beanmodel.java

freemaker安装软件

/*
 * Copyright (c) 2003 The Visigoth Software Society. All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowledgement:
 *       "This product includes software developed by the
 *        Visigoth Software Society (http://www.visigoths.org/)."
 *    Alternately, this acknowledgement may appear in the software itself,
 *    if and wherever such third-party acknowledgements normally appear.
 *
 * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the 
 *    project contributors may be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
 *    nor may "FreeMarker" or "Visigoth" appear in their names
 *    without prior written permission of the Visigoth Software Society.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Visigoth Software Society. For more
 * information on the Visigoth Software Society, please see
 * http://www.visigoths.org/
 */

package freemarker.ext.beans;

import java.beans.IndexedPropertyDescriptor;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

import freemarker.core.CollectionAndSequence;
import freemarker.core.Environment;
import freemarker.ext.util.ModelFactory;
import freemarker.ext.util.WrapperTemplateModel;
import freemarker.log.Logger;
import freemarker.template.AdapterTemplateModel;
import freemarker.template.ObjectWrapper;
import freemarker.template.SimpleScalar;
import freemarker.template.SimpleSequence;
import freemarker.template.TemplateCollectionModel;
import freemarker.template.TemplateHashModelEx;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.TemplateModelIterator;
import freemarker.template.TemplateScalarModel;

/**
 * A class that will wrap an arbitrary object into {@link freemarker.template.TemplateHashModel}
 * interface allowing calls to arbitrary property getters and invocation of
 * accessible methods on the object from a template using the
 * <tt>object.foo</tt> to access properties and <tt>object.bar(arg1, arg2)</tt> to
 * invoke methods on it. You can also use the <tt>object.foo[index]</tt> syntax to
 * access indexed properties. It uses Beans {@link java.beans.Introspector}
 * to dynamically discover the properties and methods. 
 * @author Attila Szegedi
 * @version $Id: BeanModel.java,v 1.49.2.3 2006/04/19 16:20:54 szegedia Exp $
 */

public class BeanModel
implements
    TemplateHashModelEx, AdapterTemplateModel, WrapperTemplateModel
{
    private static final Logger logger = Logger.getLogger("freemarker.beans");
    protected final Object object;
    protected final BeansWrapper wrapper;
    
    // We use this to represent an unknown value as opposed to known value of null (JR)
    private static final TemplateModel UNKNOWN = new SimpleScalar("UNKNOWN");
    
    static final ModelFactory FACTORY =
        new ModelFactory()
        {
            public TemplateModel create(Object object, ObjectWrapper wrapper)
            {
                return new BeanModel(object, (BeansWrapper)wrapper);
            }
        };

    // Cached template models that implement member properties and methods for this
    // instance. Keys are FeatureDescriptor instances (from classCache values),
    // values are either ReflectionMethodModels/ReflectionScalarModels
    private final HashMap memberMap = new HashMap();

    /**
     * Creates a new model that wraps the specified object. Note that there are
     * specialized subclasses of this class for wrapping arrays, collections,
     * enumeration, iterators, and maps. Note also that the superclass can be
     * used to wrap String objects if only scalar functionality is needed. You
     * can also choose to delegate the choice over which model class is used for
     * wrapping to {@link BeansWrapper#wrap(Object)}.
     * @param object the object to wrap into a model.
     * @param wrapper the {@link BeansWrapper} associated with this model.
     * Every model has to have an associated {@link BeansWrapper} instance. The
     * model gains many attributes from its wrapper, including the caching 
     * behavior, method exposure level, method-over-item shadowing policy etc.
     */
    public BeanModel(Object object, BeansWrapper wrapper)
    {
        this.object = object;
        this.wrapper = wrapper;
        if (object == null) {
            return;
        }
        wrapper.introspectClass(object.getClass());
    }

    /**
     * Uses Beans introspection to locate a property or method with name
     * matching the key name. If a method or property is found, it is wrapped
     * into {@link freemarker.template.TemplateMethodModelEx} (for a method or
     * indexed property), or evaluated on-the-fly and the return value wrapped
     * into appropriate model (for a simple property) Models for various
     * properties and methods are cached on a per-class basis, so the costly
     * introspection is performed only once per property or method of a class.
     * (Side-note: this also implies that any class whose method has been called
     * will be strongly referred to by the framework and will not become
     * unloadable until this class has been unloaded first. Normally this is not
     * an issue, but can be in a rare scenario where you create many classes on-
     * the-fly. Also, as the cache grows with new classes and methods introduced
     * to the framework, it may appear as if it were leaking memory. The
     * framework does, however detect class reloads (if you happen to be in an
     * environment that does this kind of things--servlet containers do it when
     * they reload a web application) and flushes the cache. If no method or
     * property matching the key is found, the framework will try to invoke
     * methods with signature
     * <tt>non-void-return-type get(java.lang.String)</tt>,
     * then <tt>non-void-return-type get(java.lang.Object)</tt>, or 
     * alternatively (if the wrapped object is a resource bundle) 
     * <tt>Object getObject(java.lang.String)</tt>.
     * @throws TemplateModelException if there was no property nor method nor
     * a generic <tt>get</tt> method to invoke.
     */
    public TemplateModel get(String key)
        throws
        TemplateModelException
    {
        Class clazz = object.getClass();
        Map classInfo = wrapper.getClassKeyMap(clazz);
        TemplateModel retval = null;
        
        try
        {
            if(wrapper.isMethodsShadowItems())
            {
                Object fd = classInfo.get(key);
                if(fd != null)
                {
                    retval = invokeThroughDescriptor(fd, classInfo);
                } else {
                    retval = invokeGenericGet(classInfo, clazz, key);
                }
            }
            else
            {
                TemplateModel model = invokeGenericGet(classInfo, clazz, key);
                final TemplateModel nullModel = wrapper.wrap(null);
                if(model != nullModel && model != UNKNOWN) 
                {