    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}