001/* ========================================================================
002 * JCommon : a free general purpose class library for the Java(tm) platform
003 * ========================================================================
004 *
005 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006 * 
007 * Project Info:  http://www.jfree.org/jcommon/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it 
010 * under the terms of the GNU Lesser General Public License as published by 
011 * the Free Software Foundation; either version 2.1 of the License, or 
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but 
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
022 * USA.  
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
025 * in the United States and other countries.]
026 * 
027 * -----------------------
028 * GenericReadHandler.java
029 * -----------------------
030 * (C)opyright 2003, by Thomas Morgner and Contributors.
031 *
032 * Original Author:  Thomas Morgner;
033 * Contributor(s):   David Gilbert (for Object Refinery Limited);
034 *
035 * $Id: GenericReadHandler.java,v 1.5 2005/10/18 13:33:32 mungady Exp $
036 *
037 * Changes
038 * -------
039 * 23-Sep-2003 : Initial version
040 *
041 */
042
043package org.jfree.xml.parser.coretypes;
044
045import java.util.ArrayList;
046import java.util.HashMap;
047
048import org.jfree.util.Log;
049import org.jfree.xml.parser.AbstractXmlReadHandler;
050import org.jfree.xml.parser.RootXmlReadHandler;
051import org.jfree.xml.parser.XmlReadHandler;
052import org.jfree.xml.parser.XmlReaderException;
053import org.jfree.xml.util.AttributeDefinition;
054import org.jfree.xml.util.ConstructorDefinition;
055import org.jfree.xml.util.GenericObjectFactory;
056import org.jfree.xml.util.LookupDefinition;
057import org.jfree.xml.util.ObjectDescriptionException;
058import org.jfree.xml.util.PropertyDefinition;
059import org.xml.sax.Attributes;
060import org.xml.sax.SAXException;
061
062/**
063 * A SAX handler for reading a generic object from an XML element.
064 */
065public class GenericReadHandler extends AbstractXmlReadHandler {
066
067    /** The object under construction. */
068    private Object object;
069    
070    /** The generic object factory. */
071    private GenericObjectFactory objectFactory;
072    
073    /** The object reference handlers. */
074    private ArrayList objectRefHandlers;
075    
076    /** The created handler. */
077    private HashMap createdHandler;
078
079    /**
080     * Creates a new handler.
081     *
082     * @param factory  the generic object factory.
083     */
084    public GenericReadHandler(final GenericObjectFactory factory) {
085        this.createdHandler = new HashMap();
086        this.objectRefHandlers = new ArrayList();
087        this.objectFactory = factory;
088    }
089
090    /**
091     * Called at the start of parsing.
092     * 
093     * @param attrs  the attributes.
094     * 
095     * @throws SAXException if there is a parsing error.
096     */
097    protected void startParsing(final Attributes attrs) throws SAXException {
098
099        try {
100            final AttributeDefinition[] attribs = this.objectFactory.getAttributeDefinitions();
101            for (int i = 0; i < attribs.length; i++) {
102                final AttributeDefinition attrDef = attribs[i];
103                final String value = attrs.getValue(attrDef.getAttributeName());
104                if (value == null) {
105                    continue;
106                }
107                final Object o = attrDef.getHandler().toPropertyValue(value);
108                this.objectFactory.setProperty(attrDef.getPropertyName(), o);
109            }
110        }
111        catch (ObjectDescriptionException ode) {
112            throw new SAXException(ode);
113        }
114    }
115
116    /**
117     * Returns the child handler.
118     * 
119     * @param tagName  the tag name.
120     * @param atts  the attributes.
121     * 
122     * @return The handler.
123     * 
124     * @throws SAXException if there is a parsing problem.
125     */
126    protected XmlReadHandler getHandlerForChild(final String tagName, final Attributes atts)
127        throws SAXException {
128        try {
129            if (tagName.equals("objectRef")) {
130                // store them all and copy the properties later when the object is created
131                final XmlReadHandler handler = new ObjectRefHandler();
132                this.objectRefHandlers.add(handler);
133                return handler;
134            }
135            final XmlReadHandler handler = getRootHandler().createHandler
136                (this.objectFactory.getTypeForTagName(tagName), tagName, atts);
137            if (handler != null) {
138                this.createdHandler.put(tagName, handler);
139            }
140            // will throw exception if handler is null...
141            return handler;
142        }
143        catch (ObjectDescriptionException ode) {
144            Log.debug ("Failed to get handler for child: ", ode);
145            throw new SAXException(ode);
146        }
147    }
148
149    /**
150     * Returns the object.
151     * 
152     * @return The object.
153     * 
154     * @throws XmlReaderException ???
155     */
156    public Object getObject() throws XmlReaderException {
157
158        if (this.object != null) {
159            return this.object;
160        }
161        final RootXmlReadHandler rootHandler = getRootHandler();
162        try {
163            for (int i = 0; i < this.objectRefHandlers.size(); i++) {
164                final ObjectRefHandler handler = (ObjectRefHandler) this.objectRefHandlers.get(i);
165                this.objectFactory.setProperty(handler.getPropertyName(), handler.getObject());
166            }
167
168            final ArrayList lookups = new ArrayList();
169            final LookupDefinition[] lookupDefs = this.objectFactory.getLookupDefinitions();
170            for (int i = 0; i < lookupDefs.length; i++) {
171                final LookupDefinition ldef = lookupDefs[i];
172                lookups.add(ldef.getPropertyName());
173                Log.debug ("lookup object: " + ldef.getPropertyName());
174
175                final Object value = rootHandler.getHelperObject(ldef.getRegistryKey());
176                if (value == null) {
177                    // todo may or may not be fatal -> define it in the xml?
178                    Log.warn ("Failed to lookup object: " + value);
179                }
180                else {
181                    this.objectFactory.setProperty(ldef.getPropertyName(), value);
182                }
183            }
184
185            final ConstructorDefinition[] conDefs = this.objectFactory.getConstructorDefinitions();
186            for (int i = 0; i < conDefs.length; i++) {
187                final ConstructorDefinition cDef = conDefs[i];
188                // if this is a lookup, then ignore
189                if (lookups.contains(cDef.getPropertyName())) {
190                    continue;
191                }
192                if (this.objectFactory.isPropertyDefinition(cDef.getPropertyName())) {
193                    final PropertyDefinition pd = this.objectFactory.getPropertyDefinitionByPropertyName(
194                        cDef.getPropertyName()
195                    );
196                    final XmlReadHandler handler = (XmlReadHandler) this.createdHandler.get(
197                        pd.getElementName()
198                    );
199                    if (handler != null) {
200                        this.objectFactory.setProperty(pd.getPropertyName(), handler.getObject());
201                    }
202                }
203                // hoping that the attribute is set ..
204            }
205
206            this.object = this.objectFactory.createObject();
207            Object oldValue = null;
208            if (this.objectFactory.getRegisterName() != null) {
209                oldValue = rootHandler.getHelperObject(this.objectFactory.getRegisterName());
210                rootHandler.setHelperObject(this.objectFactory.getRegisterName(), this.object);
211            }
212
213            final PropertyDefinition[] propertyDefs = this.objectFactory.getPropertyDefinitions();
214            for (int i = 0; i < propertyDefs.length; i++) {
215                final PropertyDefinition pdef = propertyDefs[i];
216                final XmlReadHandler handler = (XmlReadHandler) this.createdHandler.get(
217                    pdef.getElementName()
218                );
219                if (handler == null) {
220                    continue;
221                }
222                this.objectFactory.setProperty(pdef.getPropertyName(), handler.getObject());
223            }
224
225            this.objectFactory.writeObjectProperties(this.object);
226
227            if (this.objectFactory.getRegisterName() != null) {
228                rootHandler.setHelperObject(this.objectFactory.getRegisterName(), oldValue);
229            }
230        }
231        catch (ObjectDescriptionException ode) {
232            Log.error ("Unable to create object.", ode);
233            throw new XmlReaderException("Unable to create object.", ode);
234        }
235        return this.object;
236    }
237
238}