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  • Blackberry Player, custom data source

    - by Alex
    Hello I must create a custom media player within the application with support for mp3 and wav files. I read in the documentation i cant seek or get the media file duration without a custom datasoruce. I checked the demo in the JDE 4.6 but i have still problems... I cant get the duration, it return much more then the expected so i`m sure i screwed up something while i modified the code to read the mp3 file locally from the filesystem. Somebody can help me what i did wrong ? (I can hear the mp3, so the player plays it correctly from start to end) I must support OSs = 4.6. Thank You Here is my modified datasource LimitedRateStreaminSource.java * Copyright © 1998-2009 Research In Motion Ltd. Note: For the sake of simplicity, this sample application may not leverage resource bundles and resource strings. However, it is STRONGLY recommended that application developers make use of the localization features available within the BlackBerry development platform to ensure a seamless application experience across a variety of languages and geographies. For more information on localizing your application, please refer to the BlackBerry Java Development Environment Development Guide associated with this release. */ package com.halcyon.tawkwidget.model; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import javax.microedition.io.Connector; import javax.microedition.io.file.FileConnection; import javax.microedition.media.Control; import javax.microedition.media.protocol.ContentDescriptor; import javax.microedition.media.protocol.DataSource; import javax.microedition.media.protocol.SourceStream; import net.rim.device.api.io.SharedInputStream; /** * The data source used by the BufferedPlayback's media player. / public final class LimitedRateStreamingSource extends DataSource { /* The max size to be read from the stream at one time. */ private static final int READ_CHUNK = 512; // bytes /** A reference to the field which displays the load status. */ //private TextField _loadStatusField; /** A reference to the field which displays the player status. */ //private TextField _playStatusField; /** * The minimum number of bytes that must be buffered before the media file * will begin playing. */ private int _startBuffer = 200000; /** The maximum size (in bytes) of a single read. */ private int _readLimit = 32000; /** * The minimum forward byte buffer which must be maintained in order for * the video to keep playing. If the forward buffer falls below this * number, the playback will pause until the buffer increases. */ private int _pauseBytes = 64000; /** * The minimum forward byte buffer required to resume * playback after a pause. */ private int _resumeBytes = 128000; /** The stream connection over which media content is passed. */ //private ContentConnection _contentConnection; private FileConnection _fileConnection; /** An input stream shared between several readers. */ private SharedInputStream _readAhead; /** A stream to the buffered resource. */ private LimitedRateSourceStream _feedToPlayer; /** The MIME type of the remote media file. */ private String _forcedContentType; /** A counter for the total number of buffered bytes */ private volatile int _totalRead; /** A flag used to tell the connection thread to stop */ private volatile boolean _stop; /** * A flag used to indicate that the initial buffering is complete. In * other words, that the current buffer is larger than the defined start * buffer size. */ private volatile boolean _bufferingComplete; /** A flag used to indicate that the remote file download is complete. */ private volatile boolean _downloadComplete; /** The thread which retrieves the remote media file. */ private ConnectionThread _loaderThread; /** The local save file into which the remote file is written. */ private FileConnection _saveFile; /** A stream for the local save file. */ private OutputStream _saveStream; /** * Constructor. * @param locator The locator that describes the DataSource. */ public LimitedRateStreamingSource(String locator) { super(locator); } /** * Open a connection to the locator. * @throws IOException */ public void connect() throws IOException { //Open the connection to the remote file. _fileConnection = (FileConnection)Connector.open(getLocator(), Connector.READ); //Cache a reference to the locator. String locator = getLocator(); //Report status. System.out.println("Loading: " + locator); //System.out.println("Size: " + _contentConnection.getLength()); System.out.println("Size: " + _fileConnection.totalSize()); //The name of the remote file begins after the last forward slash. int filenameStart = locator.lastIndexOf('/'); //The file name ends at the first instance of a semicolon. int paramStart = locator.indexOf(';'); //If there is no semicolon, the file name ends at the end of the line. if (paramStart < 0) { paramStart = locator.length(); } //Extract the file name. String filename = locator.substring(filenameStart, paramStart); System.out.println("Filename: " + filename); //Open a local save file with the same name as the remote file. _saveFile = (FileConnection) Connector.open("file:///SDCard/blackberry/music" + filename, Connector.READ_WRITE); //If the file doesn't already exist, create it. if (!_saveFile.exists()) { _saveFile.create(); } System.out.println("---------- 1"); //Open the file for writing. _saveFile.setReadable(true); //Open a shared input stream to the local save file to //allow many simultaneous readers. SharedInputStream fileStream = SharedInputStream.getSharedInputStream(_saveFile.openInputStream()); //Begin reading at the beginning of the file. fileStream.setCurrentPosition(0); System.out.println("---------- 2"); //If the local file is smaller than the remote file... if (_saveFile.fileSize() < _fileConnection.totalSize()) { System.out.println("---------- 3"); //Did not get the entire file, set the system to try again. _saveFile.setWritable(true); System.out.println("---------- 4"); //A non-null save stream is used as a flag later to indicate that //the file download was incomplete. _saveStream = _saveFile.openOutputStream(); System.out.println("---------- 5"); //Use a new shared input stream for buffered reading. _readAhead = SharedInputStream.getSharedInputStream(_fileConnection.openInputStream()); System.out.println("---------- 6"); } else { //The download is complete. System.out.println("---------- 7"); _downloadComplete = true; //We can use the initial input stream to read the buffered media. _readAhead = fileStream; System.out.println("---------- 8"); //We can close the remote connection. _fileConnection.close(); System.out.println("---------- 9"); } if (_forcedContentType != null) { //Use the user-defined content type if it is set. System.out.println("---------- 10"); _feedToPlayer = new LimitedRateSourceStream(_readAhead, _forcedContentType); System.out.println("---------- 11"); } else { System.out.println("---------- 12"); //Otherwise, use the MIME types of the remote file. // _feedToPlayer = new LimitedRateSourceStream(_readAhead, _fileConnection)); } System.out.println("---------- 13"); } /** * Destroy and close all existing connections. */ public void disconnect() { try { if (_saveStream != null) { //Destroy the stream to the local save file. _saveStream.close(); _saveStream = null; } //Close the local save file. _saveFile.close(); if (_readAhead != null) { //Close the reader stream. _readAhead.close(); _readAhead = null; } //Close the remote file connection. _fileConnection.close(); //Close the stream to the player. _feedToPlayer.close(); } catch (Exception e) { System.err.println(e.getMessage()); } } /** * Returns the content type of the remote file. * @return The content type of the remote file. */ public String getContentType() { return _feedToPlayer.getContentDescriptor().getContentType(); } /** * Returns a stream to the buffered resource. * @return A stream to the buffered resource. */ public SourceStream[] getStreams() { return new SourceStream[] { _feedToPlayer }; } /** * Starts the connection thread used to download the remote file. */ public void start() throws IOException { //If the save stream is null, we have already completely downloaded //the file. if (_saveStream != null) { //Open the connection thread to finish downloading the file. _loaderThread = new ConnectionThread(); _loaderThread.start(); } } /** * Stop the connection thread. */ public void stop() throws IOException { //Set the boolean flag to stop the thread. _stop = true; } /** * @see javax.microedition.media.Controllable#getControl(String) */ public Control getControl(String controlType) { // No implemented Controls. return null; } /** * @see javax.microedition.media.Controllable#getControls() */ public Control[] getControls() { // No implemented Controls. return null; } /** * Force the lower level stream to a given content type. Must be called * before the connect function in order to work. * @param contentType The content type to use. */ public void setContentType(String contentType) { _forcedContentType = contentType; } /** * A stream to the buffered media resource. */ private final class LimitedRateSourceStream implements SourceStream { /** A stream to the local copy of the remote resource. */ private SharedInputStream _baseSharedStream; /** Describes the content type of the media file. */ private ContentDescriptor _contentDescriptor; /** * Constructor. Creates a LimitedRateSourceStream from * the given InputStream. * @param inputStream The input stream used to create a new reader. * @param contentType The content type of the remote file. */ LimitedRateSourceStream(InputStream inputStream, String contentType) { System.out.println("[LimitedRateSoruceStream]---------- 1"); _baseSharedStream = SharedInputStream.getSharedInputStream(inputStream); System.out.println("[LimitedRateSoruceStream]---------- 2"); _contentDescriptor = new ContentDescriptor(contentType); System.out.println("[LimitedRateSoruceStream]---------- 3"); } /** * Returns the content descriptor for this stream. * @return The content descriptor for this stream. */ public ContentDescriptor getContentDescriptor() { return _contentDescriptor; } /** * Returns the length provided by the connection. * @return long The length provided by the connection. */ public long getContentLength() { return _fileConnection.totalSize(); } /** * Returns the seek type of the stream. */ public int getSeekType() { return RANDOM_ACCESSIBLE; //return SEEKABLE_TO_START; } /** * Returns the maximum size (in bytes) of a single read. */ public int getTransferSize() { return _readLimit; } /** * Writes bytes from the buffer into a byte array for playback. * @param bytes The buffer into which the data is read. * @param off The start offset in array b at which the data is written. * @param len The maximum number of bytes to read. * @return the total number of bytes read into the buffer, or -1 if * there is no more data because the end of the stream has been reached. * @throws IOException */ public int read(byte[] bytes, int off, int len) throws IOException { System.out.println("[LimitedRateSoruceStream]---------- 5"); System.out.println("Read Request for: " + len + " bytes"); //Limit bytes read to our readLimit. int readLength = len; System.out.println("[LimitedRateSoruceStream]---------- 6"); if (readLength > getReadLimit()) { readLength = getReadLimit(); } //The number of available byes in the buffer. int available; //A boolean flag indicating that the thread should pause //until the buffer has increased sufficiently. boolean paused = false; System.out.println("[LimitedRateSoruceStream]---------- 7"); for (;;) { available = _baseSharedStream.available(); System.out.println("[LimitedRateSoruceStream]---------- 8"); if (_downloadComplete) { //Ignore all restrictions if downloading is complete. System.out.println("Complete, Reading: " + len + " - Available: " + available); return _baseSharedStream.read(bytes, off, len); } else if(_bufferingComplete) { if (paused && available > getResumeBytes()) { //If the video is paused due to buffering, but the //number of available byes is sufficiently high, //resume playback of the media. System.out.println("Resuming - Available: " + available); paused = false; return _baseSharedStream.read(bytes, off, readLength); } else if(!paused && (available > getPauseBytes() || available > readLength)) { //We have enough information for this media playback. if (available < getPauseBytes()) { //If the buffer is now insufficient, set the //pause flag. paused = true; } System.out.println("Reading: " + readLength + " - Available: " + available); return _baseSharedStream.read(bytes, off, readLength); } else if(!paused) { //Set pause until loaded enough to resume. paused = true; } } else { //We are not ready to start yet, try sleeping to allow the //buffer to increase. try { Thread.sleep(500); } catch (Exception e) { System.err.println(e.getMessage()); } } } } /** * @see javax.microedition.media.protocol.SourceStream#seek(long) */ public long seek(long where) throws IOException { _baseSharedStream.setCurrentPosition((int) where); return _baseSharedStream.getCurrentPosition(); } /** * @see javax.microedition.media.protocol.SourceStream#tell() */ public long tell() { return _baseSharedStream.getCurrentPosition(); } /** * Close the stream. * @throws IOException */ void close() throws IOException { _baseSharedStream.close(); } /** * @see javax.microedition.media.Controllable#getControl(String) */ public Control getControl(String controlType) { // No implemented controls. return null; } /** * @see javax.microedition.media.Controllable#getControls() */ public Control[] getControls() { // No implemented controls. return null; } } /** * A thread which downloads the remote file and writes it to the local file. */ private final class ConnectionThread extends Thread { /** * Download the remote media file, then write it to the local * file. * @see java.lang.Thread#run() */ public void run() { try { byte[] data = new byte[READ_CHUNK]; int len = 0; //Until we reach the end of the file. while (-1 != (len = _readAhead.read(data))) { _totalRead += len; if (!_bufferingComplete && _totalRead > getStartBuffer()) { //We have enough of a buffer to begin playback. _bufferingComplete = true; System.out.println("Initial Buffering Complete"); } if (_stop) { //Stop reading. return; } } System.out.println("Downloading Complete"); System.out.println("Total Read: " + _totalRead); //If the downloaded data is not the same size //as the remote file, something is wrong. if (_totalRead != _fileConnection.totalSize()) { System.err.println("* Unable to Download entire file *"); } _downloadComplete = true; _readAhead.setCurrentPosition(0); //Write downloaded data to the local file. while (-1 != (len = _readAhead.read(data))) { _saveStream.write(data); } } catch (Exception e) { System.err.println(e.toString()); } } } /** * Gets the minimum forward byte buffer which must be maintained in * order for the video to keep playing. * @return The pause byte buffer. */ int getPauseBytes() { return _pauseBytes; } /** * Sets the minimum forward buffer which must be maintained in order * for the video to keep playing. * @param pauseBytes The new pause byte buffer. */ void setPauseBytes(int pauseBytes) { _pauseBytes = pauseBytes; } /** * Gets the maximum size (in bytes) of a single read. * @return The maximum size (in bytes) of a single read. */ int getReadLimit() { return _readLimit; } /** * Sets the maximum size (in bytes) of a single read. * @param readLimit The new maximum size (in bytes) of a single read. */ void setReadLimit(int readLimit) { _readLimit = readLimit; } /** * Gets the minimum forward byte buffer required to resume * playback after a pause. * @return The resume byte buffer. */ int getResumeBytes() { return _resumeBytes; } /** * Sets the minimum forward byte buffer required to resume * playback after a pause. * @param resumeBytes The new resume byte buffer. */ void setResumeBytes(int resumeBytes) { _resumeBytes = resumeBytes; } /** * Gets the minimum number of bytes that must be buffered before the * media file will begin playing. * @return The start byte buffer. */ int getStartBuffer() { return _startBuffer; } /** * Sets the minimum number of bytes that must be buffered before the * media file will begin playing. * @param startBuffer The new start byte buffer. */ void setStartBuffer(int startBuffer) { _startBuffer = startBuffer; } } And in this way i use it: LimitedRateStreamingSource source = new LimitedRateStreamingSource("file:///SDCard/music3.mp3"); source.setContentType("audio/mpeg"); mediaPlayer = javax.microedition.media.Manager.createPlayer(source); mediaPlayer.addPlayerListener(this); mediaPlayer.realize(); mediaPlayer.prefetch(); After start i use mediaPlayer.getDuration it returns lets say around 24:22 (the inbuild media player in the blackberry say the file length is 4:05) I tried to get the duration in the listener and there unfortunatly returned around 64 minutes, so im sure something is not good inside the datasoruce....

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  • XSLT templates and recursion

    - by user333411
    Hi All, Im new to XSLT and am having some problems trying to format an XML document which has recursive nodes. My XML Code: Hopefully my XML shows: All <item> are nested with <items> An item can have either just attributes, or sub nodes The level to which <item> nodes are nested can be infinently deep <?xml version="1.0" encoding="utf-8" ?> - <items> <item groupID="1" name="Home" url="//" /> - <item groupID="2" name="Guides" url="/Guides/"> - <items> - <item groupID="26" name="Online-Poker-Guide" url="/Guides/Online-Poker-Guide/"> - <items> - <item> <id>107</id> - <title> - <![CDATA[ Poker Betting - Online Poker Betting Structures ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/online-poker-betting-structures ]]> </url> </item> - <item> <id>114</id> - <title> - <![CDATA[ Beginners&#39; Poker - Poker Hand Ranking ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/online-poker-hand-ranking ]]> </url> </item> - <item> <id>115</id> - <title> - <![CDATA[ Poker Terms - 4th Street and 5th Street ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/online-poker-poker-terms ]]> </url> </item> - <item> <id>116</id> - <title> - <![CDATA[ Popular Poker - The Popularity of Texas Hold&#39;em ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/online-poker-popularity-texas-holdem ]]> </url> </item> - <item> <id>364</id> - <title> - <![CDATA[ The Impact of Traditional Poker on Online Poker (and vice versa) ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/online-poker-tradional-vs-online ]]> </url> </item> - <item> <id>365</id> - <title> - <![CDATA[ The Ultimate, Absolute Online Poker Scandal ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/online-poker-scandal ]]> </url> </item> </items> - <items> - <item groupID="27" name="Beginners-Poker" url="/Guides/Online-Poker-Guide/Beginners-Poker/"> - <items> + <item> <id>101</id> - <title> - <![CDATA[ Poker Betting - All-in On the Flop ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/poker-betting-all-in-on-the-flop ]]> </url> </item> + <item> <id>102</id> - <title> - <![CDATA[ Beginners&#39; Poker - Choosing an Online Poker Room ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/beginners-poker-choosing-a-room ]]> </url> </item> + <item> <id>105</id> - <title> - <![CDATA[ Beginners&#39; Poker - Choosing What Type of Poker to Play ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/beginners-poker-choosing-type-to-play ]]> </url> </item> + <item> <id>106</id> - <title> - <![CDATA[ Online Poker - Different Types of Online Poker ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/online-poker ]]> </url> </item> + <item> <id>109</id> - <title> - <![CDATA[ Online Poker - Opening an Account at an Online Poker Site ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/online-poker-opening-an-account ]]> </url> </item> + <item> <id>111</id> - <title> - <![CDATA[ Beginners&#39; Poker - Poker Glossary ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/beginners-poker-glossary ]]> </url> </item> + <item> <id>117</id> - <title> - <![CDATA[ Poker Betting - What is a Blind? ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/poker-betting-what-is-a-blind ]]> </url> </item> - <item> <id>118</id> - <title> - <![CDATA[ Poker Betting - What is an Ante? ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/poker-betting-what-is-an-ante ]]> </url> </item> + <item> <id>119</id> - <title> - <![CDATA[ Beginners Poker - What is Bluffing? ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/online-poker-what-is-bluffing ]]> </url> </item> - <item> <id>120</id> - <title> - <![CDATA[ Poker Games - What is Community Card Poker? ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/online-poker-what-is-community-card-poker ]]> </url> </item> - <item> <id>121</id> - <title> - <![CDATA[ Online Poker - What is Online Poker? ]]> </title> - <url> - <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/online-poker-what-is-online-poker ]]> </url> </item> </items> </item> </items> </item> </items> </item> </items> The XSL code: <?xml version="1.0" encoding="ISO-8859-1"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output method="html" indent="yes"/> <xsl:template name="loop"> <xsl:for-each select="items/item"> <ul> <li><xsl:value-of select="@name" /></li> <xsl:if test="@name and child::node()"> <ul> <xsl:for-each select="items/item"> <li><xsl:value-of select="@name" />test</li> </xsl:for-each> </ul> <xsl:call-template name="loop" /> </xsl:if> <xsl:if test="child::node() and not(@name)"> <xsl:for-each select="/items"> <li><xsl:value-of select="id" /></li> </xsl:for-each> </xsl:if> </ul> </xsl:for-each> <xsl:for-each select="item/items/item"> <li>hi</li> </xsl:for-each> </xsl:template> <xsl:template match="/" name="test"> <xsl:call-template name="loop" /> </xsl:template> </xsl:stylesheet> Im trying to write the XSL so that every <items> node will render a <ul> and every <items> node will render an <li>. The XSL needs to be recursive because i cant tell how deep the nested nodes will go. Can anyone help? Regards, Al

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  • JGoodies HashMap

    - by JohnMcClane
    Hi, I'm trying to build a chart program using presentation model. Using JGoodies for data binding was relatively easy for simple types like strings or numbers. But I can't figure out how to use it on a hashmap. I'll try to explain how the chart works and what my problem is: A chart consists of DataSeries, a DataSeries consists of DataPoints. I want to have a data model and to be able to use different views on the same model (e.g. bar chart, pie chart,...). Each of them consists of three classes. For example: DataPointModel: holds the data model (value, label, category) DataPointViewModel: extends JGoodies PresentationModel. wraps around DataPointModel and holds view properties like font and color. DataPoint: abstract class, extends JComponent. Different Views must subclass and implement their own ui. Binding and creating the data model was easy, but i don't know how to bind my data series model. package at.onscreen.chart; import java.beans.PropertyChangeListener; import java.beans.PropertyChangeSupport; import java.beans.PropertyVetoException; import java.util.Collection; import java.util.HashMap; import java.util.Iterator; public class DataSeriesModel { public static String PROPERTY_DATAPOINT = "dataPoint"; public static String PROPERTY_DATAPOINTS = "dataPoints"; public static String PROPERTY_LABEL = "label"; public static String PROPERTY_MAXVALUE = "maxValue"; /** * holds the data points */ private HashMap dataPoints; /** * the label for the data series */ private String label; /** * the maximum data point value */ private Double maxValue; /** * the model supports property change notification */ private PropertyChangeSupport propertyChangeSupport; /** * default constructor */ public DataSeriesModel() { this.maxValue = Double.valueOf(0); this.dataPoints = new HashMap(); this.propertyChangeSupport = new PropertyChangeSupport(this); } /** * constructor * @param label - the series label */ public DataSeriesModel(String label) { this.dataPoints = new HashMap(); this.maxValue = Double.valueOf(0); this.label = label; this.propertyChangeSupport = new PropertyChangeSupport(this); } /** * full constructor * @param label - the series label * @param dataPoints - an array of data points */ public DataSeriesModel(String label, DataPoint[] dataPoints) { this.dataPoints = new HashMap(); this.propertyChangeSupport = new PropertyChangeSupport(this); this.maxValue = Double.valueOf(0); this.label = label; for (int i = 0; i < dataPoints.length; i++) { this.addDataPoint(dataPoints[i]); } } /** * full constructor * @param label - the series label * @param dataPoints - a collection of data points */ public DataSeriesModel(String label, Collection dataPoints) { this.dataPoints = new HashMap(); this.propertyChangeSupport = new PropertyChangeSupport(this); this.maxValue = Double.valueOf(0); this.label = label; for (Iterator it = dataPoints.iterator(); it.hasNext();) { this.addDataPoint(it.next()); } } /** * adds a new data point to the series. if the series contains a data point with same id, it will be replaced by the new one. * @param dataPoint - the data point */ public void addDataPoint(DataPoint dataPoint) { String category = dataPoint.getCategory(); DataPoint oldDataPoint = this.getDataPoint(category); this.dataPoints.put(category, dataPoint); this.setMaxValue(Math.max(this.maxValue, dataPoint.getValue())); this.propertyChangeSupport.firePropertyChange(PROPERTY_DATAPOINT, oldDataPoint, dataPoint); } /** * returns the data point with given id or null if not found * @param uid - the id of the data point * @return the data point or null if there is no such point in the table */ public DataPoint getDataPoint(String category) { return this.dataPoints.get(category); } /** * removes the data point with given id from the series, if present * @param category - the data point to remove */ public void removeDataPoint(String category) { DataPoint dataPoint = this.getDataPoint(category); this.dataPoints.remove(category); if (dataPoint != null) { if (dataPoint.getValue() == this.getMaxValue()) { Double maxValue = Double.valueOf(0); for (Iterator it = this.iterator(); it.hasNext();) { DataPoint itDataPoint = it.next(); maxValue = Math.max(itDataPoint.getValue(), maxValue); } this.setMaxValue(maxValue); } } this.propertyChangeSupport.firePropertyChange(PROPERTY_DATAPOINT, dataPoint, null); } /** * removes all data points from the series * @throws PropertyVetoException */ public void removeAll() { this.setMaxValue(Double.valueOf(0)); this.dataPoints.clear(); this.propertyChangeSupport.firePropertyChange(PROPERTY_DATAPOINTS, this.getDataPoints(), null); } /** * returns the maximum of all data point values * @return the maximum of all data points */ public Double getMaxValue() { return this.maxValue; } /** * sets the max value * @param maxValue - the max value */ protected void setMaxValue(Double maxValue) { Double oldMaxValue = this.getMaxValue(); this.maxValue = maxValue; this.propertyChangeSupport.firePropertyChange(PROPERTY_MAXVALUE, oldMaxValue, maxValue); } /** * returns true if there is a data point with given category * @param category - the data point category * @return true if there is a data point with given category, otherwise false */ public boolean contains(String category) { return this.dataPoints.containsKey(category); } /** * returns the label for the series * @return the label for the series */ public String getLabel() { return this.label; } /** * returns an iterator over the data points * @return an iterator over the data points */ public Iterator iterator() { return this.dataPoints.values().iterator(); } /** * returns a collection of the data points. the collection supports removal, but does not support adding of data points. * @return a collection of data points */ public Collection getDataPoints() { return this.dataPoints.values(); } /** * returns the number of data points in the series * @return the number of data points */ public int getSize() { return this.dataPoints.size(); } /** * adds a PropertyChangeListener * @param listener - the listener */ public void addPropertyChangeListener(PropertyChangeListener listener) { this.propertyChangeSupport.addPropertyChangeListener(listener); } /** * removes a PropertyChangeListener * @param listener - the listener */ public void removePropertyChangeListener(PropertyChangeListener listener) { this.propertyChangeSupport.removePropertyChangeListener(listener); } } package at.onscreen.chart; import java.beans.PropertyVetoException; import java.util.Collection; import java.util.Iterator; import com.jgoodies.binding.PresentationModel; public class DataSeriesViewModel extends PresentationModel { /** * default constructor */ public DataSeriesViewModel() { super(new DataSeriesModel()); } /** * constructor * @param label - the series label */ public DataSeriesViewModel(String label) { super(new DataSeriesModel(label)); } /** * full constructor * @param label - the series label * @param dataPoints - an array of data points */ public DataSeriesViewModel(String label, DataPoint[] dataPoints) { super(new DataSeriesModel(label, dataPoints)); } /** * full constructor * @param label - the series label * @param dataPoints - a collection of data points */ public DataSeriesViewModel(String label, Collection dataPoints) { super(new DataSeriesModel(label, dataPoints)); } /** * full constructor * @param model - the data series model */ public DataSeriesViewModel(DataSeriesModel model) { super(model); } /** * adds a data point to the series * @param dataPoint - the data point */ public void addDataPoint(DataPoint dataPoint) { this.getBean().addDataPoint(dataPoint); } /** * returns true if there is a data point with given category * @param category - the data point category * @return true if there is a data point with given category, otherwise false */ public boolean contains(String category) { return this.getBean().contains(category); } /** * returns the data point with given id or null if not found * @param uid - the id of the data point * @return the data point or null if there is no such point in the table */ public DataPoint getDataPoint(String category) { return this.getBean().getDataPoint(category); } /** * returns a collection of the data points. the collection supports removal, but does not support adding of data points. * @return a collection of data points */ public Collection getDataPoints() { return this.getBean().getDataPoints(); } /** * returns the label for the series * @return the label for the series */ public String getLabel() { return this.getBean().getLabel(); } /** * sets the max value * @param maxValue - the max value */ public Double getMaxValue() { return this.getBean().getMaxValue(); } /** * returns the number of data points in the series * @return the number of data points */ public int getSize() { return this.getBean().getSize(); } /** * returns an iterator over the data points * @return an iterator over the data points */ public Iterator iterator() { return this.getBean().iterator(); } /** * removes all data points from the series * @throws PropertyVetoException */ public void removeAll() { this.getBean().removeAll(); } /** * removes the data point with given id from the series, if present * @param category - the data point to remove */ public void removeDataPoint(String category) { this.getBean().removeDataPoint(category); } } package at.onscreen.chart; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import java.beans.PropertyVetoException; import java.util.Collection; import java.util.Iterator; import javax.swing.JComponent; public abstract class DataSeries extends JComponent implements PropertyChangeListener { /** * the model */ private DataSeriesViewModel model; /** * default constructor */ public DataSeries() { this.model = new DataSeriesViewModel(); this.model.addPropertyChangeListener(this); this.createComponents(); } /** * constructor * @param label - the series label */ public DataSeries(String label) { this.model = new DataSeriesViewModel(label); this.model.addPropertyChangeListener(this); this.createComponents(); } /** * full constructor * @param label - the series label * @param dataPoints - an array of data points */ public DataSeries(String label, DataPoint[] dataPoints) { this.model = new DataSeriesViewModel(label, dataPoints); this.model.addPropertyChangeListener(this); this.createComponents(); } /** * full constructor * @param label - the series label * @param dataPoints - a collection of data points */ public DataSeries(String label, Collection dataPoints) { this.model = new DataSeriesViewModel(label, dataPoints); this.model.addPropertyChangeListener(this); this.createComponents(); } /** * full constructor * @param model - the model */ public DataSeries(DataSeriesViewModel model) { this.model = model; this.model.addPropertyChangeListener(this); this.createComponents(); } /** * creates, binds and configures UI components. * data point properties can be created here as components or be painted in paintComponent. */ protected abstract void createComponents(); @Override public void propertyChange(PropertyChangeEvent evt) { this.repaint(); } /** * adds a data point to the series * @param dataPoint - the data point */ public void addDataPoint(DataPoint dataPoint) { this.model.addDataPoint(dataPoint); } /** * returns true if there is a data point with given category * @param category - the data point category * @return true if there is a data point with given category, otherwise false */ public boolean contains(String category) { return this.model.contains(category); } /** * returns the data point with given id or null if not found * @param uid - the id of the data point * @return the data point or null if there is no such point in the table */ public DataPoint getDataPoint(String category) { return this.model.getDataPoint(category); } /** * returns a collection of the data points. the collection supports removal, but does not support adding of data points. * @return a collection of data points */ public Collection getDataPoints() { return this.model.getDataPoints(); } /** * returns the label for the series * @return the label for the series */ public String getLabel() { return this.model.getLabel(); } /** * sets the max value * @param maxValue - the max value */ public Double getMaxValue() { return this.model.getMaxValue(); } /** * returns the number of data points in the series * @return the number of data points */ public int getDataPointCount() { return this.model.getSize(); } /** * returns an iterator over the data points * @return an iterator over the data points */ public Iterator iterator() { return this.model.iterator(); } /** * removes all data points from the series * @throws PropertyVetoException */ public void removeAll() { this.model.removeAll(); } /** * removes the data point with given id from the series, if present * @param category - the data point to remove */ public void removeDataPoint(String category) { this.model.removeDataPoint(category); } /** * returns the data series view model * @return - the data series view model */ public DataSeriesViewModel getViewModel() { return this.model; } /** * returns the data series model * @return - the data series model */ public DataSeriesModel getModel() { return this.model.getBean(); } } package at.onscreen.chart.builder; import java.util.Collection; import net.miginfocom.swing.MigLayout; import at.onscreen.chart.DataPoint; import at.onscreen.chart.DataSeries; import at.onscreen.chart.DataSeriesViewModel; public class BuilderDataSeries extends DataSeries { /** * default constructor */ public BuilderDataSeries() { super(); } /** * constructor * @param label - the series label */ public BuilderDataSeries(String label) { super(label); } /** * full constructor * @param label - the series label * @param dataPoints - an array of data points */ public BuilderDataSeries(String label, DataPoint[] dataPoints) { super(label, dataPoints); } /** * full constructor * @param label - the series label * @param dataPoints - a collection of data points */ public BuilderDataSeries(String label, Collection dataPoints) { super(label, dataPoints); } /** * full constructor * @param model - the model */ public BuilderDataSeries(DataSeriesViewModel model) { super(model); } @Override protected void createComponents() { this.setLayout(new MigLayout()); /* * * I want to add a new BuilderDataPoint for each data point in the model. * I want the BuilderDataPoints to be synchronized with the model. * e.g. when a data point is removed from the model, the BuilderDataPoint shall be removed * from the BuilderDataSeries * */ } } package at.onscreen.chart.builder; import javax.swing.JFormattedTextField; import javax.swing.JTextField; import at.onscreen.chart.DataPoint; import at.onscreen.chart.DataPointModel; import at.onscreen.chart.DataPointViewModel; import at.onscreen.chart.ValueFormat; import com.jgoodies.binding.adapter.BasicComponentFactory; import com.jgoodies.binding.beans.BeanAdapter; public class BuilderDataPoint extends DataPoint { /** * default constructor */ public BuilderDataPoint() { super(); } /** * constructor * @param category - the category */ public BuilderDataPoint(String category) { super(category); } /** * constructor * @param value - the value * @param label - the label * @param category - the category */ public BuilderDataPoint(Double value, String label, String category) { super(value, label, category); } /** * full constructor * @param model - the model */ public BuilderDataPoint(DataPointViewModel model) { super(model); } @Override protected void createComponents() { BeanAdapter beanAdapter = new BeanAdapter(this.getModel(), true); ValueFormat format = new ValueFormat(); JFormattedTextField value = BasicComponentFactory.createFormattedTextField(beanAdapter.getValueModel(DataPointModel.PROPERTY_VALUE), format); this.add(value, "w 80, growx, wrap"); JTextField label = BasicComponentFactory.createTextField(beanAdapter.getValueModel(DataPointModel.PROPERTY_LABEL)); this.add(label, "growx, wrap"); JTextField category = BasicComponentFactory.createTextField(beanAdapter.getValueModel(DataPointModel.PROPERTY_CATEGORY)); this.add(category, "growx, wrap"); } } To sum it up: I need to know how to bind a hash map property to JComponent.components property. JGoodies is in my opinion not very well documented, I spent a long time searching through the internet, but I did not find any solution to my problem. Hope you can help me.

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  • jQuery - Why editable-select list plugin doesn't work with latest jQuery?

    - by Binyamin
    Why editable-select list plugin<select><option>value</option>doesn't work with latest jQuery? editable-select code: /** * Copyright (c) 2009 Anders Ekdahl (http://coffeescripter.com/) * Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php) * and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses. * * Version: 1.3.1 * * Demo and documentation: http://coffeescripter.com/code/editable-select/ */ (function($) { var instances = []; $.fn.editableSelect = function(options) { var defaults = { bg_iframe: false, onSelect: false, items_then_scroll: 10, case_sensitive: false }; var settings = $.extend(defaults, options); // Only do bg_iframe for browsers that need it if(settings.bg_iframe && !$.browser.msie) { settings.bg_iframe = false; }; var instance = false; $(this).each(function() { var i = instances.length; if(typeof $(this).data('editable-selecter') == 'undefined') { instances[i] = new EditableSelect(this, settings); $(this).data('editable-selecter', i); }; }); return $(this); }; $.fn.editableSelectInstances = function() { var ret = []; $(this).each(function() { if(typeof $(this).data('editable-selecter') != 'undefined') { ret[ret.length] = instances[$(this).data('editable-selecter')]; }; }); return ret; }; var EditableSelect = function(select, settings) { this.init(select, settings); }; EditableSelect.prototype = { settings: false, text: false, select: false, wrapper: false, list_item_height: 20, list_height: 0, list_is_visible: false, hide_on_blur_timeout: false, bg_iframe: false, current_value: '', init: function(select, settings) { this.settings = settings; this.select = $(select); this.text = $('<input type="text">'); this.text.attr('name', this.select.attr('name')); this.text.data('editable-selecter', this.select.data('editable-selecter')); // Because we don't want the value of the select when the form // is submitted this.select.attr('disabled', 'disabled'); var id = this.select.attr('id'); if(!id) { id = 'editable-select'+ instances.length; }; this.text.attr('id', id); this.text.attr('autocomplete', 'off'); this.text.addClass('editable-select'); this.select.attr('id', id +'_hidden_select'); this.initInputEvents(this.text); this.duplicateOptions(); this.positionElements(); this.setWidths(); if(this.settings.bg_iframe) { this.createBackgroundIframe(); }; }, duplicateOptions: function() { var context = this; var wrapper = $(document.createElement('div')); wrapper.addClass('editable-select-options'); var option_list = $(document.createElement('ul')); wrapper.append(option_list); var options = this.select.find('option'); options.each(function() { if($(this).attr('selected')) { context.text.val($(this).val()); context.current_value = $(this).val(); }; var li = $('<li>'+ $(this).val() +'</li>'); context.initListItemEvents(li); option_list.append(li); }); this.wrapper = wrapper; this.checkScroll(); }, checkScroll: function() { var options = this.wrapper.find('li'); if(options.length > this.settings.items_then_scroll) { this.list_height = this.list_item_height * this.settings.items_then_scroll; this.wrapper.css('height', this.list_height +'px'); this.wrapper.css('overflow', 'auto'); } else { this.wrapper.css('height', 'auto'); this.wrapper.css('overflow', 'visible'); }; }, addOption: function(value) { var li = $('<li>'+ value +'</li>'); var option = $('<option>'+ value +'</option>'); this.select.append(option); this.initListItemEvents(li); this.wrapper.find('ul').append(li); this.setWidths(); this.checkScroll(); }, initInputEvents: function(text) { var context = this; var timer = false; $(document.body).click( function() { context.clearSelectedListItem(); context.hideList(); } ); text.focus( function() { // Can't use the blur event to hide the list, because the blur event // is fired in some browsers when you scroll the list context.showList(); context.highlightSelected(); } ).click( function(e) { e.stopPropagation(); context.showList(); context.highlightSelected(); } ).keydown( // Capture key events so the user can navigate through the list function(e) { switch(e.keyCode) { // Down case 40: if(!context.listIsVisible()) { context.showList(); context.highlightSelected(); } else { e.preventDefault(); context.selectNewListItem('down'); }; break; // Up case 38: e.preventDefault(); context.selectNewListItem('up'); break; // Tab case 9: context.pickListItem(context.selectedListItem()); break; // Esc case 27: e.preventDefault(); context.hideList(); return false; break; // Enter, prevent form submission case 13: e.preventDefault(); context.pickListItem(context.selectedListItem()); return false; }; } ).keyup( function(e) { // Prevent lots of calls if it's a fast typer if(timer !== false) { clearTimeout(timer); timer = false; }; timer = setTimeout( function() { // If the user types in a value, select it if it's in the list if(context.text.val() != context.current_value) { context.current_value = context.text.val(); context.highlightSelected(); }; }, 200 ); } ).keypress( function(e) { if(e.keyCode == 13) { // Enter, prevent form submission e.preventDefault(); return false; }; } ); }, initListItemEvents: function(list_item) { var context = this; list_item.mouseover( function() { context.clearSelectedListItem(); context.selectListItem(list_item); } ).mousedown( // Needs to be mousedown and not click, since the inputs blur events // fires before the list items click event function(e) { e.stopPropagation(); context.pickListItem(context.selectedListItem()); } ); }, selectNewListItem: function(direction) { var li = this.selectedListItem(); if(!li.length) { li = this.selectFirstListItem(); }; if(direction == 'down') { var sib = li.next(); } else { var sib = li.prev(); }; if(sib.length) { this.selectListItem(sib); this.scrollToListItem(sib); this.unselectListItem(li); }; }, selectListItem: function(list_item) { this.clearSelectedListItem(); list_item.addClass('selected'); }, selectFirstListItem: function() { this.clearSelectedListItem(); var first = this.wrapper.find('li:first'); first.addClass('selected'); return first; }, unselectListItem: function(list_item) { list_item.removeClass('selected'); }, selectedListItem: function() { return this.wrapper.find('li.selected'); }, clearSelectedListItem: function() { this.wrapper.find('li.selected').removeClass('selected'); }, pickListItem: function(list_item) { if(list_item.length) { this.text.val(list_item.text()); this.current_value = this.text.val(); }; if(typeof this.settings.onSelect == 'function') { this.settings.onSelect.call(this, list_item); }; this.hideList(); }, listIsVisible: function() { return this.list_is_visible; }, showList: function() { this.wrapper.show(); this.hideOtherLists(); this.list_is_visible = true; if(this.settings.bg_iframe) { this.bg_iframe.show(); }; }, highlightSelected: function() { var context = this; var current_value = this.text.val(); if(current_value.length < 0) { if(highlight_first) { this.selectFirstListItem(); }; return; }; if(!context.settings.case_sensitive) { current_value = current_value.toLowerCase(); }; var best_candiate = false; var value_found = false; var list_items = this.wrapper.find('li'); list_items.each( function() { if(!value_found) { var text = $(this).text(); if(!context.settings.case_sensitive) { text = text.toLowerCase(); }; if(text == current_value) { value_found = true; context.clearSelectedListItem(); context.selectListItem($(this)); context.scrollToListItem($(this)); return false; } else if(text.indexOf(current_value) === 0 && !best_candiate) { // Can't do return false here, since we still need to iterate over // all list items to see if there is an exact match best_candiate = $(this); }; }; } ); if(best_candiate && !value_found) { context.clearSelectedListItem(); context.selectListItem(best_candiate); context.scrollToListItem(best_candiate); } else if(!best_candiate && !value_found) { this.selectFirstListItem(); }; }, scrollToListItem: function(list_item) { if(this.list_height) { this.wrapper.scrollTop(list_item[0].offsetTop - (this.list_height / 2)); }; }, hideList: function() { this.wrapper.hide(); this.list_is_visible = false; if(this.settings.bg_iframe) { this.bg_iframe.hide(); }; }, hideOtherLists: function() { for(var i = 0; i < instances.length; i++) { if(i != this.select.data('editable-selecter')) { instances[i].hideList(); }; }; }, positionElements: function() { var offset = this.select.offset(); offset.top += this.select[0].offsetHeight; this.select.after(this.text); this.select.hide(); this.wrapper.css({top: offset.top +'px', left: offset.left +'px'}); $(document.body).append(this.wrapper); // Need to do this in order to get the list item height this.wrapper.css('visibility', 'hidden'); this.wrapper.show(); this.list_item_height = this.wrapper.find('li')[0].offsetHeight; this.wrapper.css('visibility', 'visible'); this.wrapper.hide(); }, setWidths: function() { // The text input has a right margin because of the background arrow image // so we need to remove that from the width var width = this.select.width() + 2; var padding_right = parseInt(this.text.css('padding-right').replace(/px/, ''), 10); this.text.width(width - padding_right); this.wrapper.width(width + 2); if(this.bg_iframe) { this.bg_iframe.width(width + 4); }; }, createBackgroundIframe: function() { var bg_iframe = $('<iframe frameborder="0" class="editable-select-iframe" src="about:blank;"></iframe>'); $(document.body).append(bg_iframe); bg_iframe.width(this.select.width() + 2); bg_iframe.height(this.wrapper.height()); bg_iframe.css({top: this.wrapper.css('top'), left: this.wrapper.css('left')}); this.bg_iframe = bg_iframe; } }; })(jQuery); $(function() { $('.editable-select').editableSelect( { bg_iframe: true, onSelect: function(list_item) { alert('List item text: '+ list_item.text()); // 'this' is a reference to the instance of EditableSelect // object, so you have full access to everything there // alert('Input value: '+ this.text.val()); }, case_sensitive: false, // If set to true, the user has to type in an exact // match for the item to get highlighted items_then_scroll: 10 // If there are more than 10 items, display a scrollbar } ); var select = $('.editable-select:first'); var instances = select.editableSelectInstances(); // instances[0].addOption('Germany, value added programmatically'); });

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  • Problems Allocating Objects of Derived Class Where Base Class has Abstract Virtual Functions

    - by user1743901
    I am trying to get this Zombie/Human agent based simulation running, but I am having problems with these derived classes (Human and Zombie) who have parent class "Creature". I have 3 virtual functions declared in "Creature" and all three of these are re-declared AND DEFINED in both "Human" and "Zombie". But for some reason when I have my program call "new" to allocate memory for objects of type Human or Zombie, it complains about the virtual functions being abstract. Here's the code: definitions.h #ifndef definitions_h #define definitions_h class Creature; class Item; class Coords; class Grid { public: Creature*** cboard; Item*** iboard; int WIDTH; int HEIGHT; Grid(int WIDTHVALUE, int HEIGHTVALUE); void FillGrid(); //initializes grid object with humans and zombies void Refresh(); //calls Creature::Die(),Move(),Attack(),Breed() on every square void UpdateBuffer(char** buffer); bool isEmpty(int startx, int starty, int dir); char CreatureType(int xcoord, int ycoord); char CreatureType(int startx, int starty, int dir); }; class Random { public: int* rptr; void Print(); Random(int MIN, int MAX, int LEN); ~Random(); private: bool alreadyused(int checkthis, int len, int* rptr); bool isClean(); int len; }; class Coords { public: int x; int y; int MaxX; int MaxY; Coords() {x=0; y=0; MaxX=0; MaxY=0;} Coords(int X, int Y, int WIDTH, int HEIGHT) {x=X; y=Y; MaxX=WIDTH; MaxY=HEIGHT; } void MoveRight(); void MoveLeft(); void MoveUp(); void MoveDown(); void MoveUpRight(); void MoveUpLeft(); void MoveDownRight(); void MoveDownLeft(); void MoveDir(int dir); void setx(int X) {x=X;} void sety(int Y) {y=Y;} }; class Creature { public: bool alive; Coords Location; char displayletter; Creature() {Location.x=0; Location.y=0;} Creature(int i, int j) {Location.setx(i); Location.sety(j);} virtual void Attack() =0; virtual void AttackCreature(Grid G, int attackdirection) =0; virtual void Breed() =0; void Die(); void Move(Grid G); int DecideSquare(Grid G); void MoveTo(Grid G, int dir); }; class Human : public Creature { public: bool armed; //if armed, chances of winning fight increased for next fight bool vaccinated; //if vaccinated, no chance of getting infected int bitecount; //if a human is bitten, bite count is set to a random number int breedcount; //if a human goes x steps without combat, will breed if next to a human int starvecount; //if a human does not eat in x steps, will die Human() {displayletter='H';} Human(int i, int j) {displayletter='H';} void Attack(Grid G); void AttackCreature(Grid G, int attackdirection); void Breed(Grid G); //will breed after x steps and next to human int DecideAttack(Grid G); }; class Zombie : public Creature { public: Zombie() {displayletter='Z';} Zombie(int i, int j) {displayletter='Z';} void Attack(Grid G); void AttackCreature(Grid G, int attackdirection); void Breed() {} //does nothing int DecideAttack(Grid G); void AttackCreature(Grid G, int attackdirection); }; class Item { }; #endif definitions.cpp #include <cstdlib> #include "definitions.h" Random::Random(int MIN, int MAX, int LEN) //constructor { len=LEN; rptr=new int[LEN]; //allocate array of given length for (int i=0; i<LEN; i++) { int random; do { random = rand() % (MAX-MIN+1) + MIN; } while (alreadyused(random,LEN,rptr)); rptr[i]=random; } } bool Random::alreadyused(int checkthis, int len, int* rptr) { for (int i=0; i<len; i++) { if (rptr[i]==checkthis) return 1; } return 0; } Random::~Random() { delete rptr; } Grid::Grid(int WIDTHVALUE, int HEIGHTVALUE) { WIDTH = WIDTHVALUE; HEIGHT = HEIGHTVALUE; //builds 2d array of creature pointers cboard = new Creature**[WIDTH]; for(int i=0; i<WIDTH; i++) { cboard[i] = new Creature*[HEIGHT]; } //builds 2d array of item pointers iboard = new Item**[WIDTH]; for (int i=0; i<WIDTH; i++) { iboard[i] = new Item*[HEIGHT]; } } void Grid::FillGrid() { /* For each creature pointer in grid, randomly selects whether to initalize as zombie, human, or empty square. This methodology can be changed to initialize different creature types with different probabilities */ int random; for (int i=0; i<WIDTH; i++) { for (int j=0; j<HEIGHT; j++) { Random X(1,100,1); //create a single random integer from [1,100] at X.rptr random=*(X.rptr); if (random < 20) cboard[i][j] = new Human(i,j); else if (random < 40) cboard[i][j] = new Zombie(i,j); else cboard[i][j] = NULL; } } //at this point every creature pointer should be pointing to either //a zombie, human, or NULL with varying probabilities } void Grid::UpdateBuffer(char** buffer) { for (int i=0; i<WIDTH; i++) { for (int j=0; j<HEIGHT; j++) { if (cboard[i][j]) buffer[i][j]=cboard[i][j]->displayletter; else buffer[i][j]=' '; } } } bool Grid::isEmpty(int startx, int starty, int dir) { Coords StartLocation(startx,starty,WIDTH,HEIGHT); switch(dir) { case 1: StartLocation.MoveUp(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 2: StartLocation.MoveUpRight(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 3: StartLocation.MoveRight(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 4: StartLocation.MoveDownRight(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 5: StartLocation.MoveDown(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 6: StartLocation.MoveDownLeft(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 7: StartLocation.MoveLeft(); if (cboard[StartLocation.x][StartLocation.y]) return 0; case 8: StartLocation.MoveUpLeft(); if (cboard[StartLocation.x][StartLocation.y]) return 0; } return 1; } char Grid::CreatureType(int xcoord, int ycoord) { if (cboard[xcoord][ycoord]) //if there is a creature at location xcoord,ycoord return (cboard[xcoord][ycoord]->displayletter); else //if pointer at location xcoord,ycoord is null, return null char return '\0'; } char Grid::CreatureType(int startx, int starty, int dir) { Coords StartLocation(startx,starty,WIDTH,HEIGHT); switch(dir) { case 1: StartLocation.MoveUp(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 2: StartLocation.MoveUpRight(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 3: StartLocation.MoveRight(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 4: StartLocation.MoveDownRight(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 5: StartLocation.MoveDown(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 6: StartLocation.MoveDownLeft(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 7: StartLocation.MoveLeft(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); case 8: StartLocation.MoveUpLeft(); if (cboard[StartLocation.x][StartLocation.y]) return (cboard[StartLocation.x][StartLocation.y]->displayletter); } //if function hasn't returned by now, square being looked at is pointer to null return '\0'; //return null char } void Coords::MoveRight() {(x==MaxX)? (x=0):(x++);} void Coords::MoveLeft() {(x==0)? (x=MaxX):(x--);} void Coords::MoveUp() {(y==0)? (y=MaxY):(y--);} void Coords::MoveDown() {(y==MaxY)? (y=0):(y++);} void Coords::MoveUpRight() {MoveUp(); MoveRight();} void Coords::MoveUpLeft() {MoveUp(); MoveLeft();} void Coords::MoveDownRight() {MoveDown(); MoveRight();} void Coords::MoveDownLeft() {MoveDown(); MoveLeft();} void Coords::MoveDir(int dir) { switch(dir) { case 1: MoveUp(); break; case 2: MoveUpRight(); break; case 3: MoveRight(); break; case 4: MoveDownRight(); break; case 5: MoveDown(); break; case 6: MoveDownLeft(); break; case 7: MoveLeft(); break; case 8: MoveUpLeft(); break; case 0: break; } } void Creature::Move(Grid G) { int movedir=DecideSquare(G); MoveTo(G,movedir); } int Creature::DecideSquare(Grid G) { Random X(1,8,8); //X.rptr now points to 8 unique random integers from [1,8] for (int i=0; i<8; i++) { int dir=X.rptr[i]; if (G.isEmpty(Location.x,Location.y,dir)) return dir; } return 0; } void Creature::MoveTo(Grid G, int dir) { Coords OldLocation=Location; Location.MoveDir(dir); G.cboard[Location.x][Location.y]=this; //point new location to this creature G.cboard[OldLocation.x][OldLocation.y]=NULL; //point old location to NULL } void Creature::Die() { if (!alive) { delete this; this=NULL; } } void Human::Breed(Grid G) { if (!breedcount) { Coords BreedLocation=Location; Random X(1,8,8); for (int i=0; i<8; i++) { BreedLocation.MoveDir(X.rptr[i]); if (!G.cboard[BreedLocation.x][BreedLocation.y]) { G.cboard[BreedLocation.x][BreedLocation.y])=new Human(BreedLocation.x,BreedLocation.y); return; } } } } int Human::DecideAttack(Grid G) { Coords AttackLocation=Location; Random X(1,8,8); int attackdir; for (int i=0; i<8; i++) { attackdir=X.rptr[i]; switch(G.CreatureType(Location.x,Location.y,attackdir)) { case 'H': break; case 'Z': return attackdir; case '\0': break; default: break; } } return 0; //no zombies! } int AttackRoll(int para1, int para2) { //outcome 1: Zombie wins, human dies //outcome 2: Human wins, zombie dies //outcome 3: Human wins, zombie dies, but human is bitten Random X(1,100,1); int roll= *(X.rptr); if (roll < para1) return 1; else if (roll < para2) return 2; else return 3; } void Human::AttackCreature(Grid G, int attackdirection) { Coords AttackLocation=Location; AttackLocation.MoveDir(attackdirection); int para1=33; int para2=33; if (vaccinated) para2=101; //makes attackroll > para 2 impossible, never gets infected if (armed) para1-=16; //reduces chance of zombie winning fight int roll=AttackRoll(para1,para2); //outcome 1: Zombie wins, human dies //outcome 2: Human wins, zombie dies //outcome 3: Human wins, zombie dies, but human is bitten switch(roll) { case 1: alive=0; //human (this) dies return; case 2: G.cboard[AttackLocation.x][AttackLocation.y]->alive=0; return; //zombie dies case 3: G.cboard[AttackLocation.x][AttackLocation.y]->alive=0; //zombie dies Random X(3,7,1); //human is bitten bitecount=*(X.rptr); return; } } int Zombie::DecideAttack(Grid G) { Coords AttackLocation=Location; Random X(1,8,8); int attackdir; for (int i=0; i<8; i++) { attackdir=X.rptr[i]; switch(G.CreatureType(Location.x,Location.y,attackdir)) { case 'H': return attackdir; case 'Z': break; case '\0': break; default: break; } } return 0; //no zombies! } void Zombie::AttackCreature(Grid G, int attackdirection) { int reversedirection; if (attackdirection < 9 && attackdirection>0) { (attackdirection<5)? (reversedirection=attackdirection+4):(reversedirection=attackdirection-4); } else reversedirection=0; //this should never happen //when a zombie attacks a human, the Human::AttackZombie() function is called //in the "reverse" direction, utilizing that function that has already been written Coords ZombieLocation=Location; Coords HumanLocation=Location; HumanLocation.MoveDir(attackdirection); if (G.cboard[HumanLocation.x][HumanLocation.y]) //if there is a human there, which there should be G.cboard[HumanLocation.x][HumanLocation.y]->AttackCreature(G,reversedirection); } void Zombie::Attack(Grid G) { int attackdirection=DecideAttack(G); AttackCreature(G,attackdirection); } main.cpp #include <cstdlib> #include <iostream> #include "definitions.h" using namespace std; int main(int argc, char *argv[]) { Grid G(500,500); system("PAUSE"); return EXIT_SUCCESS; }

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  • C++/boost generator module, feedback/critic please

    - by aaa
    hello. I wrote this generator, and I think to submit to boost people. Can you give me some feedback about it it basically allows to collapse multidimensional loops to flat multi-index queue. Loop can be boost lambda expressions. Main reason for doing this is to make parallel loops easier and separate algorithm from controlling structure (my fieldwork is computational chemistry where deep loops are common) 1 #ifndef _GENERATOR_HPP_ 2 #define _GENERATOR_HPP_ 3 4 #include <boost/array.hpp> 5 #include <boost/lambda/lambda.hpp> 6 #include <boost/noncopyable.hpp> 7 8 #include <boost/mpl/bool.hpp> 9 #include <boost/mpl/int.hpp> 10 #include <boost/mpl/for_each.hpp> 11 #include <boost/mpl/range_c.hpp> 12 #include <boost/mpl/vector.hpp> 13 #include <boost/mpl/transform.hpp> 14 #include <boost/mpl/erase.hpp> 15 16 #include <boost/fusion/include/vector.hpp> 17 #include <boost/fusion/include/for_each.hpp> 18 #include <boost/fusion/include/at_c.hpp> 19 #include <boost/fusion/mpl.hpp> 20 #include <boost/fusion/include/as_vector.hpp> 21 22 #include <memory> 23 24 /** 25 for loop generator which can use lambda expressions. 26 27 For example: 28 @code 29 using namespace generator; 30 using namespace boost::lambda; 31 make_for(N, N, range(bind(std::max<int>, _1, _2), N), range(_2, _3+1)); 32 // equivalent to pseudocode 33 // for l=0,N: for k=0,N: for j=max(l,k),N: for i=k,j 34 @endcode 35 36 If range is given as upper bound only, 37 lower bound is assumed to be default constructed 38 Lambda placeholders may only reference first three indices. 39 */ 40 41 namespace generator { 42 namespace detail { 43 44 using boost::lambda::constant_type; 45 using boost::lambda::constant; 46 47 /// lambda expression identity 48 template<class E, class enable = void> 49 struct lambda { 50 typedef E type; 51 }; 52 53 /// transform/construct constant lambda expression from non-lambda 54 template<class E> 55 struct lambda<E, typename boost::disable_if< 56 boost::lambda::is_lambda_functor<E> >::type> 57 { 58 struct constant : boost::lambda::constant_type<E>::type { 59 typedef typename boost::lambda::constant_type<E>::type base_type; 60 constant() : base_type(boost::lambda::constant(E())) {} 61 constant(const E &e) : base_type(boost::lambda::constant(e)) {} 62 }; 63 typedef constant type; 64 }; 65 66 /// range functor 67 template<class L, class U> 68 struct range_ { 69 typedef boost::array<int,4> index_type; 70 range_(U upper) : bounds_(typename lambda<L>::type(), upper) {} 71 range_(L lower, U upper) : bounds_(lower, upper) {} 72 73 template< typename T, size_t N> 74 T lower(const boost::array<T,N> &index) { 75 return bound<0>(index); 76 } 77 78 template< typename T, size_t N> 79 T upper(const boost::array<T,N> &index) { 80 return bound<1>(index); 81 } 82 83 private: 84 template<bool b, typename T> 85 T bound(const boost::array<T,1> &index) { 86 return (boost::fusion::at_c<b>(bounds_))(index[0]); 87 } 88 89 template<bool b, typename T> 90 T bound(const boost::array<T,2> &index) { 91 return (boost::fusion::at_c<b>(bounds_))(index[0], index[1]); 92 } 93 94 template<bool b, typename T, size_t N> 95 T bound(const boost::array<T,N> &index) { 96 using boost::fusion::at_c; 97 return (at_c<b>(bounds_))(index[0], index[1], index[2]); 98 } 99 100 boost::fusion::vector<typename lambda<L>::type, 101 typename lambda<U>::type> bounds_; 102 }; 103 104 template<typename T, size_t N> 105 struct for_base { 106 typedef boost::array<T,N> value_type; 107 virtual ~for_base() {} 108 virtual value_type next() = 0; 109 }; 110 111 /// N-index generator 112 template<typename T, size_t N, class R, class I> 113 struct for_ : for_base<T,N> { 114 typedef typename for_base<T,N>::value_type value_type; 115 typedef R range_tuple; 116 for_(const range_tuple &r) : r_(r), state_(true) { 117 boost::fusion::for_each(r_, initialize(index)); 118 } 119 /// @return new generator 120 for_* new_() { return new for_(r_); } 121 /// @return next index value and increment 122 value_type next() { 123 value_type next; 124 using namespace boost::lambda; 125 typename value_type::iterator n = next.begin(); 126 typename value_type::iterator i = index.begin(); 127 boost::mpl::for_each<I>(*(var(n))++ = var(i)[_1]); 128 129 state_ = advance<N>(r_, index); 130 return next; 131 } 132 /// @return false if out of bounds, true otherwise 133 operator bool() { return state_; } 134 135 private: 136 /// initialize indices 137 struct initialize { 138 value_type &index_; 139 mutable size_t i_; 140 initialize(value_type &index) : index_(index), i_(0) {} 141 template<class R_> void operator()(R_& r) const { 142 index_[i_++] = r.lower(index_); 143 } 144 }; 145 146 /// advance index[0:M) 147 template<size_t M> 148 struct advance { 149 /// stop recursion 150 struct stop { 151 stop(R r, value_type &index) {} 152 }; 153 /// advance index 154 /// @param r range tuple 155 /// @param index index array 156 advance(R &r, value_type &index) : index_(index), i_(0) { 157 namespace fusion = boost::fusion; 158 index[M-1] += 1; // increment index 159 fusion::for_each(r, *this); // update indices 160 state_ = index[M-1] >= fusion::at_c<M-1>(r).upper(index); 161 if (state_) { // out of bounds 162 typename boost::mpl::if_c<(M > 1), 163 advance<M-1>, stop>::type(r, index); 164 } 165 } 166 /// apply lower bound of range to index 167 template<typename R_> void operator()(R_& r) const { 168 if (i_ >= M) index_[i_] = r.lower(index_); 169 ++i_; 170 } 171 /// @return false if out of bounds, true otherwise 172 operator bool() { return state_; } 173 private: 174 value_type &index_; ///< index array reference 175 mutable size_t i_; ///< running index 176 bool state_; ///< out of bounds state 177 }; 178 179 value_type index; 180 range_tuple r_; 181 bool state_; 182 }; 183 184 185 /// polymorphic generator template base 186 template<typename T,size_t N> 187 struct For : boost::noncopyable { 188 typedef boost::array<T,N> value_type; 189 /// @return next index value and increment 190 value_type next() { return for_->next(); } 191 /// @return false if out of bounds, true otherwise 192 operator bool() const { return for_; } 193 protected: 194 /// reset smart pointer 195 void reset(for_base<T,N> *f) { for_.reset(f); } 196 std::auto_ptr<for_base<T,N> > for_; 197 }; 198 199 /// range [T,R) type 200 template<typename T, typename R> 201 struct range_type { 202 typedef range_<T,R> type; 203 }; 204 205 /// range identity specialization 206 template<typename T, class L, class U> 207 struct range_type<T, range_<L,U> > { 208 typedef range_<L,U> type; 209 }; 210 211 namespace fusion = boost::fusion; 212 namespace mpl = boost::mpl; 213 214 template<typename T, size_t N, class R1, class R2, class R3, class R4> 215 struct range_tuple { 216 // full range vector 217 typedef typename mpl::vector<R1,R2,R3,R4> v; 218 typedef typename mpl::end<v>::type end; 219 typedef typename mpl::advance_c<typename mpl::begin<v>::type, N>::type pos; 220 // [0:N) range vector 221 typedef typename mpl::erase<v, pos, end>::type t; 222 // transform into proper range fusion::vector 223 typedef typename fusion::result_of::as_vector< 224 typename mpl::transform<t,range_type<T, mpl::_1> >::type 225 >::type type; 226 }; 227 228 229 template<typename T, size_t N, 230 class R1, class R2, class R3, class R4, 231 class O> 232 struct for_type { 233 typedef typename range_tuple<T,N,R1,R2,R3,R4>::type range_tuple; 234 typedef for_<T, N, range_tuple, O> type; 235 }; 236 237 } // namespace detail 238 239 240 /// default index order, [0:N) 241 template<size_t N> 242 struct order { 243 typedef boost::mpl::range_c<size_t,0, N> type; 244 }; 245 246 /// N-loop generator, 0 < N <= 5 247 /// @tparam T index type 248 /// @tparam N number of indices/loops 249 /// @tparam R1,... range types 250 /// @tparam O index order 251 template<typename T, size_t N, 252 class R1, class R2 = void, class R3 = void, class R4 = void, 253 class O = typename order<N>::type> 254 struct for_ : detail::for_type<T, N, R1, R2, R3, R4, O>::type { 255 typedef typename detail::for_type<T, N, R1, R2, R3, R4, O>::type base_type; 256 typedef typename base_type::range_tuple range_tuple; 257 for_(const range_tuple &range) : base_type(range) {} 258 }; 259 260 /// loop range [L:U) 261 /// @tparam L lower bound type 262 /// @tparam U upper bound type 263 /// @return range 264 template<class L, class U> 265 detail::range_<L,U> range(L lower, U upper) { 266 return detail::range_<L,U>(lower, upper); 267 } 268 269 /// make 4-loop generator with specified index ordering 270 template<typename T, class R1, class R2, class R3, class R4, class O> 271 for_<T, 4, R1, R2, R3, R4, O> 272 make_for(R1 r1, R2 r2, R3 r3, R4 r4, const O&) { 273 typedef for_<T, 4, R1, R2, R3, R4, O> F; 274 return F(F::range_tuple(r1, r2, r3, r4)); 275 } 276 277 /// polymorphic generator template forward declaration 278 template<typename T,size_t N> 279 struct For; 280 281 /// polymorphic 4-loop generator 282 template<typename T> 283 struct For<T,4> : detail::For<T,4> { 284 /// generator with default index ordering 285 template<class R1, class R2, class R3, class R4> 286 For(R1 r1, R2 r2, R3 r3, R4 r4) { 287 this->reset(make_for<T>(r1, r2, r3, r4).new_()); 288 } 289 /// generator with specified index ordering 290 template<class R1, class R2, class R3, class R4, class O> 291 For(R1 r1, R2 r2, R3 r3, R4 r4, O o) { 292 this->reset(make_for<T>(r1, r2, r3, r4, o).new_()); 293 } 294 }; 295 296 } 297 298 299 #endif /* _GENERATOR_HPP_ */

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  • What are good design practices when working with Entity Framework

    - by AD
    This will apply mostly for an asp.net application where the data is not accessed via soa. Meaning that you get access to the objects loaded from the framework, not Transfer Objects, although some recommendation still apply. This is a community post, so please add to it as you see fit. Applies to: Entity Framework 1.0 shipped with Visual Studio 2008 sp1. Why pick EF in the first place? Considering it is a young technology with plenty of problems (see below), it may be a hard sell to get on the EF bandwagon for your project. However, it is the technology Microsoft is pushing (at the expense of Linq2Sql, which is a subset of EF). In addition, you may not be satisfied with NHibernate or other solutions out there. Whatever the reasons, there are people out there (including me) working with EF and life is not bad.make you think. EF and inheritance The first big subject is inheritance. EF does support mapping for inherited classes that are persisted in 2 ways: table per class and table the hierarchy. The modeling is easy and there are no programming issues with that part. (The following applies to table per class model as I don't have experience with table per hierarchy, which is, anyway, limited.) The real problem comes when you are trying to run queries that include one or many objects that are part of an inheritance tree: the generated sql is incredibly awful, takes a long time to get parsed by the EF and takes a long time to execute as well. This is a real show stopper. Enough that EF should probably not be used with inheritance or as little as possible. Here is an example of how bad it was. My EF model had ~30 classes, ~10 of which were part of an inheritance tree. On running a query to get one item from the Base class, something as simple as Base.Get(id), the generated SQL was over 50,000 characters. Then when you are trying to return some Associations, it degenerates even more, going as far as throwing SQL exceptions about not being able to query more than 256 tables at once. Ok, this is bad, EF concept is to allow you to create your object structure without (or with as little as possible) consideration on the actual database implementation of your table. It completely fails at this. So, recommendations? Avoid inheritance if you can, the performance will be so much better. Use it sparingly where you have to. In my opinion, this makes EF a glorified sql-generation tool for querying, but there are still advantages to using it. And ways to implement mechanism that are similar to inheritance. Bypassing inheritance with Interfaces First thing to know with trying to get some kind of inheritance going with EF is that you cannot assign a non-EF-modeled class a base class. Don't even try it, it will get overwritten by the modeler. So what to do? You can use interfaces to enforce that classes implement some functionality. For example here is a IEntity interface that allow you to define Associations between EF entities where you don't know at design time what the type of the entity would be. public enum EntityTypes{ Unknown = -1, Dog = 0, Cat } public interface IEntity { int EntityID { get; } string Name { get; } Type EntityType { get; } } public partial class Dog : IEntity { // implement EntityID and Name which could actually be fields // from your EF model Type EntityType{ get{ return EntityTypes.Dog; } } } Using this IEntity, you can then work with undefined associations in other classes // lets take a class that you defined in your model. // that class has a mapping to the columns: PetID, PetType public partial class Person { public IEntity GetPet() { return IEntityController.Get(PetID,PetType); } } which makes use of some extension functions: public class IEntityController { static public IEntity Get(int id, EntityTypes type) { switch (type) { case EntityTypes.Dog: return Dog.Get(id); case EntityTypes.Cat: return Cat.Get(id); default: throw new Exception("Invalid EntityType"); } } } Not as neat as having plain inheritance, particularly considering you have to store the PetType in an extra database field, but considering the performance gains, I would not look back. It also cannot model one-to-many, many-to-many relationship, but with creative uses of 'Union' it could be made to work. Finally, it creates the side effet of loading data in a property/function of the object, which you need to be careful about. Using a clear naming convention like GetXYZ() helps in that regards. Compiled Queries Entity Framework performance is not as good as direct database access with ADO (obviously) or Linq2SQL. There are ways to improve it however, one of which is compiling your queries. The performance of a compiled query is similar to Linq2Sql. What is a compiled query? It is simply a query for which you tell the framework to keep the parsed tree in memory so it doesn't need to be regenerated the next time you run it. So the next run, you will save the time it takes to parse the tree. Do not discount that as it is a very costly operation that gets even worse with more complex queries. There are 2 ways to compile a query: creating an ObjectQuery with EntitySQL and using CompiledQuery.Compile() function. (Note that by using an EntityDataSource in your page, you will in fact be using ObjectQuery with EntitySQL, so that gets compiled and cached). An aside here in case you don't know what EntitySQL is. It is a string-based way of writing queries against the EF. Here is an example: "select value dog from Entities.DogSet as dog where dog.ID = @ID". The syntax is pretty similar to SQL syntax. You can also do pretty complex object manipulation, which is well explained [here][1]. Ok, so here is how to do it using ObjectQuery< string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); The first time you run this query, the framework will generate the expression tree and keep it in memory. So the next time it gets executed, you will save on that costly step. In that example EnablePlanCaching = true, which is unnecessary since that is the default option. The other way to compile a query for later use is the CompiledQuery.Compile method. This uses a delegate: static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => ctx.DogSet.FirstOrDefault(it => it.ID == id)); or using linq static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet where dog.ID == id select dog).FirstOrDefault()); to call the query: query_GetDog.Invoke( YourContext, id ); The advantage of CompiledQuery is that the syntax of your query is checked at compile time, where as EntitySQL is not. However, there are other consideration... Includes Lets say you want to have the data for the dog owner to be returned by the query to avoid making 2 calls to the database. Easy to do, right? EntitySQL string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)).Include("Owner"); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); CompiledQuery static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet.Include("Owner") where dog.ID == id select dog).FirstOrDefault()); Now, what if you want to have the Include parametrized? What I mean is that you want to have a single Get() function that is called from different pages that care about different relationships for the dog. One cares about the Owner, another about his FavoriteFood, another about his FavotireToy and so on. Basicly, you want to tell the query which associations to load. It is easy to do with EntitySQL public Dog Get(int id, string include) { string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)) .IncludeMany(include); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); } The include simply uses the passed string. Easy enough. Note that it is possible to improve on the Include(string) function (that accepts only a single path) with an IncludeMany(string) that will let you pass a string of comma-separated associations to load. Look further in the extension section for this function. If we try to do it with CompiledQuery however, we run into numerous problems: The obvious static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.Include(include) where dog.ID == id select dog).FirstOrDefault()); will choke when called with: query_GetDog.Invoke( YourContext, id, "Owner,FavoriteFood" ); Because, as mentionned above, Include() only wants to see a single path in the string and here we are giving it 2: "Owner" and "FavoriteFood" (which is not to be confused with "Owner.FavoriteFood"!). Then, let's use IncludeMany(), which is an extension function static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.IncludeMany(include) where dog.ID == id select dog).FirstOrDefault()); Wrong again, this time it is because the EF cannot parse IncludeMany because it is not part of the functions that is recognizes: it is an extension. Ok, so you want to pass an arbitrary number of paths to your function and Includes() only takes a single one. What to do? You could decide that you will never ever need more than, say 20 Includes, and pass each separated strings in a struct to CompiledQuery. But now the query looks like this: from dog in ctx.DogSet.Include(include1).Include(include2).Include(include3) .Include(include4).Include(include5).Include(include6) .[...].Include(include19).Include(include20) where dog.ID == id select dog which is awful as well. Ok, then, but wait a minute. Can't we return an ObjectQuery< with CompiledQuery? Then set the includes on that? Well, that what I would have thought so as well: static readonly Func<Entities, int, ObjectQuery<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, ObjectQuery<Dog>>((ctx, id) => (ObjectQuery<Dog>)(from dog in ctx.DogSet where dog.ID == id select dog)); public Dog GetDog( int id, string include ) { ObjectQuery<Dog> oQuery = query_GetDog(id); oQuery = oQuery.IncludeMany(include); return oQuery.FirstOrDefault; } That should have worked, except that when you call IncludeMany (or Include, Where, OrderBy...) you invalidate the cached compiled query because it is an entirely new one now! So, the expression tree needs to be reparsed and you get that performance hit again. So what is the solution? You simply cannot use CompiledQueries with parametrized Includes. Use EntitySQL instead. This doesn't mean that there aren't uses for CompiledQueries. It is great for localized queries that will always be called in the same context. Ideally CompiledQuery should always be used because the syntax is checked at compile time, but due to limitation, that's not possible. An example of use would be: you may want to have a page that queries which two dogs have the same favorite food, which is a bit narrow for a BusinessLayer function, so you put it in your page and know exactly what type of includes are required. Passing more than 3 parameters to a CompiledQuery Func is limited to 5 parameters, of which the last one is the return type and the first one is your Entities object from the model. So that leaves you with 3 parameters. A pitance, but it can be improved on very easily. public struct MyParams { public string param1; public int param2; public DateTime param3; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where dog.Age == myParams.param2 && dog.Name == myParams.param1 and dog.BirthDate > myParams.param3 select dog); public List<Dog> GetSomeDogs( int age, string Name, DateTime birthDate ) { MyParams myParams = new MyParams(); myParams.param1 = name; myParams.param2 = age; myParams.param3 = birthDate; return query_GetDog(YourContext,myParams).ToList(); } Return Types (this does not apply to EntitySQL queries as they aren't compiled at the same time during execution as the CompiledQuery method) Working with Linq, you usually don't force the execution of the query until the very last moment, in case some other functions downstream wants to change the query in some way: static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public IEnumerable<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name); } public void DataBindStuff() { IEnumerable<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } What is going to happen here? By still playing with the original ObjectQuery (that is the actual return type of the Linq statement, which implements IEnumerable), it will invalidate the compiled query and be force to re-parse. So, the rule of thumb is to return a List< of objects instead. static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public List<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name).ToList(); //<== change here } public void DataBindStuff() { List<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } When you call ToList(), the query gets executed as per the compiled query and then, later, the OrderBy is executed against the objects in memory. It may be a little bit slower, but I'm not even sure. One sure thing is that you have no worries about mis-handling the ObjectQuery and invalidating the compiled query plan. Once again, that is not a blanket statement. ToList() is a defensive programming trick, but if you have a valid reason not to use ToList(), go ahead. There are many cases in which you would want to refine the query before executing it. Performance What is the performance impact of compiling a query? It can actually be fairly large. A rule of thumb is that compiling and caching the query for reuse takes at least double the time of simply executing it without caching. For complex queries (read inherirante), I have seen upwards to 10 seconds. So, the first time a pre-compiled query gets called, you get a performance hit. After that first hit, performance is noticeably better than the same non-pre-compiled query. Practically the same as Linq2Sql When you load a page with pre-compiled queries the first time you will get a hit. It will load in maybe 5-15 seconds (obviously more than one pre-compiled queries will end up being called), while subsequent loads will take less than 300ms. Dramatic difference, and it is up to you to decide if it is ok for your first user to take a hit or you want a script to call your pages to force a compilation of the queries. Can this query be cached? { Dog dog = from dog in YourContext.DogSet where dog.ID == id select dog; } No, ad-hoc Linq queries are not cached and you will incur the cost of generating the tree every single time you call it. Parametrized Queries Most search capabilities involve heavily parametrized queries. There are even libraries available that will let you build a parametrized query out of lamba expressions. The problem is that you cannot use pre-compiled queries with those. One way around that is to map out all the possible criteria in the query and flag which one you want to use: public struct MyParams { public string name; public bool checkName; public int age; public bool checkAge; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where (myParams.checkAge == true && dog.Age == myParams.age) && (myParams.checkName == true && dog.Name == myParams.name ) select dog); protected List<Dog> GetSomeDogs() { MyParams myParams = new MyParams(); myParams.name = "Bud"; myParams.checkName = true; myParams.age = 0; myParams.checkAge = false; return query_GetDog(YourContext,myParams).ToList(); } The advantage here is that you get all the benifits of a pre-compiled quert. The disadvantages are that you most likely will end up with a where clause that is pretty difficult to maintain, that you will incur a bigger penalty for pre-compiling the query and that each query you run is not as efficient as it could be (particularly with joins thrown in). Another way is to build an EntitySQL query piece by piece, like we all did with SQL. protected List<Dod> GetSomeDogs( string name, int age) { string query = "select value dog from Entities.DogSet where 1 = 1 "; if( !String.IsNullOrEmpty(name) ) query = query + " and dog.Name == @Name "; if( age > 0 ) query = query + " and dog.Age == @Age "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); if( !String.IsNullOrEmpty(name) ) oQuery.Parameters.Add( new ObjectParameter( "Name", name ) ); if( age > 0 ) oQuery.Parameters.Add( new ObjectParameter( "Age", age ) ); return oQuery.ToList(); } Here the problems are: - there is no syntax checking during compilation - each different combination of parameters generate a different query which will need to be pre-compiled when it is first run. In this case, there are only 4 different possible queries (no params, age-only, name-only and both params), but you can see that there can be way more with a normal world search. - Noone likes to concatenate strings! Another option is to query a large subset of the data and then narrow it down in memory. This is particularly useful if you are working with a definite subset of the data, like all the dogs in a city. You know there are a lot but you also know there aren't that many... so your CityDog search page can load all the dogs for the city in memory, which is a single pre-compiled query and then refine the results protected List<Dod> GetSomeDogs( string name, int age, string city) { string query = "select value dog from Entities.DogSet where dog.Owner.Address.City == @City "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); oQuery.Parameters.Add( new ObjectParameter( "City", city ) ); List<Dog> dogs = oQuery.ToList(); if( !String.IsNullOrEmpty(name) ) dogs = dogs.Where( it => it.Name == name ); if( age > 0 ) dogs = dogs.Where( it => it.Age == age ); return dogs; } It is particularly useful when you start displaying all the data then allow for filtering. Problems: - Could lead to serious data transfer if you are not careful about your subset. - You can only filter on the data that you returned. It means that if you don't return the Dog.Owner association, you will not be able to filter on the Dog.Owner.Name So what is the best solution? There isn't any. You need to pick the solution that works best for you and your problem: - Use lambda-based query building when you don't care about pre-compiling your queries. - Use fully-defined pre-compiled Linq query when your object structure is not too complex. - Use EntitySQL/string concatenation when the structure could be complex and when the possible number of different resulting queries are small (which means fewer pre-compilation hits). - Use in-memory filtering when you are working with a smallish subset of the data or when you had to fetch all of the data on the data at first anyway (if the performance is fine with all the data, then filtering in memory will not cause any time to be spent in the db). Singleton access The best way to deal with your context and entities accross all your pages is to use the singleton pattern: public sealed class YourContext { private const string instanceKey = "On3GoModelKey"; YourContext(){} public static YourEntities Instance { get { HttpContext context = HttpContext.Current; if( context == null ) return Nested.instance; if (context.Items[instanceKey] == null) { On3GoEntities entity = new On3GoEntities(); context.Items[instanceKey] = entity; } return (YourEntities)context.Items[instanceKey]; } } class Nested { // Explicit static constructor to tell C# compiler // not to mark type as beforefieldinit static Nested() { } internal static readonly YourEntities instance = new YourEntities(); } } NoTracking, is it worth it? When executing a query, you can tell the framework to track the objects it will return or not. What does it mean? With tracking enabled (the default option), the framework will track what is going on with the object (has it been modified? Created? Deleted?) and will also link objects together, when further queries are made from the database, which is what is of interest here. For example, lets assume that Dog with ID == 2 has an owner which ID == 10. Dog dog = (from dog in YourContext.DogSet where dog.ID == 2 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Person owner = (from o in YourContext.PersonSet where o.ID == 10 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == true; If we were to do the same with no tracking, the result would be different. ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog = oDogQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>) (from o in YourContext.PersonSet where o.ID == 10 select o); oPersonQuery.MergeOption = MergeOption.NoTracking; Owner owner = oPersonQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Tracking is very useful and in a perfect world without performance issue, it would always be on. But in this world, there is a price for it, in terms of performance. So, should you use NoTracking to speed things up? It depends on what you are planning to use the data for. Is there any chance that the data your query with NoTracking can be used to make update/insert/delete in the database? If so, don't use NoTracking because associations are not tracked and will causes exceptions to be thrown. In a page where there are absolutly no updates to the database, you can use NoTracking. Mixing tracking and NoTracking is possible, but it requires you to be extra careful with updates/inserts/deletes. The problem is that if you mix then you risk having the framework trying to Attach() a NoTracking object to the context where another copy of the same object exist with tracking on. Basicly, what I am saying is that Dog dog1 = (from dog in YourContext.DogSet where dog.ID == 2).FirstOrDefault(); ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog2 = oDogQuery.FirstOrDefault(); dog1 and dog2 are 2 different objects, one tracked and one not. Using the detached object in an update/insert will force an Attach() that will say "Wait a minute, I do already have an object here with the same database key. Fail". And when you Attach() one object, all of its hierarchy gets attached as well, causing problems everywhere. Be extra careful. How much faster is it with NoTracking It depends on the queries. Some are much more succeptible to tracking than other. I don't have a fast an easy rule for it, but it helps. So I should use NoTracking everywhere then? Not exactly. There are some advantages to tracking object. The first one is that the object is cached, so subsequent call for that object will not hit the database. That cache is only valid for the lifetime of the YourEntities object, which, if you use the singleton code above, is the same as the page lifetime. One page request == one YourEntity object. So for multiple calls for the same object, it will load only once per page request. (Other caching mechanism could extend that). What happens when you are using NoTracking and try to load the same object multiple times? The database will be queried each time, so there is an impact there. How often do/should you call for the same object during a single page request? As little as possible of course, but it does happens. Also remember the piece above about having the associations connected automatically for your? You don't have that with NoTracking, so if you load your data in multiple batches, you will not have a link to between them: ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>)(from dog in YourContext.DogSet select dog); oDogQuery.MergeOption = MergeOption.NoTracking; List<Dog> dogs = oDogQuery.ToList(); ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>)(from o in YourContext.PersonSet select o); oPersonQuery.MergeOption = MergeOption.NoTracking; List<Person> owners = oPersonQuery.ToList(); In this case, no dog will have its .Owner property set. Some things to keep in mind when you are trying to optimize the performance. No lazy loading, what am I to do? This can be seen as a blessing in disguise. Of course it is annoying to load everything manually. However, it decreases the number of calls to the db and forces you to think about when you should load data. The more you can load in one database call the better. That was always true, but it is enforced now with this 'feature' of EF. Of course, you can call if( !ObjectReference.IsLoaded ) ObjectReference.Load(); if you want to, but a better practice is to force the framework to load the objects you know you will need in one shot. This is where the discussion about parametrized Includes begins to make sense. Lets say you have you Dog object public class Dog { public Dog Get(int id) { return YourContext.DogSet.FirstOrDefault(it => it.ID == id ); } } This is the type of function you work with all the time. It gets called from all over the place and once you have that Dog object, you will do very different things to it in different functions. First, it should be pre-compiled, because you will call that very often. Second, each different pages will want to have access to a different subset of the Dog data. Some will want the Owner, some the FavoriteToy, etc. Of course, you could call Load() for each reference you need anytime you need one. But that will generate a call to the database each time. Bad idea. So instead, each page will ask for the data it wants to see when it first request for the Dog object: static public Dog Get(int id) { return GetDog(entity,"");} static public Dog Get(int id, string includePath) { string query = "select value o " + " from YourEntities.DogSet as o " +

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