/*

  * Copyright 2005-2008 The Kuali Foundation

  * 

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  * 

  * 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.kuali.rice.kns.util;

 import java.util.Collection;

 import java.util.Map;

 import java.util.Properties;

 import java.util.Set;

 import org.kuali.rice.kns.util.properties.PropertyTree;

 /**

  * This class implements the Map interface for a Properties instance. Exports all properties from the given Properties instance as

  * constants, usable from jstl. Implements the Map interface (by delegating everything to the PropertyTree, which really implements

  * the Map methods directly) so that jstl can translate ${Constants.a} into a call to ConfigConstants.get( "a" ).

  * <p>

  * The contents of this Map cannot be changed once it has been initialized. Any calls to any of the Map methods made before the

  * propertyTree has been initialized (i.e. before setProperties has been called) will throw an IllegalStateException.

  * <p>

  * Jstl converts ${Constants.a.b.c} into get("a").get("b").get("c"), so the properties are stored in a PropertyTree, which converts

  * the initial set( "a.b.c", "value" ) into construction of the necessary tree structure to support get("a").get("b").get("c").

  * <p>

  * Implicitly relies on the assumption that the JSP will be calling toString() on the result of the final <code>get</code>, since

  * <code>get</code> can only return one type, and that type must be the complex one so that further dereferencing will be

  * possible.

  * 

  * 

  */

 public abstract class JstlPropertyHolder implements Map {

     private PropertyTree propertyTree;

     /**

      * Default constructor

      */

     public JstlPropertyHolder() {

         propertyTree = null;

     }

     /**

      * Creates a propertyTree to store the given properties

      * 

      * @param properties

      */

     protected void setProperties(Properties properties) {

         propertyTree = new PropertyTree(properties);

     }

     /**

      * Copies in the given propertyTree rather than building its own. Reasonably dangerous, since that tree might presumably be

      * modified, violating the readonlyness of this datastructure.

      * 

      * @param properties

      */

     protected void setPropertyTree(PropertyTree tree) {

         propertyTree = tree;

     }

     // delegated methods

     /**

      * @see org.kuali.rice.kns.util.properties.PropertyTree#get(java.lang.Object)

      */

     public Object get(Object key) {

         if (propertyTree == null) {

             throw new IllegalStateException("propertyTree has not been initialized");

         }

         return this.propertyTree.get(key);

     }

     /**

      * @see org.kuali.rice.kns.util.properties.PropertyTree#size()

      */

     public int size() {

         if (propertyTree == null) {

             throw new IllegalStateException("propertyTree has not been initialized");

         }

         return this.propertyTree.size();

     }

     /**

      * @see org.kuali.rice.kns.util.properties.PropertyTree#clear()

      */

     public void clear() {

         if (propertyTree == null) {

             throw new IllegalStateException("propertyTree has not been initialized");

         }

         this.propertyTree.clear();

     }

     /**

      * @see org.kuali.rice.kns.util.properties.PropertyTree#isEmpty()

      */

     public boolean isEmpty() {

         if (propertyTree == null) {

             throw new IllegalStateException("propertyTree has not been initialized");

         }

         return this.propertyTree.isEmpty();

     }

     /**

      * @see org.kuali.rice.kns.util.properties.PropertyTree#containsKey(java.lang.Object)

      */

     public boolean containsKey(Object key) {

         if (propertyTree == null) {

             throw new IllegalStateException("propertyTree has not been initialized");

         }

         return this.propertyTree.containsKey(key);

     }

     /**

      * @see org.kuali.rice.kns.util.properties.PropertyTree#containsValue(java.lang.Object)

      */

     public boolean containsValue(Object value) {

         if (propertyTree == null) {

             throw new IllegalStateException("propertyTree has not been initialized");

         }

         return this.propertyTree.containsValue(value);

     }

     /**

      * @see org.kuali.rice.kns.util.properties.PropertyTree#values()

      */

     public Collection values() {

         if (propertyTree == null) {

             throw new IllegalStateException("propertyTree has not been initialized");

         }

         return this.propertyTree.values();

     }

     /**

      * @see org.kuali.rice.kns.util.properties.PropertyTree#putAll(java.util.Map)

      */

     public void putAll(Map m) {

         if (propertyTree == null) {

             throw new IllegalStateException("propertyTree has not been initialized");

         }

         this.propertyTree.putAll(m);

     }

     /**

      * @see org.kuali.rice.kns.util.properties.PropertyTree#entrySet()

      */

     public Set entrySet() {

         if (propertyTree == null) {

             throw new IllegalStateException("propertyTree has not been initialized");

         }

         return this.propertyTree.entrySet();

     }

     /**

      * @see org.kuali.rice.kns.util.properties.PropertyTree#keySet()

      */

     public Set keySet() {

         if (propertyTree == null) {

             throw new IllegalStateException("propertyTree has not been initialized");

         }

         return this.propertyTree.keySet();

     }

     /**

      * @see org.kuali.rice.kns.util.properties.PropertyTree#remove(java.lang.Object)

      */

     public Object remove(Object key) {

         if (propertyTree == null) {

             throw new IllegalStateException("propertyTree has not been initialized");

         }

         return this.propertyTree.remove(key);

     }

     /**

      * @see org.kuali.rice.kns.util.properties.PropertyTree#put(java.lang.Object, java.lang.Object)

      */

     public Object put(Object key, Object value) {

         if (propertyTree == null) {

             throw new IllegalStateException("propertyTree has not been initialized");

         }

         return this.propertyTree.put(key, value);

     }

 }