case 1: o = (int)(ls[1].getX()); p = (int)(ls[1].getY()); curCel.destroyWall(1); maze[o][p].destroyWall(2); break; case 2: o = (int)(ls[2].getX()); p = (int)(ls[2].getY()); curCel.destroyWall(3); maze[o][p].destroyWall(0); break; case 3: o = (int)(ls[3].getX()); p = (int)(ls[3].getY()); curCel.destroyWall(0); maze[o][p].destroyWall(3); break; } // push CurrentCell location on the CellStack push(new int[] {m,n}); // make the new cell CurrentCell m = o; n = p; curCel = maze[m][n]; // add 1 to VisitedCells visCel++; } // else else{ // pop the most recent cell entry off the CellStack q = pop(); m = q[0]; n = q[1]; curCel = maze[m][n]; // make it CurrentCell // endIf } // endWhile } } public int randomInt(int s) { return (int)(s* Math.random());} public void paint(Graphics g) { int k, j; width = getSize().width; height = getSize().height; double htOfRow = height / (size); double wdOfRow = width / (size); //checks verticals - destroys east border of cell for (k = 0; k < size; k++) { for (j = 0; j < size; j++) { if(maze[k][j].checkWall(2)){ g.drawLine((int) (k * wdOfRow), (int) (j * htOfRow), (int) (k * wdOfRow), (int) ((j+1) * htOfRow)); }} } //checks horizontal - destroys north border of cell for (k = 0; k < size; k++) { for (j = 0; j < size; j++) { if(maze[k][j].checkWall(3)){ g.drawLine((int) (k * wdOfRow), (int) (j * htOfRow), (int) ((k+1) * wdOfRow), (int) (j * htOfRow)); }} } } } class Cell { private final static int NORTH = 0; private final static int EAST = 1; private final static int WEST = 2; private final static int SOUTH = 3; private final static int NO = 4; private final static int START = 1; private final static int END = 2; boolean[] wall = new boolean[4]; boolean[] border = new boolean[4]; boolean[] backtrack = new boolean[4]; boolean[] solution = new boolean[4]; private boolean isVisited = false; private int Key = 0; public Cell(){ for(int i=0;i<4;i++){wall[i] = true;} } public int countWalls(){ int i, k =0; for(i=0; i<4; i++) { if (wall[i] == true) {k++;} } return k;} public boolean checkWall(int x){ switch(x){ case 0: return wall[0]; case 1: return wall[1]; case 2: return wall[2]; case 3: return wall[3]; } return true; } public void destroyWall(int x){ switch(x){ case 0: wall[0] = false; break; case 1: wall[1] = false; break; case 2: wall[2] = false; break; case 3: wall[3] = false; break; } } public void setStart(int i){Key = i;} public int getKey(){return Key;} public boolean checkVisit(){return isVisited;} public void visitCell(){isVisited = true;} }

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  • How do I prove I should put a table of values in source code instead of a database table?

    - by FastAl
    <tldr>looking for a reference to a book or other undeniably authoritative source that gives reasons when you should choose a database vs. when you should choose other storage methods. I have provided an un-authoritative list of reasons about 2/3 of the way down this post.</tldr> I have a situation at my company where a database is being used where it would be better to use another solution (in this case, an auto-generated piece of source code that contains a static lookup table, searched by binary sort). Normally, a database would be an OK solution even though the problem does not require a database, e.g, none of the elements of ACID are needed, as it is read-only data, updated about every 3-5 years (also requiring other sourcecode changes), and fits in memory, and can be keyed into via binary search (a tad faster than db, but speed is not an issue). The problem is that this code runs on our enterprise server, but is shared with several PC platforms (some disconnected, some use a central DB, etc.), and parts of it are managed by multiple programming units, parts by the DBAs, parts even by mathematicians in another department, etc. These hit their own platform’s version of their databases (containing their own copy of the static data). What happens is that every implementation, every little change, something different goes wrong. There are many other issues as well. I can’t even use a flatfile, because one mode of running on our enterprise server does not have permission to read files (only databases, and of course, its own literal storage, e.g., in-source table). Of course, other parts of the system use databases in proper, less obscure manners; there is no problem with those parts. So why don’t we just change it? I don’t have administrative ability to force a change. But I’m affected because sometimes I have to help fix the problems, but mostly because it causes outages and tons of extra IT time by other programmers and d*mmit that makes me mad! The reason neither management, nor the designers of the system, can see the problem is that they propose a solution that won’t work: increase communication; implement more safeguards and standards; etc. But every time, in a different part of the already-pared-down but still multi-step processes, a few different diligent, hard-working, top performing IT personnel make a unique subtle error that causes it to fail, sometimes after the last round of testing! And in general these are not single-person failures, but understandable miscommunications. And communication at our company is actually better than most. People just don't think that's the case because they haven't dug into the matter. However, I have it on very good word from somebody with extensive formal study of sociology and psychology that the relatively small amount of less-than-proper database usage in this gigantic cross-platform multi-source, multi-language project is bureaucratically un-maintainable. Impossible. No chance. At least with Human Beings in the loop, and it can’t be automated. In addition, the management and developers who could change this, though intelligent and capable, don’t understand the rigidity of this ‘how humans are’ issue, and are not convincible on the matter. The reason putting the static data in sourcecode will solve the problem is, although the solution is less sexy than a database, it would function with no technical drawbacks; and since the sharing of sourcecode already works very well, you basically erase any database-related effort from this section of the project, along with all the drawbacks of it that are causing problems. OK, that’s the background, for the curious. I won’t be able to convince management that this is an unfixable sociological problem, and that the real solution is coding around these limits of human nature, just as you would code around a bug in a 3rd party component that you can’t change. So what I have to do is exploit the unsuitableness of the database solution, and not do it using logic, but rather authority. I am aware of many reasons, and posts on this site giving reasons for one over the other; I’m not looking for lists of reasons like these (although you can add a comment if I've miss a doozy): WHY USE A DATABASE? instead of flatfile/other DB vs. file: if you need... Random Read / Transparent search optimization Advanced / varied / customizable Searching and sorting capabilities Transaction/rollback Locks, semaphores Concurrency control / Shared users Security 1-many/m-m is easier Easy modification Scalability Load Balancing Random updates / inserts / deletes Advanced query Administrative control of design, etc. SQL / learning curve Debugging / Logging Centralized / Live Backup capabilities Cached queries / dvlp & cache execution plans Interleaved update/read Referential integrity, avoid redundant/missing/corrupt/out-of-sync data Reporting (from on olap or oltp db) / turnkey generation tools [Disadvantages:] Important to get right the first time - professional design - but only b/c it's meant to last s/w & h/w cost Usu. over a network, speed issue (best vs. best design vs. local=even then a separate process req's marshalling/netwk layers/inter-p comm) indicies and query processing can stand in the way of simple processing (vs. flatfile) WHY USE FLATFILE: If you only need... Sequential Row processing only Limited usage append only (no reading, no master key/update) Only Update the record you're reading (fixed length recs only) Too big to fit into memory If Local disk / read-ahead network connection Portability / small system Email / cut & Paste / store as document by novice - simple format Low design learning curve but high cost later WHY USE IN-MEMORY/TABLE (tables, arrays, etc.): if you need... Processing a single db/ff record that was imported Known size of data Static data if hardcoding the table Narrow, unchanging use (e.g., one program or proc) -includes a class that will be shared, but encapsulates its data manipulation Extreme speed needed / high transaction frequency Random access - but search is dependent on implementation Following are some other posts about the topic: http://stackoverflow.com/questions/1499239/database-vs-flat-text-file-what-are-some-technical-reasons-for-choosing-one-over http://stackoverflow.com/questions/332825/are-flat-file-databases-any-good http://stackoverflow.com/questions/2356851/database-vs-flat-files http://stackoverflow.com/questions/514455/databases-vs-plain-text/514530 What I’d like to know is if anybody could recommend a hard, authoritative source containing these reasons. I’m looking for a paper book I can buy, or a reputable website with whitepapers about the issue (e.g., Microsoft, IBM), not counting the user-generated content on those sites. This will have a greater change to elicit a change that I’m looking for: less wasted programmer time, and more reliable programs. Thanks very much for your help. You win a prize for reading such a large post!

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  • Why does C qicksort function implementation works much slower (tape comparations, tape swapping) than bobble sort function?

    - by Artur Mustafin
    I'm going to implement a toy tape "mainframe" for a students, showing the quickness of "quicksort" class functions (recursive or not, does not really matters, due to the slow hardware, and well known stack reversal techniques) comparatively to the "bubblesort" function class, so, while I'm clear about the hardware implementation ans controllers, i guessed that quicksort function is much faster that other ones in terms of sequence, order and comparation distance (it is much faster to rewind the tape from the middle than from the very end, because of different speed of rewind). Unfortunately, this is not the true, this simple "bubble" code shows great improvements comparatively to the "quicksort" functions in terms of comparison distances, direction and number of comparisons and writes. So I have 3 questions: Does I have mistaken in my implememtation of quicksort function? Does I have mistaken in my implememtation of bubblesoft function? If not, why the "bubblesort" function is works much faster in (comparison and write operations) than "quicksort" function? I already have a "quicksort" function: void quicksort(float *a, long l, long r, const compare_function& compare) { long i=l, j=r, temp, m=(l+r)/2; if (l == r) return; if (l == r-1) { if (compare(a, l, r)) { swap(a, l, r); } return; } if (l < r-1) { while (1) { i = l; j = r; while (i < m && !compare(a, i, m)) i++; while (m < j && !compare(a, m, j)) j--; if (i >= j) { break; } swap(a, i, j); } if (l < m) quicksort(a, l, m, compare); if (m < r) quicksort(a, m, r, compare); return; } } and the kind of my own implememtation of the "bubblesort" function: void bubblesort(float *a, long l, long r, const compare_function& compare) { long i, j, k; if (l == r) { return; } if (l == r-1) { if (compare(a, l, r)) { swap(a, l, r); } return; } if (l < r-1) { while(l < r) { i = l; j = l; while (i < r) { i++; if (!compare(a, j, i)) { continue; } j = i; } if (l < j) { swap(a, l, j); } l++; i = r; k = r; while(l < i) { i--; if (!compare(a, i, k)) { continue; } k = i; } if (k < r) { swap(a, k, r); } r--; } return; } } I have used this sort functions in a test sample code, like this: #include <stdio.h> #include <stdlib.h> #include <math.h> #include <conio.h> long swap_count; long compare_count; typedef long (*compare_function)(float *, long, long ); typedef void (*sort_function)(float *, long , long , const compare_function& ); void init(float *, long ); void print(float *, long ); void sort(float *, long, const sort_function& ); void swap(float *a, long l, long r); long less(float *a, long l, long r); long greater(float *a, long l, long r); void bubblesort(float *, long , long , const compare_function& ); void quicksort(float *, long , long , const compare_function& ); void main() { int n; printf("n="); scanf("%d",&n); printf("\r\n"); long i; float *a = (float *)malloc(n*n*sizeof(float)); sort(a, n, &bubblesort); print(a, n); sort(a, n, &quicksort); print(a, n); free(a); } long less(float *a, long l, long r) { compare_count++; return *(a+l) < *(a+r) ? 1 : 0; } long greater(float *a, long l, long r) { compare_count++; return *(a+l) > *(a+r) ? 1 : 0; } void swap(float *a, long l, long r) { swap_count++; float temp; temp = *(a+l); *(a+l) = *(a+r); *(a+r) = temp; } float tg(float x) { return tan(x); } float ctg(float x) { return 1.0/tan(x); } void init(float *m,long n) { long i,j; for (i = 0; i < n; i++) { for (j=0; j< n; j++) { m[i + j*n] = tg(0.2*(i+1)) + ctg(0.3*(j+1)); } } } void print(float *m, long n) { long i, j; for(i = 0; i < n; i++) { for(j = 0; j < n; j++) { printf(" %5.1f", m[i + j*n]); } printf("\r\n"); } printf("\r\n"); } void sort(float *a, long n, const sort_function& sort) { long i, sort_compare = 0, sort_swap = 0; init(a,n); for(i = 0; i < n*n; i+=n) { if (fmod (i / n, 2) == 0) { compare_count = 0; swap_count = 0; sort(a, i, i+n-1, &less); if (swap_count == 0) { compare_count = 0; sort(a, i, i+n-1, &greater); } sort_compare += compare_count; sort_swap += swap_count; } } printf("compare=%ld\r\n", sort_compare); printf("swap=%ld\r\n", sort_swap); printf("\r\n"); }

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  • Segmentation fault in my C program

    - by user233542
    I don't understand why this would give me a seg fault. Any ideas? This is the function that returns the signal to stop the program (plus the other function that is called within this): double bisect(double A0,double A1,double Sol[N],double tol,double c) { double Amid,shot; while (A1-A0 > tol) { Amid = 0.5*(A0+A1); shot = shoot(Sol, Amid, c); if (shot==2.*Pi) { return Amid; } if (shot > 2.*Pi){ A1 = Amid; } else if (shot < 2.*Pi){ A0 = Amid; } } return 0.5*(A1+A0); } double shoot(double Sol[N],double A,double c) { int i,j; /*Initial Conditions*/ for (i=0;i<buff;i++) { Sol[i] = 0.; } for (i=buff+l;i<N;i++) { Sol[i] = 2.*Pi; } Sol[buff]= 0; Sol[buff+1]= A*exp(sqrt(1+3*c)*dx); for (i=buff+2;i<buff+l;i++) { Sol[i] = (dx*dx)*( sin(Sol[i-1]) + c*sin(3.*(Sol[i-1])) ) - Sol[i-2] + 2.*Sol[i-1]; } return Sol[i-1]; } The values buff, l, N are defined using a #define statement. l = 401, buff = 50, N = 2000 Here is the full code: #include <stdio.h> #include <stdlib.h> #include <math.h> #define w 10 /*characteristic width of a soliton*/ #define dx 0.05 /*distance between lattice sites*/ #define s (2*w)/dx /*size of soliton shape*/ #define l (int)(s+1) /*array length for soliton*/ #define N (int)2000 /*length of field array--lattice sites*/ #define Pi (double)4*atan(1) #define buff (int)50 double shoot(double Sol[N],double A,double c); double bisect(double A0,double A1,double Sol[N],double tol,double c); void super_pos(double antiSol[N],double Sol[N],double phi[][N]); void vel_ver(double phi[][N],double v,double c,int tsteps,double dt); int main(int argc, char **argv) { double c,Sol[N],antiSol[N],A,A0,A1,tol,v,dt; int tsteps,i; FILE *fp1,*fp2,*fp3; fp1 = fopen("soliton.dat","w"); fp2 = fopen("final-phi.dat","w"); fp3 = fopen("energy.dat","w"); printf("Please input the number of time steps:"); scanf("%d",&tsteps); printf("Also, enter the time step size:"); scanf("%lf",&dt); do{ printf("Please input the parameter c in the interval [-1/3,1]:"); scanf("%lf",&c);} while(c < (-1./3.) || c > 1.); printf("Please input the inital speed of eiter soliton:"); scanf("%lf",&v); double phi[tsteps+1][N]; tol = 0.0000001; A0 = 0.; A1 = 2.*Pi; A = bisect(A0,A1,Sol,tol,c); shoot(Sol,A,c); for (i=0;i<N;i++) { fprintf(fp1,"%d\t",i); fprintf(fp1,"%lf\n",Sol[i]); } fclose(fp1); super_pos(antiSol,Sol,phi); /*vel_ver(phi,v,c,tsteps,dt); for (i=0;i<N;i++){ fprintf(fp2,"%d\t",i); fprintf(fp2,"%lf\n",phi[tsteps][i]); }*/ } double shoot(double Sol[N],double A,double c) { int i,j; /*Initial Conditions*/ for (i=0;i<buff;i++) { Sol[i] = 0.; } for (i=buff+l;i<N;i++) { Sol[i] = 2.*Pi; } Sol[buff]= 0; Sol[buff+1]= A*exp(sqrt(1+3*c)*dx); for (i=buff+2;i<buff+l;i++) { Sol[i] = (dx*dx)*( sin(Sol[i-1]) + c*sin(3.*(Sol[i-1])) ) - Sol[i-2] + 2.*Sol[i-1]; } return Sol[i-1]; } double bisect(double A0,double A1,double Sol[N],double tol,double c) { double Amid,shot; while (A1-A0 > tol) { Amid = 0.5*(A0+A1); shot = shoot(Sol, Amid, c); if (shot==2.*Pi) { return Amid; } if (shot > 2.*Pi){ A1 = Amid; } else if (shot < 2.*Pi){ A0 = Amid; } } return 0.5*(A1+A0); } void super_pos(double antiSol[N],double Sol[N],double phi[][N]) { int i; /*for (i=0;i<N;i++) { phi[i]=0; } for (i=buffer+s;i<1950-s;i++) { phi[i]=2*Pi; }*/ for (i=0;i<N;i++) { antiSol[i] = Sol[N-i]; } /*for (i=0;i<s+1;i++) { phi[buffer+j] = Sol[j]; phi[1549+j] = antiSol[j]; }*/ for (i=0;i<N;i++) { phi[0][i] = antiSol[i] + Sol[i] - 2.*Pi; } } /* This funciton will set the 2nd input array to the derivative at the time t, for all points x in the lattice */ void deriv2(double phi[][N],double DphiDx2[][N],int t) { //double SolDer2[s+1]; int x; for (x=0;x<N;x++) { DphiDx2[t][x] = (phi[buff+x+1][t] + phi[buff+x-1][t] - 2.*phi[x][t])/(dx*dx); } /*for (i=0;i<N;i++) { ptr[i] = &SolDer2[i]; }*/ //return DphiDx2[x]; } void vel_ver(double phi[][N],double v,double c,int tsteps,double dt) { int t,x; double d1,d2,dp,DphiDx1[tsteps+1][N],DphiDx2[tsteps+1][N],dpdt[tsteps+1][N],p[tsteps+1][N]; for (t=0;t<tsteps;t++){ if (t==0){ for (x=0;x<N;x++){//inital conditions deriv2(phi,DphiDx2,t); dpdt[t][x] = DphiDx2[t][x] - sin(phi[t][x]) - sin(3.*phi[t][x]); DphiDx1[t][x] = (phi[t][x+1] - phi[t][x])/dx; p[t][x] = -v*DphiDx1[t][x]; } } for (x=0;x<N;x++){//velocity-verlet phi[t+1][x] = phi[t][x] + dt*p[t][x] + (dt*dt/2)*dpdt[t][x]; p[t+1][x] = p[t][x] + (dt/2)*dpdt[t][x]; deriv2(phi,DphiDx2,t+1); dpdt[t][x] = DphiDx2[t][x] - sin(phi[t+1][x]) - sin(3.*phi[t+1][x]); p[t+1][x] += (dt/2)*dpdt[t+1][x]; } } } So, this really isn't due to my overwriting the end of the Sol array. I've commented out both functions that I suspected of causing the problem (bisect or shoot) and inserted a print function. Two things happen. When I have code like below: double A,Pi,B,c; c=0; Pi = 4.*atan(1.); A = Pi; B = 1./4.; printf("%lf",B); B = shoot(Sol,A,c); printf("%lf",B); I get a segfault from the function, shoot. However, if I take away the shoot function so that I have: double A,Pi,B,c; c=0; Pi = 4.*atan(1.); A = Pi; B = 1./4.; printf("%lf",B); it gives me a segfault at the printf... Why!?

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  • How to use iterator in nested arraylist

    - by Muhammad Abrar
    I am trying to build an NFA with a special purpose of searching, which is totally different from regex. The State has following format class State implements List{ //GLOBAL DATA static int depth; //STATE VALUES String stateName; ArrayList<String> label = new ArrayList<>(); //Label for states //LINKS TO OTHER STATES boolean finalState; ArrayList<State> nextState ; // Link with multiple next states State preState; // previous state public State() { stateName = ""; finalState = true; nextState = new ArrayList<>(); } public void addlabel(String lbl) { if(!this.label.contains(lbl)) this.label.add(lbl); } public State(String state, String lbl) { this.stateName = state; if(!this.label.contains(lbl)) this.label.add(lbl); depth++; } public State(String state, String lbl, boolean fstate) { this.stateName = state; this.label.add(lbl); this.finalState = fstate; this.nextState = new ArrayList<>(); } void displayState() { System.out.print(this.stateName+" --> "); for(Iterator<String> it = label.iterator(); it.hasNext();) { System.out.print(it.next()+" , "); } System.out.println("\nNo of States : "+State.depth); } Next, the NFA class is public class NFA { static final String[] STATES= {"A","B","C","D","E","F","G","H","I","J","K","L","M" ,"N","O","P","Q","R","S","T","U","V","W","X","Y","Z"}; State startState; State currentState; static int level; public NFA() { startState = new State(); startState = null; currentState = new State(); currentState = null; startState = currentState; } /** * * @param st */ NFA(State startstate) { startState = new State(); startState = startstate; currentState = new State(); currentState = null; currentState = startState ; // To show that their is only one element in NFA } boolean insertState(State newState) { newState.nextState = new ArrayList<>(); if(currentState == null && startState == null ) //if empty NFA { newState.preState = null; startState = newState; currentState = newState; State.depth = 0; return true; } else { if(!Exist(newState.stateName))//Exist is used to check for duplicates { newState.preState = currentState ; currentState.nextState.add(newState); currentState = newState; State.depth++; return true; } } return false; } boolean insertState(State newState, String label) { newState.label.add(label); newState.nextState = null; newState.preState = null; if(currentState == null && startState == null) { startState = newState; currentState = newState; State.depth = 0; return true; } else { if(!Exist(newState.stateName)) { newState.preState = currentState; currentState.nextState.add(newState); currentState = newState; State.depth++; return true; } else { ///code goes here } } return false; } void markFinal(State s) { s.finalState = true; } void unmarkFinal(State s) { s.finalState = false; } boolean Exist(String s) { State temp = startState; if(startState.stateName.equals(s)) return true; Iterator<State> it = temp.nextState.iterator(); while(it.hasNext()) { Iterator<State> i = it ;//startState.nextState.iterator(); { while(i.hasNext()) { if(i.next().stateName.equals(s)) return true; } } //else // return false; } return false; } void displayNfa() { State st = startState; if(startState == null && currentState == null) { System.out.println("The NFA is empty"); } else { while(st != null) { if(!st.nextState.isEmpty()) { Iterator<State> it = st.nextState.iterator(); do { st.displayState(); st = it.next(); }while(it.hasNext()); } else { st = null; } } } System.out.println(); } /** * @param args the command line arguments */ /** * * @param args the command line arguments */ public static void main(String[] args) { // TODO code application logic here NFA l = new NFA(); State s = new State("A11", "a",false); NFA ll = new NFA(s); s = new State("A111", "a",false); ll.insertState(s); ll.insertState(new State("A1","0")); ll.insertState(new State("A1111","0")); ll.displayNfa(); int j = 1; for(int i = 0 ; i < 2 ; i++) { int rand = (int) (Math.random()* 10); State st = new State(STATES[rand],String.valueOf(i), false); if(l.insertState(st)) { System.out.println(j+" : " + STATES[rand]+" and "+String.valueOf(i)+ " inserted"); j++; } } l.displayNfa(); System.out.println("No of states inserted : "+ j--); } I want to do the following This program always skip to display the last state i.e. if there are 10 states inserted, it will display only 9. In exist() method , i used two iterator but i do not know why it is working I have no idea how to perform searching for the existing class name, when dealing with iterators. How should i keep track of current State, properly iterate through the nextState List, Label List in a depth first order. How to insert unique States i.e. if State "A" is inserted once, it should not insert it again (The exist method is not working) Best Regards

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  • Navigating MainMenu with arrow keys or controller

    - by Phil Royer
    I'm attempting to make my menu navigable with the arrow keys or via the d-pad on a controller. So Far I've had no luck. The question is: Can someone walk me through how to make my current menu or any libgdx menu keyboard accessible? I'm a bit noobish with some stuff and I come from a Javascript background. Here's an example of what I'm trying to do: http://dl.dropboxusercontent.com/u/39448/webgl/qb/qb.html For a simple menu that you can just add a few buttons to and it run out of the box use this: http://www.sadafnoor.com/blog/how-to-create-simple-menu-in-libgdx/ Or you can use my code but I use a lot of custom styles. And here's an example of my code: import aurelienribon.tweenengine.Timeline; import aurelienribon.tweenengine.Tween; import aurelienribon.tweenengine.TweenManager; import com.badlogic.gdx.Game; import com.badlogic.gdx.Gdx; import com.badlogic.gdx.Screen; import com.badlogic.gdx.graphics.GL20; import com.badlogic.gdx.graphics.Texture; import com.badlogic.gdx.graphics.g2d.Sprite; import com.badlogic.gdx.graphics.g2d.SpriteBatch; import com.badlogic.gdx.graphics.g2d.TextureAtlas; import com.badlogic.gdx.math.Vector2; import com.badlogic.gdx.scenes.scene2d.Actor; import com.badlogic.gdx.scenes.scene2d.InputEvent; import com.badlogic.gdx.scenes.scene2d.InputListener; import com.badlogic.gdx.scenes.scene2d.Stage; import com.badlogic.gdx.scenes.scene2d.ui.Skin; import com.badlogic.gdx.scenes.scene2d.ui.Table; import com.badlogic.gdx.scenes.scene2d.ui.TextButton; import com.badlogic.gdx.scenes.scene2d.utils.Align; import com.badlogic.gdx.scenes.scene2d.utils.ClickListener; import com.project.game.tween.ActorAccessor; public class MainMenu implements Screen { private SpriteBatch batch; private Sprite menuBG; private Stage stage; private TextureAtlas atlas; private Skin skin; private Table table; private TweenManager tweenManager; @Override public void render(float delta) { Gdx.gl.glClearColor(0, 0, 0, 1); Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); batch.begin(); menuBG.draw(batch); batch.end(); //table.debug(); stage.act(delta); stage.draw(); //Table.drawDebug(stage); tweenManager.update(delta); } @Override public void resize(int width, int height) { menuBG.setSize(width, height); stage.setViewport(width, height, false); table.invalidateHierarchy(); } @Override public void resume() { } @Override public void show() { stage = new Stage(); Gdx.input.setInputProcessor(stage); batch = new SpriteBatch(); atlas = new TextureAtlas("ui/atlas.pack"); skin = new Skin(Gdx.files.internal("ui/menuSkin.json"), atlas); table = new Table(skin); table.setBounds(0, 0, Gdx.graphics.getWidth(), Gdx.graphics.getHeight()); // Set Background Texture menuBackgroundTexture = new Texture("images/mainMenuBackground.png"); menuBG = new Sprite(menuBackgroundTexture); menuBG.setSize(Gdx.graphics.getWidth(), Gdx.graphics.getHeight()); // Create Main Menu Buttons // Button Play TextButton buttonPlay = new TextButton("START", skin, "inactive"); buttonPlay.addListener(new ClickListener() { @Override public void clicked(InputEvent event, float x, float y) { ((Game) Gdx.app.getApplicationListener()).setScreen(new LevelMenu()); } }); buttonPlay.addListener(new InputListener() { public boolean keyDown (InputEvent event, int keycode) { System.out.println("down"); return true; } }); buttonPlay.padBottom(12); buttonPlay.padLeft(20); buttonPlay.getLabel().setAlignment(Align.left); // Button EXTRAS TextButton buttonExtras = new TextButton("EXTRAS", skin, "inactive"); buttonExtras.addListener(new ClickListener() { @Override public void clicked(InputEvent event, float x, float y) { ((Game) Gdx.app.getApplicationListener()).setScreen(new ExtrasMenu()); } }); buttonExtras.padBottom(12); buttonExtras.padLeft(20); buttonExtras.getLabel().setAlignment(Align.left); // Button Credits TextButton buttonCredits = new TextButton("CREDITS", skin, "inactive"); buttonCredits.addListener(new ClickListener() { @Override public void clicked(InputEvent event, float x, float y) { ((Game) Gdx.app.getApplicationListener()).setScreen(new Credits()); } }); buttonCredits.padBottom(12); buttonCredits.padLeft(20); buttonCredits.getLabel().setAlignment(Align.left); // Button Settings TextButton buttonSettings = new TextButton("SETTINGS", skin, "inactive"); buttonSettings.addListener(new ClickListener() { @Override public void clicked(InputEvent event, float x, float y) { ((Game) Gdx.app.getApplicationListener()).setScreen(new Settings()); } }); buttonSettings.padBottom(12); buttonSettings.padLeft(20); buttonSettings.getLabel().setAlignment(Align.left); // Button Exit TextButton buttonExit = new TextButton("EXIT", skin, "inactive"); buttonExit.addListener(new ClickListener() { @Override public void clicked(InputEvent event, float x, float y) { Gdx.app.exit(); } }); buttonExit.padBottom(12); buttonExit.padLeft(20); buttonExit.getLabel().setAlignment(Align.left); // Adding Heading-Buttons to the cue table.add().width(190); table.add().width((table.getWidth() / 10) * 3); table.add().width((table.getWidth() / 10) * 5).height(140).spaceBottom(50); table.add().width(190).row(); table.add().width(190); table.add(buttonPlay).spaceBottom(20).width(460).height(110); table.add().row(); table.add().width(190); table.add(buttonExtras).spaceBottom(20).width(460).height(110); table.add().row(); table.add().width(190); table.add(buttonCredits).spaceBottom(20).width(460).height(110); table.add().row(); table.add().width(190); table.add(buttonSettings).spaceBottom(20).width(460).height(110); table.add().row(); table.add().width(190); table.add(buttonExit).width(460).height(110); table.add().row(); stage.addActor(table); // Animation Settings tweenManager = new TweenManager(); Tween.registerAccessor(Actor.class, new ActorAccessor()); // Heading and Buttons Fade In Timeline.createSequence().beginSequence() .push(Tween.set(buttonPlay, ActorAccessor.ALPHA).target(0)) .push(Tween.set(buttonExtras, ActorAccessor.ALPHA).target(0)) .push(Tween.set(buttonCredits, ActorAccessor.ALPHA).target(0)) .push(Tween.set(buttonSettings, ActorAccessor.ALPHA).target(0)) .push(Tween.set(buttonExit, ActorAccessor.ALPHA).target(0)) .push(Tween.to(buttonPlay, ActorAccessor.ALPHA, .5f).target(1)) .push(Tween.to(buttonExtras, ActorAccessor.ALPHA, .5f).target(1)) .push(Tween.to(buttonCredits, ActorAccessor.ALPHA, .5f).target(1)) .push(Tween.to(buttonSettings, ActorAccessor.ALPHA, .5f).target(1)) .push(Tween.to(buttonExit, ActorAccessor.ALPHA, .5f).target(1)) .end().start(tweenManager); tweenManager.update(Gdx.graphics.getDeltaTime()); } public static Vector2 getStageLocation(Actor actor) { return actor.localToStageCoordinates(new Vector2(0, 0)); } @Override public void dispose() { stage.dispose(); atlas.dispose(); skin.dispose(); menuBG.getTexture().dispose(); } @Override public void hide() { dispose(); } @Override public void pause() { } }

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  • Collision problems with drag-n-drop puzzle game.

    - by Amplify91
    I am working on an Android game similar to the Rush Hour/Traffic Jam/Blocked puzzle games. The board is a square containing rectangular pieces. Long pieces may only move horizontally, and tall pieces may only move vertically. The object is to free the red piece and move it out of the board. This game is only my second ever programming project in any language, so any tips or best practices would be appreciated along with your answer. I have a class for the game pieces called Pieces that describes how they are sized and drawn to the screen, gives them drag-and-drop functionality, and detects and handles collisions. I then have an activity class called GameView which creates my layout and creates Pieces objects to add to a RelativeLayout called Board. I have considered making Board its own class, but haven't needed to yet. Here's what my work in progress looks like: My Question: Most of this works perfectly fine except for my collision handling. It seems to be detecting collisions well but instead of pushing the pieces outside of each other when there is a collision, it frantically snaps back and forth between (what seems to be) where the piece is being dragged to and where it should be. It looks something like this: Another oddity: when the dragged piece collides with a piece to its left, the collision handling seems to work perfectly. Only piece above, below, and to the right cause problems. Here's the collision code: @Override public boolean onTouchEvent(MotionEvent event){ float eventX = event.getX(); float eventY = event.getY(); switch (event.getAction()) { case MotionEvent.ACTION_DOWN: //check if touch is on piece if (eventX > x && eventX < (x+width) && eventY > y && eventY < (y+height)){ initialX=x; initialY=y; break; }else{ return false; } case MotionEvent.ACTION_MOVE: //determine if piece should move horizontally or vertically if(width>height){ for (Pieces piece : aPieces) { //if object equals itself in array, skip to next object if(piece==this){ continue; } //if next to another piece, //do not allow to move any further towards said piece if(eventX<x&&(x==piece.right+1)){ return false; }else if(eventX>x&&(x==piece.x-width-1)){ return false; } //move normally if no collision //if collision, do not allow to move through other piece if(collides(this,piece)==false){ x = (eventX-(width/2)); }else if(collidesLeft(this,piece)){ x = piece.right+1; break; }else if(collidesRight(this,piece)){ x = piece.x-width-1; break; } } break; }else if(height>width){ for (Pieces piece : aPieces) { if(piece==this){ continue; }else if(collides(this,piece)==false){ y = (eventY-(height/2)); }else if(collidesUp(this,piece)){ y = piece.bottom+1; break; }else if(collidesDown(this,piece)){ y = piece.y-height-1; break; } } } invalidate(); break; case MotionEvent.ACTION_UP: // end move if(this.moves()){ GameView.counter++; } initialX=x; initialY=y; break; } // parse puzzle invalidate(); return true; } This takes place during onDraw: width = sizedBitmap.getWidth(); height = sizedBitmap.getHeight(); right = x+width; bottom = y+height; My collision-test methods look like this with different math for each: private boolean collidesDown(Pieces piece1, Pieces piece2){ float x1 = piece1.x; float y1 = piece1.y; float r1 = piece1.right; float b1 = piece1.bottom; float x2 = piece2.x; float y2 = piece2.y; float r2 = piece2.right; float b2 = piece2.bottom; if((y1<y2)&&(y1<b2)&&(b1>=y2)&&(b1<b2)&&((x1>=x2&&x1<=r2)||(r1>=x2&&x1<=r2))){ return true; }else{ return false; } } private boolean collides(Pieces piece1, Pieces piece2){ if(collidesLeft(piece1,piece2)){ return true; }else if(collidesRight(piece1,piece2)){ return true; }else if(collidesUp(piece1,piece2)){ return true; }else if(collidesDown(piece1,piece2)){ return true; }else{ return false; } } As a second question, should my x,y,right,bottom,width,height variables be ints instead of floats like they are now? Also, any suggestions on how to implement things better would be greatly appreciated, even if not relevant to the question! Thanks in advance for the help and for sitting through such a long question! Update: I have gotten it working almost perfectly with the following code (this doesn't include the code for vertical pieces): @Override public boolean onTouchEvent(MotionEvent event){ float eventX = event.getX(); float eventY = event.getY(); switch (event.getAction()) { case MotionEvent.ACTION_DOWN: //check if touch is on piece if (eventX > x && eventX < (x+width) && eventY > y && eventY < (y+height)){ initialX=x; initialY=y; break; }else{ return false; } case MotionEvent.ACTION_MOVE: //determine if piece should move horizontally or vertically if(width>height){ for (Pieces piece : aPieces) { //if object equals itself in array, skip to next object if(piece==this){ continue; } //check if there the possibility for a horizontal collision if(this.isAllignedHorizontallyWith(piece)){ //check for and handle collisions while moving left if(this.isRightOf(piece)){ if(eventX>piece.right+(width/2)){ x = (int)(eventX-(width/2)); //move normally }else{ x = piece.right+1; } } //check for and handle collisions while moving right if(this.isLeftOf(piece)){ if(eventX<piece.x-(width/2)){ x = (int)(eventX-(width/2)); }else{ x = piece.x-width-1; } } break; }else{ x = (int)(eventX-(width/2)); } The only problem with this code is that it only detects collisions between the moving piece and one other (with preference to one on the left). If there is a piece to collide with on the left and another on the right, it will only detect collisions with the one on the left. I think this is because once it finds a possible collision, it handles it without finishing looping through the array holding all the pieces. How do I get it to check for multiple possible collisions at the same time?

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  • PHP / MYSQL: Database empties when I use a variable in the WHERE condition of the last mysql_query

    - by Christian Cugnet
    <?php require 'connect.php'; $search = $_POST["search"]; These two queries work fine. So I used their format for the one below. $result = mysql_query("SELECT * FROM `subjects` WHERE $search = `student_id`"); $result2 = mysql_query("SELECT * FROM `grades` WHERE $search = `student_id`"); while($row = mysql_fetch_array($result)) { $row2 = mysql_fetch_array($result2); echo"<table border='1'>"; echo "<tr>"; echo "<th>Subjects:</th>"; echo "<th>Current Mark:</th>"; echo "<th>Edit Mark:</th>"; echo"</tr>"; echo"<tr>"; echo "<td>". $row['c1'] ."</td>"; echo "<td>". $row2['m1'] ."</td>"; echo "<td><input type='text' name='m1'></td>"; echo "</tr>"; echo "<tr>"; echo "<td>". $row['c2'] ."</td>"; echo "<td>". $row2['m2'] ."</td>"; echo "<td><input type='text' name='m2'></td>"; echo "</tr>"; echo "<tr>"; echo "<td>". $row['c3'] ."</td>"; echo "<td>". $row2['m3'] ."</td>"; echo "<td><input type='text' name='m3'></td>"; echo "</tr>"; echo "<tr>"; echo "<td>". $row['c4'] ."</td>"; echo "<td>". $row2['m4'] ."</td>"; echo "<td><input type='text' name='m4'></td>"; echo "</tr>"; echo "<tr>"; echo "<td>". $row['c5'] ."</td>"; echo "<td>". $row2['m5'] ."</td>"; echo "<td><input type='text' name='m5'></td>"; echo "</tr>"; echo "<tr>"; echo "<td>". $row['c6'] ."</td>"; echo "<td>". $row2['m6'] ."</td>"; echo "<td><input type='text' name='m6'></td>"; echo "</tr>"; echo "<tr>"; echo "<td>". $row['c7'] ."</td>"; echo "<td>". $row2['m7'] ."</td>"; echo "<td><input type='text' name='m7'></td>"; echo "</tr>"; echo "</table>"; echo "<input type='submit' name='submit' value='Submit'>"; echo "</form>"; } $M1 = $_POST["m1"]; $M2 = $_POST["m2"]; $M3 = $_POST["m3"]; $M4 = $_POST["m4"]; $M5 = $_POST["m5"]; $M6 = $_POST["m6"]; $M7 = $_POST["m7"]; It works if I put numbers e.x. 11111 Otherwise it just enters blank spaces into the table. I've tried '".$search."' I've tried ".$search." mysql_query("UPDATE grades SET m1 = '$M1', m2 = '$M2',m3 = '$M3',m4 = '$M4',m5 = '$M5',m6 = '$M6',m7 = '$M7' WHERE $search = `student_id`"); ?> Table +------------+---+---+---+---+---+---+---+ |student_id|m1|m2|m3|m4|m5|m6|m7| +------------+---+---+---+---+---+---+---+ ===Database d1 == Table structure for table grades |------ |Column|Type|Null|Default |------ |//student_id//|int(5)|No| |m1|text|No| |m2|text|No| |m3|text|No| |m4|text|No| |m5|text|No| |m6|text|No| |m7|text|No| == Dumping data for table grades |11111| | | | | | | |11112|fg|fd|f|f|fd|f|f ===Database d1 == Table structure for table subjects |------ |Column|Type|Null|Default |------ |//student_id//|int(11)|No| |c1|text|No| |c2|text|No| |c3|text|No| |c4|text|No| |c5|text|No| |c6|text|No| |c7|text|No| == Dumping data for table subjects |11111|English|Math|Science|Sport|IT|Art|History |11112|grdgg|vsbvbbb|bdbbrfd|bdbrb|dbrbfbf|fbdfbdbf|dbfbdfb

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  • Android App Crashes On Second Run

    - by user1091286
    My app runs fine on first run. On the Menu I added two choices options and quit. options which set up a new intent who goes to a PreferenceActivity and quit which simply call: "android.os.Process.killProcess(android.os.Process.myPid());" On the second time I run my app (after I quit from inside the emulator) it crashes.. Ideas? the menu is called by the foolowing code: @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.menu , menu); return true; } - @Override public boolean onOptionsItemSelected(MenuItem item) { // Set up a new intent between the updater service and the main screen Intent options = new Intent(this, OptionsScreenActivity.class); // Switch case on the options switch (item.getItemId()) { case R.id.options: startActivity(options); return true; case R.id.quit: android.os.Process.killProcess(android.os.Process.myPid()); return true; default: return false; } Code for SeekBarPreference: package com.testapp.logic; import com.testapp.R; import android.content.Context; import android.content.res.TypedArray; import android.preference.Preference; import android.util.AttributeSet; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.ViewParent; import android.widget.RelativeLayout; import android.widget.SeekBar; import android.widget.SeekBar.OnSeekBarChangeListener; import android.widget.TextView; public class SeekBarPreference extends Preference implements OnSeekBarChangeListener { private final String TAG = getClass().getName(); private static final String ANDROIDNS="http://schemas.android.com/apk/res/android"; private static final String PREFS="com.testapp.logic"; private static final int DEFAULT_VALUE = 5; private int mMaxValue = 100; private int mMinValue = 1; private int mInterval = 1; private int mCurrentValue; private String mUnitsLeft = ""; private String mUnitsRight = ""; private SeekBar mSeekBar; private TextView mStatusText; public SeekBarPreference(Context context, AttributeSet attrs) { super(context, attrs); initPreference(context, attrs); } public SeekBarPreference(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initPreference(context, attrs); } private void initPreference(Context context, AttributeSet attrs) { setValuesFromXml(attrs); mSeekBar = new SeekBar(context, attrs); mSeekBar.setMax(mMaxValue - mMinValue); mSeekBar.setOnSeekBarChangeListener(this); } private void setValuesFromXml(AttributeSet attrs) { mMaxValue = attrs.getAttributeIntValue(ANDROIDNS, "max", 100); mMinValue = attrs.getAttributeIntValue(PREFS, "min", 0); mUnitsLeft = getAttributeStringValue(attrs, PREFS, "unitsLeft", ""); String units = getAttributeStringValue(attrs, PREFS, "units", ""); mUnitsRight = getAttributeStringValue(attrs, PREFS, "unitsRight", units); try { String newInterval = attrs.getAttributeValue(PREFS, "interval"); if(newInterval != null) mInterval = Integer.parseInt(newInterval); } catch(Exception e) { Log.e(TAG, "Invalid interval value", e); } } private String getAttributeStringValue(AttributeSet attrs, String namespace, String name, String defaultValue) { String value = attrs.getAttributeValue(namespace, name); if(value == null) value = defaultValue; return value; } @Override protected View onCreateView(ViewGroup parent){ RelativeLayout layout = null; try { LayoutInflater mInflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); layout = (RelativeLayout)mInflater.inflate(R.layout.seek_bar_preference, parent, false); } catch(Exception e) { Log.e(TAG, "Error creating seek bar preference", e); } return layout; } @Override public void onBindView(View view) { super.onBindView(view); try { // move our seekbar to the new view we've been given ViewParent oldContainer = mSeekBar.getParent(); ViewGroup newContainer = (ViewGroup) view.findViewById(R.id.seekBarPrefBarContainer); if (oldContainer != newContainer) { // remove the seekbar from the old view if (oldContainer != null) { ((ViewGroup) oldContainer).removeView(mSeekBar); } // remove the existing seekbar (there may not be one) and add ours newContainer.removeAllViews(); newContainer.addView(mSeekBar, ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); } } catch(Exception ex) { Log.e(TAG, "Error binding view: " + ex.toString()); } updateView(view); } /** * Update a SeekBarPreference view with our current state * @param view */ protected void updateView(View view) { try { RelativeLayout layout = (RelativeLayout)view; mStatusText = (TextView)layout.findViewById(R.id.seekBarPrefValue); mStatusText.setText(String.valueOf(mCurrentValue)); mStatusText.setMinimumWidth(30); mSeekBar.setProgress(mCurrentValue - mMinValue); TextView unitsRight = (TextView)layout.findViewById(R.id.seekBarPrefUnitsRight); unitsRight.setText(mUnitsRight); TextView unitsLeft = (TextView)layout.findViewById(R.id.seekBarPrefUnitsLeft); unitsLeft.setText(mUnitsLeft); } catch(Exception e) { Log.e(TAG, "Error updating seek bar preference", e); } } public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { int newValue = progress + mMinValue; if(newValue > mMaxValue) newValue = mMaxValue; else if(newValue < mMinValue) newValue = mMinValue; else if(mInterval != 1 && newValue % mInterval != 0) newValue = Math.round(((float)newValue)/mInterval)*mInterval; // change rejected, revert to the previous value if(!callChangeListener(newValue)){ seekBar.setProgress(mCurrentValue - mMinValue); return; } // change accepted, store it mCurrentValue = newValue; mStatusText.setText(String.valueOf(newValue)); persistInt(newValue); } public void onStartTrackingTouch(SeekBar seekBar) {} public void onStopTrackingTouch(SeekBar seekBar) { notifyChanged(); } @Override protected Object onGetDefaultValue(TypedArray ta, int index){ int defaultValue = ta.getInt(index, DEFAULT_VALUE); return defaultValue; } @Override protected void onSetInitialValue(boolean restoreValue, Object defaultValue) { if(restoreValue) { mCurrentValue = getPersistedInt(mCurrentValue); } else { int temp = 0; try { temp = (Integer)defaultValue; } catch(Exception ex) { Log.e(TAG, "Invalid default value: " + defaultValue.toString()); } persistInt(temp); mCurrentValue = temp; } } } Logcat: E/AndroidRuntime( 4525): FATAL EXCEPTION: main E/AndroidRuntime( 4525): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.ui.testapp/com.logic.testapp.SeekBarPreferen ce}: java.lang.InstantiationException: can't instantiate class com.logic.testapp.SeekBarPreference; no empty constructor E/AndroidRuntime( 4525): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1879) E/AndroidRuntime( 4525): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980) E/AndroidRuntime( 4525): at android.app.ActivityThread.access$600(ActivityThread.java:122) E/AndroidRuntime( 4525): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146) E/AndroidRuntime( 4525): at android.os.Handler.dispatchMessage(Handler.java:99) E/AndroidRuntime( 4525): at android.os.Looper.loop(Looper.java:137) E/AndroidRuntime( 4525): at android.app.ActivityThread.main(ActivityThread.java:4340) E/AndroidRuntime( 4525): at java.lang.reflect.Method.invokeNative(Native Method) E/AndroidRuntime( 4525): at java.lang.reflect.Method.invoke(Method.java:511) E/AndroidRuntime( 4525): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) E/AndroidRuntime( 4525): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) E/AndroidRuntime( 4525): at dalvik.system.NativeStart.main(Native Method) E/AndroidRuntime( 4525): Caused by: java.lang.InstantiationException: can't instantiate class com.logic.testapp.SeekBarPreference; no empty construc tor E/AndroidRuntime( 4525): at java.lang.Class.newInstanceImpl(Native Method) E/AndroidRuntime( 4525): at java.lang.Class.newInstance(Class.java:1319) E/AndroidRuntime( 4525): at android.app.Instrumentation.newActivity(Instrumentation.java:1023) E/AndroidRuntime( 4525): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1870) E/AndroidRuntime( 4525): ... 11 more W/ActivityManager( 84): Force finishing activity com.ui.testapp/com.logic.testapp.SeekBarPreference W/ActivityManager( 84): Force finishing activity com.ui.testapp/.MainScreen I/WindowManager( 84): createSurface Window{41a90320 paused=false}: DRAW NOW PENDING W/ActivityManager( 84): Activity pause timeout for ActivityRecord{4104a848 com.ui.testapp/com.logic.testapp.SeekBarPreference} W/NetworkManagementSocketTagger( 84): setKernelCountSet(10021, 1) failed with errno -2 I/WindowManager( 84): createSurface Window{412bcc10 com.android.launcher/com.android.launcher2.Launcher paused=false}: DRAW NOW PENDING W/NetworkManagementSocketTagger( 84): setKernelCountSet(10045, 0) failed with errno -2 I/Process ( 4525): Sending signal. PID: 4525 SIG: 9 I/ActivityManager( 84): Process com.ui.testapp (pid 4525) has died. I/WindowManager( 84): WIN DEATH: Window{41a6c9c0 com.ui.testapp/com.ui.testapp.MainScreen paused=true}

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  • C++ function not found during compilation

    - by forthewinwin
    For a homework assignment: I'm supposed to create randomized alphabetial keys, print them to a file, and then hash each of them into a hash table using the function "goodHash", found in my below code. When I try to run the below code, it says my "goodHash" "identifier isn't found". What's wrong with my code? #include <iostream> #include <vector> #include <cstdlib> #include "math.h" #include <fstream> #include <time.h> using namespace std; // "makeKey" function to create an alphabetical key // based on 8 randomized numbers 0 - 25. string makeKey() { int k; string key = ""; for (k = 0; k < 8; k++) { int keyNumber = (rand() % 25); if (keyNumber == 0) key.append("A"); if (keyNumber == 1) key.append("B"); if (keyNumber == 2) key.append("C"); if (keyNumber == 3) key.append("D"); if (keyNumber == 4) key.append("E"); if (keyNumber == 5) key.append("F"); if (keyNumber == 6) key.append("G"); if (keyNumber == 7) key.append("H"); if (keyNumber == 8) key.append("I"); if (keyNumber == 9) key.append("J"); if (keyNumber == 10) key.append("K"); if (keyNumber == 11) key.append("L"); if (keyNumber == 12) key.append("M"); if (keyNumber == 13) key.append("N"); if (keyNumber == 14) key.append("O"); if (keyNumber == 15) key.append("P"); if (keyNumber == 16) key.append("Q"); if (keyNumber == 17) key.append("R"); if (keyNumber == 18) key.append("S"); if (keyNumber == 19) key.append("T"); if (keyNumber == 20) key.append("U"); if (keyNumber == 21) key.append("V"); if (keyNumber == 22) key.append("W"); if (keyNumber == 23) key.append("X"); if (keyNumber == 24) key.append("Y"); if (keyNumber == 25) key.append("Z"); } return key; } // "makeFile" function to produce the desired text file. // Note this only works as intended if you include the ".txt" extension, // and that a file of the same name doesn't already exist. void makeFile(string fileName, int n) { ofstream ourFile; ourFile.open(fileName); int k; // For use in below loop to compare with n. int l; // For use in the loop inside the below loop. string keyToPassTogoodHash = ""; for (k = 1; k <= n; k++) { for (l = 0; l < 8; l++) { // For-loop to write to the file ONE key ourFile << makeKey()[l]; keyToPassTogoodHash += (makeKey()[l]); } ourFile << " " << k << "\n";// Writes two spaces and the data value goodHash(keyToPassTogoodHash); // I think this has to do with the problem makeKey(); // Call again to make a new key. } } // Primary function to create our desired file! void mainFunction(string fileName, int n) { makeKey(); makeFile(fileName, n); } // Hash Table for Part 2 struct Node { int key; string value; Node* next; }; const int hashTableSize = 10; Node* hashTable[hashTableSize]; // "goodHash" function for Part 2 void goodHash(string key) { int x = 0; int y; int keyConvertedToNumber = 0; // For-loop to produce a numeric value based on the alphabetic key, // which is then hashed into hashTable using the hash function // declared below the loop (hashFunction). for (y = 0; y < 8; y++) { if (key[y] == 'A' || 'B' || 'C') x = 0; if (key[y] == 'D' || 'E' || 'F') x = 1; if (key[y] == 'G' || 'H' || 'I') x = 2; if (key[y] == 'J' || 'K' || 'L') x = 3; if (key[y] == 'M' || 'N' || 'O') x = 4; if (key[y] == 'P' || 'Q' || 'R') x = 5; if (key[y] == 'S' || 'T') x = 6; if (key[y] == 'U' || 'V') x = 7; if (key[y] == 'W' || 'X') x = 8; if (key[y] == 'Y' || 'Z') x = 9; keyConvertedToNumber = x + keyConvertedToNumber; } int hashFunction = keyConvertedToNumber % hashTableSize; Node *temp; temp = new Node; temp->value = key; temp->next = hashTable[hashFunction]; hashTable[hashFunction] = temp; } // First two lines are for Part 1, to call the functions key to Part 1. int main() { srand ( time(NULL) ); // To make sure our randomization works. mainFunction("sandwich.txt", 5); // To test program cin.get(); return 0; } I realize my code is cumbersome in some sections, but I'm a noob at C++ and don't know much to do it better. I'm guessing another way I could do it is to AFTER writing the alphabetical keys to the file, read them from the file and hash each key as I do that, but I wouldn't know how to go about coding that.

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  • Migrate existing Maven Project into an OSGI Bundle

    - by user1706291
    i am new to the whole OSGi stuff and my task is to create an OSGi Bundle out from an exisitng maven project. To get started i decided to pick the smallest part and starting with it: Here is the pom.xml project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <artifactId>cross</artifactId> <groupId>net.sf.maltcms</groupId> <version>1.2.12-SNAPSHOT</version> </parent> <artifactId>cross-main</artifactId> <packaging>jar</packaging> <name>cross-main</name> <dependencies> <dependency> <groupId>${project.groupId}</groupId> <artifactId>cross-annotations</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>${project.groupId}</groupId> <artifactId>cross-event</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>${project.groupId}</groupId> <artifactId>cross-tools</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>${project.groupId}</groupId> <artifactId>cross-exception</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>commons-codec</groupId> <artifactId>commons-codec</artifactId> <version>1.4</version> </dependency> <dependency> <groupId>${project.groupId}</groupId> <artifactId>cross-main-api</artifactId> <version>${project.version}</version> <exclusions> <exclusion> <artifactId>commons-logging</artifactId> <groupId>commons-logging</groupId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-asm</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>3.0.6.RELEASE</version> <exclusions> <exclusion> <artifactId>commons-logging</artifactId> <groupId>commons-logging</groupId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-expression</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.1</version> </dependency> <dependency> <groupId>net.sf.ehcache</groupId> <artifactId>ehcache-core</artifactId> <version>2.4.6</version> </dependency> <dependency> <groupId>${project.groupId}</groupId> <artifactId>cross-math</artifactId> <version>${project.version}</version> </dependency> <dependency> <groupId>com.db4o</groupId> <artifactId>db4o-all</artifactId> <version>8.0.249</version> </dependency> <dependency> <groupId>net.sf.mpaxs</groupId> <artifactId>mpaxs-spi</artifactId> <version>1.6.10</version> </dependency> <dependency> <groupId>net.sf.mpaxs</groupId> <artifactId>mpaxs-server</artifactId> <version>1.6.10</version> </dependency> </dependencies> I did some research and found the Apache Bundle Plugin for maven and changed the pom to this <packaging>bundle</packaging> and added <build> <plugins> <plugin> <groupId>org.apache.felix</groupId> <artifactId>maven-bundle-plugin</artifactId> <extensions>true</extensions> <configuration> <instructions> <Bundle-SymbolicName>${pom.artifactId}</Bundle-SymbolicName> </instructions> </configuration> </plugin> </plugins> </build> mvn clean install went fine and i got a jar file containing the manifest, but of course the bundle could not be resolved BundleException: The bundle "cross-main_1.2.12.SNAPSHOT [30]" could not be resolved. Reason: Missing Constraint: Import-Package: com.db4o; version="[8.0.0,9.0.0) To make a long story short: What are the possibiliteis to migrate a maven application into an OSGi Bundle? Espacially how to manage the dependencys

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  • questions regarding the use of A* with the 15-square puzzle

    - by Cheeso
    I'm trying to build an A* solver for a 15-square puzzle. The goal is to re-arrange the tiles so that they appear in their natural positions. You can only slide one tile at a time. Each possible state of the puzzle is a node in the search graph. For the h(x) function, I am using an aggregate sum, across all tiles, of the tile's dislocation from the goal state. In the above image, the 5 is at location 0,0, and it belongs at location 1,0, therefore it contributes 1 to the h(x) function. The next tile is the 11, located at 0,1, and belongs at 2,2, therefore it contributes 3 to h(x). And so on. EDIT: I now understand this is what they call "Manhattan distance", or "taxicab distance". I have been using a step count for g(x). In my implementation, for any node in the state graph, g is just +1 from the prior node's g. To find successive nodes, I just examine where I can possibly move the "hole" in the puzzle. There are 3 neighbors for the puzzle state (aka node) that is displayed: the hole can move north, west, or east. My A* search sometimes converges to a solution in 20s, sometimes 180s, and sometimes doesn't converge at all (waited 10 mins or more). I think h is reasonable. I'm wondering if I've modeled g properly. In other words, is it possible that my A* function is reaching a node in the graph via a path that is not the shortest path? Maybe have I not waited long enough? Maybe 10 minutes is not long enough? For a fully random arrangement, (assuming no parity problems), What is the average number of permutations an A* solution will examine? (please show the math) I'm going to look for logic errors in my code, but in the meantime, Any tips? (ps: it's done in Javascript). Also, no, this isn't CompSci homework. It's just a personal exploration thing. I'm just trying to learn Javascript. EDIT: I've found that the run-time is highly depend upon the heuristic. I saw the 10x factor applied to the heuristic from the article someone mentioned, and it made me wonder - why 10x? Why linear? Because this is done in javascript, I could modify the code to dynamically update an html table with the node currently being considered. This allowd me to peek at the algorithm as it was progressing. With a regular taxicab distance heuristic, I watched as it failed to converge. There were 5's and 12's in the top row, and they kept hanging around. I'd see 1,2,3,4 creep into the top row, but then they'd drop out, and other numbers would move up there. What I was hoping to see was 1,2,3,4 sort of creeping up to the top, and then staying there. I thought to myself - this is not the way I solve this personally. Doing this manually, I solve the top row, then the 2ne row, then the 3rd and 4th rows sort of concurrently. So I tweaked the h(x) function to more heavily weight the higher rows and the "lefter" columns. The result was that the A* converged much more quickly. It now runs in 3 minutes instead of "indefinitely". With the "peek" I talked about, I can see the smaller numbers creep up to the higher rows and stay there. Not only does this seem like the right thing, it runs much faster. I'm in the process of trying a bunch of variations. It seems pretty clear that A* runtime is very sensitive to the heuristic. Currently the best heuristic I've found uses the summation of dislocation * ((4-i) + (4-j)) where i and j are the row and column, and dislocation is the taxicab distance. One interesting part of the result I got: with a particular heuristic I find a path very quickly, but it is obviously not the shortest path. I think this is because I am weighting the heuristic. In one case I got a path of 178 steps in 10s. My own manual effort produce a solution in 87 moves. (much more than 10s). More investigation warranted. So the result is I am seeing it converge must faster, and the path is definitely not the shortest. I have to think about this more. Code: var stop = false; function Astar(start, goal, callback) { // start and goal are nodes in the graph, represented by // an array of 16 ints. The goal is: [1,2,3,...14,15,0] // Zero represents the hole. // callback is a method to call when finished. This runs a long time, // therefore we need to use setTimeout() to break it up, to avoid // the browser warning like "Stop running this script?" // g is the actual distance traveled from initial node to current node. // h is the heuristic estimate of distance from current to goal. stop = false; start.g = start.dontgo = 0; // calcHeuristic inserts an .h member into the array calcHeuristicDistance(start); // start the stack with one element var closed = []; // set of nodes already evaluated. var open = [ start ]; // set of nodes to evaluate (start with initial node) var iteration = function() { if (open.length==0) { // no more nodes. Fail. callback(null); return; } var current = open.shift(); // get highest priority node // update the browser with a table representation of the // node being evaluated $("#solution").html(stateToString(current)); // check solution returns true if current == goal if (checkSolution(current,goal)) { // reconstructPath just records the position of the hole // through each node var path= reconstructPath(start,current); callback(path); return; } closed.push(current); // get the set of neighbors. This is 3 or fewer nodes. // (nextStates is optimized to NOT turn directly back on itself) var neighbors = nextStates(current, goal); for (var i=0; i<neighbors.length; i++) { var n = neighbors[i]; // skip this one if we've already visited it if (closed.containsNode(n)) continue; // .g, .h, and .previous get assigned implicitly when // calculating neighbors. n.g is nothing more than // current.g+1 ; // add to the open list if (!open.containsNode(n)) { // slot into the list, in priority order (minimum f first) open.priorityPush(n); n.previous = current; } } if (stop) { callback(null); return; } setTimeout(iteration, 1); }; // kick off the first iteration iteration(); return null; }

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  • StringIndexOutOfBoundsException error in main method

    - by Ro Siv
    I am obtaining a StringIndexOutOfBoundsError when running my main method. Here is the output of my program in the command line. "Please enter the shift, 1 for day, 2 for night" 1 "you entered a number for the shift" "Please enter the hourly pay Rate" 2 "you entered a number for the pay Rate" "Please enter the employees name" brenda "cat6b" "your value you entered is correct 0-9 or a - z" "Please enter the employee number" 100e "cat41" "your value you entered is correct 0-9 or a - z" "Please enter current date in XXYYZZZZ format, X is day, Y is month, Z is year" 10203933 "cat81 " "your value you entered is correct 0-9 or a - z" 90 1 valye of array is 1 81 0 value of array is 0 82 2 value of array is 2 83 0 value of array is 0 84 3 value of array is 3 85 9 value of array is 9 86 3 value of array is 3 87 3 value of array is 3 "Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 8 at java.lang.String.charAt(String.java:658) at ProductionWorker<init>(ProductionWorker.java:66) at labBookFiftyFour.main(labBookFiftyFour.java:58)" "Press any key to continue . . ." Ignore the cat parts in the code, i was using a println statement to test the code. Ignore the value of array output as well, as i wanted to use an array in the program later on. Here is my main method. import java.math.*; import java.text.DecimalFormat; import java.io.*; import java.util.*; public class labBookFiftyFour { public static void main(String[] args) { Scanner myInput = new Scanner(System.in); int shift = -1; double pRate = -2; String name = " "; String number = " "; String date = " "; while(shift < 0 || pRate < 0 ) { System.out.println("Please enter the shift, 1 for day, 2 for night"); if(myInput.hasNextInt()){ System.out.println("you entered a number for the shift"); shift = myInput.nextInt(); } System.out.println("Please enter the hourly pay Rate"); if(myInput.hasNextDouble()){ System.out.println("you entered a number for the pay Rate"); pRate = myInput.nextDouble(); } else if (myInput.hasNext()) { System.out.println("Please enter a proper value"); myInput.next(); } else { System.err.println("No more input"); System.exit(1); } } myInput.nextLine(); //consume newLine System.out.println("Please enter the employees name"); name = myInput.nextLine(); //use your isValid method if(isValid(name)) { System.out.println("your value you entered is correct 0-9 or a - z "); } System.out.println("Please enter the employee number"); number = myInput.nextLine(); //use your isValid method if(isValid(number)) { System.out.println("your value you entered is correct 0-9 or a - z "); } System.out.println("Please enter current date in XXYYZZZZ format, X is day, Y is month, Z is year"); date = myInput.nextLine(); //use your isValid method if(isValid(date)) { System.out.println("your value you entered is correct 0-9 or a - z "); } ProductionWorker myWorker = new ProductionWorker(shift, pRate, name, number, date); //int day and night , double payRate System.out.println("THis is the shift " + myWorker.getShift() + " This is the pay Rate " + myWorker.getPRate() + " " + myWorker.getName() + " " + myWorker.getNumber() + " " + myWorker.getDate()); } //Made this method for testing String input for 0-9 or a - z values , put AFTER main method, but before end of class public static boolean isValid(String stringName) //This method has to be static, for some reason? { System.out.println("cat" + stringName.length() + stringName.charAt(0)); boolean flag = true; int index = 0; while(index < stringName.length()) { if(Character.isLetterOrDigit(stringName.charAt(index))) { flag = true; } else { flag = false; } ++index; } return flag; } } Here is my employeeOne. java Superclass public class employeeOne { private String name; private String number; private String date; public employeeOne(String name, String number, String date) { this.name = name; this.number = number; this.date = date; } public String getName() { return name; } public String getNumber() { return number; } public String getDate() { return date; } } Here is my ProductionWorker.java subclass, which extends employeeOne public class ProductionWorker extends employeeOne { private int shift; //shift represents day or night, day = 1, night = 2 private double pRate; //hourly pay rate public ProductionWorker(int shift, double pRate, String name, String number, String date) { super(name, number, date); this.shift = shift; if(this.shift >= 3 || this.shift <= 0) { System.out.println("You entered an out of bounds shift date, enter 1 for day or 2 for night, else shift will be day"); this.shift = 1; } this.pRate = pRate; boolean goodSoFar = true; int indexNum = 0; int indexDate = 0; if(name.length() <= 10 && number.length() <= 4 && date.length() < 9 ) { goodSoFar = true; } else { goodSoFar = false; } while(goodSoFar && indexNum < 3) //XXXL XXX digits 1-9, L is a letter A -M { if(Character.isDigit(number.charAt(indexNum))) { goodSoFar = true; } else { goodSoFar = false; } ++indexNum; } while(goodSoFar && indexNum < 4) { if(Character.isLetter(number.charAt(indexNum))) { goodSoFar = true; } else if(Character.isDigit(number.charAt(indexNum))) { goodSoFar = false; } else if(Character.isDigit(number.charAt(indexNum)) == false && Character.isLetter(number.charAt(indexNum)) == false) { goodSoFar = false; } ++indexNum; } int[] dateValues = new int[date.length()]; while(goodSoFar && indexDate <= date.length()) //XXYYZZZZ { System.out.println("" + date.length() + indexDate + " " + date.charAt(indexDate)); if(Character.isDigit(date.charAt(indexDate))) { dateValues[indexDate] = Character.getNumericValue(date.charAt(indexDate)); System.out.println("value of array is " + dateValues[indexDate]); ++indexDate; } else { goodSoFar = false; } } if(goodSoFar) { System.out.println("your input is good so far"); } else { System.out.println("your input is wrong for name or number or date"); } } public int getShift() { return shift; } public double getPRate() { return pRate; } }

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  • Create a class that inherets DrawableGameComponent in XNA as a CLASS with custom functions

    - by user3675013
    using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Media; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Content; namespace TileEngine { class Renderer : DrawableGameComponent { public Renderer(Game game) : base(game) { } SpriteBatch spriteBatch ; protected override void LoadContent() { base.LoadContent(); } public override void Draw(GameTime gameTime) { base.Draw(gameTime); } public override void Update(GameTime gameTime) { base.Update(gameTime); } public override void Initialize() { base.Initialize(); } public RenderTarget2D new_texture(int width, int height) { Texture2D TEX = new Texture2D(GraphicsDevice, width, height); //create the texture to render to RenderTarget2D Mine = new RenderTarget2D(GraphicsDevice, width, height); GraphicsDevice.SetRenderTarget(Mine); //set the render device to the reference provided //maybe base.draw can be used with spritebatch. Idk. We'll see if the order of operation //works out. Wish I could call base.draw here. return Mine; //I'm hoping that this returns the same instance and not a copy. } public void draw_texture(int width, int height, RenderTarget2D Mine) { GraphicsDevice.SetRenderTarget(null); //Set the renderer to render to the backbuffer again Rectangle drawrect = new Rectangle(0, 0, width, height); //Set the rendering size to what we want spriteBatch.Begin(); //This uses spritebatch to draw the texture directly to the screen spriteBatch.Draw(Mine, drawrect, Color.White); //This uses the color white spriteBatch.End(); //ends the spritebatch //Call base.draw after this since it doesn't seem to recognize inside the function //maybe base.draw can be used with spritebatch. Idk. We'll see if the order of operation //works out. Wish I could call base.draw here. } } } I solved a previous issue where I wasn't allowed to access GraphicsDevice outside the main Default 'main' class Ie "Game" or "Game1" etc. Now I have a new issue. FYi no one told me that it would be possible to use GraphicsDevice References to cause it to not be null by using the drawable class. (hopefully after this last bug is solved it doesn't still return null) Anyways at present the problem is that I can't seem to get it to initialize as an instance in my main program. Ie Renderer tileClipping; and I'm unable to use it such as it is to be noted i haven't even gotten to testing these two steps below but before it compiled but when those functions of this class were called it complained that it can't render to a null device. Which meant that the device wasn't being initialized. I had no idea why. It took me hours to google this. I finally figured out the words I needed.. which were "do my rendering in XNA in a seperate class" now I haven't used the addcomponent function because I don't want it to only run these functions automatically and I want to be able to call the custom ones. In a nutshell what I want is: *access to rendering targets and graphics device OUTSIDE default class *passing of Rendertarget2D (which contain textures and textures should automatically be passed with a rendering target? ) *the device should be passed to this function as well OR the device should be passed to this function as a byproduct of passing the rendertarget (which is automatically associated with the render device it was given originally) *I'm assuming I'm dealing with abstracted pointers here so when I pass a class object or instance, I should be recieving the SAME object , I referenced, and not a copy that has only the lifespan of the function running. *the purpose for all these options: I want to initialize new 2d textures on the fly to customize tileclipping and even the X , y Offsets of where a WHOLE texture will be rendered, and the X and Y offsets of where tiles will be rendered ON that surface. This is why. And I'll be doing region based lighting effects per tile or even per 8X8 pixel spaces.. we'll see I'll also be doing sprite rotations on the whole texture then copying it again to a circular masked texture, and then doing a second copy for only solid tiles for masked rotated collisions on sprites. I'll be checking the masked pixels for my collision, and using raycasting possibly to check for collisions on those areas. The sprite will stay in the center, when this rotation happens. Here is a detailed diagram: http://i.stack.imgur.com/INf9K.gif I'll be using texture2D for steps 4-6 I suppose for steps 1 as well. Now ontop of that, the clipping size (IE the sqaure rendered) will be able to be shrunk or increased, on a per frame basis Therefore I can't use the same static size for my main texture2d and I can't use just the backbuffer Or we get the annoying flicker. Also I will have multiple instances of the renderer class so that I can freely pass textures around as if they are playing cards (in a sense) layering them ontop of eachother, cropping them how i want and such. and then using spritebatch to simply draw them at the locations I want. Hopefully this makes sense, and yes I will be planning on using alpha blending but only after all tiles have been drawn.. The masked collision is important and Yes I am avoiding using math on the tile rendering and instead resorting to image manipulation in video memory which is WHY I need this to work the way I'm intending it to work and not in the default way that XNA seems to handle graphics. Thanks to anyone willing to help. I hate the code form offered, because then I have to rely on static presence of an update function. What if I want to kill that update function or that object, but have it in memory, but just have it temporarily inactive? I'm making the assumption here the update function of one of these gamecomponents is automatic ? Anyways this is as detailed as I can make this post hopefully someone can help me solve the issue. Instead of tell me "derrr don't do it this wayyy" which is what a few people told me (but they don't understand the actual goal I have in mind) I'm trying to create basically a library where I can copy images freely no matter the size, i just have to specify the size in the function then as long as a reference to that object exists it should be kept alive? right? :/ anyways.. Anything else? I Don't know. I understand object oriented coding but I don't understand this XNA It's beggining to feel impossible to do anything custom in it without putting ALL my rendering code into the draw function of the main class tileClipping.new_texture(GraphicsDevice, width, height) tileClipping.Draw_texture(...)

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  • Sorting linked lists in Pascal

    - by user3712174
    I'm doing my final project for Informatics class and I can't get my sorting procedure to work. Have a look at my program, specifically the bolded part (some things are in Croatian. - if you need something translated, let me know): type pokazivac=^slog; slog=record prezime_ime:string[30]; redni_broj:string[2]; fakultet:string[50]; bodovi:integer; sljedeci:pokazivac; end; var pocetni, trenutni, prethodni:pokazivac; i:integer; procedure racunaj; var i,a,c:integer; b,d,e,f,g,h,j:real; begin write('Postotak bodova (u decimalnom zapisu) koje ucenik ostvaruje na temelju prosjeka ocjena - '); readln(e); e:=e*1000/4; write('Prosjek ocjena u prvom razredu : '); readln(f); f:=f/5*e; write('Prosjek ocjena u drugom razredu : '); readln(g); g:=g/5*e; write('Prosjek ocjena u trecem razredu : '); readln(h); h:=h/5*e; write('Prosjek ocjena u cetvrtom razredu : '); readln(j); j:=j/5*e; d:=f+g+h+j; write('Broj predmeta (ne racunajuci hrvatski jezik, strani jezik i matematiku) koju je ucenik/ca polagao na maturi - '); readln(a); write('Postotak rijesnosti ispita iz hrvatskog jezika te zatim maksimum bodova koje je ucenik/ca mogao ostvariti - '); readln(b); readln(c); d:=d+b*c; write('Postotak rijesnosti ispita iz stranog jezika te zatim maksimum bodova koje je ucenik/ca mogao ostvariti - '); readln(b); readln(c); d:=d+(b*c); write('Postotak rijesnosti ispita iz matematike te zatim maksimum bodova koje je ucenik/ca mogao ostvariti - '); readln(b); readln(c); d:=d+(b*c); for i:=1 to a do begin writeln('Postotak rijesnosti dodatnog predmeta te zatim maksimum bodova koje je ucenik/ca mogao ostvariti - '); readln(b); readln(c); d:=d+(b*c); end; d:=round(d); writeln('Vas broj bodova je: ', d:4:2); write('Za nastavak pritisnite ENTER..'); readln; end; procedure unos; begin new(trenutni); write('Redni broj ucenika - ');readln(trenutni^.redni_broj); write('Prezime i ime - ');readln(trenutni^.prezime_ime); write('Naziv fakultet - ');readln(trenutni^.fakultet); write('Bodovi - ');readln(trenutni^.bodovi); trenutni^.sljedeci:=pocetni; pocetni:=trenutni; end; procedure ispis; begin writeln(); writeln('Lista popisanih ucenika:'); writeln(); trenutni:=pocetni; while trenutni<>NIL do begin with trenutni^do begin writeln('IME: ',prezime_ime); writeln('FAKULTET: ',fakultet); writeln('BODOVI: ',bodovi); writeln(); end; trenutni:=trenutni^.sljedeci; end; writeln(); write('Za nastavak pritisnite ENTER..'); readln; end; procedure brisi; var s:string; begin trenutni:= pocetni; prethodni:=pocetni; write('Redni broj ucenika kojeg zelite izbrisati - '); readln(s); while trenutni<>NIL do begin if trenutni^.redni_broj=s then begin prethodni^.sljedeci:=trenutni^.sljedeci; dispose(trenutni); break; end; trenutni:=trenutni^.sljedeci; end; end; procedure izmjeni; var s:string; begin trenutni:=pocetni; write('Redni broj ucenika cije podatke zelite izmijeniti - '); readln(s); while trenutni<> NIL do begin if trenutni^.redni_broj=s then begin write(trenutni^.prezime_ime, ' - '); readln(trenutni^.prezime_ime); write(trenutni^.fakultet, ' - '); readln(trenutni^.fakultet); write(trenutni^.bodovi, ' - '); readln(trenutni^.bodovi); break; end; trenutni:=trenutni^.sljedeci; end; end; **procedure sortiraj; var t1,t2,t:pokazivac; begin t1:=pocetni; while t1 <> NIL do begin t2:=t1^.sljedeci; while t2<>NIL do if t2^.bodovi<t1^.bodovi then begin new(t); t^.redni_broj:=t1^.redni_broj; t^.prezime_ime:=t1^.prezime_ime; t^.fakultet:=t1^.fakultet; t^.bodovi:=t1^.bodovi; t1^.redni_broj:=t2^.redni_broj; t1^.prezime_ime:=t2^.prezime_ime; t1^.fakultet:=t2^.fakultet; t1^.bodovi:=t2^.bodovi; t2^.redni_broj:=t^.redni_broj; t2^.prezime_ime:=t^.prezime_ime; t2^.fakultet:=t^.fakultet; t2^.bodovi:=t^.bodovi; dispose(t); end; t2:=t2^.sljedeci; end; t1:=t1^.sljedeci; write('Za nastavak pritisnite ENTER..'); readln; end;** begin pocetni:=NIL; trenutni:=NIL; writeln('******************************************'); writeln('**********DOBRODOSLI U FAX-O-MAT**********'); writeln('******************************************'); repeat writeln('1 - Racunaj broj bodova'); writeln('2 - Dodaj ucenika'); writeln('3 - Brisi ucenika'); writeln('4 - Ispis liste'); writeln('5 - Izmjeni podatke'); writeln('6 - Sortiraj listu prema broju bodova'); writeln('0 - Kraj'); readln(i); case i of 1:racunaj; 2:unos; 3:brisi; 4:ispis; 5:izmjeni; 6:sortiraj; end; until i=0; end. Either it crashes with a fatal error, or when I press the number 6, nothing happens. The pointer keeps blinking and I can't enter any more numbers.

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  • Problem with java and conditional (game of life)

    - by Muad'Dib
    Hello everybody, I'm trying to implement The Game of Life in java, as an exercise to learn this language. Unfortunately I have a problem, as I don't seem able to make this program run correctly. I implemented a torodial sum (the plane is a donut) with no problem: int SumNeighbours (int i, int j) { int value = 0; value = world[( i - 1 + row ) % row][( j - 1 + column ) % column]+world[( i - 1 + row ) % row][j]+world[( i - 1 + row ) % row][( j + 1 ) % column]; value = value + world[i][( j - 1 + column ) % column] + world[i][( j + 1 ) % column]; value = value + world[( i + 1 ) % row][( j - 1 + column ) % column] + world[( i + 1 ) % row][j]+world[ ( i+1 ) % row ][( j + 1 ) % column]; return value; } And it sums correctly when I test it: void NextWorldTest () { int count; int [][] nextWorld = new int[row][row]; nextWorld = world; for (int i=0; i<row; i++) { for (int j=0; j<column; j++) { count = SumNeighbours(i,j); System.out.print(" " + count + " "); } System.out.println(); } world=nextWorld; } Unfortunately when I add the conditions of game of life (born/death) the program stop working correctly, as it seems not able anymore to count correctly the alive cells in the neighborhood. It counts where there are none, and it doesn't count when there are some. E.g.: it doesn't count the one below some living cells. It's a very odd behaviour, and it's been giving me a headache for 3 days now... maybe I'm missing something basic about variables? Here you can find the class. void NextWorld () { int count; int [][] nextWorld = new int[row][column]; nextWorld = world; for (int i=0; i<row; i++) { for (int j=0; j<column; j++) { count = SumNeighbours(i,j); System.out.print(" " + count + " "); if ( ( world[i][j] == 0) && ( count == 3 ) ) { nextWorld[i][j] = 1; } else if ( ( world[i][j] == 1 ) && ( (count == 3) || (count == 2) )) { nextWorld[i][j] = 1; } else { nextWorld[i][j]=0; } } System.out.println(); } world=nextWorld; } } Am I doing something wrong? Below you can find the full package. package com.GaOL; public class GameWorld { int [][] world; int row; int column; public int GetRow() { return row; } public int GetColumn() { return column; } public int GetWorld (int i, int j) { return world[i][j]; } void RandomGen (int size, double p1) { double randomCell; row = size; column = size; world = new int[row][column]; for (int i = 0; i<row; i++ ) { for (int j = 0; j<column; j++ ) { randomCell=Math.random(); if (randomCell < 1-p1) { world[i][j] = 0; } else { world[i][j] = 1; } } } } void printToConsole() { double test = 0; for (int i=0; i<row; i++) { for (int j=0; j<column; j++) { if ( world[i][j] == 0 ) { System.out.print(" "); } else { System.out.print(" * "); test++; } } System.out.println(""); } System.out.println("ratio is " + test/(row*column)); } int SumNeighbours (int i, int j) { int value = 0; value = world[( i - 1 + row ) % row][( j - 1 + column ) % column]+world[( i - 1 + row ) % row][j]+world[( i - 1 + row ) % row][( j + 1 ) % column]; value = value + world[i][( j - 1 + column ) % column] + world[i][( j + 1 ) % column]; value = value + world[( i + 1 ) % row][( j - 1 + column ) % column] + world[( i + 1 ) % row][j]+world[ ( i+1 ) % row ][( j + 1 ) % column]; return value; } void NextWorldTest () { int count; int [][] nextWorld = new int[row][row]; nextWorld = world; for (int i=0; i<row; i++) { for (int j=0; j<column; j++) { count = SumNeighbours(i,j); System.out.print(" " + count + " "); } System.out.println(); } world=nextWorld; } void NextWorld () { int count; int [][] nextWorld = new int[row][column]; nextWorld = world; for (int i=0; i<row; i++) { for (int j=0; j<column; j++) { count = SumNeighbours(i,j); System.out.print(" " + count + " "); if ( ( world[i][j] == 0) && ( count == 3 ) ) { nextWorld[i][j] = 1; } else if ( ( world[i][j] == 1 ) && ( (count == 3) || (count == 2) )) { nextWorld[i][j] = 1; } else { nextWorld[i][j]=0; } } System.out.println(); } world=nextWorld; } } and here the test class: package com.GaOL; public class GameTestClass { public static void main(String[] args) { GameWorld prova = new GameWorld(); prova.RandomGen(10, 0.02); for (int i=0; i<3; i++) { prova.printToConsole(); prova.NextWorld(); } } }

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  • Can ping IP address and nslookup hostname but cannot ping hostname

    - by jao
    On a windows 2003 server I can nslookup www.google.com which returns Server: localhost Address: 127.0.0.1 Non-authoritative answer: Name: www.l.google.com Addresses: 74.125.79.104, 74.125.79.147, 74.125.79.99 Aliases: www.google.com I can then ping 74.125.79.104: Pinging 74.125.79.104 with 32 bytes of data: Reply from 74.125.79.104: bytes=32 time=16ms TTL=54 Reply from 74.125.79.104: bytes=32 time=32ms TTL=54 Reply from 74.125.79.104: bytes=32 time=15ms TTL=54 Reply from 74.125.79.104: bytes=32 time=15ms TTL=54 Ping statistics for 74.125.79.104: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 15ms, Maximum = 32ms, Average = 19ms But I cannot ping www.google.com: Ping request could not find host www.google.com. Please check the name and try again. (this one is different from the other question in that this one has a TLD, it is not a local domain.) Update: I am running a dns server at localhost (127.0.0.1). Even when I change it to use for example opendns, it still can nslookup hostname and ping ip address, but not ping hostname. So what is wrong? Update 2: here is the ipconfig /all result: Windows IP Configuration Host Name . . . . . . . . . . . . : SERVER Primary Dns Suffix . . . . . . . : NETWORK.local Node Type . . . . . . . . . . . . : Unknown IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : NETWORK.local Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Broadcom NetXtreme Gigabit Ethernet #2 Physical Address. . . . . . . . . : 00-0F-1F-56-3B-AA DHCP Enabled. . . . . . . . . . . : No IP Address. . . . . . . . . . . . : 192.168.7.2 Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 192.168.7.1 DNS Servers . . . . . . . . . . . : 127.0.0.1 Update 3: Thanks everyone for their help and suggestions. I appreciate that. Ipconfig /flushdns returns: Sucessfully flushed the DNS resolver cache Ipconfig /displaydns returns: 2.7.168.192.in-addr.arpa ---------------------------------------- Record Name . . . . . : 2.7.168.192.in-addr.arpa. Record Type . . . . . : 12 Time To Live . . . . : 0 Data Length . . . . . : 4 Section . . . . . . . : Answer PTR Record . . . . . : webserver.mydomainname.com 1.0.0.127.in-addr.arpa ---------------------------------------- Record Name . . . . . : 1.0.0.127.in-addr.arpa. Record Type . . . . . : 12 Time To Live . . . . : 0 Data Length . . . . . : 4 Section . . . . . . . : Answer PTR Record . . . . . : localhost Update 4: Wireshark shows the following: 3 11.540542 208.67.220.220 192.168.7.2 DNS Standard query response A 74.125.79.99 A 74.125.79.104 A 74.125.79.147 6 42.056794 192.168.7.2 192.168.7.255 NBNS Name query NB WWW.GOOGLE.COM<00> which is weird: when I ping, it sends a packet to 192.168.7.255 instead of asking the DNS server for an address

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  • TCP packets larger than 4 KB don't get a reply from Linux

    - by pts
    I'm running Linux 3.2.51 in a virtual machine (192.168.33.15). I'm sending Ethernet frames to it. I'm writing custom software trying to emulate a TCP peer, the other peer is Linux running in the virtual machine guest. I've noticed that TCP packets larger than about 4 KB are ignored (i.e. dropped without an ACK) by the Linux guest. If I decrease the packet size by 50 bytes, I get an ACK. I'm not sending new payload data until the Linux guest fully ACKs the previous one. I've increased ifconfig eth0 mtu 51000, and ping -c 1 -s 50000 goes through (from guest to my emulator) and the Linux guest gets a reply of the same size. I've also increased sysctl -w net.ipv4.tcp_rmem='70000 87380 87380 and tried with sysctl -w net.ipv4.tcp_mtu_probing=1 (and also =0). There is no IPv3 packet fragmentation, all packets have the DF flag set. It works the other way round: the Linux guest can send TCP packets of 6900 bytes of payload and my emulator understands them. This is very strange to me, because only TCP packets seem to be affected (large ICMP packets go through). Any idea what can be imposing this limit? Any idea how to do debug it in the Linux kernel? See the tcpdump -n -vv output below. tcpdump was run on the Linux guest. The last line is interesting: 4060 bytes of TCP payload is sent to the guest, and it doesn't get any reply packet from the Linux guest for half a minute. 14:59:32.000057 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [S], cksum 0x8da0 (correct), seq 10000000, win 14600, length 0 14:59:32.000086 IP (tos 0x10, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 44) 192.168.33.15.22 > 192.168.33.1.36522: Flags [S.], cksum 0xc37f (incorrect -> 0x5999), seq 1415680476, ack 10000001, win 19920, options [mss 9960], length 0 14:59:32.000218 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0xa752 (correct), ack 1, win 14600, length 0 14:59:32.000948 IP (tos 0x10, ttl 64, id 53777, offset 0, flags [DF], proto TCP (6), length 66) 192.168.33.15.22 > 192.168.33.1.36522: Flags [P.], cksum 0xc395 (incorrect -> 0xfa01), seq 1:27, ack 1, win 19920, length 26 14:59:32.001575 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0xa738 (correct), ack 27, win 14600, length 0 14:59:32.001585 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 65) 192.168.33.1.36522 > 192.168.33.15.22: Flags [P.], cksum 0x48d6 (correct), seq 1:26, ack 27, win 14600, length 25 14:59:32.001589 IP (tos 0x10, ttl 64, id 53778, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.15.22 > 192.168.33.1.36522: Flags [.], cksum 0xc37b (incorrect -> 0x9257), ack 26, win 19920, length 0 14:59:32.001680 IP (tos 0x10, ttl 64, id 53779, offset 0, flags [DF], proto TCP (6), length 496) 192.168.33.15.22 > 192.168.33.1.36522: Flags [P.], seq 27:483, ack 26, win 19920, length 456 14:59:32.001784 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0xa557 (correct), ack 483, win 14600, length 0 14:59:32.006367 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 1136) 192.168.33.1.36522 > 192.168.33.15.22: Flags [P.], seq 26:1122, ack 483, win 14600, length 1096 14:59:32.044150 IP (tos 0x10, ttl 64, id 53780, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.15.22 > 192.168.33.1.36522: Flags [.], cksum 0xc37b (incorrect -> 0x8c47), ack 1122, win 19920, length 0 14:59:32.045310 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 312) 192.168.33.1.36522 > 192.168.33.15.22: Flags [P.], seq 1122:1394, ack 483, win 14600, length 272 14:59:32.045322 IP (tos 0x10, ttl 64, id 53781, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.15.22 > 192.168.33.1.36522: Flags [.], cksum 0xc37b (incorrect -> 0x8b37), ack 1394, win 19920, length 0 14:59:32.925726 IP (tos 0x10, ttl 64, id 53782, offset 0, flags [DF], proto TCP (6), length 1112) 192.168.33.15.22 > 192.168.33.1.36522: Flags [.], seq 483:1555, ack 1394, win 19920, length 1072 14:59:32.925750 IP (tos 0x10, ttl 64, id 53784, offset 0, flags [DF], proto TCP (6), length 312) 192.168.33.15.22 > 192.168.33.1.36522: Flags [P.], seq 1555:1827, ack 1394, win 19920, length 272 14:59:32.927131 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0x9bcf (correct), ack 1555, win 14600, length 0 14:59:32.927148 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0x9abf (correct), ack 1827, win 14600, length 0 14:59:32.932248 IP (tos 0x10, ttl 64, id 53785, offset 0, flags [DF], proto TCP (6), length 56) 192.168.33.15.22 > 192.168.33.1.36522: Flags [P.], cksum 0xc38b (incorrect -> 0xd247), seq 1827:1843, ack 1394, win 19920, length 16 14:59:32.932366 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0x9aaf (correct), ack 1843, win 14600, length 0 14:59:32.964295 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 104) 192.168.33.1.36522 > 192.168.33.15.22: Flags [P.], seq 1394:1458, ack 1843, win 14600, length 64 14:59:32.964310 IP (tos 0x10, ttl 64, id 53786, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.15.22 > 192.168.33.1.36522: Flags [.], cksum 0xc37b (incorrect -> 0x85a7), ack 1458, win 19920, length 0 14:59:32.964561 IP (tos 0x10, ttl 64, id 53787, offset 0, flags [DF], proto TCP (6), length 88) 192.168.33.15.22 > 192.168.33.1.36522: Flags [P.], seq 1843:1891, ack 1458, win 19920, length 48 14:59:32.965185 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0x9a3f (correct), ack 1891, win 14600, length 0 14:59:32.965196 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 104) 192.168.33.1.36522 > 192.168.33.15.22: Flags [P.], seq 1458:1522, ack 1891, win 14600, length 64 14:59:32.965233 IP (tos 0x10, ttl 64, id 53788, offset 0, flags [DF], proto TCP (6), length 88) 192.168.33.15.22 > 192.168.33.1.36522: Flags [P.], seq 1891:1939, ack 1522, win 19920, length 48 14:59:32.965970 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0x99cf (correct), ack 1939, win 14600, length 0 14:59:32.965979 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 568) 192.168.33.1.36522 > 192.168.33.15.22: Flags [P.], seq 1522:2050, ack 1939, win 14600, length 528 14:59:32.966112 IP (tos 0x10, ttl 64, id 53789, offset 0, flags [DF], proto TCP (6), length 520) 192.168.33.15.22 > 192.168.33.1.36522: Flags [P.], seq 1939:2419, ack 2050, win 19920, length 480 14:59:32.970059 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0x95df (correct), ack 2419, win 14600, length 0 14:59:32.970089 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 616) 192.168.33.1.36522 > 192.168.33.15.22: Flags [P.], seq 2050:2626, ack 2419, win 14600, length 576 14:59:32.981159 IP (tos 0x10, ttl 64, id 53790, offset 0, flags [DF], proto TCP (6), length 72) 192.168.33.15.22 > 192.168.33.1.36522: Flags [P.], cksum 0xc39b (incorrect -> 0xa84f), seq 2419:2451, ack 2626, win 19920, length 32 14:59:32.982347 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0x937f (correct), ack 2451, win 14600, length 0 14:59:32.982357 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 104) 192.168.33.1.36522 > 192.168.33.15.22: Flags [P.], seq 2626:2690, ack 2451, win 14600, length 64 14:59:32.982401 IP (tos 0x10, ttl 64, id 53791, offset 0, flags [DF], proto TCP (6), length 88) 192.168.33.15.22 > 192.168.33.1.36522: Flags [P.], seq 2451:2499, ack 2690, win 19920, length 48 14:59:32.982570 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0x930f (correct), ack 2499, win 14600, length 0 14:59:32.982702 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 104) 192.168.33.1.36522 > 192.168.33.15.22: Flags [P.], seq 2690:2754, ack 2499, win 14600, length 64 14:59:33.020066 IP (tos 0x10, ttl 64, id 53792, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.15.22 > 192.168.33.1.36522: Flags [.], cksum 0xc37b (incorrect -> 0x7e07), ack 2754, win 19920, length 0 14:59:33.983503 IP (tos 0x10, ttl 64, id 53793, offset 0, flags [DF], proto TCP (6), length 72) 192.168.33.15.22 > 192.168.33.1.36522: Flags [P.], cksum 0xc39b (incorrect -> 0x2aa7), seq 2499:2531, ack 2754, win 19920, length 32 14:59:33.983810 IP (tos 0x10, ttl 64, id 53794, offset 0, flags [DF], proto TCP (6), length 88) 192.168.33.15.22 > 192.168.33.1.36522: Flags [P.], seq 2531:2579, ack 2754, win 19920, length 48 14:59:33.984100 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0x92af (correct), ack 2531, win 14600, length 0 14:59:33.984139 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0x927f (correct), ack 2579, win 14600, length 0 14:59:34.022914 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 104) 192.168.33.1.36522 > 192.168.33.15.22: Flags [P.], seq 2754:2818, ack 2579, win 14600, length 64 14:59:34.022939 IP (tos 0x10, ttl 64, id 53795, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.15.22 > 192.168.33.1.36522: Flags [.], cksum 0xc37b (incorrect -> 0x7d77), ack 2818, win 19920, length 0 14:59:34.023554 IP (tos 0x10, ttl 64, id 53796, offset 0, flags [DF], proto TCP (6), length 88) 192.168.33.15.22 > 192.168.33.1.36522: Flags [P.], seq 2579:2627, ack 2818, win 19920, length 48 14:59:34.027571 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 40) 192.168.33.1.36522 > 192.168.33.15.22: Flags [.], cksum 0x920f (correct), ack 2627, win 14600, length 0 14:59:34.027603 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto TCP (6), length 4100) 192.168.33.1.36522 > 192.168.33.15.22: Flags [P.], seq 2818:6878, ack 2627, win 14600, length 4060

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  • Tomcat 7 taking ages to start up after upgrade

    - by Lawrence
    I recently updated my server installation from Tomcat 6 to Tomcat 7, in order to take advantage of better connection pooling. My project uses Hibernate, for object persistance, a Mysql 5.5.20 database, and memcached for caching. When I was using Tomcat 6, Tomcat would start in about 8 seconds. After moving to Tomcat 7, it now takes between 75 - 80 seconds to start (this is on a Macbook pro 15", core i7 2Ghz, 8Gb of RAM). The only thing that has really changed between during the move from Tomcat 6 to 7 has been my context.xml file, which controls the connection pooling information: <Context antiJARLocking="true" reloadable="true" path=""> <Resource name="jdbc/test-db" auth="Container" type="javax.sql.DataSource" factory="org.apache.tomcat.jdbc.pool.DataSourceFactory" testOnBorrow="true" testOnReturn="false" testWhileIdle="true" validationQuery="SELECT 1" validationQueryTimeout="20000" validationInterval="30000" timeBetweenEvictionRunsMillis="60000" logValidationErrors="true" autoReconnect="true" username="webuser" password="xxxxxxx" driverClassName="com.mysql.jdbc.Driver" url="jdbc:mysql://databasename.us-east-1.rds.amazonaws.com:3306/test-db" maxActive="15" minIdle="2" maxIdle="10" maxWait="10000" maxAge="7200000"/> </Context> Now, as you can see, the database is running on Amazon RDS (where our live servers are), and thus is about 200ms round trip time away from my machine. I have already checked that I have security permissions to that database from my machine, (and anyway, it connects after 75 secs, so it cant be that). My initial thought was that Tomcat 7 and hibernate are doing something weird (like pre-instantiating a bunch of connections or something), and the latency to the database is amplifying the effects. While trying to diagnose the problem, I used jstack to get a stack trace of the Tomcat 7 server while its doing its startup thing. Here is the stack trace... Full thread dump Java HotSpot(TM) 64-Bit Server VM (20.12-b01-434 mixed mode): "Attach Listener" daemon prio=9 tid=7fa4c0038800 nid=0x10c39a000 waiting on condition [00000000] java.lang.Thread.State: RUNNABLE "Abandoned connection cleanup thread" daemon prio=5 tid=7fa4bb810000 nid=0x10f3ba000 in Object.wait() [10f3b9000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <7f40a0070> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118) - locked <7f40a0070> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134) at com.mysql.jdbc.NonRegisteringDriver$1.run(NonRegisteringDriver.java:93) "PoolCleaner[545768040:1352724902327]" daemon prio=5 tid=7fa4be852800 nid=0x10e772000 in Object.wait() [10e771000] java.lang.Thread.State: TIMED_WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <7f40c7c90> (a java.util.TaskQueue) at java.util.TimerThread.mainLoop(Timer.java:509) - locked <7f40c7c90> (a java.util.TaskQueue) at java.util.TimerThread.run(Timer.java:462) "localhost-startStop-1" daemon prio=5 tid=7fa4bd034800 nid=0x10d66b000 runnable [10d668000] java.lang.Thread.State: RUNNABLE at java.net.SocketInputStream.socketRead0(Native Method) at java.net.SocketInputStream.read(SocketInputStream.java:129) at com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:114) at com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:161) at com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:189) - locked <7f3673be0> (a com.mysql.jdbc.util.ReadAheadInputStream) at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3014) at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3467) at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3456) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3997) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2468) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2629) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2713) - locked <7f366a1c0> (a com.mysql.jdbc.JDBC4Connection) at com.mysql.jdbc.ConnectionImpl.configureClientCharacterSet(ConnectionImpl.java:1930) at com.mysql.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:3571) at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2445) at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2215) - locked <7f366a1c0> (a com.mysql.jdbc.JDBC4Connection) at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:813) at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) at sun.reflect.GeneratedConstructorAccessor10.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:399) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:334) at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:278) at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:182) at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:699) at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:631) at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:485) at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:143) at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:116) - locked <7f34f0dc8> (a org.apache.tomcat.jdbc.pool.DataSource) at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:103) at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:539) at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:237) at org.apache.naming.factory.ResourceFactory.getObjectInstance(ResourceFactory.java:143) at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:304) at org.apache.naming.NamingContext.lookup(NamingContext.java:843) at org.apache.naming.NamingContext.lookup(NamingContext.java:154) at org.apache.naming.NamingContext.lookup(NamingContext.java:831) at org.apache.naming.NamingContext.lookup(NamingContext.java:168) at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1061) at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:671) at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:270) at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119) at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5173) - locked <7f46b07f0> (a org.apache.catalina.core.StandardContext) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) - locked <7f46b07f0> (a org.apache.catalina.core.StandardContext) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) at java.util.concurrent.FutureTask.run(FutureTask.java:138) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:680) "Catalina-startStop-1" daemon prio=5 tid=7fa4b7a5e800 nid=0x10d568000 waiting on condition [10d567000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <7f480e970> (a java.util.concurrent.FutureTask$Sync) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:811) at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:969) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1281) at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:218) at java.util.concurrent.FutureTask.get(FutureTask.java:83) at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123) - locked <7f453c630> (a org.apache.catalina.core.StandardHost) at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:800) - locked <7f453c630> (a org.apache.catalina.core.StandardHost) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) - locked <7f453c630> (a org.apache.catalina.core.StandardHost) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) at java.util.concurrent.FutureTask.run(FutureTask.java:138) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:680) "GC Daemon" daemon prio=2 tid=7fa4b9912800 nid=0x10d465000 in Object.wait() [10d464000] java.lang.Thread.State: TIMED_WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <7f4506d28> (a sun.misc.GC$LatencyLock) at sun.misc.GC$Daemon.run(GC.java:100) - locked <7f4506d28> (a sun.misc.GC$LatencyLock) "Low Memory Detector" daemon prio=5 tid=7fa4b480b800 nid=0x10c8ae000 runnable [00000000] java.lang.Thread.State: RUNNABLE "C2 CompilerThread1" daemon prio=9 tid=7fa4b480b000 nid=0x10c7ab000 waiting on condition [00000000] java.lang.Thread.State: RUNNABLE "C2 CompilerThread0" daemon prio=9 tid=7fa4b480a000 nid=0x10c6a8000 waiting on condition [00000000] java.lang.Thread.State: RUNNABLE "Signal Dispatcher" daemon prio=9 tid=7fa4b4809800 nid=0x10c5a5000 runnable [00000000] java.lang.Thread.State: RUNNABLE "Surrogate Locker Thread (Concurrent GC)" daemon prio=5 tid=7fa4b4808800 nid=0x10c4a2000 waiting on condition [00000000] java.lang.Thread.State: RUNNABLE "Finalizer" daemon prio=8 tid=7fa4b793f000 nid=0x10c297000 in Object.wait() [10c296000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <7f451c8f0> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:118) - locked <7f451c8f0> (a java.lang.ref.ReferenceQueue$Lock) at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:134) at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159) "Reference Handler" daemon prio=10 tid=7fa4b793e000 nid=0x10c194000 in Object.wait() [10c193000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <7f452e168> (a java.lang.ref.Reference$Lock) at java.lang.Object.wait(Object.java:485) at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116) - locked <7f452e168> (a java.lang.ref.Reference$Lock) "main" prio=5 tid=7fa4b7800800 nid=0x104329000 waiting on condition [104327000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <7f480e9a0> (a java.util.concurrent.FutureTask$Sync) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:811) at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:969) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1281) at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:218) at java.util.concurrent.FutureTask.get(FutureTask.java:83) at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123) - locked <7f451fd90> (a org.apache.catalina.core.StandardEngine) at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:302) - locked <7f451fd90> (a org.apache.catalina.core.StandardEngine) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) - locked <7f451fd90> (a org.apache.catalina.core.StandardEngine) at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443) - locked <7f451fd90> (a org.apache.catalina.core.StandardEngine) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) - locked <7f453e810> (a org.apache.catalina.core.StandardService) at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:732) - locked <7f4506d58> (a [Lorg.apache.catalina.Service;) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) - locked <7f44f7ba0> (a org.apache.catalina.core.StandardServer) at org.apache.catalina.startup.Catalina.start(Catalina.java:684) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:322) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:451) "VM Thread" prio=9 tid=7fa4b7939800 nid=0x10c091000 runnable "Gang worker#0 (Parallel GC Threads)" prio=9 tid=7fa4b7802000 nid=0x10772b000 runnable "Gang worker#1 (Parallel GC Threads)" prio=9 tid=7fa4b7802800 nid=0x10782e000 runnable "Gang worker#2 (Parallel GC Threads)" prio=9 tid=7fa4b7803000 nid=0x107931000 runnable "Gang worker#3 (Parallel GC Threads)" prio=9 tid=7fa4b7804000 nid=0x107a34000 runnable "Gang worker#4 (Parallel GC Threads)" prio=9 tid=7fa4b7804800 nid=0x107b37000 runnable "Gang worker#5 (Parallel GC Threads)" prio=9 tid=7fa4b7805000 nid=0x107c3a000 runnable "Gang worker#6 (Parallel GC Threads)" prio=9 tid=7fa4b7805800 nid=0x107d3d000 runnable "Gang worker#7 (Parallel GC Threads)" prio=9 tid=7fa4b7806800 nid=0x107e40000 runnable "Concurrent Mark-Sweep GC Thread" prio=9 tid=7fa4b78e3800 nid=0x10bd0b000 runnable "Gang worker#0 (Parallel CMS Threads)" prio=9 tid=7fa4b78e2800 nid=0x10b305000 runnable "Gang worker#1 (Parallel CMS Threads)" prio=9 tid=7fa4b78e3000 nid=0x10b408000 runnable "VM Periodic Task Thread" prio=10 tid=7fa4b4815800 nid=0x10c9b1000 waiting on condition "Exception Catcher Thread" prio=10 tid=7fa4b7801800 nid=0x104554000 runnable JNI global references: 919 The only thing I can figure out from this is that it looks like the mysql jdbc drivers might have something to do with the long start up (the various stack traces I took during the start up process all pretty much look the same as this). Could anyone shed some light on what might be causing this? Have I done something dense in my context.xml? Is hibernate perhaps to blame?

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  • Something very strange with network

    - by Rodnower
    Hello, I have Windows 7 and I have very strange thing with my network. Some time I was connected through wireless router and my IP was 192.168.2.103, router's IP was 192.168.2.1 and some other IP was 192.168.2.100. The last I get from page "active DHCP clients" of web interface of the router and from "wireless clients" I may to see that 192.168.2.100 not (!) belong to my MAC address. Router build by EDimax. So after that I disabled wireless function of the router and restarted it. In this time I had not ping to 192.168.2.1. Also I had not any other connection, not wireless nor cable, but (!) I still had ping to 192.168.2.100 and I not understand what this voodoo is... C:\Users\Andrey>ping 192.168.2.100 Pinging 192.168.2.100 with 32 bytes of data: Reply from 192.168.2.100: bytes=32 time<1ms TTL=128 Reply from 192.168.2.100: bytes=32 time<1ms TTL=128 Reply from 192.168.2.100: bytes=32 time<1ms TTL=128 Reply from 192.168.2.100: bytes=32 time<1ms TTL=128 Ping statistics for 192.168.2.100: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms This is what I had: C:\Users\Andrey>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : Andrey-PC Primary Dns Suffix . . . . . . . : Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No Wireless LAN adapter Wireless Network Connection 3: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Microsoft Virtual WiFi Miniport Adapter #2 Physical Address. . . . . . . . . : 06-1D-7D-40-61-EB DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Wireless LAN adapter Wireless Network Connection: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Gigabyte GN-WS50G (mini) PCI-E WLAN Card Physical Address. . . . . . . . . : 00-1D-7D-40-61-EB DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Ethernet adapter Local Area Connection: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Marvell Yukon 88E8055 PCI-E Gigabit Ethernet Controller Physical Address. . . . . . . . . : 00-1B-24-B6-09-91 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes C:\Users\Andrey>arp -a -v Interface: 127.0.0.1 --- 0x1 Internet Address Physical Address Type 224.0.0.22 static 239.255.255.250 static Interface: 0.0.0.0 --- 0xffffffff Internet Address Physical Address Type 192.168.2.1 00-0e-2e-d2-8c-af invalid 192.168.2.255 ff-ff-ff-ff-ff-ff static 224.0.0.22 01-00-5e-00-00-16 static 224.0.0.252 01-00-5e-00-00-fc static 239.255.255.250 01-00-5e-7f-ff-fa static 255.255.255.255 ff-ff-ff-ff-ff-ff static Interface: 0.0.0.0 --- 0xffffffff Internet Address Physical Address Type 192.168.2.1 00-0e-2e-ff-f1-f6 dynamic 192.168.2.101 00-27-19-bc-8b-9c dynamic 192.168.2.102 00-16-e6-6c-ae-d4 dynamic 192.168.2.255 ff-ff-ff-ff-ff-ff static 224.0.0.22 01-00-5e-00-00-16 static 224.0.0.252 01-00-5e-00-00-fc static 239.255.255.250 01-00-5e-7f-ff-fa static 255.255.255.255 ff-ff-ff-ff-ff-ff static Interface: 0.0.0.0 --- 0xffffffff Internet Address Physical Address Type 224.0.0.22 01-00-5e-00-00-16 static 255.255.255.255 ff-ff-ff-ff-ff-ff static C:\Users\Andrey>route print =========================================================================== Interface List 14...06 1d 7d 40 61 eb ......Microsoft Virtual WiFi Miniport Adapter #2 13...00 1d 7d 40 61 eb ......Gigabyte GN-WS50G (mini) PCI-E WLAN Card 11...00 1b 24 b6 09 91 ......Marvell Yukon 88E8055 PCI-E Gigabit Ethernet Controller 1...........................Software Loopback Interface 1 =========================================================================== IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 127.0.0.0 255.0.0.0 On-link 127.0.0.1 306 127.0.0.1 255.255.255.255 On-link 127.0.0.1 306 127.255.255.255 255.255.255.255 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 127.0.0.1 306 255.255.255.255 255.255.255.255 On-link 127.0.0.1 306 =========================================================================== Persistent Routes: None IPv6 Route Table =========================================================================== Active Routes: If Metric Network Destination Gateway 1 306 ::1/128 On-link 1 306 ff00::/8 On-link =========================================================================== Persistent Routes: None Only after reboot I lost ping to there: C:\Users\Andrey>ping 192.168.2.100 Pinging 192.168.2.100 with 32 bytes of data: PING: transmit failed. General failure. PING: transmit failed. General failure. PING: transmit failed. General failure. PING: transmit failed. General failure. Ping statistics for 192.168.2.100: Packets: Sent = 4, Received = 0, Lost = 4 (100% loss), So what this mysterious cache is? Thank you for ahead.

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  • An Introduction to ASP.NET Web API

    - by Rick Strahl
    Microsoft recently released ASP.NET MVC 4.0 and .NET 4.5 and along with it, the brand spanking new ASP.NET Web API. Web API is an exciting new addition to the ASP.NET stack that provides a new, well-designed HTTP framework for creating REST and AJAX APIs (API is Microsoft’s new jargon for a service, in case you’re wondering). Although Web API ships and installs with ASP.NET MVC 4, you can use Web API functionality in any ASP.NET project, including WebForms, WebPages and MVC or just a Web API by itself. And you can also self-host Web API in your own applications from Console, Desktop or Service applications. If you're interested in a high level overview on what ASP.NET Web API is and how it fits into the ASP.NET stack you can check out my previous post: Where does ASP.NET Web API fit? In the following article, I'll focus on a practical, by example introduction to ASP.NET Web API. All the code discussed in this article is available in GitHub: https://github.com/RickStrahl/AspNetWebApiArticle [republished from my Code Magazine Article and updated for RTM release of ASP.NET Web API] Getting Started To start I’ll create a new empty ASP.NET application to demonstrate that Web API can work with any kind of ASP.NET project. Although you can create a new project based on the ASP.NET MVC/Web API template to quickly get up and running, I’ll take you through the manual setup process, because one common use case is to add Web API functionality to an existing ASP.NET application. This process describes the steps needed to hook up Web API to any ASP.NET 4.0 application. Start by creating an ASP.NET Empty Project. Then create a new folder in the project called Controllers. Add a Web API Controller Class Once you have any kind of ASP.NET project open, you can add a Web API Controller class to it. Web API Controllers are very similar to MVC Controller classes, but they work in any kind of project. Add a new item to this folder by using the Add New Item option in Visual Studio and choose Web API Controller Class, as shown in Figure 1. Figure 1: This is how you create a new Controller Class in Visual Studio   Make sure that the name of the controller class includes Controller at the end of it, which is required in order for Web API routing to find it. Here, the name for the class is AlbumApiController. For this example, I’ll use a Music Album model to demonstrate basic behavior of Web API. The model consists of albums and related songs where an album has properties like Name, Artist and YearReleased and a list of songs with a SongName and SongLength as well as an AlbumId that links it to the album. You can find the code for the model (and the rest of these samples) on Github. To add the file manually, create a new folder called Model, and add a new class Album.cs and copy the code into it. There’s a static AlbumData class with a static CreateSampleAlbumData() method that creates a short list of albums on a static .Current that I’ll use for the examples. Before we look at what goes into the controller class though, let’s hook up routing so we can access this new controller. Hooking up Routing in Global.asax To start, I need to perform the one required configuration task in order for Web API to work: I need to configure routing to the controller. Like MVC, Web API uses routing to provide clean, extension-less URLs to controller methods. Using an extension method to ASP.NET’s static RouteTable class, you can use the MapHttpRoute() (in the System.Web.Http namespace) method to hook-up the routing during Application_Start in global.asax.cs shown in Listing 1.using System; using System.Web.Routing; using System.Web.Http; namespace AspNetWebApi { public class Global : System.Web.HttpApplication { protected void Application_Start(object sender, EventArgs e) { RouteTable.Routes.MapHttpRoute( name: "AlbumVerbs", routeTemplate: "albums/{title}", defaults: new { symbol = RouteParameter.Optional, controller="AlbumApi" } ); } } } This route configures Web API to direct URLs that start with an albums folder to the AlbumApiController class. Routing in ASP.NET is used to create extensionless URLs and allows you to map segments of the URL to specific Route Value parameters. A route parameter, with a name inside curly brackets like {name}, is mapped to parameters on the controller methods. Route parameters can be optional, and there are two special route parameters – controller and action – that determine the controller to call and the method to activate respectively. HTTP Verb Routing Routing in Web API can route requests by HTTP Verb in addition to standard {controller},{action} routing. For the first examples, I use HTTP Verb routing, as shown Listing 1. Notice that the route I’ve defined does not include an {action} route value or action value in the defaults. Rather, Web API can use the HTTP Verb in this route to determine the method to call the controller, and a GET request maps to any method that starts with Get. So methods called Get() or GetAlbums() are matched by a GET request and a POST request maps to a Post() or PostAlbum(). Web API matches a method by name and parameter signature to match a route, query string or POST values. In lieu of the method name, the [HttpGet,HttpPost,HttpPut,HttpDelete, etc] attributes can also be used to designate the accepted verbs explicitly if you don’t want to follow the verb naming conventions. Although HTTP Verb routing is a good practice for REST style resource APIs, it’s not required and you can still use more traditional routes with an explicit {action} route parameter. When {action} is supplied, the HTTP verb routing is ignored. I’ll talk more about alternate routes later. When you’re finished with initial creation of files, your project should look like Figure 2.   Figure 2: The initial project has the new API Controller Album model   Creating a small Album Model Now it’s time to create some controller methods to serve data. For these examples, I’ll use a very simple Album and Songs model to play with, as shown in Listing 2. public class Song { public string AlbumId { get; set; } [Required, StringLength(80)] public string SongName { get; set; } [StringLength(5)] public string SongLength { get; set; } } public class Album { public string Id { get; set; } [Required, StringLength(80)] public string AlbumName { get; set; } [StringLength(80)] public string Artist { get; set; } public int YearReleased { get; set; } public DateTime Entered { get; set; } [StringLength(150)] public string AlbumImageUrl { get; set; } [StringLength(200)] public string AmazonUrl { get; set; } public virtual List<Song> Songs { get; set; } public Album() { Songs = new List<Song>(); Entered = DateTime.Now; // Poor man's unique Id off GUID hash Id = Guid.NewGuid().GetHashCode().ToString("x"); } public void AddSong(string songName, string songLength = null) { this.Songs.Add(new Song() { AlbumId = this.Id, SongName = songName, SongLength = songLength }); } } Once the model has been created, I also added an AlbumData class that generates some static data in memory that is loaded onto a static .Current member. The signature of this class looks like this and that's what I'll access to retrieve the base data:public static class AlbumData { // sample data - static list public static List<Album> Current = CreateSampleAlbumData(); /// <summary> /// Create some sample data /// </summary> /// <returns></returns> public static List<Album> CreateSampleAlbumData() { … }} You can check out the full code for the data generation online. Creating an AlbumApiController Web API shares many concepts of ASP.NET MVC, and the implementation of your API logic is done by implementing a subclass of the System.Web.Http.ApiController class. Each public method in the implemented controller is a potential endpoint for the HTTP API, as long as a matching route can be found to invoke it. The class name you create should end in Controller, which is how Web API matches the controller route value to figure out which class to invoke. Inside the controller you can implement methods that take standard .NET input parameters and return .NET values as results. Web API’s binding tries to match POST data, route values, form values or query string values to your parameters. Because the controller is configured for HTTP Verb based routing (no {action} parameter in the route), any methods that start with Getxxxx() are called by an HTTP GET operation. You can have multiple methods that match each HTTP Verb as long as the parameter signatures are different and can be matched by Web API. In Listing 3, I create an AlbumApiController with two methods to retrieve a list of albums and a single album by its title .public class AlbumApiController : ApiController { public IEnumerable<Album> GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); return albums; } public Album GetAlbum(string title) { var album = AlbumData.Current .SingleOrDefault(alb => alb.AlbumName.Contains(title)); return album; }} To access the first two requests, you can use the following URLs in your browser: http://localhost/aspnetWebApi/albumshttp://localhost/aspnetWebApi/albums/Dirty%20Deeds Note that you’re not specifying the actions of GetAlbum or GetAlbums in these URLs. Instead Web API’s routing uses HTTP GET verb to route to these methods that start with Getxxx() with the first mapping to the parameterless GetAlbums() method and the latter to the GetAlbum(title) method that receives the title parameter mapped as optional in the route. Content Negotiation When you access any of the URLs above from a browser, you get either an XML or JSON result returned back. The album list result for Chrome 17 and Internet Explorer 9 is shown Figure 3. Figure 3: Web API responses can vary depending on the browser used, demonstrating Content Negotiation in action as these two browsers send different HTTP Accept headers.   Notice that the results are not the same: Chrome returns an XML response and IE9 returns a JSON response. Whoa, what’s going on here? Shouldn’t we see the same result in both browsers? Actually, no. Web API determines what type of content to return based on Accept headers. HTTP clients, like browsers, use Accept headers to specify what kind of content they’d like to see returned. Browsers generally ask for HTML first, followed by a few additional content types. Chrome (and most other major browsers) ask for: Accept: text/html, application/xhtml+xml,application/xml; q=0.9,*/*;q=0.8 IE9 asks for: Accept: text/html, application/xhtml+xml, */* Note that Chrome’s Accept header includes application/xml, which Web API finds in its list of supported media types and returns an XML response. IE9 does not include an Accept header type that works on Web API by default, and so it returns the default format, which is JSON. This is an important and very useful feature that was missing from any previous Microsoft REST tools: Web API automatically switches output formats based on HTTP Accept headers. Nowhere in the server code above do you have to explicitly specify the output format. Rather, Web API determines what format the client is requesting based on the Accept headers and automatically returns the result based on the available formatters. This means that a single method can handle both XML and JSON results.. Using this simple approach makes it very easy to create a single controller method that can return JSON, XML, ATOM or even OData feeds by providing the appropriate Accept header from the client. By default you don’t have to worry about the output format in your code. Note that you can still specify an explicit output format if you choose, either globally by overriding the installed formatters, or individually by returning a lower level HttpResponseMessage instance and setting the formatter explicitly. More on that in a minute. Along the same lines, any content sent to the server via POST/PUT is parsed by Web API based on the HTTP Content-type of the data sent. The same formats allowed for output are also allowed on input. Again, you don’t have to do anything in your code – Web API automatically performs the deserialization from the content. Accessing Web API JSON Data with jQuery A very common scenario for Web API endpoints is to retrieve data for AJAX calls from the Web browser. Because JSON is the default format for Web API, it’s easy to access data from the server using jQuery and its getJSON() method. This example receives the albums array from GetAlbums() and databinds it into the page using knockout.js.$.getJSON("albums/", function (albums) { // make knockout template visible $(".album").show(); // create view object and attach array var view = { albums: albums }; ko.applyBindings(view); }); Figure 4 shows this and the next example’s HTML output. You can check out the complete HTML and script code at http://goo.gl/Ix33C (.html) and http://goo.gl/tETlg (.js). Figu Figure 4: The Album Display sample uses JSON data loaded from Web API.   The result from the getJSON() call is a JavaScript object of the server result, which comes back as a JavaScript array. In the code, I use knockout.js to bind this array into the UI, which as you can see, requires very little code, instead using knockout’s data-bind attributes to bind server data to the UI. Of course, this is just one way to use the data – it’s entirely up to you to decide what to do with the data in your client code. Along the same lines, I can retrieve a single album to display when the user clicks on an album. The response returns the album information and a child array with all the songs. The code to do this is very similar to the last example where we pulled the albums array:$(".albumlink").live("click", function () { var id = $(this).data("id"); // title $.getJSON("albums/" + id, function (album) { ko.applyBindings(album, $("#divAlbumDialog")[0]); $("#divAlbumDialog").show(); }); }); Here the URL looks like this: /albums/Dirty%20Deeds, where the title is the ID captured from the clicked element’s data ID attribute. Explicitly Overriding Output Format When Web API automatically converts output using content negotiation, it does so by matching Accept header media types to the GlobalConfiguration.Configuration.Formatters and the SupportedMediaTypes of each individual formatter. You can add and remove formatters to globally affect what formats are available and it’s easy to create and plug in custom formatters.The example project includes a JSONP formatter that can be plugged in to provide JSONP support for requests that have a callback= querystring parameter. Adding, removing or replacing formatters is a global option you can use to manipulate content. It’s beyond the scope of this introduction to show how it works, but you can review the sample code or check out my blog entry on the subject (http://goo.gl/UAzaR). If automatic processing is not desirable in a particular Controller method, you can override the response output explicitly by returning an HttpResponseMessage instance. HttpResponseMessage is similar to ActionResult in ASP.NET MVC in that it’s a common way to return an abstract result message that contains content. HttpResponseMessage s parsed by the Web API framework using standard interfaces to retrieve the response data, status code, headers and so on[MS2] . Web API turns every response – including those Controller methods that return static results – into HttpResponseMessage instances. Explicitly returning an HttpResponseMessage instance gives you full control over the output and lets you mostly bypass WebAPI’s post-processing of the HTTP response on your behalf. HttpResponseMessage allows you to customize the response in great detail. Web API’s attention to detail in the HTTP spec really shows; many HTTP options are exposed as properties and enumerations with detailed IntelliSense comments. Even if you’re new to building REST-based interfaces, the API guides you in the right direction for returning valid responses and response codes. For example, assume that I always want to return JSON from the GetAlbums() controller method and ignore the default media type content negotiation. To do this, I can adjust the output format and headers as shown in Listing 4.public HttpResponseMessage GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); // Create a new HttpResponse with Json Formatter explicitly var resp = new HttpResponseMessage(HttpStatusCode.OK); resp.Content = new ObjectContent<IEnumerable<Album>>( albums, new JsonMediaTypeFormatter()); // Get Default Formatter based on Content Negotiation //var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); resp.Headers.ConnectionClose = true; resp.Headers.CacheControl = new CacheControlHeaderValue(); resp.Headers.CacheControl.Public = true; return resp; } This example returns the same IEnumerable<Album> value, but it wraps the response into an HttpResponseMessage so you can control the entire HTTP message result including the headers, formatter and status code. In Listing 4, I explicitly specify the formatter using the JsonMediaTypeFormatter to always force the content to JSON.  If you prefer to use the default content negotiation with HttpResponseMessage results, you can create the Response instance using the Request.CreateResponse method:var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); This provides you an HttpResponse object that's pre-configured with the default formatter based on Content Negotiation. Once you have an HttpResponse object you can easily control most HTTP aspects on this object. What's sweet here is that there are many more detailed properties on HttpResponse than the core ASP.NET Response object, with most options being explicitly configurable with enumerations that make it easy to pick the right headers and response codes from a list of valid codes. It makes HTTP features available much more discoverable even for non-hardcore REST/HTTP geeks. Non-Serialized Results The output returned doesn’t have to be a serialized value but can also be raw data, like strings, binary data or streams. You can use the HttpResponseMessage.Content object to set a number of common Content classes. Listing 5 shows how to return a binary image using the ByteArrayContent class from a Controller method. [HttpGet] public HttpResponseMessage AlbumArt(string title) { var album = AlbumData.Current.FirstOrDefault(abl => abl.AlbumName.StartsWith(title)); if (album == null) { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found")); return resp; } // kinda silly - we would normally serve this directly // but hey - it's a demo. var http = new WebClient(); var imageData = http.DownloadData(album.AlbumImageUrl); // create response and return var result = new HttpResponseMessage(HttpStatusCode.OK); result.Content = new ByteArrayContent(imageData); result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg"); return result; } The image retrieval from Amazon is contrived, but it shows how to return binary data using ByteArrayContent. It also demonstrates that you can easily return multiple types of content from a single controller method, which is actually quite common. If an error occurs - such as a resource can’t be found or a validation error – you can return an error response to the client that’s very specific to the error. In GetAlbumArt(), if the album can’t be found, we want to return a 404 Not Found status (and realistically no error, as it’s an image). Note that if you are not using HTTP Verb-based routing or not accessing a method that starts with Get/Post etc., you have to specify one or more HTTP Verb attributes on the method explicitly. Here, I used the [HttpGet] attribute to serve the image. Another option to handle the error could be to return a fixed placeholder image if no album could be matched or the album doesn’t have an image. When returning an error code, you can also return a strongly typed response to the client. For example, you can set the 404 status code and also return a custom error object (ApiMessageError is a class I defined) like this:return Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found") );   If the album can be found, the image will be returned. The image is downloaded into a byte[] array, and then assigned to the result’s Content property. I created a new ByteArrayContent instance and assigned the image’s bytes and the content type so that it displays properly in the browser. There are other content classes available: StringContent, StreamContent, ByteArrayContent, MultipartContent, and ObjectContent are at your disposal to return just about any kind of content. You can create your own Content classes if you frequently return custom types and handle the default formatter assignments that should be used to send the data out . Although HttpResponseMessage results require more code than returning a plain .NET value from a method, it allows much more control over the actual HTTP processing than automatic processing. It also makes it much easier to test your controller methods as you get a response object that you can check for specific status codes and output messages rather than just a result value. Routing Again Ok, let’s get back to the image example. Using the original routing we have setup using HTTP Verb routing there's no good way to serve the image. In order to return my album art image I’d like to use a URL like this: http://localhost/aspnetWebApi/albums/Dirty%20Deeds/image In order to create a URL like this, I have to create a new Controller because my earlier routes pointed to the AlbumApiController using HTTP Verb routing. HTTP Verb based routing is great for representing a single set of resources such as albums. You can map operations like add, delete, update and read easily using HTTP Verbs. But you cannot mix action based routing into a an HTTP Verb routing controller - you can only map HTTP Verbs and each method has to be unique based on parameter signature. You can't have multiple GET operations to methods with the same signature. So GetImage(string id) and GetAlbum(string title) are in conflict in an HTTP GET routing scenario. In fact, I was unable to make the above Image URL work with any combination of HTTP Verb plus Custom routing using the single Albums controller. There are number of ways around this, but all involve additional controllers.  Personally, I think it’s easier to use explicit Action routing and then add custom routes if you need to simplify your URLs further. So in order to accommodate some of the other examples, I created another controller – AlbumRpcApiController – to handle all requests that are explicitly routed via actions (/albums/rpc/AlbumArt) or are custom routed with explicit routes defined in the HttpConfiguration. I added the AlbumArt() method to this new AlbumRpcApiController class. For the image URL to work with the new AlbumRpcApiController, you need a custom route placed before the default route from Listing 1.RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); Now I can use either of the following URLs to access the image: Custom route: (/albums/rpc/{title}/image)http://localhost/aspnetWebApi/albums/PowerAge/image Action route: (/albums/rpc/action/{title})http://localhost/aspnetWebAPI/albums/rpc/albumart/PowerAge Sending Data to the Server To send data to the server and add a new album, you can use an HTTP POST operation. Since I’m using HTTP Verb-based routing in the original AlbumApiController, I can implement a method called PostAlbum()to accept a new album from the client. Listing 6 shows the Web API code to add a new album.public HttpResponseMessage PostAlbum(Album album) { if (!this.ModelState.IsValid) { // my custom error class var error = new ApiMessageError() { message = "Model is invalid" }; // add errors into our client error model for client foreach (var prop in ModelState.Values) { var modelError = prop.Errors.FirstOrDefault(); if (!string.IsNullOrEmpty(modelError.ErrorMessage)) error.errors.Add(modelError.ErrorMessage); else error.errors.Add(modelError.Exception.Message); } return Request.CreateResponse<ApiMessageError>(HttpStatusCode.Conflict, error); } // update song id which isn't provided foreach (var song in album.Songs) song.AlbumId = album.Id; // see if album exists already var matchedAlbum = AlbumData.Current .SingleOrDefault(alb => alb.Id == album.Id || alb.AlbumName == album.AlbumName); if (matchedAlbum == null) AlbumData.Current.Add(album); else matchedAlbum = album; // return a string to show that the value got here var resp = Request.CreateResponse(HttpStatusCode.OK, string.Empty); resp.Content = new StringContent(album.AlbumName + " " + album.Entered.ToString(), Encoding.UTF8, "text/plain"); return resp; } The PostAlbum() method receives an album parameter, which is automatically deserialized from the POST buffer the client sent. The data passed from the client can be either XML or JSON. Web API automatically figures out what format it needs to deserialize based on the content type and binds the content to the album object. Web API uses model binding to bind the request content to the parameter(s) of controller methods. Like MVC you can check the model by looking at ModelState.IsValid. If it’s not valid, you can run through the ModelState.Values collection and check each binding for errors. Here I collect the error messages into a string array that gets passed back to the client via the result ApiErrorMessage object. When a binding error occurs, you’ll want to return an HTTP error response and it’s best to do that with an HttpResponseMessage result. In Listing 6, I used a custom error class that holds a message and an array of detailed error messages for each binding error. I used this object as the content to return to the client along with my Conflict HTTP Status Code response. If binding succeeds, the example returns a string with the name and date entered to demonstrate that you captured the data. Normally, a method like this should return a Boolean or no response at all (HttpStatusCode.NoConent). The sample uses a simple static list to hold albums, so once you’ve added the album using the Post operation, you can hit the /albums/ URL to see that the new album was added. The client jQuery code to call the POST operation from the client with jQuery is shown in Listing 7. var id = new Date().getTime().toString(); var album = { "Id": id, "AlbumName": "Power Age", "Artist": "AC/DC", "YearReleased": 1977, "Entered": "2002-03-11T18:24:43.5580794-10:00", "AlbumImageUrl": http://ecx.images-amazon.com/images/…, "AmazonUrl": http://www.amazon.com/…, "Songs": [ { "SongName": "Rock 'n Roll Damnation", "SongLength": 3.12}, { "SongName": "Downpayment Blues", "SongLength": 4.22 }, { "SongName": "Riff Raff", "SongLength": 2.42 } ] } $.ajax( { url: "albums/", type: "POST", contentType: "application/json", data: JSON.stringify(album), processData: false, beforeSend: function (xhr) { // not required since JSON is default output xhr.setRequestHeader("Accept", "application/json"); }, success: function (result) { // reload list of albums page.loadAlbums(); }, error: function (xhr, status, p3, p4) { var err = "Error"; if (xhr.responseText && xhr.responseText[0] == "{") err = JSON.parse(xhr.responseText).message; alert(err); } }); The code in Listing 7 creates an album object in JavaScript to match the structure of the .NET Album class. This object is passed to the $.ajax() function to send to the server as POST. The data is turned into JSON and the content type set to application/json so that the server knows what to convert when deserializing in the Album instance. The jQuery code hooks up success and failure events. Success returns the result data, which is a string that’s echoed back with an alert box. If an error occurs, jQuery returns the XHR instance and status code. You can check the XHR to see if a JSON object is embedded and if it is, you can extract it by de-serializing it and accessing the .message property. REST standards suggest that updates to existing resources should use PUT operations. REST standards aside, I’m not a big fan of separating out inserts and updates so I tend to have a single method that handles both. But if you want to follow REST suggestions, you can create a PUT method that handles updates by forwarding the PUT operation to the POST method:public HttpResponseMessage PutAlbum(Album album) { return PostAlbum(album); } To make the corresponding $.ajax() call, all you have to change from Listing 7 is the type: from POST to PUT. Model Binding with UrlEncoded POST Variables In the example in Listing 7 I used JSON objects to post a serialized object to a server method that accepted an strongly typed object with the same structure, which is a common way to send data to the server. However, Web API supports a number of different ways that data can be received by server methods. For example, another common way is to use plain UrlEncoded POST  values to send to the server. Web API supports Model Binding that works similar (but not the same) as MVC's model binding where POST variables are mapped to properties of object parameters of the target method. This is actually quite common for AJAX calls that want to avoid serialization and the potential requirement of a JSON parser on older browsers. For example, using jQUery you might use the $.post() method to send a new album to the server (albeit one without songs) using code like the following:$.post("albums/",{AlbumName: "Dirty Deeds", YearReleased: 1976 … },albumPostCallback); Although the code looks very similar to the client code we used before passing JSON, here the data passed is URL encoded values (AlbumName=Dirty+Deeds&YearReleased=1976 etc.). Web API then takes this POST data and maps each of the POST values to the properties of the Album object in the method's parameter. Although the client code is different the server can both handle the JSON object, or the UrlEncoded POST values. Dynamic Access to POST Data There are also a few options available to dynamically access POST data, if you know what type of data you're dealing with. If you have POST UrlEncoded values, you can dynamically using a FormsDataCollection:[HttpPost] public string PostAlbum(FormDataCollection form) { return string.Format("{0} - released {1}", form.Get("AlbumName"),form.Get("RearReleased")); } The FormDataCollection is a very simple object, that essentially provides the same functionality as Request.Form[] in ASP.NET. Request.Form[] still works if you're running hosted in an ASP.NET application. However as a general rule, while ASP.NET's functionality is always available when running Web API hosted inside of an  ASP.NET application, using the built in classes specific to Web API makes it possible to run Web API applications in a self hosted environment outside of ASP.NET. If your client is sending JSON to your server, and you don't want to map the JSON to a strongly typed object because you only want to retrieve a few simple values, you can also accept a JObject parameter in your API methods:[HttpPost] public string PostAlbum(JObject jsonData) { dynamic json = jsonData; JObject jalbum = json.Album; JObject juser = json.User; string token = json.UserToken; var album = jalbum.ToObject<Album>(); var user = juser.ToObject<User>(); return String.Format("{0} {1} {2}", album.AlbumName, user.Name, token); } There quite a few options available to you to receive data with Web API, which gives you more choices for the right tool for the job. Unfortunately one shortcoming of Web API is that POST data is always mapped to a single parameter. This means you can't pass multiple POST parameters to methods that receive POST data. It's possible to accept multiple parameters, but only one can map to the POST content - the others have to come from the query string or route values. I have a couple of Blog POSTs that explain what works and what doesn't here: Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API   Handling Delete Operations Finally, to round out the server API code of the album example we've been discussin, here’s the DELETE verb controller method that allows removal of an album by its title:public HttpResponseMessage DeleteAlbum(string title) { var matchedAlbum = AlbumData.Current.Where(alb => alb.AlbumName == title) .SingleOrDefault(); if (matchedAlbum == null) return new HttpResponseMessage(HttpStatusCode.NotFound); AlbumData.Current.Remove(matchedAlbum); return new HttpResponseMessage(HttpStatusCode.NoContent); } To call this action method using jQuery, you can use:$(".removeimage").live("click", function () { var $el = $(this).parent(".album"); var txt = $el.find("a").text(); $.ajax({ url: "albums/" + encodeURIComponent(txt), type: "Delete", success: function (result) { $el.fadeOut().remove(); }, error: jqError }); }   Note the use of the DELETE verb in the $.ajax() call, which routes to DeleteAlbum on the server. DELETE is a non-content operation, so you supply a resource ID (the title) via route value or the querystring. Routing Conflicts In all requests with the exception of the AlbumArt image example shown so far, I used HTTP Verb routing that I set up in Listing 1. HTTP Verb Routing is a recommendation that is in line with typical REST access to HTTP resources. However, it takes quite a bit of effort to create REST-compliant API implementations based only on HTTP Verb routing only. You saw one example that didn’t really fit – the return of an image where I created a custom route albums/{title}/image that required creation of a second controller and a custom route to work. HTTP Verb routing to a controller does not mix with custom or action routing to the same controller because of the limited mapping of HTTP verbs imposed by HTTP Verb routing. To understand some of the problems with verb routing, let’s look at another example. Let’s say you create a GetSortableAlbums() method like this and add it to the original AlbumApiController accessed via HTTP Verb routing:[HttpGet] public IQueryable<Album> SortableAlbums() { var albums = AlbumData.Current; // generally should be done only on actual queryable results (EF etc.) // Done here because we're running with a static list but otherwise might be slow return albums.AsQueryable(); } If you compile this code and try to now access the /albums/ link, you get an error: Multiple Actions were found that match the request. HTTP Verb routing only allows access to one GET operation per parameter/route value match. If more than one method exists with the same parameter signature, it doesn’t work. As I mentioned earlier for the image display, the only solution to get this method to work is to throw it into another controller. Because I already set up the AlbumRpcApiController I can add the method there. First, I should rename the method to SortableAlbums() so I’m not using a Get prefix for the method. This also makes the action parameter look cleaner in the URL - it looks less like a method and more like a noun. I can then create a new route that handles direct-action mapping:RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); As I am explicitly adding a route segment – rpc – into the route template, I can now reference explicit methods in the Web API controller using URLs like this: http://localhost/AspNetWebApi/rpc/SortableAlbums Error Handling I’ve already done some minimal error handling in the examples. For example in Listing 6, I detected some known-error scenarios like model validation failing or a resource not being found and returning an appropriate HttpResponseMessage result. But what happens if your code just blows up or causes an exception? If you have a controller method, like this:[HttpGet] public void ThrowException() { throw new UnauthorizedAccessException("Unauthorized Access Sucka"); } You can call it with this: http://localhost/AspNetWebApi/albums/rpc/ThrowException The default exception handling displays a 500-status response with the serialized exception on the local computer only. When you connect from a remote computer, Web API throws back a 500  HTTP Error with no data returned (IIS then adds its HTML error page). The behavior is configurable in the GlobalConfiguration:GlobalConfiguration .Configuration .IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Never; If you want more control over your error responses sent from code, you can throw explicit error responses yourself using HttpResponseException. When you throw an HttpResponseException the response parameter is used to generate the output for the Controller action. [HttpGet] public void ThrowError() { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.BadRequest, new ApiMessageError("Your code stinks!")); throw new HttpResponseException(resp); } Throwing an HttpResponseException stops the processing of the controller method and immediately returns the response you passed to the exception. Unlike other Exceptions fired inside of WebAPI, HttpResponseException bypasses the Exception Filters installed and instead just outputs the response you provide. In this case, the serialized ApiMessageError result string is returned in the default serialization format – XML or JSON. You can pass any content to HttpResponseMessage, which includes creating your own exception objects and consistently returning error messages to the client. Here’s a small helper method on the controller that you might use to send exception info back to the client consistently:private void ThrowSafeException(string message, HttpStatusCode statusCode = HttpStatusCode.BadRequest) { var errResponse = Request.CreateResponse<ApiMessageError>(statusCode, new ApiMessageError() { message = message }); throw new HttpResponseException(errResponse); } You can then use it to output any captured errors from code:[HttpGet] public void ThrowErrorSafe() { try { List<string> list = null; list.Add("Rick"); } catch (Exception ex) { ThrowSafeException(ex.Message); } }   Exception Filters Another more global solution is to create an Exception Filter. Filters in Web API provide the ability to pre- and post-process controller method operations. An exception filter looks at all exceptions fired and then optionally creates an HttpResponseMessage result. Listing 8 shows an example of a basic Exception filter implementation.public class UnhandledExceptionFilter : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { HttpStatusCode status = HttpStatusCode.InternalServerError; var exType = context.Exception.GetType(); if (exType == typeof(UnauthorizedAccessException)) status = HttpStatusCode.Unauthorized; else if (exType == typeof(ArgumentException)) status = HttpStatusCode.NotFound; var apiError = new ApiMessageError() { message = context.Exception.Message }; // create a new response and attach our ApiError object // which now gets returned on ANY exception result var errorResponse = context.Request.CreateResponse<ApiMessageError>(status, apiError); context.Response = errorResponse; base.OnException(context); } } Exception Filter Attributes can be assigned to an ApiController class like this:[UnhandledExceptionFilter] public class AlbumRpcApiController : ApiController or you can globally assign it to all controllers by adding it to the HTTP Configuration's Filters collection:GlobalConfiguration.Configuration.Filters.Add(new UnhandledExceptionFilter()); The latter is a great way to get global error trapping so that all errors (short of hard IIS errors and explicit HttpResponseException errors) return a valid error response that includes error information in the form of a known-error object. Using a filter like this allows you to throw an exception as you normally would and have your filter create a response in the appropriate output format that the client expects. For example, an AJAX application can on failure expect to see a JSON error result that corresponds to the real error that occurred rather than a 500 error along with HTML error page that IIS throws up. You can even create some custom exceptions so you can differentiate your own exceptions from unhandled system exceptions - you often don't want to display error information from 'unknown' exceptions as they may contain sensitive system information or info that's not generally useful to users of your application/site. This is just one example of how ASP.NET Web API is configurable and extensible. Exception filters are just one example of how you can plug-in into the Web API request flow to modify output. Many more hooks exist and I’ll take a closer look at extensibility in Part 2 of this article in the future. Summary Web API is a big improvement over previous Microsoft REST and AJAX toolkits. The key features to its usefulness are its ease of use with simple controller based logic, familiar MVC-style routing, low configuration impact, extensibility at all levels and tight attention to exposing and making HTTP semantics easily discoverable and easy to use. Although none of the concepts used in Web API are new or radical, Web API combines the best of previous platforms into a single framework that’s highly functional, easy to work with, and extensible to boot. I think that Microsoft has hit a home run with Web API. Related Resources Where does ASP.NET Web API fit? Sample Source Code on GitHub Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API Creating a JSONP Formatter for ASP.NET Web API Removing the XML Formatter from ASP.NET Web API Applications© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • You Might Be a DBA

    - by BuckWoody
    With all apologies to Jeff Foxworthy, I was up late Friday night on a holiday weekend (which translated into T-SQL becomes “Maintenance Window”) and I got bored in between the two or three minutes I had between clicks. So I started a “Twitter” meme – and it just took off. I haven’t cleaned these up much, but here, in author order as of Saturday the 29th of May is the list “You might be a DBA” from around the Twitterverse: buckwoody Your two main enemies are developers and SAN admins #youmightbeaDBA  buckwoody People can use Access as a cross or garlic on you #youmightbeaDBA  buckwoody You always plan an exit strategy, even when entering a McDonald's #youmightbeaDBA  buckwoody You can't explain to your family what you really do for a living #youmightbeaDBA  buckwoody You have at least one set of scripts you won't share #youmightbeaDBA  buckwoody You have an opinion on the best code-beautifier #youmightbeaDBA  buckwoody You have children older than the rest of your team #youmightbeaDBA  buckwoody You and the Oracle DBA would kill each other, but you'll happily fight off a developer together first #youmightbeaDBA  buckwoody You've threatened to quit if they give anyone the sa password on production #youmightbeaDBA  buckwoody You've sent a vendor suggestions on improving their database design or code (and been ignored) #youmightbeaDBA  buckwoody You've sent a vendor suggestions on improving their database design or code (and been ignored) #youmightbeaDBA  buckwoody You have an opinion on the best code-beautifier #youmightbeaDBA  buckwoody You have at least one set of scripts you won't share #youmightbeaDBA  buckwoody You refer to co-workers as "carbon-units" #youmightbeaDBA  buckwoody Being paranoid is on your resume at the top #youmightbeaDBA  buckwoody Everyone comes to your cube to find the MSDN DVD's #youmightbeaDBA  buckwoody You always plan an exit strategy, even when entering a McDonald's #youmightbeaDBA  buckwoody You've worn down developers to get your way by explaining normalization levels #youmightbeaDBA  buckwoody You refer to clothes as "Data Abstractions" #youmightbeaDBA  buckwoody Users pester you to be able to put data in a database, then they pester you to take it out and put it in Excel #youmightbeaDBA  buckwoody Others try to de-duplicate data, you try to copy it to more than three locations #youmightbeaDBA  buckwoody You have at least one DLT tape in the trunk of your car #youmightbeaDBA  buckwoody You use twitter and facebook to talk with colleagues because there's no one else in your company that does what you do #youmightbeaDBA  buckwoody Your spouse knows what "ETL" means #youmightbeaDBA  buckwoody You've referred to yourself as the "Data Janitor" #youmightbeaDBA  buckwoody You don't have positive connotations of the word "upgrade" #youmightbeaDBA  buckwoody You get your coffee before you check your servers, because you know you won't get any if you don't #youmightbeaDBA  buckwoody You always come to work through the back door so no one hijacks you on the way to your cube #youmightbeaDBA  buckwoody You check your server logs before you check your e-mail in the morning so you can reply "Yeah, I already fixed that." #youmightbeaDBA  buckwoody You have more conference badges than clean socks #youmightbeaDBA  buckwoody Your coffee mug says "It depends" #youmightbeaDBA  buckwoody You can convince a boss that you need 16GB of RAM in your laptop #youmightbeaDBA  buckwoody You've used ebay to find production equipment #youmightbeaDBA  buckwoody You pad all project timelines by 2X, and you still miss them #youmightbeaDBA  buckwoody You know when your company is acquiring another even before the CFO #youmightbeaDBA  buckwoody You pad all project timelines by 2X, and you still miss them #youmightbeaDBA  buckwoody You call aspirin "work vitamins" #youmightbeaDBA  buckwoody You get the same amount of sleep even after you have a child #youmightbeaDBA  buckwoody You obsess about performance metrics from over one year ago #youmightbeaDBA  buckwoody The first thing you buy after the database software is aftermarket tools to manage the database software #youmightbeaDBA  buckwoody You've tried to convince someone else to become a DBA #youmightbeaDBA  buckwoody You use twitter and facebook to talk with colleagues because there's no one else in your company that does what you do #youmightbeaDBA  buckwoody You only know other DBA's by their Tweet Handle #youmightbeaDBA  buckwoody You've explained the difference between 32 and 64-bit to more than one manager in terms they can understand, using puppets #youmightbeaDBA  buckwoody Your two main enemies are developers and SAN admins #youmightbeaDBA  buckwoody You've driven to the Datacenter to install SQL Server because "you don't trust those NOC admins" #youmightbeaDBA  buckwoody You pay more for faster Internet connections than cable at home so you don't have to drive in #youmightbeaDBA  buckwoody You call texting a "queuing system" #youmightbeaDBA  buckwoody You know that if someone can read Perl, they manage an Oracle system #youmightbeaDBA  buckwoody You have an e-mail rule for backup notifications #youmightbeaDBA  buckwoody Your food pyramid includes coffee, salt and fat #youmightbeaDBA  buckwoody You wish everything had a graphical query plan #youmightbeaDBA  buckwoody You refactor your e-mails #youmightbeaDBA  buckwoody You've gotten more help from twitter and facebook than all your years in college #youmightbeaDBA  buckwoody You would pay money for a license plate that has the letters S-Q-L together #youmightbeaDBA  buckwoody You have actually considered making a RAID array from thumb drives #youmightbeaDBA  buckwoody Everything on your laptop is installed from your MSDN subscription #youmightbeaDBA  buckwoody You've written blog posts on technology you've never actually implemented in production #youmightbeaDBA  buckwoody Everything on your laptop is installed from your MSDN subscription #youmightbeaDBA  buckwoody @MidnightDBA Click the #youmightbeaDBA tag. I've had WAY too much coffee today.  buckwoody There is no other position that is 1-deep except you and the CEO #youmightbeaDBA  buckwoody When you watch "The Office" you call it "OJT" #youmightbeaDBA  buckwoody You would pay money for a license plate that has the letters S-Q-L together #youmightbeaDBA  buckwoody Your blog would make a "best practices" or "worst practices" book #youmightbeaDBA  buckwoody You have actually considered making a RAID array from thumb drives #youmightbeaDBA  buckwoody The first thing you install on your netbook is SSMS #youmightbeaDBA  buckwoody Everything on your laptop is installed from your MSDN subscription #youmightbeaDBA  buckwoody Your watch is set to UTC because it's just easier #youmightbeaDBA  buckwoody You make plenty of money, but you're excited to get a $2.00 squeeze-ball from Quest and Redgate #youmightbeaDBA  buckwoody You make plenty of money, but you're excited to get a $2.00 squeeze-ball from Quest and Redgate #youmightbeaDBA  buckwoody You think data can be represented as something OTHER than XML #youmightbeaDBA  buckwoody You tell people that you made a database query go faster, and expect them to be happy for you #youmightbeaDBA  buckwoody You take the word "NoSQL" as a personal attack #youmightbeaDBA  buckwoody People can use Access as a cross or garlic on you #youmightbeaDBA  buckwoody * == bad #youmightbeaDBA  buckwoody * == bad #youmightbeaDBA  buckwoody There are just as many females in your technical field as males #youmightbeaDBA  buckwoody People can use Access as a cross or garlic on you #youmightbeaDBA  buckwoody You've gotten more help from twitter and facebook than all your years in college #youmightbeaDBA  buckwoody You think that something OTHER than the database might be the performance bottleneck #youmightbeaDBA  buckwoody You refer to time as a "Clustered Index" #youmightbeaDBA  buckwoody You know why "user" refers to both business people and crack addicts #youmightbeaDBA  buckwoody You make plenty of money, but you're excited to get a $2.00 squeeze-ball from Quest and Redgate #youmightbeaDBA  buckwoody You can't explain to your family what you really do for a living #youmightbeaDBA  buckwoody You tell people that you made a database query go faster, and expect them to be happy for you #youmightbeaDBA  buckwoody You think a millisecond is a really long time #youmightbeaDBA  buckwoody You're sitting and typing #youmightbeaDBA when you could be outside #youmightbeaDBA  buckwoody You can't wait for a technical conference so you can wear a kilt - and you're not Scottish #youmightbeaDBA  buckwoody You know that "DBA" stands for "Default Blame Acceptor" #youmightbeaDBA  buckwoody People can use Access as a cross or garlic on you #youmightbeaDBA  buckwoody You know what "the truth, thole truth and nothing but the truth, so help me Codd" means #youmightbeaDBA  buckwoody You've gotten more help from twitter and facebook than all your years in college #youmightbeaDBA  buckwoody You can't talk fast enough to get a concept out of your head so you tweet it instead #youmightbeaDBA  buckwoody You cry when someone doesn't use a WHERE clause #youmightbeaDBA  buckwoody You think data can be represented as something OTHER than XML #youmightbeaDBA  buckwoody You think "Set theory" is not an verb but a noun #youmightbeaDBA  buckwoody You try to convince random strangers to vote on your Connect item #youmightbeaDBA  buckwoody You think 3 hours of contiguous sleep is a good thing #youmightbeaDBA or #youmightbeamother  buckwoody You don't like Oracle, and not just because of what she did to Neo #youmightbeaDBA  buckwoody You know when to say "sequel" and "s-q-l" #youmightbeaDBA  buckwoody You know where the data is #youmightbeaDBA  buckwoody You refer to your children as "Fully Redundant Mirrors" #youmightbeaDBA  buckwoody Holiday == "Maintenance Window" #youmightbeaDBA  buckwoody Your laptop is more powerful than the servers in most companies - including your own #youmightbeaDBA  buckwoody You capitalize SELECTed words #youmightbeaDBA  buckwoody You take the word "NoSQL" as a personal attack #youmightbeaDBA  buckwoody You know why "user" refers to both business people and crack addicts #youmightbeaDBA  buckwoody You cringe in public when the word "upgrade" is used in a sentence #youmightbeaDBA  buckwoody Holiday == "Maintenance Window" #youmightbeaDBA  buckwoody All Data Is MetaData means something to you #youmightbeaDBA  buckwoody You've never seen the driveway to your house in the daylight #youmightbeaDBA  buckwoody You think that something OTHER than the database might be the performance bottleneck #youmightbeaDBA  buckwoody Most of your bloodstream is composed of caffeine #youmightbeaDBA  buckwoody Your task list is labeled "CRUD Matrix" #youmightbeaDBA  buckwoody You call your wife/husband a "Linked Server" #youmightbeaDBA  anonythemouse When someone tells you they are going to take a dump and you wonder of which database then #youmightbeaDBA  anonythemouse When it's 11pm on a holiday weekend and you are working #youmightbeaDBA  anonythemouse When you sit down at a table and look for it's primary key #youmightbeaDBA  anonythemouse When getting milk from the fridge you check the expiry date is > getdate() #youmightbeaDBA  blakmk when you wake up dreaming about sql #youmightbeaDBA  CharlesGarver You think a @buckwoody bobblehead would be a cool thing to have on the dashboard of your car #youmightbeaDBA  CharlesGarver Your friends don't understand why you think there's a difference between single and double quotes #youmightbeaDBA  CharlesGarver Even the newest employees know your name from all the downtime notices you've sent out #youmightbeaDBA  CharlesGarver You sometimes feel anxious and think "I should test restoring those backups" and then the feeling passes #youmightbeadba  CharlesGarver You know what a co-worker means when they ask "how is your squirrel server?" #youmightbeadba  CharlesGarver You can't sleep at night and you ponder the logisitcs of collecting every copy of Access for the world's biggest bonfire #youmightbeaDBA  CharlesGarver You can't sleep at night and you ponder the logisitcs of collecting every copy of Access for the world's biggest bonfire #youmightbeaDBA  CharlesGarver You're willing to move someone's job up in priority for a box of #voodoodonuts #youmightbeaDBA  CharlesGarver Each person in your company seems to think you work for THEM #youmightbeaDBA  CharlesGarver You have a Love/Hate relationship going on with #Microsoft #youmightbeaDBA  CharlesGarver People ask you to troubleshoot their Access program #youmightbeaDBA  CharlesGarver The first words you hear in the morning are 'your voicemail box is full' #youmightbeaDBA  CharlesGarver The thought of disrupting 500 people's work so you can do something doesn't phase you #youmightbeaDBA  CharlesGarver You can't sleep at night and you ponder the logisitcs of collecting every copy of Access for the world's biggest bonfire #youmightbeaDBA  CharlesGarver Your home computer is backed up in 3 different places #youmightbeaDBA  CharlesGarver Your wardrobe for work includes pajamas #youmightbeaDBA  CharlesGarver Someone tells you to look in the INDEX and you look puzzled before finally going to the back of the book. #youmightbeaDBA  chuckboycejr If you have ever set up a SQLAgent job to email your mobile phone to serve as an alarm clock #youmightbeaDBA  chuckboycejr If you'd rather meet Itzik than Jay Z #youmightbeaDBA  chuckboycejr If you'd rather meet Itzik than Jay Z #youmightbeaDBA  chuckboycejr If you'd wrestle a SysAdmin to the ground to implement #DPA best practices as per @aspiringgeek #youmightbeaDBA  databaseguy I need to be up in 7 hours, so I'm off to bed! I'll have to read the rest of @buckwoody's #youmightbeaDBA posts in the AM. (g'night Buck!)  databaseguy When people ask you about your house, the first thing you describe is the network. #youmightbeaDBA  databaseguy The last thing you say at the office each day is, "is anybody else here? I'm shutting off the lights!" #youmightbeaDBA  databaseguy Your blood pressure rises when you read application specs drafted by marketing. #youmightbeaDBA  databaseguy A good day at work is one when nobody pays you no mind. #youmightbeaDBA  databaseguy You care about latches and wait states. #youmightbeaDBA  databaseguy You have worked over 200 hours on a performance tuning project that required no application changes at all. #youmightbeaDBA  databaseguy The late-night security guard knows the names of your spouse and kids. #youmightbeaDBA  databaseguy You have had vigorous debates about whether it should be pronounced "sequel" or "ess-queue-ell". #youmightbeaDBA  databaseguy You have VPN and RDP software installed on your phone ... just in case. #youmightbeaDBA  databaseguy You have edited a data file by hand, just to see what would happen. #youmightbeaDBA  databaseguy You decorate your office walls with database catalog posters. #youmightbeaDBA  databaseguy You've built programs that access data just to keep other developers from asking you to run queries all the time. #youmightbeaDBA  databaseguy When you watch movies like The Matrix, you find yourself calculating the fasibility of storing all that data. #youmightbeaDBA  databaseguy You have tried to convince someone to spend money on an SSD storage array. #youmightbeaDBA  databaseguy When CPU is spiked on a server, you want to gather forensic evidence. #youmightbeaDBA  databaseguy You have to remind developers not to push code to production without checking if the database is ready. #youmightbeaDBA  databaseguy Nobody cares what you wear to work, as long as the thing keeps running. #youmightbeaDBA  databaseguy Telepathy is a job requirement when working with app dev teams. #youmightbeaDBA  databaseguy You read database statistics for the educational value. #youmightbeaDBA  databaseguy And your boss freely admits this to anyone within earshot. #youmightbeaDBA  databaseguy Your boss cannot explain or understand what you do. #youmightbeaDBA  databaseguy You envision ERDs when you see a GUI. #youmightbeaDBA  databaseguy You say things like "applications come and go, but data lasts forever." #youmightbeaDBA  databaseguy You have memorized the names of several of the AdventureWorks employees. #youmightbeaDBA  databaseguy You know what MAXDOP setting you can get away with for a big query based on current server load. #youmightbeaDBA  databaseguy And you immediately recognize the recursion in my last tweet. #youmightbeaDBA  databaseguy You find 50 simultaneous tweets from @buckwoody about #youmightbeaDBA :O)  DBAishness You have "funny stories" about the times your developers accidentally deleted the T-log in their test environment. #youmightbeaDBA  DBAishness Planning to slice and dice your MDW data with PowerPivot makes you giggle like a schoolgirl. #youmightbeaDBA  donalddotfarmer You think @buckwoody lives in the "real world." #youmightbeaDBA  jamach09 @buckwoody #youmightbeaDBA Why go outside when you can sit in the nice cool server room?  jamach09 If you refer to procreation as "Replication", #youmightbeaDBA.  jamach09 If you think ORM is a four-letter word, #youmightbeaDBA  JamesMarsh If you have ever preached the value of Source Code Control, #YouMightBeADBA  jethrocarr @venzann You store your shopping list in a ACID compliant DB #youmightbeaDBA  joe_positive @buckwoody thought it stood for "Don't Bother Asking" #youmightbeaDBA  joe_positive when you check your IT Events Calendar before making weekend plans #youmightbeaDBA  LadyRuna You cringe whenever someone calls Excel a database #youmightbeaDBA  LadyRuna When the waiter says he'll be your server today, you ask how many terabytes he is #youmightbeaDBA  LadyRuna you always call the asterisk a "Star" #youmightbeaDBA  LadyRuna You walk into a server room, say "Nice RACK!" and everyone there knows you're talking about server rack... #youmightbeaDBA  LadyRuna You receive more messages from servers than from friends #youmightbeaDBA  LadyRuna hmmm... #youmightbeaDBA if your recipe for gumbo is "SELECT * FROM Refrigerator"  markjholmes @SQLSoldier Heh. #youmightbeaDBA if you correct other DBAs' spelling of @PaulRandal  markjholmes #youmightbeaDBA if you actually test RAID5 vs RAID10 on your SAN because when it comes to configuration, "it depends."  markjholmes #youmightbeaDBA if you have at least 3 definitions of the word "cluster"  MarlonRibunal 3 Words: @BrentO, snicker, & Access #youmightbeaDBA  MarlonRibunal @onpnt @mikeSQL my appeal was a couple of mins late. Enjoying #youmightbeaDBA  MarlonRibunal @mikeSQL @onpnt pls, don't mention bacon #youmightbeaDBA  merv @buckwoody You HATE 3-way joins #youmightbeaDBA  MidnightDBA If you're up at midnight Tweeting about SQL #youmightbeaDBA  MidnightDBA @buckwoody I'd noticed that. :) #youmightbeaDBA  mikeSQL when people talk about "their type" you're thinking varchar, bigint, binary, etc #youmightbeadba  mikeSQL people ask you to go to lunch , but you can't go because you're attending #SQLlunch #youmightbeadba  mikeSQL you laugh for hours at all of the #sqlmoviequotes ....things in which a normal individual would scratch their head at. #youmightbeadba  mikeSQL you laugh for hours at all of the #sqlmoviequotes ....things in which a normal individual would scratch their head at. #youmightbeadba  mrdenny If you think that @buckwoody's demo using PowerPivot to analyze index usage data from DMVs is awesome then #youmightbeaDBA  mrdenny You wish @PaulRandal still worked at Microsoft so that they would make a bobble head of him #youmightbeadba  mrdenny When it's 11pm on a holiday weekend, and your posting stupid jokes on Twitter then #youmightbeadba  mrdenny If you go out with friends and wonder why no one's wearing a kilt then #YouMightBeADBA  mrdenny You can't do basic math, but you know off the top of your head how many CALs $14,412 can buy you. #YoumightbeaDBA  mrdenny If you've ever setup a SQL Job to email you to get you out of a regularly scheduled meeting #YouMightBeADBA.  mrdenny You throw up in your mouth a little when ever you here the word "Access". Even if it doesn't relate to a MS product. #YouMightBeADBA  msdtjones You spend more time listening to @buckwoody than your wife #youmightbeaDBA  NFDotCom You perform "hail deltas" on a regular basis. #YouMightBeADBA  NoelMcKinney If you tell your wife you want to go to Columbus Ohio for your wedding anniversary so you can attend #sqlsat42 then #youmightbeaDBA  NoelMcKinney You read a union is on strike and wonder if it's a UNION ALL #youmightbeaDBA  NoelMcKinney You read a union is on strike and wonder if it's a UNION ALL #youmightbeaDBA  NoelMcKinney Someone asks you to throw another log on the fire and you tell them not to worry about it because Autogrowth is turned on #youmightbeaDBA  Nuurdygirl Even if you have a girlfriend...its possible #youmightbeadba. Yeah-i said its possible!  Nuurdygirl When your girlfriend has to lean around the laptop to kiss you goodnight #youmightbeadba  Old_Man_Fish If you worry about how big your package is and how long it takes to finish #youmightbeaDBA  Old_Man_Fish If you no longer wonder if someone is in trouble or died if you are getting calls at 2AM #youmightbeaDBA  Old_Man_Fish If, when you hear the word ACCESS with no connotation you blood pressure jumps 50 points, #youmightbeaDBA  onpnt When you hear the word inject you immediately get concerned if your databases are OK #youmightbeaDBA  onpnt Your servers haven't been rebooted in a year #youmightbeaDBA  onpnt You know why it's funny when @PaulRandal has the word, "Sheep" in a tweet #youmightbeaDBA  onpnt You have read BOL without actually having a problem to figure out #youmightbeaDBA  onpnt You can type "SELECT columns FROM tables" without typos but tipen ni Banglish ares a messis #youmightbeaDBA  onpnt DR strategies doesn't include the word, RAID in them #youmightbeaDBA  onpnt you can move a SQL Server instance to a new server without the users ever knowing #youmightbeaDBA  onpnt You have made an SSIS package that is more than one step #youmightbeaDBA  onpnt You have the balls to say no to your boss when they ask for the sa password #youmightbeaDBA  onpnt you google to trouble shoot a problem and end up at your own blog (and it fixes it) #youmightbeaDBA  onpnt You talk your wife into moving the family vacation a week earlier so you can attend the areas local SSUG meeting #youmightbeaDBA  onpnt you can explain to a nontechnical person what a deadlock is #youmightbeaDBA  onpnt You hope a girl asks you what your collation is #youmightbeaDBA  onpnt you make jokes that include the words shrink, truncate and 1205. And you are the only one that laughs at them #youmightbeaDBA  onpnt You rate your ability to stay awake to work longer on blogs, twitter, forums and your day to day job with the 5 9's goal #youmightbeaDBA  onpnt you have major surgery and beg the doctor to release you back to work 5 days later because you miss your servers #youmightbeaDBA #TrueStory  onpnt You do have backups and you know how to use them #youmightbeaDBA  onpnt It's the network #youmightbeaDBA  onpnt When the developers get to work your mood changes rapidly #youmightbeaDBA  onpnt When someone says, "PASS", you first think of karaoke #youmightbeaDBA  onpnt Recruiters try to get you to call them *just* because they think you'll give them @BrentO contact info #youmightbeaDBA  onpnt You chuckle every time you go to grab the "CLR" Calcium, Lime and Rust Remover to clean something #youmightbeaDBA  onpnt @MarlonRibunal @mikeSQL Sorry man, it was already in motion ;-) #youmightbeaDBA  onpnt When you have an "I love bacon" sticker on your laptop. #youmightbeaDBA http://twitpic.com/1ry671  onpnt You sing SELECT statements in the shower #youmightbeaDBA  onpnt When you see a chicken it doesn't remind you of food. It reminds you of a guy named Jorge #youmightbeaDBA  onpnt At time, SQL is your mistress #youmightbeaDBA  onpnt Your wife wonders if SQL is the code name of your mistress at times #youmightbeaDBA  onpnt it's Friday and you are on twitter thinking really hard about what would be funny for hash tag #youmightbeaDBA  onpnt You organize your wife's "decorative"pillows on the bed in a B-Tree structure #youmightbeaDBA  PaulWhiteNZ If you: SELECT TOP (1) milk FROM fridge WHERE use_by_date >= GET_DATE() ORDER BY use_by_date ASC #YouMightBeaDBA  RonDBA #youmightbeaDBA if you read @buckwoody's and @BrentO's blogs.  ryaneastabrook @buckwoody omg, you have to stand up a website with these on them, they are awesome #youmightbeaDBA  soulvy @StrateSQL @LadyRuna Or a "Splat" #youmightbeaDBA  speedracer You can still fall asleep after three cups of coffee #youmightbeaDBA  speedracer You retweet @buckwoody on a Friday night #youmightbeaDBA  speedracer You can still fall asleep after three cups of coffee #youmightbeaDBA  speedracer Developers make you twitch #youmightbeaDBA  sqlagentman You know what X/1024*8 is. #YouMightBeADBA  SqlAsylum Your still in the office at 5:00 on memorial day weekend. #youmightbeadba :)  SQLBob Whenever someone you know gets pregnant you bring up INNER JOINs or SQL Injection attacks... #youmightbeaDBA  SQLChicken You know one or more SQL folks in the community with an animal in their username #youmightbeaDBA  SQLChicken You've used one or more car analogies to explain how a database works #youmightbeaDBA  SQLChicken “@sqljoe: #youmightbeaDBA if you applied to attend #sqlu and requested @SQLChicken to pull strings for you” lmao nice!  SQLChicken When talking about SSIS your discussions break down into various jokes about packages #youmightbeaDBA  SQLChicken Just SEEING the code for cursors makes you break out in hives #youmightbeaDBA  SQLChicken Just SEEING the code for cursors makes you break out in hives #youmightbeaDBA  SQLCraftsman You coined the phrase "Magic SAN Dust" because calling a vendor's marketing claims BS is not acceptable in a meeting. #YouMightBeADBA  SQLCraftsman If you hear about a new feature with the acronym "DAC" and wonder what disaster of a feature it is attached to this time. #YouMightBeADBA  SQLCraftsman You really own a "Stick of Much Developer Whacking" #YouMightBeADBA  SQLCraftsman You coined the phrase "Magic SAN Dust" because calling a vendor's marketing claims BS is not acceptable in a meeting. #YouMightBeADBA  SQLCraftsman Default Blame Acceptor #YouMightBeADBA  SQLCraftsman If you hear about a new feature with the acronym "DAC" and wonder what disaster of a feature it is attached to this time. #YouMightBeADBA  SQLCraftsman Default Blame Acceptor #YouMightBeADBA  SQLCraftsman If you hear about a new feature with the acronym "DAC" and wonder what disaster of a feature it is attached to this time. #YouMightBeADBA  sqljoe #youmightbeaDBA if you wished your wife knew T-sql. USE ShoppingList SELECT NecessaryItems from Supermarket WHERE Category<> ("junk food")  sqljoe #youmightbeaDBA if the first thing you kiss when you wake up is your mobile for not waking you up in the middle of the night  sqljoe #youmightbeaDBA if your wife has a "Do Not Fly" family vacation list of her own including your laptop and mobile  sqljoe #youmightbeaDBA if you have researched for DBA Anonymous groups and attended a #SSUG willing to drop your database (vice)  sqljoe #youmightbeaDBA if your only maintenance windows are staff meetings  sqljoe #youmightbeaDBA if you think of yourself as "The One" in The Matrix "balancing the equation" from The Architect's (developers) poor coding  sqljoe #youmightbeaDBA if you think @PaulRandal should have played the Oracle in The Matrix  sqljoe #youmightbeaDBA if home CD & Movie collection is stored in secured containers,in logical order & naming convention,and with a backup copy  sqljoe #youmightbeaDBA if you applied to attend #sqlu and requested @SQLChicken to pull strings for you  sqljoe #youmightbeaDBA if you have tried to TiVo @MidnightDBA broadcasts  sqljoe #youmightbeaDBA if your #sql user group feels like #AA meetings  sqljoe #youmightbeaDBA if you thought of bringing your #sql books to #sqlsaturday and #sqlpass for autographs  sqljoe #youmightbeaDBA if #sqlpass feels like the #oscars  sqljoe #youmightbeaDBA if you are proud of your small package  SQLLawman #youmightbeaDBA when you hear MDX and Acura is not first thought that comes to mind.  sqlrunner If your wife double checks that there isn't a SQLSat within 200 miles of your vacation destination #youmightbeaDBA  sqlrunner When you're on a conference call and your wife thinks your speaking in a foreign language #youmightbeaDBA  sqlrunner When you're on a conference call and your wife thinks your speaking in a foreign language #youmightbeaDBA  sqlrunner You treat the word 'access' as a verb, not a noun #youmightbeaDBA  sqlrunner If you are happy with sub-second performance #youmightbeaDBA  sqlrunner When you know the names of the NOC people AND their families #youmightbeadba  sqlrunner When you know the names of the NOC people AND their families #youmightbeadba  sqlrunner Your company set's up international phone coverage for your cruise #youmightbeaDBA  sqlsamson @buckwoody if your manager asks you for data and you respond with "there's a script for that" #youmightbeadba  sqlsamson @buckwoody If you receive more messages from your server then your spouse #youmightbeadba  SQLSoldier You've spent all night Valentines Day upgrading the SQL Servers and forgot to tell your wife you'd be working late. #youmightbeadba  SQLSoldier You're flattered when someone calls you a geek. #youmightbeadba  SQLSoldier @llangit @mrdenny it's 11pm on a holiday weekend, & your reading stupid jokes on Twitter then #youmightbeadba  SQLSoldier Your manager borrows lunch money from you because your salary is 30% higher than his. #youmightbeaDBA  SQLSoldier You think "intellisense" is a double negative because it's not intelligent nor makes sense. #youmightbeaDBA  SQLSoldier 75% of the emails you receive at home have the phrase "now following you on Twitter!" in the subject line. #youmightbeaDBA  SQLSoldier You petition Ken Burns to remake Office Space because it should have been 18 hours long. #youmightbeaDBA  SQLSoldier You select a candidate for a Jr DBA position because his resume said he's willing to get your coffee. #youmightbeaDBA  SQLSoldier Somebody misquotes @PaulRandall and you call him on your cell to verify. #youmightbeaDBA  SQLSoldier You wish the elevator in your building was slower because it's the last time you'll be left alone all day. #youmightbeaDBA  SQLSoldier The developers sacrifice small animals before giving you their code for review. #youmightbeaDBA  SQLSoldier Developers bring you coffee and a BLT when you review their code. #youmightbeaDBA #IWish  SQLSoldier You can get out of any family get-together by saying you have to work and nobody questions it. #youmightbeaDBA  SQLSoldier You've requested a HP Superdome for you "test" box. #youmightbeaDBA  SQLSoldier Your leave work early because your internet connection to the data center is better at home #youmightbeaDBA  SQLSoldier The new CEO asks you to justify your salary, so you go on vacation for 2 weeks. And he never questions you again. #youmightbeaDBA  SQLSoldier You cheer when Milton burns down the company in Office Space #youmightbeaDBA  SQLSoldier A dev. asks if you've heard about some great new feature in SQL and you show the 16 blog posts you wrote on it ... last year #youmightbeaDBA  SQLSoldier Your dev team is still testing SQL 2008 and you're already planning for SQL 11. #youmightbeaDBA #TrueStory  SQLSoldier The new CEO asks you to justify your salary, so you go on vacation for 2 weeks. And he never questions you again. #youmightbeaDBA  SQLSoldier Your dev team is still testing SQL 2008 and you're already planning for SQL 11. #youmightbeaDBA  SQLSoldier You use a cell phone service coverage map to plan your next vacation. #youmightbeaDBA  SQLSoldier You come in to work at 7 AM because it gives you at least 3 hours without any developers around. #youmightbeaDBA  SQLSoldier You figure out a way to make take your wife on a cruise and deduct it as a business expense. #youmightbeaDBA #sqlcruise  SQLSoldier You name your cat SQLDog because the name @SQLCat was already taken. #youmightbeaDBA  SQLSoldier You rate your blog posts based on the number of retweets you get. #youmightbeaDBA  SQLSoldier You disable random logins just to mess with people. #youmightbeaDBA  SQLSoldier You fall for the pickup line, "Hey baby, what's your collation?" #youmightbeaDBA  SQLSoldier You can blame an outage on anyone in the company because you're the only one that knows how to find out what really happened #youmightbeaDBA  SQLSoldier You can blame an outage on anyone in the company because you're the only one that knows how to find out what really happened #youmightbeaDBA  SQLSoldier You cheer when Milton burns down the company in Office Space #youmightbeaDBA  SQLSoldier Your leave work early because your internet connection to the data center is better at home #youmightbeaDBA  SQLSoldier You cheer when Milton burns down the company in Office Space #youmightbeaDBA  SQLSoldier Your think the 4 food groups are coffee, bacon, fast food, and Mountain Dew. #youmightbeaDBA  SQLSoldier You tell someone your job title and they ask "What?" You describe it and they ask "What?". So you say "computer geek". #youmightbeaDBA  SQLSoldier The #1 referrer to your blog is Twitter.com. #youmightbeaDBA  SQLSoldier Your idea of a good time on a Saturday involves free training. #youmightbeaDBA #sqlsat43  SQLSoldier You write a book that all of your co-workers have and none have read it. #youmightbeaDBA  SQLSoldier You write a book that sells a couple thousand copies and is heralded a best seller. #youmightbeaDBA  SQLSoldier No matter how sick you are, you go to work if it's time to pass the pager on to the next guy. #youmightbeaDBA #TrueStory  SQLSoldier You go out on the town, and strangers walk up to you and say, "Hey you're that SQL guy" #youmightbeaDBA #TrueStory  SQLSoldier Your wife asks you to fix something, and you request a downtime window. #youmightbeaDBA  SQLSoldier Your wife asks when you'll be home, and you tell her that you wish you knew. #youmightbeaDBA  SQLSoldier Your best pickup line, "Hey baby, what's your collation?" #youmightbeaDBA  SQLSoldier Your wife asks when you'll be home, and you tell her that you wish you knew. #youmightbeaDBA  SQLSoldier You know that @BuckWoody is not someone's porno name. #youmightbeaDBA  SQLSoldier You list TSQL as your native language on the 2010 census. #youmightbeaDBA  SQLSoldier Starbucks' stock price drops every time you go on vacation. #youmightbeaDBA  SQLSoldier You're happy when the web master says that the website is down. #youmightbeaDBA  SQLSoldier You know that @BuckWoody is not someone's porno name. #youmightbeaDBA  SQLSoldier You get mad when someone calls your car a "heap" because you've always considered it to be a "clustered index". #youmightbeaDBA  SQLSoldier Your blog has more hits than your company's website. #youmightbeaDBA  SQLSoldier You systematically remove the asterisk key from all keyboards in the company except yours. #youmightbeaDBA  SQLSoldier When asked if you recycle, you reply that you run sp_cycle_errorlog every night at midnight #youmightbeaDBA  SQLSoldier You wouldn't allow someone named @AdamMachanic to work on your car. #youmightbeaDBA  SQLSoldier You switch offices every 3 days to avoid developers #youmightbeaDBA  SQLSoldier PSS has your number on speed dial. #youmightbeaDBA  SQLSoldier You frown when you they tell Neo that he's going to the Oracle #youmightbeaDBA  swhaley you regretted saying "This shouldn't effect production" #youmightbeaDBA  swhaley you regretted saying "This shouldn't effect production" #youmightbeaDBA  Tarwn A pleasurable saturday means spending the day learning more about what you already do the rest of the week #youmightbeaDBA ...oh, wait...  thelostforum For great justice; all our base are belong to YOU !! #youmightbeadba  thelostforum @SQLSoldier: You need a witness to use a mirror #youmightbeaDBA ;)  TimCost you capitalize key words. always. everywhere. you can't help it, usually don't even notice. #youmightbeaDBA  Toshana Your the only one in your company not impressed with the developers new application. #youmightbeaDBA  venzann Coming soon from a (respected) book publisher - @buckwoody's #youmightbeaDBA  venzann He's on a role tonight. @buckwoody is summing up my life with his #youmightbeaDBA tweets...  venzann I love the #youmightbeaDBA tag. Found at least 6 new DBAs to follow..  venzann He's on a role tonight. @buckwoody is summing up my life with his #youmightbeaDBA tweets...  venzann You use #sqlhelp as a primary resource during troubleshooting #youmightbeaDBA  venzann You insist on stricter password security for your sql servers than you implement on your own laptop #youmightbeaDBA  WesBrownSQL @buckwoody you are up so late the only tweets you see are from @buckwoody #youmightbeaDBA  WesBrownSQL @SQLSoldier you are upgrading all your 2005 prod servers to 2008 R2 on a three day weekend... #youmightbeaDBA  zippy1981 #youmightbeaDBA if everytime you do something with #mongodb you think of the Vulcan proverb "only Nixon could go to China."  Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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