1 files changed, 93 insertions, 0 deletions
diff --git a/simple/simple-common/src/main/java/org/simpleframework/common/KeyMap.java b/simple/simple-common/src/main/java/org/simpleframework/common/KeyMap.java
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+++ b/simple/simple-common/src/main/java/org/simpleframework/common/KeyMap.java
@@ -0,0 +1,93 @@
+/*
+ * KeyMap.java May 2007
+ *
+ * Copyright (C) 2007, Niall Gallagher <niallg@users.sf.net>
+ *
+ * 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.simpleframework.common;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * The <code>KeyMap</code> object is used to represent a map of values
+ * keyed using a known string. This also ensures that the keys and
+ * the values added to this hash map can be acquired in an independent
+ * list of values, ensuring that modifications to the map do not have
+ * an impact on the lists provided, and vice versa. The key map can
+ * also be used in a fore each look using the string keys.
+ * 
+ * @author Niall Gallagher
+ */
+public class KeyMap<T> extends LinkedHashMap<String, T> implements Iterable<String> {
+   
+   /**
+    * Constructor for the <code>KeyMap</code> object. This creates
+    * a hash map that can expose the keys and values of the map as
+    * an independent <code>List</code> containing the values. This
+    * can also be used within a for loop for convenience.
+    */
+   public KeyMap() {
+     super();            
+   }          
+   
+   /**
+    * This is used to produce an <code>Iterator</code> of values 
+    * that can be used to acquire the contents of the key map within
+    * a for each loop. The key map can be modified while it is been
+    * iterated as the iterator is an independent list of values.
+    * 
+    * @return this returns an iterator of the keys in the map
+    */
+   public Iterator<String> iterator() {
+      return getKeys().iterator();
+   }
+
+   /**
+    * This is used to produce a <code>List</code> of the keys in
+    * the map. The list produced is a copy of the internal keys and
+    * so can be modified and used without affecting this map object.
+    * 
+    * @return this returns an independent list of the key values
+    */
+   public List<String> getKeys() {
+     Set<String> keys = keySet();
+     
+     if(keys == null) {
+        return new ArrayList<String>();
+     }
+     return new ArrayList<String>(keys);      
+   }
+   
+   /**
+    * This is used to produce a <code>List</code> of the values in
+    * the map. The list produced is a copy of the internal values and
+    * so can be modified and used without affecting this map object.
+    * 
+    * @return this returns an independent list of the values
+    */   
+   public List<T> getValues() {
+      Collection<T> values = values();
+      
+      if(values == null) {
+         return new ArrayList<T>();          
+      }
+      return new ArrayList<T>(values);
+   }
+ }
+\ No newline at end of file