    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     * ObjectFactoryLoader.java
    029     * ------------------------
    030     * (C) Copyright 2002-2005, by Thomas Morgner and Contributors.
    031     *
    032     * Original Author:  Thomas Morgner;
    033     * Contributor(s):   -;
    034     *
    035     * $Id: ObjectFactoryLoader.java,v 1.4 2005/10/18 13:33:53 mungady Exp $
    036     *
    037     * Changes
    038     * -------
    039     * 24-Sep-2003: Initial version
    040     *
    041     */
    042
    043    package org.jfree.xml.util;
    044
    045    import java.net.URL;
    046    import java.util.ArrayList;
    047    import java.util.Arrays;
    048    import java.util.HashMap;
    049    import java.util.Iterator;
    050
    051    import org.jfree.util.Log;
    052    import org.jfree.xml.attributehandlers.AttributeHandler;
    053
    054    /**
    055     * The object factory loader loads the xml specification for the generic
    056     * handlers. The specification may be distributed over multiple files.
    057     * <p>
    058     * This class provides the model management for the reader and writer.
    059     * The instantiation of the handlers is done elsewhere.
    060     *
    061     * @author TM
    062     */
    063    public class ObjectFactoryLoader extends AbstractModelReader implements ObjectFactory {
    064
    065        /** Maps classes to GenericObjectFactory instances. */
    066        private HashMap objectMappings;
    067
    068        /** Manual mappings. */
    069        private HashMap manualMappings;
    070
    071        /** Multiplex mappings. */
    072        private HashMap multiplexMappings;
    073
    074        /** The target class. */
    075        private Class target;
    076
    077        /** The register name. */
    078        private String registerName;
    079
    080        /** The property definition. */
    081        private ArrayList propertyDefinition;
    082
    083        /** The attribute definition. */
    084        private ArrayList attributeDefinition;
    085
    086        /** The constructor definition. */
    087        private ArrayList constructorDefinition;
    088
    089        /** The lookup definitions. */
    090        private ArrayList lookupDefinitions;
    091
    092        /** The ordered names. */
    093        private ArrayList orderedNames;
    094
    095        /** The base class. */
    096        private String baseClass;
    097
    098        /** The attribute name. */
    099        private String attributeName;
    100
    101        /** The multiplex entries. */
    102        private ArrayList multiplexEntries;
    103
    104        /**
    105         * Creates a new object factory loader for the given base file.
    106         *
    107         * @param resourceName the URL of the initial specification file.
    108         *
    109         * @throws ObjectDescriptionException if the file could not be parsed.
    110         */
    111        public ObjectFactoryLoader(final URL resourceName) throws ObjectDescriptionException {
    112            this.objectMappings = new HashMap();
    113            this.manualMappings = new HashMap();
    114            this.multiplexMappings = new HashMap();
    115            parseXml(resourceName);
    116            rebuildSuperClasses();
    117        }
    118
    119        private void rebuildSuperClasses() throws ObjectDescriptionException {
    120            this.propertyDefinition = new ArrayList();
    121            this.attributeDefinition = new ArrayList();
    122            this.constructorDefinition = new ArrayList();
    123            this.lookupDefinitions = new ArrayList();
    124            this.orderedNames = new ArrayList();
    125
    126            final HashMap newObjectDescriptions = new HashMap();
    127            final Iterator it = this.objectMappings.keySet().iterator();
    128            while (it.hasNext()) {
    129                final Object key = it.next();
    130                final GenericObjectFactory gef = (GenericObjectFactory) this.objectMappings.get(key);
    131                performSuperClassUpdate(gef);
    132
    133                final PropertyDefinition[] propertyDefs = (PropertyDefinition[])
    134                this.propertyDefinition.toArray(new PropertyDefinition[0]);
    135                final LookupDefinition[] lookupDefs = (LookupDefinition[])
    136                this.lookupDefinitions.toArray(new LookupDefinition[0]);
    137                final AttributeDefinition[] attribDefs = (AttributeDefinition[])
    138                this.attributeDefinition.toArray(new AttributeDefinition[0]);
    139                final ConstructorDefinition[] constructorDefs = (ConstructorDefinition[])
    140                this.constructorDefinition.toArray(new ConstructorDefinition[0]);
    141                final String[] orderedNamesDefs = (String[])
    142                this.orderedNames.toArray(new String[0]);
    143
    144                final GenericObjectFactory objectFactory = new GenericObjectFactory
    145                    (gef.getBaseClass(), gef.getRegisterName(), constructorDefs,
    146                        propertyDefs, lookupDefs, attribDefs, orderedNamesDefs);
    147                newObjectDescriptions.put(key, objectFactory);
    148
    149                this.propertyDefinition.clear();
    150                this.attributeDefinition.clear();
    151                this.constructorDefinition.clear();
    152                this.lookupDefinitions.clear();
    153                this.orderedNames.clear();
    154            }
    155
    156            this.objectMappings.clear();
    157            this.objectMappings = newObjectDescriptions;
    158
    159            this.propertyDefinition = null;
    160            this.attributeDefinition = null;
    161            this.constructorDefinition = null;
    162            this.lookupDefinitions = null;
    163            this.orderedNames = null;
    164        }
    165
    166        private void performSuperClassUpdate(final GenericObjectFactory gef) {
    167            // first handle the super classes, ...
    168            final Class superClass = gef.getBaseClass().getSuperclass();
    169            if (superClass != null && !superClass.equals(Object.class)) {
    170                final GenericObjectFactory superGef = (GenericObjectFactory) this.objectMappings.get(
    171                    superClass
    172                );
    173                if (superGef != null) {
    174                    performSuperClassUpdate(superGef);
    175                }
    176            }
    177
    178            // and finally append all local properties ...
    179            this.propertyDefinition.addAll(Arrays.asList(gef.getPropertyDefinitions()));
    180            this.attributeDefinition.addAll(Arrays.asList(gef.getAttributeDefinitions()));
    181            this.constructorDefinition.addAll(Arrays.asList(gef.getConstructorDefinitions()));
    182            this.lookupDefinitions.addAll(Arrays.asList(gef.getLookupDefinitions()));
    183            this.orderedNames.addAll(Arrays.asList(gef.getOrderedPropertyNames()));
    184        }
    185
    186        /**
    187         * Starts a object definition. The object definition collects all properties of
    188         * an bean-class and defines, which constructor should be used when creating the
    189         * class.
    190         *
    191         * @param className the class name of the defined object
    192         * @param register the (optional) register name, to lookup and reference the object later.
    193         * @param ignore  ignore?
    194         *
    195         * @return true, if the definition was accepted, false otherwise.
    196         * @throws ObjectDescriptionException if an unexpected error occured.
    197         */
    198        protected boolean startObjectDefinition(final String className, final String register, final boolean ignore)
    199            throws ObjectDescriptionException {
    200
    201            if (ignore) {
    202                return false;
    203            }
    204            this.target = loadClass(className);
    205            if (this.target == null) {
    206                Log.warn(new Log.SimpleMessage("Failed to load class ", className));
    207                return false;
    208            }
    209            this.registerName = register;
    210            this.propertyDefinition = new ArrayList();
    211            this.attributeDefinition = new ArrayList();
    212            this.constructorDefinition = new ArrayList();
    213            this.lookupDefinitions = new ArrayList();
    214            this.orderedNames = new ArrayList();
    215            return true;
    216        }
    217
    218        /**
    219         * Handles an attribute definition. This method gets called after the object definition
    220         * was started. The method will be called for every defined attribute property.
    221         *
    222         * @param name the name of the property
    223         * @param attribName the xml-attribute name to use later.
    224         * @param handlerClass the attribute handler class.
    225         * @throws ObjectDescriptionException if an error occured.
    226         */
    227        protected void handleAttributeDefinition(final String name, final String attribName, final String handlerClass)
    228            throws ObjectDescriptionException {
    229            final AttributeHandler handler = loadAttributeHandler(handlerClass);
    230            this.orderedNames.add(name);
    231            this.attributeDefinition.add(new AttributeDefinition(name, attribName, handler));
    232        }
    233
    234        /**
    235         * Handles an element definition. This method gets called after the object definition
    236         * was started. The method will be called for every defined element property. Element
    237         * properties are used to describe complex objects.
    238         *
    239         * @param name the name of the property
    240         * @param element the xml-tag name for the child element.
    241         * @throws ObjectDescriptionException if an error occurs.
    242         */
    243        protected void handleElementDefinition(final String name, final String element)
    244            throws ObjectDescriptionException {
    245            this.orderedNames.add(name);
    246            this.propertyDefinition.add(new PropertyDefinition(name, element));
    247        }
    248
    249        /**
    250         * Handles an lookup definition. This method gets called after the object definition
    251         * was started. The method will be called for every defined lookup property. Lookup properties
    252         * reference previously created object using the object's registry name.
    253         *
    254         * @param name the property name of the base object
    255         * @param lookupKey the register key of the referenced object
    256         * @throws ObjectDescriptionException if an error occured.
    257         */
    258        protected void handleLookupDefinition(final String name, final String lookupKey)
    259            throws ObjectDescriptionException {
    260            final LookupDefinition ldef = new LookupDefinition(name, lookupKey);
    261            this.orderedNames.add(name);
    262            this.lookupDefinitions.add(ldef);
    263        }
    264
    265        /**
    266         * Finializes the object definition.
    267         *
    268         * @throws ObjectDescriptionException if an error occures.
    269         */
    270        protected void endObjectDefinition()
    271            throws ObjectDescriptionException {
    272
    273            final PropertyDefinition[] propertyDefs = (PropertyDefinition[])
    274            this.propertyDefinition.toArray(new PropertyDefinition[0]);
    275            final LookupDefinition[] lookupDefs = (LookupDefinition[])
    276            this.lookupDefinitions.toArray(new LookupDefinition[0]);
    277            final AttributeDefinition[] attribDefs = (AttributeDefinition[])
    278            this.attributeDefinition.toArray(new AttributeDefinition[0]);
    279            final ConstructorDefinition[] constructorDefs = (ConstructorDefinition[])
    280            this.constructorDefinition.toArray(new ConstructorDefinition[0]);
    281            final String[] orderedNamesDefs = (String[])
    282            this.orderedNames.toArray(new String[0]);
    283
    284            final GenericObjectFactory objectFactory = new GenericObjectFactory
    285                (this.target, this.registerName, constructorDefs,
    286                    propertyDefs, lookupDefs, attribDefs, orderedNamesDefs);
    287            this.objectMappings.put(this.target, objectFactory);
    288        }
    289
    290        /**
    291         * Handles a constructor definition. Only one constructor can be defined for
    292         * a certain object type. The constructor will be filled using the given properties.
    293         *
    294         * @param propertyName the property name of the referenced local property
    295         * @param parameterClass the parameter class for the parameter.
    296         */
    297        protected void handleConstructorDefinition(final String propertyName, final String parameterClass) {
    298            final Class c = loadClass(parameterClass);
    299            this.orderedNames.add(propertyName);
    300            this.constructorDefinition.add(new ConstructorDefinition(propertyName, c));
    301        }
    302
    303        /**
    304         * Handles a manual mapping definition. The manual mapping maps specific
    305         * read and write handlers to a given base class. Manual mappings always
    306         * override any other definition.
    307         *
    308         * @param className the base class name
    309         * @param readHandler the class name of the read handler
    310         * @param writeHandler the class name of the write handler
    311         * @return true, if the mapping was accepted, false otherwise.
    312         * @throws ObjectDescriptionException if an unexpected error occured.
    313         */
    314        protected boolean handleManualMapping(final String className, final String readHandler, final String writeHandler)
    315            throws ObjectDescriptionException {
    316
    317            if (!this.manualMappings.containsKey(className)) {
    318                final Class loadedClass = loadClass(className);
    319                this.manualMappings.put(loadedClass, new ManualMappingDefinition
    320                    (loadedClass, readHandler, writeHandler));
    321                return true;
    322            }
    323            return false;
    324        }
    325
    326        /**
    327         * Starts a multiplex mapping. Multiplex mappings are used to define polymorphic
    328         * argument handlers. The mapper will collect all derived classes of the given
    329         * base class and will select the corresponding mapping based on the given type
    330         * attribute.
    331         *
    332         * @param className the base class name
    333         * @param typeAttr the xml-attribute name containing the mapping key
    334         */
    335        protected void startMultiplexMapping(final String className, final String typeAttr) {
    336            this.baseClass = className;
    337            this.attributeName = typeAttr;
    338            this.multiplexEntries = new ArrayList();
    339        }
    340
    341        /**
    342         * Defines an entry for the multiplex mapping. The new entry will be activated
    343         * when the base mappers type attribute contains this <code>typename</code> and
    344         * will resolve to the handler for the given classname.
    345         *
    346         * @param typeName the type value for this mapping.
    347         * @param className the class name to which this mapping resolves.
    348         * @throws ObjectDescriptionException if an error occurs.
    349         */
    350        protected void handleMultiplexMapping(final String typeName, final String className)
    351            throws ObjectDescriptionException {
    352            this.multiplexEntries.add
    353                (new MultiplexMappingEntry(typeName, className));
    354        }
    355
    356        /**
    357         * Finializes the multiplexer mapping.
    358         *
    359         * @throws ObjectDescriptionException if an error occurs.
    360         */
    361        protected void endMultiplexMapping() throws ObjectDescriptionException {
    362            final MultiplexMappingEntry[] mappings = (MultiplexMappingEntry[])
    363            this.multiplexEntries.toArray(new MultiplexMappingEntry[0]);
    364            final Class c = loadClass(this.baseClass);
    365            this.multiplexMappings.put(c,
    366                new MultiplexMappingDefinition(c, this.attributeName, mappings));
    367            this.multiplexEntries = null;
    368        }
    369
    370        /**
    371         * Loads an instantiates the attribute handler specified by the given
    372         * class name.
    373         *
    374         * @param attribute the attribute handlers classname.
    375         * @return the created attribute handler instance
    376         * @throws ObjectDescriptionException if the handler could not be loaded.
    377         */
    378        private AttributeHandler loadAttributeHandler(final String attribute)
    379            throws ObjectDescriptionException {
    380
    381            final Class c = loadClass(attribute);
    382            try {
    383                return (AttributeHandler) c.newInstance();
    384            }
    385            catch (Exception e) {
    386                throw new ObjectDescriptionException
    387                    ("Invalid attribute handler specified: " + attribute);
    388            }
    389        }
    390
    391        /**
    392         * Checks, whether the factory has a description for the given class.
    393         *
    394         * @param c the class to be handled by the factory.
    395         * @return true, if an description exists for the given class, false otherwise.
    396         */
    397        public boolean isGenericHandler(final Class c) {
    398            return this.objectMappings.containsKey(c);
    399        }
    400
    401        /**
    402         * Returns a factory instance for the given class. The factory is independent
    403         * from all previously generated instances.
    404         *
    405         * @param c the class
    406         * @return the object factory.
    407         */
    408        public GenericObjectFactory getFactoryForClass(final Class c) {
    409            final GenericObjectFactory factory = (GenericObjectFactory) this.objectMappings.get(c);
    410            if (factory == null) {
    411                return null;
    412            }
    413            return factory.getInstance();
    414        }
    415
    416        /**
    417         * Returns the manual mapping definition for the given class, or null, if
    418         * not manual definition exists.
    419         *
    420         * @param c the class for which to check the existence of the definition
    421         * @return the manual mapping definition or null.
    422         */
    423        public ManualMappingDefinition getManualMappingDefinition(final Class c) {
    424            return (ManualMappingDefinition) this.manualMappings.get(c);
    425        }
    426
    427        /**
    428         * Returns the multiplex definition for the given class, or null, if no
    429         * such definition exists.
    430         *
    431         * @param c the class for which to check the existence of the multiplexer
    432         * @return the multiplexer for the class, or null if no multiplexer exists.
    433         */
    434        public MultiplexMappingDefinition getMultiplexDefinition(final Class c) {
    435            final MultiplexMappingDefinition definition = (MultiplexMappingDefinition)
    436            this.multiplexMappings.get(c);
    437            return definition;
    438        }
    439
    440    }