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• Point inside Oriented Bounding Box?

  - by Milo

  I have an OBB2D class based on SAT. This is my point in OBB method: public boolean pointInside(float x, float y) { float newy = (float) (Math.sin(angle) * (y - center.y) + Math.cos(angle) * (x - center.x)); float newx = (float) (Math.cos(angle) * (x - center.x) - Math.sin(angle) * (y - center.y)); return (newy > center.y - (getHeight() / 2)) && (newy < center.y + (getHeight() / 2)) && (newx > center.x - (getWidth() / 2)) && (newx < center.x + (getWidth() / 2)); } public boolean pointInside(Vector2D v) { return pointInside(v.x,v.y); } Here is the rest of the class; the parts that pertain: public class OBB2D { private Vector2D projVec = new Vector2D(); private static Vector2D projAVec = new Vector2D(); private static Vector2D projBVec = new Vector2D(); private static Vector2D tempNormal = new Vector2D(); private Vector2D deltaVec = new Vector2D(); private ArrayList<Vector2D> collisionPoints = new ArrayList<Vector2D>(); // Corners of the box, where 0 is the lower left. private Vector2D corner[] = new Vector2D[4]; private Vector2D center = new Vector2D(); private Vector2D extents = new Vector2D(); private RectF boundingRect = new RectF(); private float angle; //Two edges of the box extended away from corner[0]. private Vector2D axis[] = new Vector2D[2]; private double origin[] = new double[2]; public OBB2D(float centerx, float centery, float w, float h, float angle) { for(int i = 0; i < corner.length; ++i) { corner[i] = new Vector2D(); } for(int i = 0; i < axis.length; ++i) { axis[i] = new Vector2D(); } set(centerx,centery,w,h,angle); } public OBB2D(float left, float top, float width, float height) { for(int i = 0; i < corner.length; ++i) { corner[i] = new Vector2D(); } for(int i = 0; i < axis.length; ++i) { axis[i] = new Vector2D(); } set(left + (width / 2), top + (height / 2),width,height,0.0f); } public void set(float centerx,float centery,float w, float h,float angle) { float vxx = (float)Math.cos(angle); float vxy = (float)Math.sin(angle); float vyx = (float)-Math.sin(angle); float vyy = (float)Math.cos(angle); vxx *= w / 2; vxy *= (w / 2); vyx *= (h / 2); vyy *= (h / 2); corner[0].x = centerx - vxx - vyx; corner[0].y = centery - vxy - vyy; corner[1].x = centerx + vxx - vyx; corner[1].y = centery + vxy - vyy; corner[2].x = centerx + vxx + vyx; corner[2].y = centery + vxy + vyy; corner[3].x = centerx - vxx + vyx; corner[3].y = centery - vxy + vyy; this.center.x = centerx; this.center.y = centery; this.angle = angle; computeAxes(); extents.x = w / 2; extents.y = h / 2; computeBoundingRect(); } //Updates the axes after the corners move. Assumes the //corners actually form a rectangle. private void computeAxes() { axis[0].x = corner[1].x - corner[0].x; axis[0].y = corner[1].y - corner[0].y; axis[1].x = corner[3].x - corner[0].x; axis[1].y = corner[3].y - corner[0].y; // Make the length of each axis 1/edge length so we know any // dot product must be less than 1 to fall within the edge. for (int a = 0; a < axis.length; ++a) { float l = axis[a].length(); float ll = l * l; axis[a].x = axis[a].x / ll; axis[a].y = axis[a].y / ll; origin[a] = corner[0].dot(axis[a]); } } public void computeBoundingRect() { boundingRect.left = JMath.min(JMath.min(corner[0].x, corner[3].x), JMath.min(corner[1].x, corner[2].x)); boundingRect.top = JMath.min(JMath.min(corner[0].y, corner[1].y),JMath.min(corner[2].y, corner[3].y)); boundingRect.right = JMath.max(JMath.max(corner[1].x, corner[2].x), JMath.max(corner[0].x, corner[3].x)); boundingRect.bottom = JMath.max(JMath.max(corner[2].y, corner[3].y),JMath.max(corner[0].y, corner[1].y)); } public void set(RectF rect) { set(rect.centerX(),rect.centerY(),rect.width(),rect.height(),0.0f); } // Returns true if other overlaps one dimension of this. private boolean overlaps1Way(OBB2D other) { for (int a = 0; a < axis.length; ++a) { double t = other.corner[0].dot(axis[a]); // Find the extent of box 2 on axis a double tMin = t; double tMax = t; for (int c = 1; c < corner.length; ++c) { t = other.corner[c].dot(axis[a]); if (t < tMin) { tMin = t; } else if (t > tMax) { tMax = t; } } // We have to subtract off the origin // See if [tMin, tMax] intersects [0, 1] if ((tMin > 1 + origin[a]) || (tMax < origin[a])) { // There was no intersection along this dimension; // the boxes cannot possibly overlap. return false; } } // There was no dimension along which there is no intersection. // Therefore the boxes overlap. return true; } public void moveTo(float centerx, float centery) { float cx,cy; cx = center.x; cy = center.y; deltaVec.x = centerx - cx; deltaVec.y = centery - cy; for (int c = 0; c < 4; ++c) { corner[c].x += deltaVec.x; corner[c].y += deltaVec.y; } boundingRect.left += deltaVec.x; boundingRect.top += deltaVec.y; boundingRect.right += deltaVec.x; boundingRect.bottom += deltaVec.y; this.center.x = centerx; this.center.y = centery; computeAxes(); } // Returns true if the intersection of the boxes is non-empty. public boolean overlaps(OBB2D other) { if(right() < other.left()) { return false; } if(bottom() < other.top()) { return false; } if(left() > other.right()) { return false; } if(top() > other.bottom()) { return false; } if(other.getAngle() == 0.0f && getAngle() == 0.0f) { return true; } return overlaps1Way(other) && other.overlaps1Way(this); } public Vector2D getCenter() { return center; } public float getWidth() { return extents.x * 2; } public float getHeight() { return extents.y * 2; } public void setAngle(float angle) { set(center.x,center.y,getWidth(),getHeight(),angle); } public float getAngle() { return angle; } public void setSize(float w,float h) { set(center.x,center.y,w,h,angle); } public float left() { return boundingRect.left; } public float right() { return boundingRect.right; } public float bottom() { return boundingRect.bottom; } public float top() { return boundingRect.top; } public RectF getBoundingRect() { return boundingRect; } public boolean overlaps(float left, float top, float right, float bottom) { if(right() < left) { return false; } if(bottom() < top) { return false; } if(left() > right) { return false; } if(top() > bottom) { return false; } return true; } public static float distance(float ax, float ay,float bx, float by) { if (ax < bx) return bx - ay; else return ax - by; } public Vector2D project(float ax, float ay) { projVec.x = Float.MAX_VALUE; projVec.y = Float.MIN_VALUE; for (int i = 0; i < corner.length; ++i) { float dot = Vector2D.dot(corner[i].x,corner[i].y,ax,ay); projVec.x = JMath.min(dot, projVec.x); projVec.y = JMath.max(dot, projVec.y); } return projVec; } public Vector2D getCorner(int c) { return corner[c]; } public int getNumCorners() { return corner.length; } public boolean pointInside(float x, float y) { float newy = (float) (Math.sin(angle) * (y - center.y) + Math.cos(angle) * (x - center.x)); float newx = (float) (Math.cos(angle) * (x - center.x) - Math.sin(angle) * (y - center.y)); return (newy > center.y - (getHeight() / 2)) && (newy < center.y + (getHeight() / 2)) && (newx > center.x - (getWidth() / 2)) && (newx < center.x + (getWidth() / 2)); } public boolean pointInside(Vector2D v) { return pointInside(v.x,v.y); } public ArrayList<Vector2D> getCollsionPoints(OBB2D b) { collisionPoints.clear(); for(int i = 0; i < corner.length; ++i) { if(b.pointInside(corner[i])) { collisionPoints.add(corner[i]); } } for(int i = 0; i < b.corner.length; ++i) { if(pointInside(b.corner[i])) { collisionPoints.add(b.corner[i]); } } return collisionPoints; } }; What could be wrong? When I getCollisionPoints for 2 OBBs I know are penetrating, it returns no points. Thanks

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• Point of contact of 2 OBBs?

  - by Milo

  I'm working on the physics for my GTA2-like game so I can learn more about game physics. The collision detection and resolution are working great. I'm now just unsure how to compute the point of contact when I hit a wall. Here is my OBB class: public class OBB2D { private Vector2D projVec = new Vector2D(); private static Vector2D projAVec = new Vector2D(); private static Vector2D projBVec = new Vector2D(); private static Vector2D tempNormal = new Vector2D(); private Vector2D deltaVec = new Vector2D(); // Corners of the box, where 0 is the lower left. private Vector2D corner[] = new Vector2D[4]; private Vector2D center = new Vector2D(); private Vector2D extents = new Vector2D(); private RectF boundingRect = new RectF(); private float angle; //Two edges of the box extended away from corner[0]. private Vector2D axis[] = new Vector2D[2]; private double origin[] = new double[2]; public OBB2D(float centerx, float centery, float w, float h, float angle) { for(int i = 0; i < corner.length; ++i) { corner[i] = new Vector2D(); } for(int i = 0; i < axis.length; ++i) { axis[i] = new Vector2D(); } set(centerx,centery,w,h,angle); } public OBB2D(float left, float top, float width, float height) { for(int i = 0; i < corner.length; ++i) { corner[i] = new Vector2D(); } for(int i = 0; i < axis.length; ++i) { axis[i] = new Vector2D(); } set(left + (width / 2), top + (height / 2),width,height,0.0f); } public void set(float centerx,float centery,float w, float h,float angle) { float vxx = (float)Math.cos(angle); float vxy = (float)Math.sin(angle); float vyx = (float)-Math.sin(angle); float vyy = (float)Math.cos(angle); vxx *= w / 2; vxy *= (w / 2); vyx *= (h / 2); vyy *= (h / 2); corner[0].x = centerx - vxx - vyx; corner[0].y = centery - vxy - vyy; corner[1].x = centerx + vxx - vyx; corner[1].y = centery + vxy - vyy; corner[2].x = centerx + vxx + vyx; corner[2].y = centery + vxy + vyy; corner[3].x = centerx - vxx + vyx; corner[3].y = centery - vxy + vyy; this.center.x = centerx; this.center.y = centery; this.angle = angle; computeAxes(); extents.x = w / 2; extents.y = h / 2; computeBoundingRect(); } //Updates the axes after the corners move. Assumes the //corners actually form a rectangle. private void computeAxes() { axis[0].x = corner[1].x - corner[0].x; axis[0].y = corner[1].y - corner[0].y; axis[1].x = corner[3].x - corner[0].x; axis[1].y = corner[3].y - corner[0].y; // Make the length of each axis 1/edge length so we know any // dot product must be less than 1 to fall within the edge. for (int a = 0; a < axis.length; ++a) { float l = axis[a].length(); float ll = l * l; axis[a].x = axis[a].x / ll; axis[a].y = axis[a].y / ll; origin[a] = corner[0].dot(axis[a]); } } public void computeBoundingRect() { boundingRect.left = JMath.min(JMath.min(corner[0].x, corner[3].x), JMath.min(corner[1].x, corner[2].x)); boundingRect.top = JMath.min(JMath.min(corner[0].y, corner[1].y),JMath.min(corner[2].y, corner[3].y)); boundingRect.right = JMath.max(JMath.max(corner[1].x, corner[2].x), JMath.max(corner[0].x, corner[3].x)); boundingRect.bottom = JMath.max(JMath.max(corner[2].y, corner[3].y),JMath.max(corner[0].y, corner[1].y)); } public void set(RectF rect) { set(rect.centerX(),rect.centerY(),rect.width(),rect.height(),0.0f); } // Returns true if other overlaps one dimension of this. private boolean overlaps1Way(OBB2D other) { for (int a = 0; a < axis.length; ++a) { double t = other.corner[0].dot(axis[a]); // Find the extent of box 2 on axis a double tMin = t; double tMax = t; for (int c = 1; c < corner.length; ++c) { t = other.corner[c].dot(axis[a]); if (t < tMin) { tMin = t; } else if (t > tMax) { tMax = t; } } // We have to subtract off the origin // See if [tMin, tMax] intersects [0, 1] if ((tMin > 1 + origin[a]) || (tMax < origin[a])) { // There was no intersection along this dimension; // the boxes cannot possibly overlap. return false; } } // There was no dimension along which there is no intersection. // Therefore the boxes overlap. return true; } public void moveTo(float centerx, float centery) { float cx,cy; cx = center.x; cy = center.y; deltaVec.x = centerx - cx; deltaVec.y = centery - cy; for (int c = 0; c < 4; ++c) { corner[c].x += deltaVec.x; corner[c].y += deltaVec.y; } boundingRect.left += deltaVec.x; boundingRect.top += deltaVec.y; boundingRect.right += deltaVec.x; boundingRect.bottom += deltaVec.y; this.center.x = centerx; this.center.y = centery; computeAxes(); } // Returns true if the intersection of the boxes is non-empty. public boolean overlaps(OBB2D other) { if(right() < other.left()) { return false; } if(bottom() < other.top()) { return false; } if(left() > other.right()) { return false; } if(top() > other.bottom()) { return false; } if(other.getAngle() == 0.0f && getAngle() == 0.0f) { return true; } return overlaps1Way(other) && other.overlaps1Way(this); } public Vector2D getCenter() { return center; } public float getWidth() { return extents.x * 2; } public float getHeight() { return extents.y * 2; } public void setAngle(float angle) { set(center.x,center.y,getWidth(),getHeight(),angle); } public float getAngle() { return angle; } public void setSize(float w,float h) { set(center.x,center.y,w,h,angle); } public float left() { return boundingRect.left; } public float right() { return boundingRect.right; } public float bottom() { return boundingRect.bottom; } public float top() { return boundingRect.top; } public RectF getBoundingRect() { return boundingRect; } public boolean overlaps(float left, float top, float right, float bottom) { if(right() < left) { return false; } if(bottom() < top) { return false; } if(left() > right) { return false; } if(top() > bottom) { return false; } return true; } public static float distance(float ax, float ay,float bx, float by) { if (ax < bx) return bx - ay; else return ax - by; } public Vector2D project(float ax, float ay) { projVec.x = Float.MAX_VALUE; projVec.y = Float.MIN_VALUE; for (int i = 0; i < corner.length; ++i) { float dot = Vector2D.dot(corner[i].x,corner[i].y,ax,ay); projVec.x = JMath.min(dot, projVec.x); projVec.y = JMath.max(dot, projVec.y); } return projVec; } public Vector2D getCorner(int c) { return corner[c]; } public int getNumCorners() { return corner.length; } public static float collisionResponse(OBB2D a, OBB2D b, Vector2D outNormal) { float depth = Float.MAX_VALUE; for (int i = 0; i < a.getNumCorners() + b.getNumCorners(); ++i) { Vector2D edgeA; Vector2D edgeB; if(i >= a.getNumCorners()) { edgeA = b.getCorner((i + b.getNumCorners() - 1) % b.getNumCorners()); edgeB = b.getCorner(i % b.getNumCorners()); } else { edgeA = a.getCorner((i + a.getNumCorners() - 1) % a.getNumCorners()); edgeB = a.getCorner(i % a.getNumCorners()); } tempNormal.x = edgeB.x -edgeA.x; tempNormal.y = edgeB.y - edgeA.y; tempNormal.normalize(); projAVec.equals(a.project(tempNormal.x,tempNormal.y)); projBVec.equals(b.project(tempNormal.x,tempNormal.y)); float distance = OBB2D.distance(projAVec.x, projAVec.y,projBVec.x,projBVec.y); if (distance > 0.0f) { return 0.0f; } else { float d = Math.abs(distance); if (d < depth) { depth = d; outNormal.equals(tempNormal); } } } float dx,dy; dx = b.getCenter().x - a.getCenter().x; dy = b.getCenter().y - a.getCenter().y; float dot = Vector2D.dot(dx,dy,outNormal.x,outNormal.y); if(dot > 0) { outNormal.x = -outNormal.x; outNormal.y = -outNormal.y; } return depth; } public Vector2D getMoveDeltaVec() { return deltaVec; } }; Thanks!

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• JMS Step 3 - Using the QueueReceive.java Sample Program to Read a Message from a JMS Queue

  - by John-Brown.Evans

  JMS Step 3 - Using the QueueReceive.java Sample Program to Read a Message from a JMS Queue ol{margin:0;padding:0} .c18_3{vertical-align:top;width:487.3pt;border-style:solid;background-color:#f3f3f3;border-color:#000000;border-width:1pt;padding:0pt 5pt 0pt 5pt} .c20_3{vertical-align:top;width:487.3pt;border-style:solid;border-color:#ffffff;border-width:1pt;padding:5pt 5pt 5pt 5pt} .c19_3{background-color:#ffffff} .c17_3{list-style-type:circle;margin:0;padding:0} .c12_3{list-style-type:disc;margin:0;padding:0} .c6_3{font-style:italic;font-weight:bold} .c10_3{color:inherit;text-decoration:inherit} .c1_3{font-size:10pt;font-family:"Courier New"} .c2_3{line-height:1.0;direction:ltr} .c9_3{padding-left:0pt;margin-left:72pt} .c15_3{padding-left:0pt;margin-left:36pt} .c3_3{color:#1155cc;text-decoration:underline} .c5_3{height:11pt} .c14_3{border-collapse:collapse} .c7_3{font-family:"Courier New"} .c0_3{background-color:#ffff00} .c16_3{font-size:18pt} .c8_3{font-weight:bold} .c11_3{font-size:24pt} .c13_3{font-style:italic} .c4_3{direction:ltr} .title{padding-top:24pt;line-height:1.15;text-align:left;color:#000000;font-size:36pt;font-family:"Arial";font-weight:bold;padding-bottom:6pt}.subtitle{padding-top:18pt;line-height:1.15;text-align:left;color:#666666;font-style:italic;font-size:24pt;font-family:"Georgia";padding-bottom:4pt} li{color:#000000;font-size:10pt;font-family:"Arial"} p{color:#000000;font-size:10pt;margin:0;font-family:"Arial"} h1{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:24pt;font-family:"Arial";font-weight:normal} h2{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:18pt;font-family:"Arial";font-weight:normal} h3{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:14pt;font-family:"Arial";font-weight:normal} h4{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:12pt;font-family:"Arial";font-weight:normal} h5{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:11pt;font-family:"Arial";font-weight:normal} h6{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:10pt;font-family:"Arial";font-weight:normal} This post continues the series of JMS articles which demonstrate how to use JMS queues in a SOA context. In the first post, JMS Step 1 - How to Create a Simple JMS Queue in Weblogic Server 11g we looked at how to create a JMS queue and its dependent objects in WebLogic Server. In the previous post, JMS Step 2 - Using the QueueSend.java Sample Program to Send a Message to a JMS Queue I showed how to write a message to that JMS queue using the QueueSend.java sample program. In this article, we will use a similar sample, the QueueReceive.java program to read the message from that queue. Please review the previous posts if you have not already done so, as they contain prerequisites for executing the sample in this article. 1. Source code The following java code will be used to read the message(s) from the JMS queue. As with the previous example, it is based on a sample program shipped with the WebLogic Server installation. The sample is not installed by default, but needs to be installed manually using the WebLogic Server Custom Installation option, together with many, other useful samples. You can either copy-paste the following code into your editor, or install all the samples. The knowledge base article in My Oracle Support: How To Install WebLogic Server and JMS Samples in WLS 10.3.x (Doc ID 1499719.1) describes how to install the samples. QueueReceive.java package examples.jms.queue; import java.util.Hashtable; import javax.jms.*; import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.NamingException; /** * This example shows how to establish a connection to * and receive messages from a JMS queue. The classes in this * package operate on the same JMS queue. Run the classes together to * witness messages being sent and received, and to browse the queue * for messages. This class is used to receive and remove messages * from the queue. * * @author Copyright (c) 1999-2005 by BEA Systems, Inc. All Rights Reserved. */ public class QueueReceive implements MessageListener { // Defines the JNDI context factory. public final static String JNDI_FACTORY="weblogic.jndi.WLInitialContextFactory"; // Defines the JMS connection factory for the queue. public final static String JMS_FACTORY="jms/TestConnectionFactory"; // Defines the queue. public final static String QUEUE="jms/TestJMSQueue"; private QueueConnectionFactory qconFactory; private QueueConnection qcon; private QueueSession qsession; private QueueReceiver qreceiver; private Queue queue; private boolean quit = false; /** * Message listener interface. * @param msg message */ public void onMessage(Message msg) { try { String msgText; if (msg instanceof TextMessage) { msgText = ((TextMessage)msg).getText(); } else { msgText = msg.toString(); } System.out.println("Message Received: "+ msgText ); if (msgText.equalsIgnoreCase("quit")) { synchronized(this) { quit = true; this.notifyAll(); // Notify main thread to quit } } } catch (JMSException jmse) { System.err.println("An exception occurred: "+jmse.getMessage()); } } /** * Creates all the necessary objects for receiving * messages from a JMS queue. * * @param ctx JNDI initial context * @param queueName name of queue * @exception NamingException if operation cannot be performed * @exception JMSException if JMS fails to initialize due to internal error */ public void init(Context ctx, String queueName) throws NamingException, JMSException { qconFactory = (QueueConnectionFactory) ctx.lookup(JMS_FACTORY); qcon = qconFactory.createQueueConnection(); qsession = qcon.createQueueSession(false, Session.AUTO_ACKNOWLEDGE); queue = (Queue) ctx.lookup(queueName); qreceiver = qsession.createReceiver(queue); qreceiver.setMessageListener(this); qcon.start(); } /** * Closes JMS objects. * @exception JMSException if JMS fails to close objects due to internal error */ public void close()throws JMSException { qreceiver.close(); qsession.close(); qcon.close(); } /** * main() method. * * @param args WebLogic Server URL * @exception Exception if execution fails */ public static void main(String[] args) throws Exception { if (args.length != 1) { System.out.println("Usage: java examples.jms.queue.QueueReceive WebLogicURL"); return; } InitialContext ic = getInitialContext(args[0]); QueueReceive qr = new QueueReceive(); qr.init(ic, QUEUE); System.out.println( "JMS Ready To Receive Messages (To quit, send a \"quit\" message)."); // Wait until a "quit" message has been received. synchronized(qr) { while (! qr.quit) { try { qr.wait(); } catch (InterruptedException ie) {} } } qr.close(); } private static InitialContext getInitialContext(String url) throws NamingException { Hashtable env = new Hashtable(); env.put(Context.INITIAL_CONTEXT_FACTORY, JNDI_FACTORY); env.put(Context.PROVIDER_URL, url); return new InitialContext(env); } } 2. How to Use This Class 2.1 From the file system on Linux This section describes how to use the class from the file system of a WebLogic Server installation. Log in to a machine with a WebLogic Server installation and create a directory to contain the source and code matching the package name, e.g. span$HOME/examples/jms/queue. Copy the above QueueReceive.java file to this directory. Set the CLASSPATH and environment to match the WebLogic server environment. Go to $MIDDLEWARE_HOME/user_projects/domains/base_domain/bin  and execute . ./setDomainEnv.sh Collect the following information required to run the script: The JNDI name of the JMS queue to use In the WebLogic server console > Services > Messaging > JMS Modules > Module name, (e.g. TestJMSModule) > JMS queue name, (e.g. TestJMSQueue) select the queue and note its JNDI name, e.g. jms/TestJMSQueue The JNDI name of the connection factory to use to connect to the queue Follow the same path as above to get the connection factory for the above queue, e.g. TestConnectionFactory and its JNDI name e.g. jms/TestConnectionFactory The URL and port of the WebLogic server running the above queue Check the JMS server for the above queue and the managed server it is targeted to, for example soa_server1. Now find the port this managed server is listening on, by looking at its entry under Environment > Servers in the WLS console, e.g. 8001 The URL for the server to be passed to the QueueReceive program will therefore be t3://host.domain:8001 e.g. t3://jbevans-lx.de.oracle.com:8001 Edit Queue Receive .java and enter the above queue name and connection factory respectively under ... public final static String JMS_FACTORY="jms/TestConnectionFactory"; ... public final static String QUEUE="jms/TestJMSQueue"; ... Compile Queue Receive .java using javac Queue Receive .java Go to the source’s top-level directory and execute it using java examples.jms.queue.Queue Receive   t3://jbevans-lx.de.oracle.com:8001 This will print a message that it is ready to receive messages or to send a “quit” message to end. The program will read all messages in the queue and print them to the standard output until it receives a message with the payload “quit”. 2.2 From JDeveloper The steps from JDeveloper are the same as those used for the previous program QueueSend.java, which is used to send a message to the queue. So we won't repeat them here. Please see the previous blog post at JMS Step 2 - Using the QueueSend.java Sample Program to Send a Message to a JMS Queue and apply the same steps in that example to the QueueReceive.java program. This concludes the example. In the following post we will create a BPEL process which writes a message based on an XML schema to the queue.

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• Adding Vertices to a dynamic mesh via Method Call

  - by Raven Dreamer

  I have a C# Struct with a static method, "Get Shape" which populates a List with the vertices of a polyhedron. Method Signature: public static void GetShape(Block b, int x, int y, int z, List<Vector3> vertices, List<int> triangles, List<Vector2> uvs, List<Vector2> uv2s) Adding directly to the vertices list (via vertices.Add(vector3) ), the code works as expected, and the new polyhedron appears when I trigger the method. However, I want to do some processing on the vertices I'm adding (a rotation), and the most sensible way I can think to do that is by creating a separate list of Vector3s, and then combining the lists when I'm done. However, vertices.AddRange(newVerts) does not add the shape to the mesh, nor does a foreach loop with verts.Add(vertices[i]). And this is before I've added in any of the processing! I have a feeling this might stem from passing the list of vertices in as a parameter, rather than returning a list and then adding to the vertices in the calling object, but since I'm filling 4 lists, I was trying to avoid having to create a data struct to return all four at once. Any ideas? The working version of the method is reprinted below, in full: public static void GetShape(Block b, int x, int y, int z, List<Vector3> vertices, List<int> triangles, List<Vector2> uvs, List<Vector2> uv2s) { //List<Vector3> vertices = new List<Vector3>(); int l_blockShape = b.blockShape; int l_blockType = b.blockType; //CheckFace checks if the block is empty //if this block is empty, don't draw anything. int vertexIndex; //only y faces need to be hidden. //if((l_blockShape & BlockShape.NegZFace) == BlockShape.NegZFace) { vertexIndex = vertices.Count; //top left, top right, bottom right, bottom left vertices.Add(new Vector3(x+.2f, y + 1, z+.2f)); vertices.Add(new Vector3(x+.8f, y + 1, z+.2f)); vertices.Add(new Vector3(x+.8f, y , z+.2f)); vertices.Add(new Vector3(x+.2f, y , z+.2f)); // first triangle for the face triangles.Add(vertexIndex); triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+3); // second triangle for the face triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+2); triangles.Add(vertexIndex+3); //UVs for the face uvs.Add( new Vector2(0,1)); uvs.Add( new Vector2(1,1)); uvs.Add( new Vector2(1,0)); uvs.Add( new Vector2(0,0)); //UV2s (lightmapping?) uv2s.Add( new Vector2(0,1)); uv2s.Add( new Vector2(1,1)); uv2s.Add( new Vector2(1,0)); uv2s.Add( new Vector2(0,0)); } //XY Z+1 face //if((l_blockShape & BlockShape.PosZFace) == BlockShape.PosZFace) { vertexIndex = vertices.Count; //top left, top right, bottom right, bottom left vertices.Add(new Vector3(x+.8f, y + 1, z+.8f)); vertices.Add(new Vector3(x+.2f, y + 1, z+.8f)); vertices.Add(new Vector3(x+.2f, y , z+.8f)); vertices.Add(new Vector3(x+.8f, y , z+.8f)); // first triangle for the face triangles.Add(vertexIndex); triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+3); // second triangle for the face triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+2); triangles.Add(vertexIndex+3); //UVs for the face uvs.Add( new Vector2(0,1)); uvs.Add( new Vector2(1,1)); uvs.Add( new Vector2(1,0)); uvs.Add( new Vector2(0,0)); //UV2s (lightmapping?) uv2s.Add( new Vector2(0,1)); uv2s.Add( new Vector2(1,1)); uv2s.Add( new Vector2(1,0)); uv2s.Add( new Vector2(0,0)); } //ZY face //if((l_blockShape & BlockShape.NegXFace) == BlockShape.NegXFace) { vertexIndex = vertices.Count; //top left, top right, bottom right, bottom left vertices.Add(new Vector3(x+.2f, y + 1, z+.8f)); vertices.Add(new Vector3(x+.2f, y + 1, z+.2f)); vertices.Add(new Vector3(x+.2f, y , z+.2f)); vertices.Add(new Vector3(x+.2f, y , z+.8f)); // first triangle for the face triangles.Add(vertexIndex); triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+3); // second triangle for the face triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+2); triangles.Add(vertexIndex+3); //UVs for the face uvs.Add( new Vector2(0,1)); uvs.Add( new Vector2(1,1)); uvs.Add( new Vector2(1,0)); uvs.Add( new Vector2(0,0)); //UV2s (lightmapping?) uv2s.Add( new Vector2(0,1)); uv2s.Add( new Vector2(1,1)); uv2s.Add( new Vector2(1,0)); uv2s.Add( new Vector2(0,0)); } //ZY X+1 face // if((l_blockShape & BlockShape.PosXFace) == BlockShape.PosXFace) { vertexIndex = vertices.Count; //top left, top right, bottom right, bottom left vertices.Add(new Vector3(x+.8f, y + 1, z+.2f)); vertices.Add(new Vector3(x+.8f, y + 1, z+.8f)); vertices.Add(new Vector3(x+.8f, y , z+.8f)); vertices.Add(new Vector3(x+.8f, y , z+.2f)); // first triangle for the face triangles.Add(vertexIndex); triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+3); // second triangle for the face triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+2); triangles.Add(vertexIndex+3); //UVs for the face uvs.Add( new Vector2(0,1)); uvs.Add( new Vector2(1,1)); uvs.Add( new Vector2(1,0)); uvs.Add( new Vector2(0,0)); //UV2s (lightmapping?) uv2s.Add( new Vector2(0,1)); uv2s.Add( new Vector2(1,1)); uv2s.Add( new Vector2(1,0)); uv2s.Add( new Vector2(0,0)); } //ZX face if((l_blockShape & BlockShape.NegYFace) == BlockShape.NegYFace) { vertexIndex = vertices.Count; //top left, top right, bottom right, bottom left vertices.Add(new Vector3(x+.8f, y , z+.8f)); vertices.Add(new Vector3(x+.8f, y , z+.2f)); vertices.Add(new Vector3(x+.2f, y , z+.2f)); vertices.Add(new Vector3(x+.2f, y , z+.8f)); // first triangle for the face triangles.Add(vertexIndex+3); triangles.Add(vertexIndex+1); triangles.Add(vertexIndex); // second triangle for the face triangles.Add(vertexIndex+3); triangles.Add(vertexIndex+2); triangles.Add(vertexIndex+1); //UVs for the face uvs.Add( new Vector2(0,1)); uvs.Add( new Vector2(1,1)); uvs.Add( new Vector2(1,0)); uvs.Add( new Vector2(0,0)); //UV2s (lightmapping?) uv2s.Add( new Vector2(0,1)); uv2s.Add( new Vector2(1,1)); uv2s.Add( new Vector2(1,0)); uv2s.Add( new Vector2(0,0)); } //ZX + 1 face if((l_blockShape & BlockShape.PosYFace) == BlockShape.PosYFace) { vertexIndex = vertices.Count; //top left, top right, bottom right, bottom left vertices.Add(new Vector3(x+.8f, y+1 , z+.2f)); vertices.Add(new Vector3(x+.8f, y+1 , z+.8f)); vertices.Add(new Vector3(x+.2f, y+1 , z+.8f)); vertices.Add(new Vector3(x+.2f, y+1 , z+.2f)); // first triangle for the face triangles.Add(vertexIndex+3); triangles.Add(vertexIndex+1); triangles.Add(vertexIndex); // second triangle for the face triangles.Add(vertexIndex+3); triangles.Add(vertexIndex+2); triangles.Add(vertexIndex+1); //UVs for the face uvs.Add( new Vector2(0,1)); uvs.Add( new Vector2(1,1)); uvs.Add( new Vector2(1,0)); uvs.Add( new Vector2(0,0)); //UV2s (lightmapping?) uv2s.Add( new Vector2(0,1)); uv2s.Add( new Vector2(1,1)); uv2s.Add( new Vector2(1,0)); uv2s.Add( new Vector2(0,0)); } }

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• Pygame: Save a list of objects/classes/surfaces

  - by Sam Tubb

  I am working on a game, in which you can create mazes. You place blocks on a 16x16 grid, while choosing from a variety of block to make the level with. Whenever you create a block, it adds this class: class Block(object): def __init__(self,x,y,spr): self.x=x self.y=y self.sprite=spr self.rect=self.sprite.get_rect(x=self.x,y=self.y) to a list called instances. I tried shelving it to a .bin file, but it returns some error dealing with surfaces. How can I go about saving and loading levels? Any help is appreciated! :) Here is the whole code for reference: import pygame from pygame.locals import * #initstuff pygame.init() screen=pygame.display.set_mode((640,480)) pygame.display.set_caption('PiMaze') instances=[] #loadsprites menuspr=pygame.image.load('images/menu.png').convert() b1spr=pygame.image.load('images/b1.png').convert() b2spr=pygame.image.load('images/b2.png').convert() currentbspr=b1spr curspr=pygame.image.load('images/curs.png').convert() curspr.set_colorkey((0,255,0)) #menu menuspr.set_alpha(185) menurect=menuspr.get_rect(x=-260,y=4) class MenuItem(object): def __init__(self,pos,spr): self.x=pos[0] self.y=pos[1] self.sprite=spr self.pos=(self.x,self.y) self.rect=self.sprite.get_rect(x=self.x,y=self.y) class Block(object): def __init__(self,x,y,spr): self.x=x self.y=y self.sprite=spr self.rect=self.sprite.get_rect(x=self.x,y=self.y) while True: #menu items b1menu=b1spr.get_rect(x=menurect.left+32,y=48) b2menu=b2spr.get_rect(x=menurect.left+64,y=48) menuitems=[MenuItem(b1menu,b1spr),MenuItem(b2menu,b2spr)] screen.fill((20,30,85)) mse=pygame.mouse.get_pos() key=pygame.key.get_pressed() placepos=((mse[0]/16)*16,(mse[1]/16)*16) if key[K_q]: if mse[0]<260: if menurect.right<255: menurect.right+=1 else: if menurect.left>-260: menurect.left-=1 else: if menurect.left>-260: menurect.left-=1 for e in pygame.event.get(): if e.type==QUIT: exit() if menurect.right<100: if e.type==MOUSEBUTTONUP: if e.button==1: to_remove = [i for i in instances if i.rect.collidepoint(placepos)] for i in to_remove: instances.remove(i) if not to_remove: instances.append(Block(placepos[0],placepos[1],currentbspr)) for i in instances: screen.blit(i.sprite,i.rect) if not key[K_q]: screen.blit(curspr,placepos) screen.blit(menuspr,menurect) for item in menuitems: screen.blit(item.sprite,item.pos) if item.rect.collidepoint(mse): if pygame.mouse.get_pressed()==(1,0,0): currentbspr=item.sprite pygame.draw.rect(screen, ((255,0,0)), item, 1) pygame.display.flip()

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• Character Jump Control

  - by Abdullah Sorathia

  I would like to know how can I control the jump movement of a character in Unity3D. Basically I am trying to program the jump in such a way that while a jump is in progress the character is allowed to move either left or right in mid-air when the corresponding keys are pressed. With my script the character will correctly move to the left when, for example, the left key is pressed, but when the right key is pressed afterwards, the character moves to the right before the movement to the left is completed. Following is the script: void Update () { if(touchingPlatform && Input.GetButtonDown("Jump")){ rigidbody.AddForce(jumpVelocity, ForceMode.VelocityChange); touchingPlatform = false; isJump=true; } //left & right movement Vector3 moveDir = Vector3.zero; if(Input.GetKey ("right")||Input.GetKey ("left")){ moveDir.x = Input.GetAxis("Horizontal"); // get result of AD keys in X if(ShipCurrentSpeed==0) { transform.position += moveDir * 3f * Time.deltaTime; }else if(ShipCurrentSpeed<=15) { transform.position += moveDir * ShipCurrentSpeed * 2f * Time.deltaTime; }else { transform.position += moveDir * 30f * Time.deltaTime; } }

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• Control convention for circular movement?

  - by Christian

  I'm currently doing a kind of training project in Unity (still a beginner). It's supposed to be somewhat like Breakout, but instead of just going left and right I want the paddle to circle around the center point. This is all fine and dandy, but the problem I have is: how do you control this with a keyboard or gamepad? For touch and mouse control I could work around the problem by letting the paddle follow the cursor/finger, but with the other control methods I'm a bit stumped. With a keyboard for example, I could either make it so that the Left arrow always moves the paddle clockwise (it starts at the bottom of the circle), or I could link it to the actual direction - meaning that if the paddle is at the bottom, it goes left and up along the circle or, if it's in the upper hemisphere, it moves left and down, both times toward the outer left point of the circle. Both feel kind of weird. With the first one, it can be counter intuitive to press Left to move the paddle right when it's in the upper area, while in the second method you'd need to constantly switch buttons to keep moving. So, long story short: is there any kind of existing standard, convention or accepted example for this type of movement and the corresponding controls? I didn't really know what to google for (control conventions for circular movement was one of the searches I tried, but it didn't give me much), and I also didn't really find anything about this on here. If there is a Question that I simply didn't see, please excuse the duplicate.

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• 15 Puzzle Shuffle Method Issues

  - by Codemiester

  I am making a 15 puzzle game in C# that allows the user to enter a custom row and column value up to a maximum of a 10 x 10 puzzle. Because of this I am having problems with the shuffle method. I want to make it so the puzzle is always solvable. By first creating a winning puzzle then shuffling the empty space. The problem is it is too inefficient to call every click event each time. I need a way to invoke the click event of a button adjacent to the empty space but not diagonal. I also use an invisible static button for the empty spot. The PuzzlePiece class inherits from Button. I am not too sure how to do this. I would appreciate any help. Thanks here is what I have: private void shuffleBoard() { //5 is just for test purposes for (int i = 0; i < 5; i++) { foreach (Control item in this.Controls) { if (item is PuzzlePiece) { ((PuzzlePiece)item).PerformClick(); } } } } void PuzzlePiece_Click(object sender, EventArgs e) { PuzzlePiece piece = (PuzzlePiece)sender; if (piece.Right == puzzleForm.emptyPiece.Left && piece.Top == puzzleForm.emptyPiece.Top) { movePiece(piece); } else if (piece.Left == puzzleForm.emptyPiece.Right && piece.Top == puzzleForm.emptyPiece.Top) { movePiece(piece); } else if (piece.Top == puzzleForm.emptyPiece.Bottom && piece.Left == puzzleForm.emptyPiece.Left) { movePiece(piece); } else if (piece.Bottom == puzzleForm.emptyPiece.Top && piece.Left == puzzleForm.emptyPiece.Left) { movePiece(piece); } }

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• How can I guarantee a solvable Fifteen Puzzle shuffle?

  - by Codemiester

  I am making a 15 Puzzle game in C# that allows the user to enter a custom row and column value up to a maximum of a 10 x 10 puzzle. I am having problems with the shuffle method. I want to make it so the puzzle is always solvable by first creating a winning puzzle then shuffling the empty space. The problem is it is too inefficient to call every click event each time. I need a way to invoke the click event of a button adjacent to the empty space but not diagonal. I also use an invisible static button for the empty spot. The PuzzlePiece class inherits from Button. I am not too sure how to do this. Here is what I have: private void shuffleBoard() { //5 is just for test purposes for (int i = 0; i < 5; i++) { foreach (Control item in this.Controls) { if (item is PuzzlePiece) { ((PuzzlePiece)item).PerformClick(); } } } } void PuzzlePiece_Click(object sender, EventArgs e) { PuzzlePiece piece = (PuzzlePiece)sender; if (piece.Right == puzzleForm.emptyPiece.Left && piece.Top == puzzleForm.emptyPiece.Top) { movePiece(piece); } else if (piece.Left == puzzleForm.emptyPiece.Right && piece.Top == puzzleForm.emptyPiece.Top) { movePiece(piece); } else if (piece.Top == puzzleForm.emptyPiece.Bottom && piece.Left == puzzleForm.emptyPiece.Left) { movePiece(piece); } else if (piece.Bottom == puzzleForm.emptyPiece.Top && piece.Left == puzzleForm.emptyPiece.Left) { movePiece(piece); } }

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• How to eliminate NULL fields in TSQL

  - by salvationishere

  I am developing a TSQL query in SSMS 2008 R2. I am trying to develop this query to identify one record / client. Because some of these values are NULL, I am currently doing LEFT JOINS on most of the tables. But the problem with the LEFT JOINs is that now I get 1 record for some clients. But if I change this to INNER JOINs then some clients are excluded entirely because they have NULL values for these columns. How do I limit the query result to just one record / client regardless of NULL values? And if there are non-NULL values then I want it to choose the record with non-NULL values. Here is some of my current output: group_profile_id profile_name license_number is_accepting is_accepting_placement managing_office region vendor_name vendor_id applicant_type Office Address status_description Cert Date2 race ethnicity_desc religion 9CD932F1-6BE1-4F80-AB81-0CE32C565BCF Atreides Foster Home 1 Atreides1 1 Yes Manchester, NH Gulf Atlantic Atreides1 00000007 Treatment Foster Home 4042 Arrakis Avenue, Springfield, VT 05156 Open/Re-opened 2011-06-01 00:00:00.000 NULL NULL NULL DCE354D5-A7CC-409F-B5A3-89BF664B7718 Averitte, Leon and Sandra 00000044 1 Yes Birmingham, AL Gulf Atlantic AL Averitte, Leon and Sandra 00000044 Treatment Foster Home 3816 5th Avenue, Bessemer, AL 35020, (205)482-4307 Open/Re-opened 2011-08-05 00:00:00.000 NULL NULL NULL DCE354D5-A7CC-409F-B5A3-89BF664B7718 Averitte, Leon and Sandra 00000044 1 Yes Birmingham, AL Gulf Atlantic AL Averitte, Leon and Sandra 00000044 Treatment Foster Home 3816 5th Avenue, Bessemer, AL 35020, (205)482-4307 Open/Re-opened 2011-08-05 00:00:00.000 Caucasian/White Non Hispanic NULL AD02A43C-6F38-4F35-8C9E-E12422690BFB Bass, Matthew and Sarah 00000076 1 Yes Jacks on, MS Central Gulf Coast MS Bass, Matthew and Sarah 00000076 Treatment Foster Home 506 Eagelwood Drive, Florence, MS 39073, (601)665-7169 Open/Re-opened 2011-04-01 00:00:00.000 NULL NULL NULL AD02A43C-6F38-4F35-8C9E-E12422690BFB Bass, Matthew and Sarah 00000076 1 Yes Jackson, MS Central Gulf Coast MS Bass, Matthew and Sarah 00000076 Treatment Foster Home 506 Eagelwood Drive, Florence, MS 39073, (601)665-7169 Open/Re-opened 2011-04-01 00:00:00.000 Caucasian/White NULL Baptist You can see that both Averitte and Bass profile names have one record with NULL race, ethnicity, religion. How do I eliminate these rows (rows 2 and 4)? Here is my query currently: select distinct gp.group_profile_id, gp.profile_name, gp.license_number, gp.is_accepting, case when gp.is_accepting = 1 then 'Yes' when gp.is_accepting = 0 then 'No ' end as is_accepting_placement, mo.profile_name as managing_office, regions.[region_description] as region, pv.vendor_name, pv.id as vendor_id, at.description as applicant_type, dbo.GetGroupAddress(gp.group_profile_id, null, 0) as [Office Address], gsv.status_description, ri.[description] as race, ethnicity.description as ethnicity_desc, religion.description as religion from group_profile gp With (NoLock) --Office Information inner join group_profile_type gpt With (NoLock) on gp.group_profile_type_id = gpt.group_profile_type_id and gpt.type_code = 'FOSTERHOME' and gp.agency_id = @agency_id and gp.is_deleted = 0 inner join group_profile mo With (NoLock) on gp.managing_office_id = mo.group_profile_id left outer join payor_vendor pv With (NoLock) on gp.payor_vendor_id = pv.payor_vendor_id left outer join applicant_type at With (NoLock) on gp.applicant_type_id = at.applicant_type_id and at.is_foster_home = 1 inner join group_status_view gsv With (NoLock) on gp.group_profile_id = gsv.group_profile_id and gsv.status_value = 'OPEN' and gsv.effective_date = (Select max(b.effective_date) from group_status_view b With (NoLock) where gp.group_profile_id = b.group_profile_id) left outer join regions With (NoLock) on isnull(mo.regions_id, gp.regions_id) = regions.regions_id left join enrollment en on en.group_profile_id = gp.group_profile_id join event_log el on el.event_log_id = en.event_log_id left join people client on client.people_id = el.people_id left join race With (NoLock) on el.people_id = race.people_id left join group_profile_race gpr with (nolock) on gpr.race_info_id = race.race_info_id left join race_info ri with (nolock) on ri.race_info_id = gpr.race_info_id left join ethnicity With(NoLock) On client.ethnicity = ethnicity.ethnicity_id left join religion on client.religion = religion.religion_id

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• Is Fast Enumeration messing with my text output?

  - by Dan Ray

  Here I am iterating through an array of NSDictionary objects (inside the parsed JSON response of the EXCELLENT MapQuest directions API). I want to build up an HTML string to put into a UIWebView. My code says: for (NSDictionary *leg in legs ) { NSString *thisLeg = [NSString stringWithFormat:@"<br>%@ - %@", [leg valueForKey:@"narrative"], [leg valueForKey:@"distance"]]; NSLog(@"This leg's string is %@", thisLeg); [directionsOutput appendString:thisLeg]; } The content of directionsOutput (which is an NSMutableString) contains ALL the values for [leg valueForKey:@"narrative"], wrapped up in parens, followed by a hyphen, followed by all the parenthesized values for [leg valueForKey:@"distance"]. So I put in that NSLog call... and I get the same thing there! It appears that the for() is somehow batching up our output values as we iterate, and putting out the output only once. How do I make it not do this but instead do what I actually want, which is an iterative output as I iterate? Here's what NSLog gets. Yes, I know I need to figure out NSNumberFormatter. ;-) This leg's string is ( "Start out going NORTH on INFINITE LOOP.", "Turn LEFT to stay on INFINITE LOOP.", "Turn RIGHT onto N DE ANZA BLVD.", "Merge onto I-280 S toward SAN JOSE.", "Merge onto CA-87 S via EXIT 3A.", "Take the exit on the LEFT.", "Merge onto CA-85 S via EXIT 1A on the LEFT toward GILROY.", "Merge onto US-101 S via EXIT 1A on the LEFT toward LOS ANGELES.", "Take the CA-152 E/10TH ST exit, EXIT 356.", "Turn LEFT onto CA-152/E 10TH ST/PACHECO PASS HWY. Continue to follow CA-152/PACHECO PASS HWY.", "Turn SLIGHT RIGHT.", "Turn SLIGHT RIGHT onto PACHECO PASS HWY/CA-152 E. Continue to follow CA-152 E.", "Merge onto I-5 S toward LOS ANGELES.", "Take the CA-46 exit, EXIT 278, toward LOST HILLS/WASCO.", "Turn LEFT onto CA-46/PASO ROBLES HWY. Continue to follow CA-46.", "Merge onto CA-99 S toward BAKERSFIELD.", "Merge onto CA-58 E via EXIT 24 toward TEHACHAPI/MOJAVE.", "Merge onto I-15 N via the exit on the LEFT toward I-40/LAS VEGAS.", "Keep RIGHT to take I-40 E via EXIT 140A toward NEEDLES (Passing through ARIZONA, NEW MEXICO, TEXAS, OKLAHOMA, and ARKANSAS, then crossing into TENNESSEE).", "Merge onto I-40 E via EXIT 12C on the LEFT toward NASHVILLE (Crossing into NORTH CAROLINA).", "Merge onto I-40 BR E/US-421 S via EXIT 188 on the LEFT toward WINSTON-SALEM.", "Take the CLOVERDALE AVE exit, EXIT 4.", "Turn LEFT onto CLOVERDALE AVE SW.", "Turn SLIGHT LEFT onto N HAWTHORNE RD.", "Turn RIGHT onto W NORTHWEST BLVD.", "1047 W NORTHWEST BLVD is on the LEFT." ) - ( 0.0020000000949949026, 0.07800000160932541, 0.14000000059604645, 7.827000141143799, 5.0329999923706055, 0.15299999713897705, 5.050000190734863, 20.871000289916992, 0.3050000071525574, 2.802999973297119, 0.10199999809265137, 37.78000259399414, 124.50700378417969, 0.3970000147819519, 25.264001846313477, 20.475000381469727, 125.8580093383789, 4.538000106811523, 1693.0350341796875, 628.8970336914062, 3.7990000247955322, 0.19099999964237213, 0.4099999964237213, 0.257999986410141, 0.5170000195503235, 0 )

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• Creating a second login page that automatically logs in the user

  - by nsilva

  I have a login page as follows: <form action="?" method="post" id="frm-useracc-login" name="frm-useracc-login" > <div id="login-username-wrap" > <div class="login-input-item left"> <div class="div-search-label left"> <div id="div-leftheader-wrap"> <p class="a-topheader-infotext left"><strong>Username: </strong></p> </div> </div> <div class="login-input-content left div-subrow-style ui-corner-all"> <input type="text" tabindex="1" name="txt-username" id="txt-username" class="input-txt-med required addr-search-input txt-username left"> </div> </div> </div> <div id="login-password-wrap" > <div class="login-input-item left"> <div class="div-search-label left"> <div id="div-leftheader-wrap"> <p class="a-topheader-infotext left"><strong>Password: </strong></p> </div> </div> <div class="login-input-content left div-subrow-style ui-corner-all"> <input type="password" tabindex="1" name="txt-password" id="txt-password" class="input-txt-med required addr-search-input txt-password left"> </div> </div> </div> <div id="login-btn-bottom" class="centre-div"> <div id="login-btn-right"> <button name="btn-login" id="btn-login" class="btn-med ui-button ui-state-default ui-button-text-only ui-corner-all btn-hover-anim btn-row-wrapper left">Login</button> <button name="btn-cancel" id="btn-cancel" class="btn-med ui-button ui-state-default ui-button-text-only ui-corner-all btn-hover-anim btn-row-wrapper left">Cancel</button><br /><br /> </div> </div> </form> And here my session.controller.php file: Click Here Basically, what I want to do is create a second login page that automatically passes the value to the session controller and logs in. For example, if I go to login-guest.php, I would put the default values for username and password and then have a jquery click event that automatically logs them in using $("#btn-login").trigger('click'); The problem is that the session controller automatically goes back to login.php if the session has timed out and I'm not sure how I could go about achieving this. Any help would be much appreciated!

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• Mysql - help me optimize this query (improved question)

  - by sandeepan-nath

  About the system: - There are tutors who create classes and packs - A tags based search approach is being followed.Tag relations are created when new tutors register and when tutors create packs (this makes tutors and packs searcheable). For details please check the section How tags work in this system? below. Following is the concerned query SELECT SUM(DISTINCT( t.tag LIKE "%Dictatorship%" )) AS key_1_total_matches, SUM(DISTINCT( t.tag LIKE "%democracy%" )) AS key_2_total_matches, COUNT(DISTINCT( od.id_od )) AS tutor_popularity, CASE WHEN ( IF(( wc.id_wc > 0 ), ( wc.wc_api_status = 1 AND wc.wc_type = 0 AND wc.class_date > '2010-06-01 22:00:56' AND wccp.status = 1 AND ( wccp.country_code = 'IE' OR wccp.country_code IN ( 'INT' ) ) ), 0) ) THEN 1 ELSE 0 END AS 'classes_published', CASE WHEN ( IF(( lp.id_lp > 0 ), ( lp.id_status = 1 AND lp.published = 1 AND lpcp.status = 1 AND ( lpcp.country_code = 'IE' OR lpcp.country_code IN ( 'INT' ) ) ), 0) ) THEN 1 ELSE 0 END AS 'packs_published', td . *, u . * FROM tutor_details AS td JOIN users AS u ON u.id_user = td.id_user LEFT JOIN learning_packs_tag_relations AS lptagrels ON td.id_tutor = lptagrels.id_tutor LEFT JOIN learning_packs AS lp ON lptagrels.id_lp = lp.id_lp LEFT JOIN learning_packs_categories AS lpc ON lpc.id_lp_cat = lp.id_lp_cat LEFT JOIN learning_packs_categories AS lpcp ON lpcp.id_lp_cat = lpc.id_parent LEFT JOIN learning_pack_content AS lpct ON ( lp.id_lp = lpct.id_lp ) LEFT JOIN webclasses_tag_relations AS wtagrels ON td.id_tutor = wtagrels.id_tutor LEFT JOIN webclasses AS wc ON wtagrels.id_wc = wc.id_wc LEFT JOIN learning_packs_categories AS wcc ON wcc.id_lp_cat = wc.id_wp_cat LEFT JOIN learning_packs_categories AS wccp ON wccp.id_lp_cat = wcc.id_parent LEFT JOIN order_details AS od ON td.id_tutor = od.id_author LEFT JOIN orders AS o ON od.id_order = o.id_order LEFT JOIN tutors_tag_relations AS ttagrels ON td.id_tutor = ttagrels.id_tutor JOIN tags AS t ON ( t.id_tag = ttagrels.id_tag ) OR ( t.id_tag = lptagrels.id_tag ) OR ( t.id_tag = wtagrels.id_tag ) WHERE ( u.country = 'IE' OR u.country IN ( 'INT' ) ) AND CASE WHEN ( ( t.id_tag = lptagrels.id_tag ) AND ( lp.id_lp 0 ) ) THEN lp.id_status = 1 AND lp.published = 1 AND lpcp.status = 1 AND ( lpcp.country_code = 'IE' OR lpcp.country_code IN ( 'INT' ) ) ELSE 1 END AND CASE WHEN ( ( t.id_tag = wtagrels.id_tag ) AND ( wc.id_wc 0 ) ) THEN wc.wc_api_status = 1 AND wc.wc_type = 0 AND wc.class_date '2010-06-01 22:00:56' AND wccp.status = 1 AND ( wccp.country_code = 'IE' OR wccp.country_code IN ( 'INT' ) ) ELSE 1 END AND CASE WHEN ( od.id_od 0 ) THEN od.id_author = td.id_tutor AND o.order_status = 'paid' AND CASE WHEN ( od.id_wc 0 ) THEN od.can_attend_class = 1 ELSE 1 END ELSE 1 END GROUP BY td.id_tutor HAVING key_1_total_matches = 1 AND key_2_total_matches = 1 ORDER BY tutor_popularity DESC, u.surname ASC, u.name ASC LIMIT 0, 20 The problem The results returned by the above query are correct (AND logic working as per expectation), but the time taken by the query rises alarmingly for heavier data and for the current data I have it is like 25 seconds as against normal query timings of the order of 0.005 - 0.0002 seconds, which makes it totally unusable. It is possible that some of the delay is being caused because all the possible fields have not yet been indexed. The tag field of tags table is indexed. Is there something faulty with the query? What can be the reason behind 20+ seconds of execution time? How tags work in this system? When a tutor registers, tags are entered and tag relations are created with respect to tutor's details like name, surname etc. When a Tutors create packs, again tags are entered and tag relations are created with respect to pack's details like pack name, description etc. tag relations for tutors stored in tutors_tag_relations and those for packs stored in learning_packs_tag_relations. All individual tags are stored in tags table. The explain query output:- Please see this screenshot - http://www.test.examvillage.com/Explain_query.jpg

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• Styling an Input Field

  - by John

  Hello When I try to alter the CSS for the input field named "title" below, which is classed by "submissionfield", the position changes, but the height, length, and font of the field do not change. How could I make the height of the input field "title" 22 px, the length 550 px, and the font Times New Roman? The CSS below does not do it. Thanks in advance, John echo '<form action="http://www...com/.../submit2.php" method="post"> <input type="hidden" value="'.$_SESSION['loginid'].'" name="uid"> <div class="submissiontitle"><label for="title">Story Title:</label></div> <div class="submissionfield"><input name="title" type="title" id="title" maxlength="1000"></div> <div class="urltitle"><label for="url">Link:</label></div> <div class="urlfield"><input name="url" type="url" id="url" maxlength="500"></div> <div class="submissionbutton"><input name="submit" type="submit" value="Submit"></div> </form> '; The CSS: .submissiontitle { position:absolute; width:100px; left:30px; top:200px; text-align: left; margin-bottom:3px; padding:0px; font-family:Arial, Helvetica, sans-serif; font-size: 12px; color:#000000; } .submissionfield { position:absolute; width:550px; left:50px; top:230px; text-align: left; margin-bottom:3px; padding:0px; font-family: "Times New Roman", Times, serif; font-size: 22px; color:#000000; } .urltitle { position:absolute; width:250px; left:30px; top:300px; text-align: left; margin-bottom:3px; padding:0px; font-family:Arial, Helvetica, sans-serif; font-size: 12px; color:#000000; } .urlfield { position:absolute; width:550px; left:30px; top:330px; text-align: left; margin-bottom:3px; padding:0px; font-family:Arial, Helvetica, sans-serif; font-size: 11px; color:#000000; } .submissionbutton { position:absolute; width:250px; left:30px; top:380px; text-align: left; margin-bottom:3px; padding:0px; font-family:Arial, Helvetica, sans-serif; font-size: 11px; color:#000000; } .submittitle { position:absolute; width:250px; left:30px; top:150px; text-align: left; margin-bottom:3px; padding:0px; font-family:Arial, Helvetica, sans-serif; font-size: 12px; color:#000000; }

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• How to properly use the .each() command in jQuery

  - by sadmicrowave

  I have a script that checks the class (integer) of a , runs a switch statement to change that integer value to text and appends the text to another in the same listitem tag. I use the .each() function because each listitem starts with class=_[user ID] -- each user can have up to 5 entries.. Enough explaining -- heres the code: <HTML> <li class='_44074'><div class='_12' style='width:380px;'><div style='width:60px; float:left;'>1st</div><div class='verify-type' style='float:left; width:160px;'></div><div style='float:left; width:120px;'>04/26/10 07:29 AM</div></div></li> <li class='_44074'><div class='_6' style='width:380px;'><div style='width:60px; float:left;'>2nd</div><div class='verify-type' style='float:left; width:160px;'></div><div style='float:left; width:120px;'>04/23/10 03:29 PM</div></div></li> <li class='_44074'><div class='_12' style='width:380px;'><div style='width:60px; float:left;'>3rd</div><div class='verify-type' style='float:left; width:160px;'></div><div style='float:left; width:120px;'>04/23/10 03:18 PM</div></div></li> <li class='_44074'><div class='_2' style='width:380px;'><div style='width:60px; float:left;'>4th</div><div class='verify-type' style='float:left; width:160px;'></div><div style='float:left; width:120px;'>04/23/10 02:28 PM</div></div></li> </HTML> when I use the .each() function to scan through each of the listitems begining with the entered user id it only finds the first value (in this case _12) and applies that to all the entries; instead of finding _12, _6, _12, _2 it finds _12, _12, _12, _12...here is the java: $("div#history-menu div#history-text li." + valueid).each(function(){ valueid = $("div#center-box input").val(); checkedvalue=""; checkedvalue = $("div#history-menu div#history-text li." + valueid + " div").attr('class'); switch(checkedvalue){ case '_2':lcCheckedMessage = "Shoes"; break; case '_4':lcCheckedMessage = "Shoe Straps"; break; case '_6':lcCheckedMessage = "Shoes & Shoe Straps"; break; case '_8':lcCheckedMessage = "Wrist Straps"; break; case '_10':lcCheckedMessage = "Shoes & Wrist Strap"; break; case '_12':lcCheckedMessage = "Shoe Straps & Wrist Strap"; break; }; $("div#history-menu div#history-text li." + valueid + " ." + checkedvalue + " .verify-type").text(lcCheckedMessage); });

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• How can you force a floating div to be the height of its parent?

  - by ErnieStings

  HTML markup: <div class="planRisk"> <div class="innerPlanRiskRight"> <div class="rmPlanFrequency">10 </div> <div class="rmPlanSeverity"> 5</div> <div class="rmPlanRiskFactor">50 </div> <div class="rmPlanNumSolutions">2</div> <div class="rmPlanPercentComplete">34% </div> <div class="rmPlanDeletePlanRisk"> X </div> </div> <div class="rmPlanRiskTitle"> Pandemic Influenza</div> </div> CSS: .planRisk{background-color:#DEECD1; border:1px solid #BEBEBE;} .innerPlanRiskRight{float:right; color:#000000;} .rmPlanFrequency{float:left; width:46px;background-color:#d9dee1; text-align:center; border-right:1px solid #ebebeb; padding:0.2em;} .rmPlanSeverity{float:left; width:46px; background-color:#dbe1d4; text-align:center; border-right:1px solid #ebebeb; padding:0.2em;} .rmPlanRiskFactor{float:left; width:46px; background-color:#e5d5da; text-align:center; border-right:1px solid #ebebeb; padding:0.2em;} .rmPlanNumSolutions{float:left; width:46px; background-color:#dae4e4; text-align:center; border-right:1px solid #ebebeb; padding:0.2em;} .rmPlanPercentComplete{float:left; width:46px; background-color:#dddddd; text-align:center; padding:0.2em; } .rmPlanDeletePlanRisk{float:left; width:30px; background-color:#DEECD1; text-align:center; padding:0.2em;} .rmPlanRiskTitle{padding:0.2em; } .rmPlanSolutionContainer{background-color:#f0f9e8; border: 0 1px 1px; border-left:1px solid #CDCDCD; border-right:1px solid #cdcdcd; } .innerSolutionRight{float:right;} .rmPlanSolution{border-bottom:1px solid #CDCDCD; padding-left:1em;} .rmPlanSolutionPercentComplete{float:left; width:46px; background-color:#E2EADA; padding-left:0.2em; padding-right:0.2em; text-align:center;} .rmPlanDeleteSolution{float:left; width:30px; text-align:center; padding-left:0.2em; padding-right:0.2em; }

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• Need a hand understanding this Java code please :-)

  - by Brian

  Hi all, Just wondering if anyone would be able to take a look at this code for implementing the quicksort algorithm and answer me a few questions, please :-) public class Run { /*************************************************************************** * Quicksort code from Sedgewick 7.1, 7.2. **************************************************************************/ public static void quicksort(double[] a) { //shuffle(a); // to guard against worst-case quicksort(a, 0, a.length - 1, 0); } static void quicksort(final double[] a, final int left, final int right, final int tdepth) { if (right <= left) return; final int i = partition(a, left, right); if ((tdepth < 4) && ((i - left) > 1000)) { final Thread t = new Thread() { public void run() { quicksort(a, left, i - 1, tdepth + 1); } }; t.start(); quicksort(a, i + 1, right, tdepth + 1); try { t.join(); } catch (InterruptedException e) { throw new RuntimeException("Cancelled", e); } } else { quicksort(a, left, i - 1, tdepth); quicksort(a, i + 1, right, tdepth); } } // partition a[left] to a[right], assumes left < right private static int partition(double[] a, int left, int right) { int i = left - 1; int j = right; while (true) { while (less(a[++i], a[right])) // find item on left to swap ; // a[right] acts as sentinel while (less(a[right], a[--j])) // find item on right to swap if (j == left) break; // don't go out-of-bounds if (i >= j) break; // check if pointers cross exch(a, i, j); // swap two elements into place } exch(a, i, right); // swap with partition element return i; } // is x < y ? private static boolean less(double x, double y) { return (x < y); } // exchange a[i] and a[j] private static void exch(double[] a, int i, int j) { double swap = a[i]; a[i] = a[j]; a[j] = swap; } // shuffle the array a[] private static void shuffle(double[] a) { int N = a.length; for (int i = 0; i < N; i++) { int r = i + (int) (Math.random() * (N - i)); // between i and N-1 exch(a, i, r); } } // test client public static void main(String[] args) { int N = 5000000; // Integer.parseInt(args[0]); // generate N random real numbers between 0 and 1 long start = System.currentTimeMillis(); double[] a = new double[N]; for (int i = 0; i < N; i++) a[i] = Math.random(); long stop = System.currentTimeMillis(); double elapsed = (stop - start) / 1000.0; System.out.println("Generating input: " + elapsed + " seconds"); // sort them start = System.currentTimeMillis(); quicksort(a); stop = System.currentTimeMillis(); elapsed = (stop - start) / 1000.0; System.out.println("Quicksort: " + elapsed + " seconds"); } } My questions are: What is the purpose of the variable tdepth? Is this considered a "proper" implementation of a parallel quicksort? I ask becuase it doesn't use implements Runnable or extends Thread... If it doesn't already, is it possible to modify this code to use multiple threads? By passing in the number of threads you want to use as a parameter, for example...? Many thanks, Brian

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• Android Canvas.drawString display problem

  - by Arkaha

  Hello everyone! I encounter this problem when displaying text on SurfaceView, some chars can climb up on others, code is here: private static void fakeDraw(Canvas c) { Paint mPaint = new Paint(); int color = 0xff000000; mPaint.setColor(color); mPaint.setStrokeWidth(2); mPaint.setStyle(Style.FILL); mPaint.setAntiAlias(true); FontMetricsInt fm = mPaint.getFontMetricsInt(); int fh = Math.abs(fm.top); int left = 0; int top = 100; Rect smallClip = new Rect(left, top-fh, left + 200, top + 30); Rect bigClip = new Rect(0, 0, getW(), getH()); c.drawRect(bigClip, mPaint); String text1 = "Evi"; String text2 = ">>"; String text3 = "Tom"; color = 0xff303030; mPaint.setColor(color); c.drawRect(smallClip, mPaint); color = 0xffffffff; mPaint.setColor(color); c.drawText(text1, left, top, mPaint); Rect bounds = new Rect(); mPaint.getTextBounds(text1, 0, text1.length(), bounds); left += bounds.width(); c.drawText(text2, left, top, mPaint); left -= bounds.width(); top += 12; c.drawText(text3, left, top, mPaint); mPaint.getTextBounds(text3, 0, text3.length(), bounds); left += bounds.width(); c.drawText(text2, left, top, mPaint); } In the case of a second text Tom all displayed correctly, but the first text Evi not. The problem is that the chars draws in Evi draw space(last char "i")!! It is possible to see if you zoom the picture, what am I doing wrong and how to fix this? screen shot can be found here:

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• Show/Hide button (text) for Accordion

  - by Kevin

  Have an accordion with a "view" button to open close the accordion panel (using jQuery Tools), but I would like to have dynamic text that says "show/hide" depending on the state... Here is the code for the accordion in asp.NET <div id="accordion"> <% foreach (var eventModel in ViewModel) { %> <% var isNewMonth = eventModel.Date.Month != previousMonth; %> <% if (isNewMonth && previousMonth > 0) { %></table></div><% } %> <% previousMonth = eventModel.Date.Month; %> <% if (isNewMonth) { %> <h2><%= string.Concat(eventModel.Date.ToString("MMMM"), " ", eventModel.Date.Year) %> <span style="float:right;"><a href="#" class="button blue small">View</a></span></h2> <div class="pane" style="display:block"> <table id="listTable" width="100%" cellpadding="3" cellspacing="0" border="0"> <tr align="left" valign="top"><th align="left" valign="top">Date</th><th align="left" valign="top">Event</th><th align="left" valign="top">Event Type</th></tr> <% } %> <tr align="left" valign="top"><td align="left" valign="top"><b><span id="date" style="float:left;"> <%= string.Concat(eventModel.Date.ToString("MMMM"), " ", eventModel.Date.Day, " </span><span id='day' style='float:left'>" + eventModel.Date.DayOfWeek + "</span> ")%></b></td><td align="left" valign="top" ><%= Html.ActionLink(eventModel.Name.Truncate(40), "event", "register", new { id = eventModel.Id }, null)%></td><td align="left" valign="top"><%= string.Concat(" ", eventModel.Sport)%></td></tr> <% } %> <% if (ViewModel.Count > 0) { %></table></div><% } %> </div> Here is the initialization script using jQuery: $(function() { $("#accordion").tabs("#accordion div.pane", {tabs: 'h2', effect: 'slide', initialIndex: 0}); $(".small").click(function() { moveToTop(); }); });

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• Values of generated column not appearing in table

  - by msh210

  I'm using mysql version 5.1.41-3ubuntu12.10 (Ubuntu). mysql> show create table tt\G *************************** 1. row *************************** Table: tt Create Table: CREATE TABLE `tt` ( `pz` int(8) DEFAULT NULL, `os` varchar(8) DEFAULT NULL, `uz` int(11) NOT NULL, `p` bigint(21) NOT NULL DEFAULT '0', `c` decimal(23,0) DEFAULT NULL, KEY `pz` (`pz`), KEY `uz` (`uz`), KEY `os` (`os`), KEY `pz_2` (`pz`,`uz`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 1 row in set (0.00 sec) mysql> select pz,uz,pz*uz, -> if(pz*uz,1,.5), -> left(pz,2) pl,left(lpad(uz,5,0),2) ul, -> p from tt limit 10; +-------+----+-------+----------------+--------+----+--------+ | pz | uz | pz*uz | if(pz*uz,1,.5) | pl | ul | p | +-------+----+-------+----------------+--------+----+--------+ | NULL | 0 | NULL | 0.5 | NULL | 00 | 4080 | | NULL | 0 | NULL | 0.5 | NULL | 00 | 323754 | | 89101 | 0 | 0 | 0.5 | 89 | 00 | 6880 | | 0 | 0 | 0 | 0.5 | 0 | 00 | 11591 | | 89110 | 0 | 0 | 0.5 | 89 | 00 | 72 | | 78247 | 0 | 0 | 0.5 | 78 | 00 | 27 | | 90062 | 0 | 0 | 0.5 | 90 | 00 | 5 | | 63107 | 0 | 0 | 0.5 | 63 | 00 | 4 | | NULL | 0 | NULL | 0.5 | NULL | 00 | 54561 | | 94102 | 0 | 0 | 0.5 | 94 | 00 | 12499 | +-------+----+-------+----------------+--------+----+--------+ So far so good. As you see, 0.5 appears as a value of if(pz*uz,1,.5). The problem is: mysql> select os, -> if(pz*uz,left(pz,2)<=>left(lpad(uz,5,0),2),.5) uptwo, -> if(pz*uz,left(pz,3)<=>left(lpad(uz,5,0),3),.5) upthree, -> sum(p) p,sum(c) c -> from tt t -> group by os,uptwo,upthree order by null; +----+-------+---------+---------+-------+ | os | uptwo | upthree | p | c | +----+-------+---------+---------+-------+ | u | 1 | 1 | 52852 | 318 | | i | 1 | 1 | 7046563 | 21716 | | m | 1 | 1 | 1252166 | 7337 | | i | 0 | 0 | 1830284 | 4033 | | m | 0 | 0 | 294612 | 1714 | | i | 1 | 0 | 911486 | 3560 | | m | 1 | 0 | 145182 | 1136 | | u | 0 | 0 | 12144 | 23 | | u | 1 | 0 | 1571 | 8 | +----+-------+---------+---------+-------+ Although I group by uptwo, 0.5 doesn't appear in that column. What happened to the 0.5 values? Edit: As noted in the comments to Todd Gibson's answer, I also tried it with if(pz*uz,cast(left(pz,2)<=>left(lpad(uz,5,0),2) as decimal),.5) instead of if(pz*uz,left(pz,2)<=>left(lpad(uz,5,0),2),.5), but it, too, didn't work.

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• Worst Case number of rotations for BST to AVL algorithm?

  - by spacker_lechuck

  I have a basic algorithm below and I know that the worst case input BST is one that has degenerated to a linked list from inserts to only one side. How would I compute the worst case complexity in terms of number of rotations for this BST to AVL conversion algorithm? IF tree is right heavy { IF tree's right subtree is left heavy { Perform Double Left rotation } ELSE { Perform Single Left rotation } } ELSE IF tree is left heavy { IF tree's left subtree is right heavy { Perform Double Right rotation } ELSE { Perform Single Right rotation } }

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• How to see if type is instance of a class in Haskell?

  - by Raekye

  I'm probably doing this completely wrong (the unhaskell way); I'm just learning so please let me know if there's a better way to approach this. Context: I'm writing a bunch of tree structures. I want to reuse my prettyprint function for binary trees. Not all trees can use the generic Node/Branch data type though; different trees need different extra data. So to reuse the prettyprint function I thought of creating a class different trees would be instances of: class GenericBinaryTree a where is_leaf :: a -> Bool left :: a -> a node :: a -> b right :: a -> a This way they only have to implement methods to retrieve the left, right, and current node value, and prettyprint doesn't need to know about the internal structure. Then I get down to here: prettyprint_helper :: GenericBinaryTree a => a -> [String] prettyprint_helper tree | is_leaf tree = [] | otherwise = ("{" ++ (show (node tree)) ++ "}") : (prettyprint_subtree (left tree) (right tree)) where prettyprint_subtree left right = ((pad "+- " "| ") (prettyprint_helper right)) ++ ((pad "`- " " ") (prettyprint_helper left)) pad first rest = zipWith (++) (first : repeat rest) And I get the Ambiguous type variable 'a0' in the constraint: (Show a0) arising from a use of 'show' error for (show (node tree)) Here's an example of the most basic tree data type and instance definition (my other trees have other fields but they're irrelevant to the generic prettyprint function) data Tree a = Branch (Tree a) a (Tree a) | Leaf instance GenericBinaryTree (Tree a) where is_leaf Leaf = True is_leaf _ = False left (Branch left node right) = left right (Branch left node right) = right node (Branch left node right) = node I could have defined node :: a -> [String] and deal with the stringification in each instance/type of tree, but this feels neater. In terms of prettyprint, I only need a string representation, but if I add other generic binary tree functions later I may want the actual values. So how can I write this to work whether the node value is an instance of Show or not? Or what other way should I be approaching this problem? In an object oriented language I could easily check whether a class implements something, or if an object has a method. I can't use something like prettyprint :: Show a => a -> String Because it's not the tree that needs to be showable, it's the value inside the tree (returned by function node) that needs to be showable. I also tried changing node to Show b => a -> b without luck (and a bunch of other type class/preconditions/whatever/I don't even know what I'm doing anymore).

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• Oracle Coherence, Split-Brain and Recovery Protocols In Detail

  - by Ricardo Ferreira

  This article provides a high level conceptual overview of Split-Brain scenarios in distributed systems. It will focus on a specific example of cluster communication failure and recovery in Oracle Coherence. This includes a discussion on the witness protocol (used to remove failed cluster members) and the panic protocol (used to resolve Split-Brain scenarios). Note that the removal of cluster members does not necessarily indicate a Split-Brain condition. Oracle Coherence does not (and cannot) detect a Split-Brain as it occurs, the condition is only detected when cluster members that previously lost contact with each other regain contact. Cluster Topology and Configuration In order to create an good didactic for the article, let's assume a cluster topology and configuration. In this example we have a six member cluster, consisting of one JVM on each physical machine. The member IDs are as follows: Member ID  IP Address  1  10.149.155.76  2  10.149.155.77  3  10.149.155.236  4  10.149.155.75  5  10.149.155.79  6  10.149.155.78 Members 1, 2, and 3 are connected to a switch, and members 4, 5, and 6 are connected to a second switch. There is a link between the two switches, which provides network connectivity between all of the machines. Member 1 is the first member to join this cluster, thus making it the senior member. Member 6 is the last member to join this cluster. Here is a log snippet from Member 6 showing the complete member set: 2010-02-26 15:27:57.390/3.062 Oracle Coherence GE 3.5.3/465p2 <Info> (thread=main, member=6): Started DefaultCacheServer... SafeCluster: Name=cluster:0xDDEB Group{Address=224.3.5.3, Port=35465, TTL=4} MasterMemberSet ( ThisMember=Member(Id=6, Timestamp=2010-02-26 15:27:58.635, Address=10.149.155.78:8088, MachineId=1102, Location=process:228, Role=CoherenceServer) OldestMember=Member(Id=1, Timestamp=2010-02-26 15:27:06.931, Address=10.149.155.76:8088, MachineId=1100, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:511, Role=CoherenceServer) ActualMemberSet=MemberSet(Size=6, BitSetCount=2 Member(Id=1, Timestamp=2010-02-26 15:27:06.931, Address=10.149.155.76:8088, MachineId=1100, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:511, Role=CoherenceServer) Member(Id=2, Timestamp=2010-02-26 15:27:17.847, Address=10.149.155.77:8088, MachineId=1101, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:296, Role=CoherenceServer) Member(Id=3, Timestamp=2010-02-26 15:27:24.892, Address=10.149.155.236:8088, MachineId=1260, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:32459, Role=CoherenceServer) Member(Id=4, Timestamp=2010-02-26 15:27:39.574, Address=10.149.155.75:8088, MachineId=1099, Location=process:800, Role=CoherenceServer) Member(Id=5, Timestamp=2010-02-26 15:27:49.095, Address=10.149.155.79:8088, MachineId=1103, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:3229, Role=CoherenceServer) Member(Id=6, Timestamp=2010-02-26 15:27:58.635, Address=10.149.155.78:8088, MachineId=1102, Location=process:228, Role=CoherenceServer) ) RecycleMillis=120000 RecycleSet=MemberSet(Size=0, BitSetCount=0 ) ) At approximately 15:30, the connection between the two switches is severed: Thirty seconds later (the default packet timeout in development mode) the logs indicate communication failures across the cluster. In this example, the communication failure was caused by a network failure. In a production setting, this type of communication failure can have many root causes, including (but not limited to) network failures, excessive GC, high CPU utilization, swapping/virtual memory, and exceeding maximum network bandwidth. In addition, this type of failure is not necessarily indicative of a split brain. Any communication failure will be logged in this fashion. Member 2 logs a communication failure with Member 5: 2010-02-26 15:30:32.638/196.928 Oracle Coherence GE 3.5.3/465p2 <Warning> (thread=PacketPublisher, member=2): Timeout while delivering a packet; requesting the departure confirmation for Member(Id=5, Timestamp=2010-02-26 15:27:49.095, Address=10.149.155.79:8088, MachineId=1103, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:3229, Role=CoherenceServer) by MemberSet(Size=2, BitSetCount=2 Member(Id=1, Timestamp=2010-02-26 15:27:06.931, Address=10.149.155.76:8088, MachineId=1100, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:511, Role=CoherenceServer) Member(Id=4, Timestamp=2010-02-26 15:27:39.574, Address=10.149.155.75:8088, MachineId=1099, Location=process:800, Role=CoherenceServer) ) The Coherence clustering protocol (TCMP) is a reliable transport mechanism built on UDP. In order for the protocol to be reliable, it requires an acknowledgement (ACK) for each packet delivered. If a packet fails to be acknowledged within the configured timeout period, the Coherence cluster member will log a packet timeout (as seen in the log message above). When this occurs, the cluster member will consult with other members to determine who is at fault for the communication failure. If the witness members agree that the suspect member is at fault, the suspect is removed from the cluster. If the witnesses unanimously disagree, the accuser is removed. This process is known as the witness protocol. Since Member 2 cannot communicate with Member 5, it selects two witnesses (Members 1 and 4) to determine if the communication issue is with Member 5 or with itself (Member 2). However, Member 4 is on the switch that is no longer accessible by Members 1, 2 and 3; thus a packet timeout for member 4 is recorded as well: 2010-02-26 15:30:35.648/199.938 Oracle Coherence GE 3.5.3/465p2 <Warning> (thread=PacketPublisher, member=2): Timeout while delivering a packet; requesting the departure confirmation for Member(Id=4, Timestamp=2010-02-26 15:27:39.574, Address=10.149.155.75:8088, MachineId=1099, Location=process:800, Role=CoherenceServer) by MemberSet(Size=2, BitSetCount=2 Member(Id=1, Timestamp=2010-02-26 15:27:06.931, Address=10.149.155.76:8088, MachineId=1100, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:511, Role=CoherenceServer) Member(Id=6, Timestamp=2010-02-26 15:27:58.635, Address=10.149.155.78:8088, MachineId=1102, Location=process:228, Role=CoherenceServer) ) Member 1 has the ability to confirm the departure of member 4, however Member 6 cannot as it is also inaccessible. At the same time, Member 3 sends a request to remove Member 6, which is followed by a report from Member 3 indicating that Member 6 has departed the cluster: 2010-02-26 15:30:35.706/199.996 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=Cluster, member=2): MemberLeft request for Member 6 received from Member(Id=3, Timestamp=2010-02-26 15:27:24.892, Address=10.149.155.236:8088, MachineId=1260, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:32459, Role=CoherenceServer) 2010-02-26 15:30:35.709/199.999 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=Cluster, member=2): MemberLeft notification for Member 6 received from Member(Id=3, Timestamp=2010-02-26 15:27:24.892, Address=10.149.155.236:8088, MachineId=1260, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:32459, Role=CoherenceServer) The log for Member 3 determines how Member 6 departed the cluster: 2010-02-26 15:30:35.161/191.694 Oracle Coherence GE 3.5.3/465p2 <Warning> (thread=PacketPublisher, member=3): Timeout while delivering a packet; requesting the departure confirmation for Member(Id=6, Timestamp=2010-02-26 15:27:58.635, Address=10.149.155.78:8088, MachineId=1102, Location=process:228, Role=CoherenceServer) by MemberSet(Size=2, BitSetCount=2 Member(Id=1, Timestamp=2010-02-26 15:27:06.931, Address=10.149.155.76:8088, MachineId=1100, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:511, Role=CoherenceServer) Member(Id=2, Timestamp=2010-02-26 15:27:17.847, Address=10.149.155.77:8088, MachineId=1101, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:296, Role=CoherenceServer) ) 2010-02-26 15:30:35.165/191.698 Oracle Coherence GE 3.5.3/465p2 <Info> (thread=Cluster, member=3): Member departure confirmed by MemberSet(Size=2, BitSetCount=2 Member(Id=1, Timestamp=2010-02-26 15:27:06.931, Address=10.149.155.76:8088, MachineId=1100, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:511, Role=CoherenceServer) Member(Id=2, Timestamp=2010-02-26 15:27:17.847, Address=10.149.155.77:8088, MachineId=1101, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:296, Role=CoherenceServer) ); removing Member(Id=6, Timestamp=2010-02-26 15:27:58.635, Address=10.149.155.78:8088, MachineId=1102, Location=process:228, Role=CoherenceServer) In this case, Member 3 happened to select two witnesses that it still had connectivity with (Members 1 and 2) thus resulting in a simple decision to remove Member 6. Given the departure of Member 6, Member 2 is left with a single witness to confirm the departure of Member 4: 2010-02-26 15:30:35.713/200.003 Oracle Coherence GE 3.5.3/465p2 <Info> (thread=Cluster, member=2): Member departure confirmed by MemberSet(Size=1, BitSetCount=2 Member(Id=1, Timestamp=2010-02-26 15:27:06.931, Address=10.149.155.76:8088, MachineId=1100, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:511, Role=CoherenceServer) ); removing Member(Id=4, Timestamp=2010-02-26 15:27:39.574, Address=10.149.155.75:8088, MachineId=1099, Location=process:800, Role=CoherenceServer) In the meantime, Member 4 logs a missing heartbeat from the senior member. This message is also logged on Members 5 and 6. 2010-02-26 15:30:07.906/150.453 Oracle Coherence GE 3.5.3/465p2 <Info> (thread=PacketListenerN, member=4): Scheduled senior member heartbeat is overdue; rejoining multicast group. Next, Member 4 logs a TcpRing failure with Member 2, thus resulting in the termination of Member 2: 2010-02-26 15:30:21.421/163.968 Oracle Coherence GE 3.5.3/465p2 <D4> (thread=Cluster, member=4): TcpRing: Number of socket exceptions exceeded maximum; last was "java.net.SocketTimeoutException: connect timed out"; removing the member: 2 For quick process termination detection, Oracle Coherence utilizes a feature called TcpRing which is a sparse collection of TCP/IP-based connections between different members in the cluster. Each member in the cluster is connected to at least one other member, which (if at all possible) is running on a different physical box. This connection is not used for any data transfer, only heartbeat communications are sent once a second per each link. If a certain number of exceptions are thrown while trying to re-establish a connection, the member throwing the exceptions is removed from the cluster. Member 5 logs a packet timeout with Member 3 and cites witnesses Members 4 and 6: 2010-02-26 15:30:29.791/165.037 Oracle Coherence GE 3.5.3/465p2 <Warning> (thread=PacketPublisher, member=5): Timeout while delivering a packet; requesting the departure confirmation for Member(Id=3, Timestamp=2010-02-26 15:27:24.892, Address=10.149.155.236:8088, MachineId=1260, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:32459, Role=CoherenceServer) by MemberSet(Size=2, BitSetCount=2 Member(Id=4, Timestamp=2010-02-26 15:27:39.574, Address=10.149.155.75:8088, MachineId=1099, Location=process:800, Role=CoherenceServer) Member(Id=6, Timestamp=2010-02-26 15:27:58.635, Address=10.149.155.78:8088, MachineId=1102, Location=process:228, Role=CoherenceServer) ) 2010-02-26 15:30:29.798/165.044 Oracle Coherence GE 3.5.3/465p2 <Info> (thread=Cluster, member=5): Member departure confirmed by MemberSet(Size=2, BitSetCount=2 Member(Id=4, Timestamp=2010-02-26 15:27:39.574, Address=10.149.155.75:8088, MachineId=1099, Location=process:800, Role=CoherenceServer) Member(Id=6, Timestamp=2010-02-26 15:27:58.635, Address=10.149.155.78:8088, MachineId=1102, Location=process:228, Role=CoherenceServer) ); removing Member(Id=3, Timestamp=2010-02-26 15:27:24.892, Address=10.149.155.236:8088, MachineId=1260, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:32459, Role=CoherenceServer) Eventually we are left with two distinct clusters consisting of Members 1, 2, 3 and Members 4, 5, 6, respectively. In the latter cluster, Member 4 is promoted to senior member. The connection between the two switches is restored at 15:33. Upon the restoration of the connection, the cluster members immediately receive cluster heartbeats from the two senior members. In the case of Members 1, 2, and 3, the following is logged: 2010-02-26 15:33:14.970/369.066 Oracle Coherence GE 3.5.3/465p2 <Warning> (thread=Cluster, member=1): The member formerly known as Member(Id=4, Timestamp=2010-02-26 15:30:35.341, Address=10.149.155.75:8088, MachineId=1099, Location=process:800, Role=CoherenceServer) has been forcefully evicted from the cluster, but continues to emit a cluster heartbeat; henceforth, the member will be shunned and its messages will be ignored. Likewise for Members 4, 5, and 6: 2010-02-26 15:33:14.343/336.890 Oracle Coherence GE 3.5.3/465p2 <Warning> (thread=Cluster, member=4): The member formerly known as Member(Id=1, Timestamp=2010-02-26 15:30:31.64, Address=10.149.155.76:8088, MachineId=1100, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:511, Role=CoherenceServer) has been forcefully evicted from the cluster, but continues to emit a cluster heartbeat; henceforth, the member will be shunned and its messages will be ignored. This message indicates that a senior heartbeat is being received from members that were previously removed from the cluster, in other words, something that should not be possible. For this reason, the recipients of these messages will initially ignore them. After several iterations of these messages, the existence of multiple clusters is acknowledged, thus triggering the panic protocol to reconcile this situation. When the presence of more than one cluster (i.e. Split-Brain) is detected by a Coherence member, the panic protocol is invoked in order to resolve the conflicting clusters and consolidate into a single cluster. The protocol consists of the removal of smaller clusters until there is one cluster remaining. In the case of equal size clusters, the one with the older Senior Member will survive. Member 1, being the oldest member, initiates the protocol: 2010-02-26 15:33:45.970/400.066 Oracle Coherence GE 3.5.3/465p2 <Warning> (thread=Cluster, member=1): An existence of a cluster island with senior Member(Id=4, Timestamp=2010-02-26 15:27:39.574, Address=10.149.155.75:8088, MachineId=1099, Location=process:800, Role=CoherenceServer) containing 3 nodes have been detected. Since this Member(Id=1, Timestamp=2010-02-26 15:27:06.931, Address=10.149.155.76:8088, MachineId=1100, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:511, Role=CoherenceServer) is the senior of an older cluster island, the panic protocol is being activated to stop the other island's senior and all junior nodes that belong to it. Member 3 receives the panic: 2010-02-26 15:33:45.803/382.336 Oracle Coherence GE 3.5.3/465p2 <Error> (thread=Cluster, member=3): Received panic from senior Member(Id=1, Timestamp=2010-02-26 15:27:06.931, Address=10.149.155.76:8088, MachineId=1100, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:511, Role=CoherenceServer) caused by Member(Id=4, Timestamp=2010-02-26 15:27:39.574, Address=10.149.155.75:8088, MachineId=1099, Location=process:800, Role=CoherenceServer) Member 4, the senior member of the younger cluster, receives the kill message from Member 3: 2010-02-26 15:33:44.921/367.468 Oracle Coherence GE 3.5.3/465p2 <Error> (thread=Cluster, member=4): Received a Kill message from a valid Member(Id=3, Timestamp=2010-02-26 15:27:24.892, Address=10.149.155.236:8088, MachineId=1260, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:32459, Role=CoherenceServer); stopping cluster service. In turn, Member 4 requests the departure of its junior members 5 and 6: 2010-02-26 15:33:44.921/367.468 Oracle Coherence GE 3.5.3/465p2 <Error> (thread=Cluster, member=4): Received a Kill message from a valid Member(Id=3, Timestamp=2010-02-26 15:27:24.892, Address=10.149.155.236:8088, MachineId=1260, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:32459, Role=CoherenceServer); stopping cluster service. 2010-02-26 15:33:43.343/349.015 Oracle Coherence GE 3.5.3/465p2 <Error> (thread=Cluster, member=6): Received a Kill message from a valid Member(Id=4, Timestamp=2010-02-26 15:27:39.574, Address=10.149.155.75:8088, MachineId=1099, Location=process:800, Role=CoherenceServer); stopping cluster service. Once Members 4, 5, and 6 restart, they rejoin the original cluster with senior member 1. The log below is from Member 4. Note that it receives a different member id when it rejoins the cluster. 2010-02-26 15:33:44.921/367.468 Oracle Coherence GE 3.5.3/465p2 <Error> (thread=Cluster, member=4): Received a Kill message from a valid Member(Id=3, Timestamp=2010-02-26 15:27:24.892, Address=10.149.155.236:8088, MachineId=1260, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:32459, Role=CoherenceServer); stopping cluster service. 2010-02-26 15:33:46.921/369.468 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=Cluster, member=4): Service Cluster left the cluster 2010-02-26 15:33:47.046/369.593 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=Invocation:InvocationService, member=4): Service InvocationService left the cluster 2010-02-26 15:33:47.046/369.593 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=OptimisticCache, member=4): Service OptimisticCache left the cluster 2010-02-26 15:33:47.046/369.593 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=ReplicatedCache, member=4): Service ReplicatedCache left the cluster 2010-02-26 15:33:47.046/369.593 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=DistributedCache, member=4): Service DistributedCache left the cluster 2010-02-26 15:33:47.046/369.593 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=Invocation:Management, member=4): Service Management left the cluster 2010-02-26 15:33:47.046/369.593 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=Cluster, member=4): Member 6 left service Management with senior member 5 2010-02-26 15:33:47.046/369.593 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=Cluster, member=4): Member 6 left service DistributedCache with senior member 5 2010-02-26 15:33:47.046/369.593 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=Cluster, member=4): Member 6 left service ReplicatedCache with senior member 5 2010-02-26 15:33:47.046/369.593 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=Cluster, member=4): Member 6 left service OptimisticCache with senior member 5 2010-02-26 15:33:47.046/369.593 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=Cluster, member=4): Member 6 left service InvocationService with senior member 5 2010-02-26 15:33:47.046/369.593 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=Cluster, member=4): Member(Id=6, Timestamp=2010-02-26 15:33:47.046, Address=10.149.155.78:8088, MachineId=1102, Location=process:228, Role=CoherenceServer) left Cluster with senior member 4 2010-02-26 15:33:49.218/371.765 Oracle Coherence GE 3.5.3/465p2 <Info> (thread=main, member=n/a): Restarting cluster 2010-02-26 15:33:49.421/371.968 Oracle Coherence GE 3.5.3/465p2 <D5> (thread=Cluster, member=n/a): Service Cluster joined the cluster with senior service member n/a 2010-02-26 15:33:49.625/372.172 Oracle Coherence GE 3.5.3/465p2 <Info> (thread=Cluster, member=n/a): This Member(Id=5, Timestamp=2010-02-26 15:33:50.499, Address=10.149.155.75:8088, MachineId=1099, Location=process:800, Role=CoherenceServer, Edition=Grid Edition, Mode=Development, CpuCount=2, SocketCount=1) joined cluster "cluster:0xDDEB" with senior Member(Id=1, Timestamp=2010-02-26 15:27:06.931, Address=10.149.155.76:8088, MachineId=1100, Location=site:usdhcp.oraclecorp.com,machine:dhcp-burlington6-4fl-east-10-149,process:511, Role=CoherenceServer, Edition=Grid Edition, Mode=Development, CpuCount=2, SocketCount=2) Cool isn't it?

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• ASP.NET MVC 2 Model Binding for a Collection

  - by nmarun

  Yes, my yet another post on Model Binding (previous one is here), but this one uses features presented in MVC 2. How I got to writing this blog? Well, I’m on a project where we’re doing some MVC things for a shopping cart. Let me show you what I was working with. Below are my model classes: 1: public class Product 2: { 3: public int Id { get; set; } 4: public string Name { get; set; } 5: public int Quantity { get; set; } 6: public decimal UnitPrice { get; set; } 7: } 8:   9: public class Totals 10: { 11: public decimal SubTotal { get; set; } 12: public decimal Tax { get; set; } 13: public decimal Total { get; set; } 14: } 15:   16: public class Basket 17: { 18: public List<Product> Products { get; set; } 19: public Totals Totals { get; set;} 20: } The view looks as below:  1: <h2>Shopping Cart</h2> 2:   3: <% using(Html.BeginForm()) { %> 4: 5: <h3>Products</h3> 6: <% for (int i = 0; i < Model.Products.Count; i++) 7: { %> 8: <div style="width: 100px;float:left;">Id</div> 9: <div style="width: 100px;float:left;"> 10: <%= Html.TextBox("ID", Model.Products[i].Id) %> 11: </div> 12: <div style="clear:both;"></div> 13: <div style="width: 100px;float:left;">Name</div> 14: <div style="width: 100px;float:left;"> 15: <%= Html.TextBox("Name", Model.Products[i].Name) %> 16: </div> 17: <div style="clear:both;"></div> 18: <div style="width: 100px;float:left;">Quantity</div> 19: <div style="width: 100px;float:left;"> 20: <%= Html.TextBox("Quantity", Model.Products[i].Quantity)%> 21: </div> 22: <div style="clear:both;"></div> 23: <div style="width: 100px;float:left;">Unit Price</div> 24: <div style="width: 100px;float:left;"> 25: <%= Html.TextBox("UnitPrice", Model.Products[i].UnitPrice)%> 26: </div> 27: <div style="clear:both;"><hr /></div> 28: <% } %> 29: 30: <h3>Totals</h3> 31: <div style="width: 100px;float:left;">Sub Total</div> 32: <div style="width: 100px;float:left;"> 33: <%= Html.TextBox("SubTotal", Model.Totals.SubTotal)%> 34: </div> 35: <div style="clear:both;"></div> 36: <div style="width: 100px;float:left;">Tax</div> 37: <div style="width: 100px;float:left;"> 38: <%= Html.TextBox("Tax", Model.Totals.Tax)%> 39: </div> 40: <div style="clear:both;"></div> 41: <div style="width: 100px;float:left;">Total</div> 42: <div style="width: 100px;float:left;"> 43: <%= Html.TextBox("Total", Model.Totals.Total)%> 44: </div> 45: <div style="clear:both;"></div> 46: <p /> 47: <input type="submit" name="Submit" value="Submit" /> 48: <% } %> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Nothing fancy, just a bunch of div’s containing textboxes and a submit button. Just make note that the textboxes have the same name as the property they are going to display. Yea, yea, I know. I’m displaying unit price as a textbox instead of a label, but that’s beside the point (and trust me, this will not be how it’ll look on the production site!!). The way my controller works is that initially two dummy products are added to the basked object and the Totals are calculated based on what products were added in what quantities and their respective unit price. So when the page loads in edit mode, where the user can change the quantity and hit the submit button. In the ‘post’ version of the action method, the Totals get recalculated and the new total will be displayed on the screen. Here’s the code: 1: public ActionResult Index() 2: { 3: Product product1 = new Product 4: { 5: Id = 1, 6: Name = "Product 1", 7: Quantity = 2, 8: UnitPrice = 200m 9: }; 10:   11: Product product2 = new Product 12: { 13: Id = 2, 14: Name = "Product 2", 15: Quantity = 1, 16: UnitPrice = 150m 17: }; 18:   19: List<Product> products = new List<Product> { product1, product2 }; 20:   21: Basket basket = new Basket 22: { 23: Products = products, 24: Totals = ComputeTotals(products) 25: }; 26: return View(basket); 27: } 28:   29: [HttpPost] 30: public ActionResult Index(Basket basket) 31: { 32: basket.Totals = ComputeTotals(basket.Products); 33: return View(basket); 34: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } That’s that. Now I run the app, I see two products with the totals section below them. I look at the view source and I see that the input controls have the right ID, the right name and the right value as well. 1: <input id="ID" name="ID" type="text" value="1" /> 2: <input id="Name" name="Name" type="text" value="Product 1" /> 3: ... 4: <input id="ID" name="ID" type="text" value="2" /> 5: <input id="Name" name="Name" type="text" value="Product 2" /> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } So just as a regular user would do, I change the quantity value of one of the products and hit the submit button. The ‘post’ version of the Index method gets called and I had put a break-point on line 32 in the above snippet. When I hovered my mouse on the ‘basked’ object, happily assuming that the object would be all bound and ready for use, I was surprised to see both basket.Products and basket.Totals were null. Huh? A little research and I found out that the reason the DefaultModelBinder could not do its job is because of a naming mismatch on the input controls. What I mean is that when you have to bind to a custom .net type, you need more than just the property name. You need to pass a qualified name to the name property of the input control. I modified my view and the emitted code looked as below: 1: <input id="Product_Name" name="Product.Name" type="text" value="Product 1" /> 2: ... 3: <input id="Product_Name" name="Product.Name" type="text" value="Product 2" /> 4: ... 5: <input id="Totals_SubTotal" name="Totals.SubTotal" type="text" value="550" /> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now, I update the quantity and hit the submit button and I see that the Totals object is populated, but the Products list is still null. Once again I went: ‘Hmm.. time for more research’. I found out that the way to do this is to provide the name as: 1: <%= Html.TextBox(string.Format("Products[{0}].ID", i), Model.Products[i].Id) %> 2: <!-- this will be rendered as --> 3: <input id="Products_0__ID" name="Products[0].ID" type="text" value="1" /> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } It was only now that I was able to see both the products and the totals being properly bound in the ‘post’ action method. Somehow, I feel this is kinda ‘clunky’ way of doing things. Seems like people at MS felt in a similar way and offered us a much cleaner way to solve this issue. The simple solution is that instead of using a Textbox, we can either use a TextboxFor or an EditorFor helper method. This one directly spits out the name of the input property as ‘Products[0].ID and so on. Cool right? I totally fell for this and changed my UI to contain EditorFor helper method. At this point, I ran the application, changed the quantity field and pressed the submit button. Of course my basket object parameter in my action method was correctly bound after these changes. I let the app complete the rest of the lines in the action method. When the page finally rendered, I did see that the quantity was changed to what I entered before the post. But, wait a minute, the totals section did not reflect the changes and showed the old values. My status: COMPLETELY PUZZLED! Just to recap, this is what my ‘post’ Index method looked like: 1: [HttpPost] 2: public ActionResult Index(Basket basket) 3: { 4: basket.Totals = ComputeTotals(basket.Products); 5: return View(basket); 6: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } A careful debug confirmed that the basked.Products[0].Quantity showed the updated value and the ComputeTotals() method also returns the correct totals. But still when I passed this basket object, it ended up showing the old totals values only. I began playing a bit with the code and my first guess was that the input controls got their values from the ModelState object. For those who don’t know, the ModelState is a temporary storage area that ASP.NET MVC uses to retain incoming attempted values plus binding and validation errors. Also, the fact that input controls populate the values using data taken from: Previously attempted values recorded in the ModelState["name"].Value.AttemptedValue Explicitly provided value (<%= Html.TextBox("name", "Some value") %>) ViewData, by calling ViewData.Eval("name") FYI: ViewData dictionary takes precedence over ViewData's Model properties – read more here. These two indicators led to my guess. It took me quite some time, but finally I hit this post where Brad brilliantly explains why this is the preferred behavior. My guess was right and I, accordingly modified my code to reflect the following way: 1: [HttpPost] 2: public ActionResult Index(Basket basket) 3: { 4: // read the following posts to see why the ModelState 5: // needs to be cleared before passing it the view 6: // http://forums.asp.net/t/1535846.aspx 7: // http://forums.asp.net/p/1527149/3687407.aspx 8: if (ModelState.IsValid) 9: { 10: ModelState.Clear(); 11: } 12:   13: basket.Totals = ComputeTotals(basket.Products); 14: return View(basket); 15: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } What this does is that in the case where your ModelState IS valid, it clears the dictionary. This enables the values to be read from the model directly and not from the ModelState. So the verdict is this: If you need to pass other parameters (like html attributes and the like) to your input control, use 1: <%= Html.TextBox(string.Format("Products[{0}].ID", i), Model.Products[i].Id) %> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Since, in EditorFor, there is no direct and simple way of passing this information to the input control. If you don’t have to pass any such ‘extra’ piece of information to the control, then go the EditorFor way. The code used in the post can be found here.

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• Facebook page design is not working in IE8 [closed]

  - by PrateekSaluja

  Hello Experts, We have designed a face book page.It is working fine in all browser including IE7 but it is not working in IE8.We checked then we got if we run our code outside the face book page it works in IE8 but when we put our code into face book page its not working.Here is the css code what we are using for IE8. <!--[if lt IE 8]> <style> .nv_a { width:90px; height:27px; float:left; text-align:center; padding-top:8px; } .nvt_a { width:66px; height:27px; float:left; text-align:center; padding-top:8px; } .nv_a a { width:90px; height:27px; float:left; padding-top:8px; text-align:center; color:#000; display:inline-block; text-decoration:none; background-color:#e0e0e0; border-top:solid 1px #999; border-left:solid 1px #999; border-right:solid 1px #999; border-bottom:solid 1px #999; } .nv_a a:hover { width:90px; height:27px; padding-top:8px; float:left; color:#000; text-align:center; background-color:#ccc; } .nvt_a a { width:66px; height:27px; float:left; padding-top:8px; text-align:center; color:#000; display:inline-block; text-decoration:none; background-color:#e0e0e0; border-top:solid 1px #999; border-left:solid 1px #999; border-right:solid 1px #999; border-bottom:solid 1px #999; border:1px solid red; } Please help us to solve the issue.

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