/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.util.Map;
import java.util.List;
import java.util.ArrayList;
import java.util.Set;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Collection;
import java.util.Collections;
/**
* <p>Decorates a {@link DynaBean} to provide <code>Map</code> behaviour.</p>
*
* <p>The motivation for this implementation is to provide access to {@link DynaBean}
* properties in technologies that are unaware of BeanUtils and {@link DynaBean}s -
* such as the expression languages of JSTL and JSF.</p>
*
* <p>This can be achieved either by wrapping the {@link DynaBean} prior to
* providing it to the technolody to process or by providing a <code>Map</code>
* accessor method on the DynaBean implementation:
* <pre><code>
* public Map getMap() {
* return new DynaBeanMapDecorator(this);
* }</code></pre>
* </ul>
* </p>
*
* <p>This, for example, could be used in JSTL in the following way to access
* a DynaBean's <code>fooProperty</code>:
* <ul><li><code>${myDynaBean.<b>map</b>.fooProperty}</code></li></ul>
* </p>
*
* <h3>Usage</h3>
*
* <p>To decorate a {@link DynaBean} simply instantiate this class with the
* target {@link DynaBean}:</p>
*
* <ul><li><code>Map fooMap = new DynaBeanMapDecorator(fooDynaBean);</code></li></ul>
*
* <p>The above example creates a <b><i>read only</i></b> <code>Map</code>.
* To create a <code>Map</code> which can be modified, construct a
* <code>DynaBeanMapDecorator</code> with the <b><i>read only</i></b>
* attribute set to <code>false</code>:</p>
*
* <ul><li><code>Map fooMap = new DynaBeanMapDecorator(fooDynaBean, false);</code></li></ul>
*
* <h3>Limitations</h3>
* <p>In this implementation the <code>entrySet()</code>, <code>keySet()</code>
* and <code>values()</code> methods create an <b><i>unmodifiable</i></b>
* <code>Set</code> and it does not support the Map's <code>clear()</code>
* and <code>remove()</code> operations.</p>
*
* @since BeanUtils 1.8.0
* @version $Revision: 546471 $ $Date: 2007-06-12 13:57:20 +0100 (Tue, 12 Jun 2007) $
*/
public class DynaBeanMapDecorator implements Map {
private DynaBean dynaBean;
private boolean readOnly;
private transient Set keySet;
// ------------------- Constructors ----------------------------------
/**
* Constructs a read only Map for the specified
* {@link DynaBean}.
*
* @param dynaBean The dyna bean being decorated
* @throws IllegalArgumentException if the {@link DynaBean} is null.
*/
public DynaBeanMapDecorator(DynaBean dynaBean) {
this(dynaBean, true);
}
/**
* Construct a Map for the specified {@link DynaBean}.
*
* @param dynaBean The dyna bean being decorated
* @param readOnly <code>true</code> if the Mpa is read only
* otherwise <code>false</code>
* @throws IllegalArgumentException if the {@link DynaBean} is null.
*/
public DynaBeanMapDecorator(DynaBean dynaBean, boolean readOnly) {
if (dynaBean == null) {
throw new IllegalArgumentException("DynaBean is null");
}
this.dynaBean = dynaBean;
this.readOnly = readOnly;
}
// ------------------- public Methods --------------------------------
/**
* Indicate whether the Map is read only.
*
* @return <code>true</code> if the Map is read only,
* otherwise <code>false</code>.
*/
public boolean isReadOnly() {
return readOnly;
}
// ------------------- java.util.Map Methods -------------------------
/**
* clear() operation is not supported.
*
* @throws UnsupportedOperationException
*/
public void clear() {
throw new UnsupportedOperationException();
}
/**
* Indicate whether the {@link DynaBean} contains a specified
* value for one (or more) of its properties.
*
* @param key The {@link DynaBean}'s property name
* @return <code>true</code> if one of the {@link DynaBean}'s
* properties contains a specified value.
*/
public boolean containsKey(Object key) {
DynaClass dynaClass = getDynaBean().getDynaClass();
DynaProperty dynaProperty = dynaClass.getDynaProperty(toString(key));
return (dynaProperty == null ? false : true);
}
/**
* Indicates whether the decorated {@link DynaBean} contains
* a specified value.
*
* @param value The value to check for.
* @return <code>true</code> if one of the the {@link DynaBean}'s
* properties contains the specified value, otherwise
* <code>false</code>.
*/
public boolean containsValue(Object value) {
DynaProperty[] properties = getDynaProperties();
for (int i = 0; i < properties.length; i++) {
String key = properties[i].getName();
Object prop = getDynaBean().get(key);
if (value == null) {
if (prop == null) {
return true;
}
} else {
if (value.equals(prop)) {
return true;
}
}
}
return false;
}
/**
* <p>Returns the Set of the property/value mappings
* in the decorated {@link DynaBean}.</p>
*
* <p>Each element in the Set is a <code>Map.Entry</code>
* type.</p>
*
* @return An unmodifiable set of the DynaBean
* property name/value pairs
*/
public Set entrySet() {
DynaProperty[] properties = getDynaProperties();
Set set = new HashSet(properties.length);
for (int i = 0; i < properties.length; i++) {
String key = properties[i].getName();
Object value = getDynaBean().get(key);
set.add(new MapEntry(key, value));
}
return Collections.unmodifiableSet(set);
}
/**
* Return the value for the specified key from
* the decorated {@link DynaBean}.
*
* @param key The {@link DynaBean}'s property name
* @return The value for the specified property.
*/
public Object get(Object key) {
return getDynaBean().get(toString(key));
}
/**
* Indicate whether the decorated {@link DynaBean} has
* any properties.
*
* @return <code>true</code> if the {@link DynaBean} has
* no properties, otherwise <code>false</code>.
*/
public boolean isEmpty() {
return (getDynaProperties().length == 0);
}
/**
* <p>Returns the Set of the property
* names in the decorated {@link DynaBean}.</p>
*
* <p><b>N.B.</b>For {@link DynaBean}s whose associated {@link DynaClass}
* is a {@link MutableDynaClass} a new Set is created every
* time, otherwise the Set is created only once and cached.</p>
*
* @return An unmodifiable set of the {@link DynaBean}s
* property names.
*/
public Set keySet() {
if (keySet != null) {
return keySet;
}
// Create a Set of the keys
DynaProperty[] properties = getDynaProperties();
Set set = new HashSet(properties.length);
for (int i = 0; i < properties.length; i++) {
set.add(properties[i].getName());
}
set = Collections.unmodifiableSet(set);
// Cache the keySet if Not a MutableDynaClass
DynaClass dynaClass = getDynaBean().getDynaClass();
if (!(dynaClass instanceof MutableDynaClass)) {
keySet = set;
}
return set;
}
/**
* Set the value for the specified property in
* the decorated {@link DynaBean}.
*
* @param key The {@link DynaBean}'s property name
* @param value The value for the specified property.
* @return The previous property's value.
* @throws UnsupportedOperationException if
* <code>isReadOnly()</code> is true.
*/
public Object put(Object key, Object value) {
if (isReadOnly()) {
throw new UnsupportedOperationException("Map is read only");
}
String property = toString(key);
Object previous = getDynaBean().get(property);
getDynaBean().set(property, value);
return previous;
}
/**
* Copy the contents of a Map to the decorated {@link DynaBean}.
*
* @param map The Map of values to copy.
* @throws UnsupportedOperationException if
* <code>isReadOnly()</code> is true.
*/
public void putAll(Map map) {
if (isReadOnly()) {
throw new UnsupportedOperationException("Map is read only");
}
Iterator keys = map.keySet().iterator();
while (keys.hasNext()) {
Object key = keys.next();
put(key, map.get(key));
}
}
/**
* remove() operation is not supported.
*
* @param key The {@link DynaBean}'s property name
* @return the value removed
* @throws UnsupportedOperationException
*/
public Object remove(Object key) {
throw new UnsupportedOperationException();
}
/**
* Returns the number properties in the decorated
* {@link DynaBean}.
* @return The number of properties.
*/
public int size() {
return getDynaProperties().length;
}
/**
* Returns the set of property values in the
* decorated {@link DynaBean}.
*
* @return Unmodifiable collection of values.
*/
public Collection values() {
DynaProperty[] properties = getDynaProperties();
List values = new ArrayList(properties.length);
for (int i = 0; i < properties.length; i++) {
String key = properties[i].getName();
Object value = getDynaBean().get(key);
values.add(value);
}
return Collections.unmodifiableList(values);
}
// ------------------- protected Methods -----------------------------
/**
* Provide access to the underlying {@link DynaBean}
* this Map decorates.
*
* @return the decorated {@link DynaBean}.
*/
public DynaBean getDynaBean() {
return dynaBean;
}
// ------------------- private Methods -------------------------------
/**
* Convenience method to retrieve the {@link DynaProperty}s
* for this {@link DynaClass}.
*
* @return The an array of the {@link DynaProperty}s.
*/
private DynaProperty[] getDynaProperties() {
return getDynaBean().getDynaClass().getDynaProperties();
}
/**
* Convenience method to convert an Object
* to a String.
*
* @param obj The Object to convert
* @return String representation of the object
*/
private String toString(Object obj) {
return (obj == null ? null : obj.toString());
}
/**
* Map.Entry implementation.
*/
private static class MapEntry implements Map.Entry {
private Object key;
private Object value;
MapEntry(Object key, Object value) {
this.key = key;
this.value = value;
}
public boolean equals(Object o) {
if (!(o instanceof Map.Entry)) {
return false;
}
Map.Entry e = (Map.Entry)o;
return ((key.equals(e.getKey())) &&
(value == null ? e.getValue() == null
: value.equals(e.getValue())));
}
public int hashCode() {
return key.hashCode() + (value == null ? 0 : value.hashCode());
}
public Object getKey() {
return key;
}
public Object getValue() {
return value;
}
public Object setValue(Object value) {
throw new UnsupportedOperationException();
}
}
}
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