1 files changed, 96 insertions, 0 deletions
diff --git a/server/src/com/vaadin/server/KeyMapper.java b/server/src/com/vaadin/server/KeyMapper.java
new file mode 100644
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+++ b/server/src/com/vaadin/server/KeyMapper.java
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+/* 
+ * Copyright 2011 Vaadin Ltd.
+ * 
+ * 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 com.vaadin.server;
+
+import java.io.Serializable;
+import java.util.HashMap;
+
+/**
+ * <code>KeyMapper</code> is the simple two-way map for generating textual keys
+ * for objects and retrieving the objects later with the key.
+ * 
+ * @author Vaadin Ltd.
+ * @since 3.0
+ */
+public class KeyMapper<V> implements Serializable {
+
+    private int lastKey = 0;
+
+    private final HashMap<V, String> objectKeyMap = new HashMap<V, String>();
+
+    private final HashMap<String, V> keyObjectMap = new HashMap<String, V>();
+
+    /**
+     * Gets key for an object.
+     * 
+     * @param o
+     *            the object.
+     */
+    public String key(V o) {
+
+        if (o == null) {
+            return "null";
+        }
+
+        // If the object is already mapped, use existing key
+        String key = objectKeyMap.get(o);
+        if (key != null) {
+            return key;
+        }
+
+        // If the object is not yet mapped, map it
+        key = String.valueOf(++lastKey);
+        objectKeyMap.put(o, key);
+        keyObjectMap.put(key, o);
+
+        return key;
+    }
+
+    /**
+     * Retrieves object with the key.
+     * 
+     * @param key
+     *            the name with the desired value.
+     * @return the object with the key.
+     */
+    public V get(String key) {
+        return keyObjectMap.get(key);
+    }
+
+    /**
+     * Removes object from the mapper.
+     * 
+     * @param removeobj
+     *            the object to be removed.
+     */
+    public void remove(V removeobj) {
+        final String key = objectKeyMap.get(removeobj);
+
+        if (key != null) {
+            objectKeyMap.remove(removeobj);
+            keyObjectMap.remove(key);
+        }
+    }
+
+    /**
+     * Removes all objects from the mapper.
+     */
+    public void removeAll() {
+        objectKeyMap.clear();
+        keyObjectMap.clear();
+    }
+}