beanutilsbean.java

apache beanutils开源项目源码

/*
 * Copyright 2001-2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */ 


package org.apache.commons.beanutils;


import java.beans.IndexedPropertyDescriptor;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Array;
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.Iterator;
import java.util.Map;
import java.util.WeakHashMap;

import org.apache.commons.collections.FastHashMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;


/**
 * <p>JavaBean property population methods.</p>
 *
 * <p>This class provides implementations for the utility methods in
 * {@link BeanUtils}.
 * Different instances can be used to isolate caches between classloaders
 * and to vary the value converters registered.</p>
 *
 * @author Craig R. McClanahan
 * @author Ralph Schaer
 * @author Chris Audley
 * @author Rey Fran鏾is
 * @author Gregor Ra齧an
 * @version $Revision: 1.16 $ $Date: 2004/02/28 13:18:33 $
 * @see BeanUtils
 * @since 1.7
 */

public class BeanUtilsBean {


    // ------------------------------------------------------ Private Class Variables

    /** 
     * Contains <code>BeanUtilsBean</code> instances indexed by context classloader.
     */
    private static final ContextClassLoaderLocal 
            beansByClassLoader = new ContextClassLoaderLocal() {
                        // Creates the default instance used when the context classloader is unavailable
                        protected Object initialValue() {
                            return new BeanUtilsBean();
                        }
                    };
    
    /** 
     * Gets the instance which provides the functionality for {@link BeanUtils}.
     * This is a pseudo-singleton - an single instance is provided per (thread) context classloader.
     * This mechanism provides isolation for web apps deployed in the same container. 
     */
    public synchronized static BeanUtilsBean getInstance() {
        return (BeanUtilsBean) beansByClassLoader.get();
    }

    /** 
     * Sets the instance which provides the functionality for {@link BeanUtils}.
     * This is a pseudo-singleton - an single instance is provided per (thread) context classloader.
     * This mechanism provides isolation for web apps deployed in the same container. 
     */
    public synchronized static void setInstance(BeanUtilsBean newInstance) {
        beansByClassLoader.set(newInstance);
    }

    // --------------------------------------------------------- Attributes

    /**
     * Logging for this instance
     */
    private Log log = LogFactory.getLog(BeanUtils.class);
    
    /** Used to perform conversions between object types when setting properties */
    private ConvertUtilsBean convertUtilsBean;
    
    /** Used to access properties*/
    private PropertyUtilsBean propertyUtilsBean;

    // --------------------------------------------------------- Constuctors

    /** 
     * <p>Constructs an instance using new property 
     * and conversion instances.</p>
     */
    public BeanUtilsBean() {
        this(new ConvertUtilsBean(), new PropertyUtilsBean());
    }

    /** 
     * <p>Constructs an instance using given property and conversion instances.</p>
     *
     * @param convertUtilsBean use this <code>ConvertUtilsBean</code> 
     * to perform conversions from one object to another
     * @param propertyUtilsBean use this <code>PropertyUtilsBean</code>
     * to access properties
     */
    public BeanUtilsBean(		
                            ConvertUtilsBean convertUtilsBean, 
                            PropertyUtilsBean propertyUtilsBean) {
                            
        this.convertUtilsBean = convertUtilsBean;
        this.propertyUtilsBean = propertyUtilsBean;
    }

    // --------------------------------------------------------- Public Methods

    /**
     * <p>Clone a bean based on the available property getters and setters,
     * even if the bean class itself does not implement Cloneable.</p>
     *
     * <p>
     * <strong>Note:</strong> this method creates a <strong>shallow</strong> clone.
     * In other words, any objects referred to by the bean are shared with the clone
     * rather than being cloned in turn.
     * </p>
     *
     * @param bean Bean to be cloned
     *
     * @exception IllegalAccessException if the caller does not have
     *  access to the property accessor method
     * @exception InstantiationException if a new instance of the bean's
     *  class cannot be instantiated
     * @exception InvocationTargetException if the property accessor method
     *  throws an exception
     * @exception NoSuchMethodException if an accessor method for this
     *  property cannot be found
     */
    public Object cloneBean(Object bean)
            throws IllegalAccessException, InstantiationException,
            InvocationTargetException, NoSuchMethodException {

        if (log.isDebugEnabled()) {
            log.debug("Cloning bean: " + bean.getClass().getName());
        }
        Class clazz = bean.getClass();
        Object newBean = null;
        if (bean instanceof DynaBean) {
            newBean = ((DynaBean) bean).getDynaClass().newInstance();
        } else {
            newBean = bean.getClass().newInstance();
        }
        getPropertyUtils().copyProperties(newBean, bean);
        return (newBean);

    }


    /**
     * <p>Copy property values from the origin bean to the destination bean
     * for all cases where the property names are the same.  For each
     * property, a conversion is attempted as necessary.  All combinations of
     * standard JavaBeans and DynaBeans as origin and destination are
     * supported.  Properties that exist in the origin bean, but do not exist
     * in the destination bean (or are read-only in the destination bean) are
     * silently ignored.</p>
     *
     * <p>If the origin "bean" is actually a <code>Map</code>, it is assumed
     * to contain String-valued <strong>simple</strong> property names as the keys, pointing at
     * the corresponding property values that will be converted (if necessary)
     * and set in the destination bean. <strong>Note</strong> that this method
     * is intended to perform a "shallow copy" of the properties and so complex
     * properties (for example, nested ones) will not be copied.</p>
     *
     * <p>This method differs from <code>populate()</code>, which
     * was primarily designed for populating JavaBeans from the map of request
     * parameters retrieved on an HTTP request, is that no scalar->indexed
     * or indexed->scalar manipulations are performed.  If the origin property
     * is indexed, the destination property must be also.</p>
     *
     * <p>If you know that no type conversions are required, the
     * <code>copyProperties()</code> method in {@link PropertyUtils} will
     * execute faster than this method.</p>
     *
     * <p><strong>FIXME</strong> - Indexed and mapped properties that do not
     * have getter and setter methods for the underlying array or Map are not
     * copied by this method.</p>
     *
     * @param dest Destination bean whose properties are modified
     * @param orig Origin bean whose properties are retrieved
     *
     * @exception IllegalAccessException if the caller does not have
     *  access to the property accessor method
     * @exception IllegalArgumentException if the <code>dest</code> or
     *  <code>orig</code> argument is null
     * @exception InvocationTargetException if the property accessor method
     *  throws an exception
     */
    public void copyProperties(Object dest, Object orig)
        throws IllegalAccessException, InvocationTargetException {

        // Validate existence of the specified beans
        if (dest == null) {
            throw new IllegalArgumentException
                    ("No destination bean specified");
        }
        if (orig == null) {
            throw new IllegalArgumentException("No origin bean specified");
        }
        if (log.isDebugEnabled()) {
            log.debug("BeanUtils.copyProperties(" + dest + ", " +
                      orig + ")");
        }

        // Copy the properties, converting as necessary
        if (orig instanceof DynaBean) {
            DynaProperty origDescriptors[] =
                ((DynaBean) orig).getDynaClass().getDynaProperties();
            for (int i = 0; i < origDescriptors.length; i++) {
                String name = origDescriptors[i].getName();
                if (getPropertyUtils().isWriteable(dest, name)) {
                    Object value = ((DynaBean) orig).get(name);
                    copyProperty(dest, name, value);
                }
            }
        } else if (orig instanceof Map) {
            Iterator names = ((Map) orig).keySet().iterator();
            while (names.hasNext()) {
                String name = (String) names.next();
                if (getPropertyUtils().isWriteable(dest, name)) {
                    Object value = ((Map) orig).get(name);
                    copyProperty(dest, name, value);
                }
            }
        } else /* if (orig is a standard JavaBean) */ {
            PropertyDescriptor origDescriptors[] =
                getPropertyUtils().getPropertyDescriptors(orig);
            for (int i = 0; i < origDescriptors.length; i++) {
                String name = origDescriptors[i].getName();
                if ("class".equals(name)) {
                    continue; // No point in trying to set an object's class
                }
                if (getPropertyUtils().isReadable(orig, name) &&
                    getPropertyUtils().isWriteable(dest, name)) {
                    try {
                        Object value =
                            getPropertyUtils().getSimpleProperty(orig, name);
                        copyProperty(dest, name, value);
                    } catch (NoSuchMethodException e) {
                        ; // Should not happen
                    }
                }
            }
        }

    }


    /**
     * <p>Copy the specified property value to the specified destination bean,
     * performing any type conversion that is required.  If the specified
     * bean does not have a property of the specified name, or the property
     * is read only on the destination bean, return without
     * doing anything.  If you have custom destination property types, register
     * {@link Converter}s for them by calling the <code>register()</code>
     * method of {@link ConvertUtils}.</p>
     *
     * <p><strong>IMPLEMENTATION RESTRICTIONS</strong>:</p>
     * <ul>
     * <li>Does not support destination properties that are indexed,
     *     but only an indexed setter (as opposed to an array setter)
     *     is available.</li>
     * <li>Does not support destination properties that are mapped,
     *     but only a keyed setter (as opposed to a Map setter)
     *     is available.</li>
     * <li>The desired property type of a mapped setter cannot be
     *     determined (since Maps support any data type), so no conversion
     *     will be performed.</li>
     * </ul>
     *
     * @param bean Bean on which setting is to be performed
     * @param name Property name (can be nested/indexed/mapped/combo)
     * @param value Value to be set
     *
     * @exception IllegalAccessException if the caller does not have
     *  access to the property accessor method
     * @exception InvocationTargetException if the property accessor method
     *  throws an exception
     */
    public void copyProperty(Object bean, String name, Object value)
        throws IllegalAccessException, InvocationTargetException {

        // Trace logging (if enabled)
        if (log.isTraceEnabled()) {
            StringBuffer sb = new StringBuffer("  copyProperty(");
            sb.append(bean);
            sb.append(", ");
            sb.append(name);
            sb.append(", ");
            if (value == null) {
                sb.append("<NULL>");
            } else if (value instanceof String) {
                sb.append((String) value);
            } else if (value instanceof String[]) {
                String values[] = (String[]) value;
                sb.append('[');
                for (int i = 0; i < values.length; i++) {
                    if (i > 0) {
                        sb.append(',');
                    }
                    sb.append(values[i]);
                }
                sb.append(']');
            } else {
                sb.append(value.toString());
            }
            sb.append(')');
            log.trace(sb.toString());
        }

        // Resolve any nested expression to get the actual target bean
        Object target = bean;
        int delim = name.lastIndexOf(PropertyUtils.NESTED_DELIM);
        if (delim >= 0) {
            try {
                target =
                    getPropertyUtils().getProperty(bean, name.substring(0, delim));
            } catch (NoSuchMethodException e) {
                return; // Skip this property setter
            }
            name = name.substring(delim + 1);
            if (log.isTraceEnabled()) {
                log.trace("    Target bean = " + target);
                log.trace("    Target name = " + name);
            }
        }

        // Declare local variables we will require
        String propName = null;          // Simple name of target property
        Class type = null;               // Java type of target property
        int index = -1;                  // Indexed subscript value (if any)
        String key = null;               // Mapped key value (if any)

        // Calculate the target property name, index, and key values
        propName = name;
        int i = propName.indexOf(PropertyUtils.INDEXED_DELIM);