Sharing org.simantics.acorn for everyone to use

[simantics/platform.git] / bundles / org.simantics.acorn / src / org / simantics / acorn / internal / BijectionMap.java

diff --git a/bundles/org.simantics.acorn/src/org/simantics/acorn/internal/BijectionMap.java b/bundles/org.simantics.acorn/src/org/simantics/acorn/internal/BijectionMap.java
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+/*******************************************************************************
+ * Copyright (c) 2007, 2010 Association for Decentralized Information Management
+ * in Industry THTH ry.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     VTT Technical Research Centre of Finland - initial API and implementation
+ *******************************************************************************/
+/*
+ * Created on Jan 21, 2005
+ * 
+ * Copyright Toni Kalajainen
+ * 
+ * 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.simantics.acorn.internal;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Bijection map is a Map that has no values or keys, only 1:1 mappings
+ * of values. These value/keys will be called with left and right side
+ * values.
+ * 
+ * Each value can exist only once on a side
+ * 
+ * @author Toni Kalajainen
+ */
+public class BijectionMap<L, R> {
+
+    /** The keys of tableLeft are left-side-values and
+     * values are right-side-values */
+    private final Map<L, R> tableLeft = new HashMap<L, R>();
+    /** The keys of tableRight are right-side-values and
+     * values on it are left-side-values */
+    private final Map<R, L> tableRight = new HashMap<R, L>();
+
+    public boolean containsLeft(L leftValue)
+    {
+        return tableLeft.containsKey(leftValue);
+    }
+
+    public boolean containsRight(R rightValue)
+    {
+        return tableRight.containsKey(rightValue);
+    }
+
+    public void map(L leftValue, R rightValue)
+    {
+        // Remove possible old mapping
+        R oldRight = tableLeft.remove(leftValue);
+        if (oldRight != null) {
+            tableRight.remove(oldRight);
+        } else {
+            L oldLeft = tableRight.remove(rightValue);
+            if (oldLeft != null) {
+                tableLeft.remove(oldLeft);
+            }
+        }
+
+        tableLeft.put(leftValue, rightValue);
+        tableRight.put(rightValue, leftValue);
+    }
+
+    public int size()
+    {
+        return tableLeft.size();
+    }
+
+    public L getLeft(R rightValue) {
+        return tableRight.get(rightValue);
+    }
+
+    public R getRight(L leftValue) {
+        return tableLeft.get(leftValue);
+    }
+
+    public R removeWithLeft(L leftValue) {
+        R rightValue = tableLeft.remove(leftValue);
+        if (rightValue!=null)
+            tableRight.remove(rightValue);
+        return rightValue;
+    }
+
+    public L removeWithRight(R rightValue) {
+        L leftValue = tableRight.remove(rightValue);
+        if (leftValue!=null)
+            tableLeft.remove(leftValue);
+        return leftValue;
+    }
+
+    public Set<L> getLeftSet() {
+        return tableLeft.keySet();
+    }
+
+    public Set<R> getRightSet() {
+        return tableRight.keySet();
+    }
+
+    public void clear() {
+        tableLeft.clear();
+        tableRight.clear();
+    }
+}