/*

  * 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 08:57:20 -0400 (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();

         }

     }

 }