Source for org.jfree.xml.writer.RootXmlWriteHandler

   1: /* ========================================================================
   2:  * JCommon : a free general purpose class library for the Java(tm) platform
   3:  * ========================================================================
   4:  *
   5:  * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
   6:  * 
   7:  * Project Info:  http://www.jfree.org/jcommon/index.html
   8:  *
   9:  * This library is free software; you can redistribute it and/or modify it 
  10:  * under the terms of the GNU Lesser General Public License as published by 
  11:  * the Free Software Foundation; either version 2.1 of the License, or 
  12:  * (at your option) any later version.
  13:  *
  14:  * This library is distributed in the hope that it will be useful, but 
  15:  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
  16:  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
  17:  * License for more details.
  18:  *
  19:  * You should have received a copy of the GNU Lesser General Public
  20:  * License along with this library; if not, write to the Free Software
  21:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
  22:  * USA.  
  23:  *
  24:  * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
  25:  * in the United States and other countries.]
  26:  * 
  27:  * ------------------------
  28:  * RootXmlWriteHandler.java
  29:  * ------------------------
  30:  * (C) Copyright 2002-2005, by Object Refinery Limited.
  31:  *
  32:  * Original Author:  Peter Becker;
  33:  * Contributor(s):   -;
  34:  *
  35:  * $Id: RootXmlWriteHandler.java,v 1.5 2005/10/18 13:35:06 mungady Exp $
  36:  *
  37:  * Changes
  38:  * -------
  39:  * 23-Dec-2003 : Added missing Javadocs (DG);
  40:  *
  41:  */
  42: package org.jfree.xml.writer;
  43: 
  44: import java.awt.BasicStroke;
  45: import java.awt.Color;
  46: import java.awt.Font;
  47: import java.awt.GradientPaint;
  48: import java.awt.Insets;
  49: import java.awt.Paint;
  50: import java.awt.RenderingHints;
  51: import java.awt.Stroke;
  52: import java.awt.geom.Point2D;
  53: import java.awt.geom.Rectangle2D;
  54: import java.io.IOException;
  55: import java.util.ArrayList;
  56: import java.util.LinkedList;
  57: import java.util.List;
  58: import java.util.Stack;
  59: import java.util.Vector;
  60: 
  61: import org.jfree.util.ObjectUtilities;
  62: import org.jfree.xml.util.ManualMappingDefinition;
  63: import org.jfree.xml.util.MultiplexMappingDefinition;
  64: import org.jfree.xml.util.MultiplexMappingEntry;
  65: import org.jfree.xml.util.ObjectFactory;
  66: import org.jfree.xml.util.SimpleObjectFactory;
  67: import org.jfree.xml.writer.coretypes.BasicStrokeWriteHandler;
  68: import org.jfree.xml.writer.coretypes.ColorWriteHandler;
  69: import org.jfree.xml.writer.coretypes.FontWriteHandler;
  70: import org.jfree.xml.writer.coretypes.GenericWriteHandler;
  71: import org.jfree.xml.writer.coretypes.GradientPaintWriteHandler;
  72: import org.jfree.xml.writer.coretypes.InsetsWriteHandler;
  73: import org.jfree.xml.writer.coretypes.ListWriteHandler;
  74: import org.jfree.xml.writer.coretypes.Point2DWriteHandler;
  75: import org.jfree.xml.writer.coretypes.Rectangle2DWriteHandler;
  76: import org.jfree.xml.writer.coretypes.RenderingHintsWriteHandler;
  77: 
  78: /**
  79:  * A root handler for writing objects to XML format.
  80:  */
  81: public abstract class RootXmlWriteHandler {
  82: 
  83:     /** A map containg the manual mappings. */
  84:     private SimpleObjectFactory classToHandlerMapping;
  85: 
  86:     /**
  87:      * Creates a new RootXmlWrite handler with the default mappings enabled.
  88:      */
  89:     public RootXmlWriteHandler() {
  90:         this.classToHandlerMapping = new SimpleObjectFactory();
  91: 
  92:         // set up handling for Paint objects
  93:         final MultiplexMappingEntry[] paintEntries = new MultiplexMappingEntry[2];
  94:         paintEntries[0] = new MultiplexMappingEntry("color", Color.class.getName());
  95:         paintEntries[1] = new MultiplexMappingEntry("gradientPaint", GradientPaint.class.getName());
  96:         addMultiplexMapping(Paint.class, "type", paintEntries);
  97:         addManualMapping(GradientPaint.class, GradientPaintWriteHandler.class);
  98:         addManualMapping(Color.class, ColorWriteHandler.class);
  99: 
 100:         // set up handling for Point2D objects
 101:         final MultiplexMappingEntry[] point2DEntries = new MultiplexMappingEntry[2];
 102:         point2DEntries[0] = new MultiplexMappingEntry("float", Point2D.Float.class.getName());
 103:         point2DEntries[1] = new MultiplexMappingEntry("double", Point2D.Double.class.getName());
 104:         addMultiplexMapping(Point2D.class, "type", point2DEntries);
 105:         addManualMapping(Point2D.Float.class, Point2DWriteHandler.class);
 106:         addManualMapping(Point2D.Double.class, Point2DWriteHandler.class);
 107: 
 108:         // set up handling for Stroke objects
 109:         final MultiplexMappingEntry[] strokeEntries = new MultiplexMappingEntry[1];
 110:         strokeEntries[0] = new MultiplexMappingEntry("basic", BasicStroke.class.getName());
 111:         addMultiplexMapping(Stroke.class, "type", strokeEntries);
 112:         addManualMapping(BasicStroke.class, BasicStrokeWriteHandler.class);
 113: 
 114:         // set up handling for Rectangle2D objects
 115:         final MultiplexMappingEntry[] rectangle2DEntries = new MultiplexMappingEntry[2];
 116:         rectangle2DEntries[0] = new MultiplexMappingEntry(
 117:             "float", Rectangle2D.Float.class.getName()
 118:         );
 119:         rectangle2DEntries[1] = new MultiplexMappingEntry(
 120:             "double", Rectangle2D.Double.class.getName()
 121:         );
 122:         addMultiplexMapping(Rectangle2D.class, "type", rectangle2DEntries);
 123:         addManualMapping(Rectangle2D.Float.class, Rectangle2DWriteHandler.class);
 124:         addManualMapping(Rectangle2D.Double.class, Rectangle2DWriteHandler.class);
 125: 
 126:         // set up handling for List objects
 127:         final MultiplexMappingEntry[] listEntries = new MultiplexMappingEntry[4];
 128:         listEntries[0] = new MultiplexMappingEntry("array-list", ArrayList.class.getName());
 129:         listEntries[1] = new MultiplexMappingEntry("linked-list", LinkedList.class.getName());
 130:         listEntries[2] = new MultiplexMappingEntry("vector", Vector.class.getName());
 131:         listEntries[3] = new MultiplexMappingEntry("stack", Stack.class.getName());
 132:         addMultiplexMapping(List.class, "type", listEntries);
 133:         addManualMapping(LinkedList.class, ListWriteHandler.class);
 134:         addManualMapping(Vector.class, ListWriteHandler.class);
 135:         addManualMapping(ArrayList.class, ListWriteHandler.class);
 136:         addManualMapping(Stack.class, ListWriteHandler.class);
 137: 
 138:         // handle all other direct mapping types
 139:         addManualMapping(RenderingHints.class, RenderingHintsWriteHandler.class);
 140:         addManualMapping(Insets.class, InsetsWriteHandler.class);
 141:         addManualMapping(Font.class, FontWriteHandler.class);
 142:     }
 143: 
 144:     /**
 145:      * Returns the object factory.
 146:      * 
 147:      * @return the object factory.
 148:      */
 149:     protected abstract ObjectFactory getFactoryLoader();
 150: 
 151:     /**
 152:      * Adds a new manual mapping to this handler.
 153:      *
 154:      * This method provides support for the manual mapping. The manual mapping
 155:      * will become active before the multiplexers were queried. This facility
 156:      * could be used to override the model definition.
 157:      *
 158:      * @param classToWrite the class, which should be handled
 159:      * @param handler the write handler implementation for that class.
 160:      */
 161:     protected void addManualMapping(final Class classToWrite, final Class handler) {
 162:         if (handler == null) {
 163:             throw new NullPointerException("handler must not be null.");
 164:         }
 165:         if (classToWrite == null) {
 166:             throw new NullPointerException("classToWrite must not be null.");
 167:         }
 168:         if (!XmlWriteHandler.class.isAssignableFrom(handler)) {
 169:             throw new IllegalArgumentException("The given handler is no XmlWriteHandler.");
 170:         }
 171: 
 172:         this.classToHandlerMapping.addManualMapping
 173:             (new ManualMappingDefinition(classToWrite, null, handler.getName()));
 174:     }
 175: 
 176:     /**
 177:      * Adds a multiplex mapping.
 178:      * 
 179:      * @param baseClass  the base class.
 180:      * @param typeAttr  the type attribute.
 181:      * @param mdef  the mapping entries.
 182:      */
 183:     protected void addMultiplexMapping(final Class baseClass,
 184:                                        final String typeAttr,
 185:                                        final MultiplexMappingEntry[] mdef) {
 186:         
 187:         this.classToHandlerMapping.addMultiplexMapping(
 188:             new MultiplexMappingDefinition(baseClass, typeAttr, mdef)
 189:         );
 190:         
 191:     }
 192: 
 193:     /**
 194:      * Tries to find the mapping for the given class. This will first check
 195:      * the manual mapping and then try to use the object factory to resolve
 196:      * the class parameter into a write handler.
 197:      *
 198:      * @param classToWrite the class for which to find a handler.
 199:      * @return the write handler, never null.
 200:      * @throws XMLWriterException if no handler could be found for the given class.
 201:      */
 202:     protected XmlWriteHandler getMapping(final Class classToWrite) throws XMLWriterException {
 203: 
 204:         if (classToWrite == null) {
 205:             throw new NullPointerException("ClassToWrite is null.");
 206:         }
 207: 
 208:         // search direct matches, first the direct definitions ...
 209:         ManualMappingDefinition manualMapping =
 210:             this.classToHandlerMapping.getManualMappingDefinition(classToWrite);
 211:         if (manualMapping == null) {
 212:             // search the manual mappings from the xml file.
 213:             manualMapping = getFactoryLoader().getManualMappingDefinition(classToWrite);
 214:         }
 215:         if (manualMapping != null) {
 216:             return loadHandlerClass(manualMapping.getWriteHandler());
 217:         }
 218: 
 219: 
 220:         // multiplexer definitions can be safely ignored here, as they are used to
 221:         // map parent classes to more specific child classes. In this case, we already
 222:         // know the child class and can look up the handler directly.
 223: 
 224:         // of course we have to check for multiplexers later, so that we can apply
 225:         // the mutiplex-attributes.
 226: 
 227:         // and finally try the generic handler matches ...
 228:         if (this.classToHandlerMapping.isGenericHandler(classToWrite)) {
 229:             return new GenericWriteHandler(
 230:                 this.classToHandlerMapping.getFactoryForClass(classToWrite)
 231:             );
 232:         }
 233:         if (getFactoryLoader().isGenericHandler(classToWrite)) {
 234:             return new GenericWriteHandler(getFactoryLoader().getFactoryForClass(classToWrite));
 235:         }
 236: 
 237:         throw new XMLWriterException("Unable to handle " + classToWrite);
 238:     }
 239: 
 240:     /**
 241:      * Writes the given object with the specified tagname. This method will
 242:      * do nothing, if the given object is null.
 243:      *
 244:      * @param tagName  the tagname for the xml-element containing the object
 245:      * definition. The tagname must not be null.
 246:      * @param object  the object which should be written.
 247:      * @param baseClass  the base class.
 248:      * @param writer  the xml writer used to write the content, never null.
 249:      * 
 250:      * @throws IOException if an IOException occures.
 251:      * @throws XMLWriterException if an object model related error occures during
 252:      * the writing.
 253:      */
 254:     public void write(final String tagName, final Object object, final Class baseClass, final XMLWriter writer)
 255:         throws IOException, XMLWriterException {
 256:         if (object == null) {
 257:             return;
 258:         }
 259:         if (tagName == null) {
 260:             throw new NullPointerException("RootXmlWriteHandler.write(..) : tagName is null");
 261:         }
 262:         if (writer == null) {
 263:             throw new NullPointerException("RootXmlWriteHandler.write(..) : writer is null");
 264:         }
 265:         if (!baseClass.isInstance(object)) {
 266:             throw new ClassCastException("Object is no instance of " + baseClass);
 267:         }
 268:         final Class classToWrite = object.getClass();
 269:         final XmlWriteHandler handler = getMapping(classToWrite);
 270:         handler.setRootHandler(this);
 271: 
 272:         String attributeName = null;
 273:         String attributeValue = null;
 274: 
 275:         // find multiplexer for this class...
 276:         MultiplexMappingDefinition mplex =
 277:             getFactoryLoader().getMultiplexDefinition(baseClass);
 278:         if (mplex == null) {
 279:             mplex = this.classToHandlerMapping.getMultiplexDefinition(baseClass);
 280:         }
 281:         if (mplex != null) {
 282:             final MultiplexMappingEntry entry =
 283:                 mplex.getEntryForClass(classToWrite.getName());
 284:             if (entry != null) {
 285:                 attributeName = mplex.getAttributeName();
 286:                 attributeValue = entry.getAttributeValue();
 287:             }
 288:             else {
 289:                 throw new XMLWriterException(
 290:                     "Unable to find child mapping for multiplexer " 
 291:                     + baseClass + " to child " + classToWrite
 292:                 );
 293:             }
 294:         }
 295: 
 296:         handler.write(tagName, object, writer, attributeName, attributeValue);
 297:         writer.allowLineBreak();
 298:     }
 299: 
 300:     /**
 301:      * Loads the given class, and ignores all exceptions which may occur
 302:      * during the loading. If the class was invalid, null is returned instead.
 303:      *
 304:      * @param className the name of the class to be loaded.
 305:      * @return the class or null.
 306:      * 
 307:      * @throws XMLWriterException if there is a writer exception.
 308:      */
 309:     protected XmlWriteHandler loadHandlerClass(final String className)
 310:         throws XMLWriterException {
 311:         if (className == null) {
 312:             throw new XMLWriterException("LoadHanderClass: Class name not defined");
 313:         }
 314:         try {
 315:             final Class c = ObjectUtilities.getClassLoader(getClass()).loadClass(className);
 316:             return (XmlWriteHandler) c.newInstance();
 317:         }
 318:         catch (Exception e) {
 319:             // ignore buggy classes for now ..
 320:             throw new XMLWriterException("LoadHanderClass: Unable to instantiate " + className, e);
 321:         }
 322:     }
 323:     
 324: }