BeanMap.java
/*
* Copyright (c) 2008, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * 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.
*
* * Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS 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 COPYRIGHT HOLDER OR 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,
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package com.twelvemonkeys.util;
import java.beans.IndexedPropertyDescriptor;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.*;
/**
* A {@code Map} adapter for a Java Bean.
* <p>
* Ruthlessly stolen from
* <a href="http://binkley.blogspot.com/2006/08/mapping-java-bean.html">Binkley's Blog</a>
* </p>
*/
public final class BeanMap extends AbstractMap<String, Object> implements Serializable, Cloneable {
private final Object bean;
private transient Set<PropertyDescriptor> descriptors;
public BeanMap(Object pBean) throws IntrospectionException {
if (pBean == null) {
throw new IllegalArgumentException("bean == null");
}
bean = pBean;
descriptors = initDescriptors(pBean);
}
private static Set<PropertyDescriptor> initDescriptors(Object pBean) throws IntrospectionException {
final Set<PropertyDescriptor> descriptors = new HashSet<PropertyDescriptor>();
PropertyDescriptor[] propertyDescriptors = Introspector.getBeanInfo(pBean.getClass()).getPropertyDescriptors();
for (PropertyDescriptor descriptor : propertyDescriptors) {
// Skip Object.getClass(), as you probably never want it
if ("class".equals(descriptor.getName()) && descriptor.getPropertyType() == Class.class) {
continue;
}
// Only support simple setter/getters.
if (!(descriptor instanceof IndexedPropertyDescriptor)) {
descriptors.add(descriptor);
}
}
return Collections.unmodifiableSet(descriptors);
}
public Set<Entry<String, Object>> entrySet() {
return new BeanSet();
}
public Object get(final Object pKey) {
return super.get(pKey);
}
public Object put(final String pKey, final Object pValue) {
checkKey(pKey);
for (Entry<String, Object> entry : entrySet()) {
if (entry.getKey().equals(pKey)) {
return entry.setValue(pValue);
}
}
return null;
}
public Object remove(final Object pKey) {
return super.remove(checkKey(pKey));
}
public int size() {
return descriptors.size();
}
private String checkKey(final Object pKey) {
if (pKey == null) {
throw new IllegalArgumentException("key == null");
}
// NB - the cast forces CCE if key is the wrong type.
final String name = (String) pKey;
if (!containsKey(name)) {
throw new IllegalArgumentException("Bad key: " + pKey);
}
return name;
}
private Object readResolve() throws IntrospectionException {
// Initialize the property descriptors
descriptors = initDescriptors(bean);
return this;
}
private class BeanSet extends AbstractSet<Entry<String, Object>> {
public Iterator<Entry<String, Object>> iterator() {
return new BeanIterator(descriptors.iterator());
}
public int size() {
return descriptors.size();
}
}
private class BeanIterator implements Iterator<Entry<String, Object>> {
private final Iterator<PropertyDescriptor> mIterator;
public BeanIterator(final Iterator<PropertyDescriptor> pIterator) {
mIterator = pIterator;
}
public boolean hasNext() {
return mIterator.hasNext();
}
public BeanEntry next() {
return new BeanEntry(mIterator.next());
}
public void remove() {
mIterator.remove();
}
}
private class BeanEntry implements Entry<String, Object> {
private final PropertyDescriptor mDescriptor;
public BeanEntry(final PropertyDescriptor pDescriptor) {
this.mDescriptor = pDescriptor;
}
public String getKey() {
return mDescriptor.getName();
}
public Object getValue() {
return unwrap(new Wrapped() {
public Object run() throws IllegalAccessException, InvocationTargetException {
final Method method = mDescriptor.getReadMethod();
// A write-only bean.
if (method == null) {
throw new UnsupportedOperationException("No getter: " + mDescriptor.getName());
}
return method.invoke(bean);
}
});
}
public Object setValue(final Object pValue) {
return unwrap(new Wrapped() {
public Object run() throws IllegalAccessException, InvocationTargetException {
final Method method = mDescriptor.getWriteMethod();
// A read-only bean.
if (method == null) {
throw new UnsupportedOperationException("No write method for property: " + mDescriptor.getName());
}
final Object old = getValue();
method.invoke(bean, pValue);
return old;
}
});
}
public boolean equals(Object pOther) {
if (!(pOther instanceof Map.Entry)) {
return false;
}
Map.Entry entry = (Map.Entry) pOther;
Object k1 = getKey();
Object k2 = entry.getKey();
if (k1 == k2 || (k1 != null && k1.equals(k2))) {
Object v1 = getValue();
Object v2 = entry.getValue();
if (v1 == v2 || (v1 != null && v1.equals(v2))) {
return true;
}
}
return false;
}
public int hashCode() {
return (getKey() == null ? 0 : getKey().hashCode()) ^
(getValue() == null ? 0 : getValue().hashCode());
}
public String toString() {
return getKey() + "=" + getValue();
}
}
private static interface Wrapped {
Object run() throws IllegalAccessException, InvocationTargetException;
}
private static Object unwrap(final Wrapped wrapped) {
try {
return wrapped.run();
}
catch (IllegalAccessException e) {
throw new RuntimeException(e);
}
catch (final InvocationTargetException e) {
// Javadocs for setValue indicate cast is ok.
throw (RuntimeException) e.getCause();
}
}
}