SSDM-2153: reuse and close readers in thumbnail generation

SVN: 34390

common/source/java/ch/systemsx/cisd/common/utilities/IdentitySet.java

+/*
+ * Copyright 2015 ETH Zuerich, CISD
+ *
+ * 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 ch.systemsx.cisd.common.utilities;
+
+import java.util.IdentityHashMap;
+import java.util.LinkedList;
+
+/**
+ * Implementation of a set (not implementing java Set interface) that uses objects identity instead of hashCode and equals
+ * 
+ * @author Jakub Straszewski
+ */
+public class IdentitySet<T>
+{
+    IdentityHashMap<T, Object> map = new IdentityHashMap<>();
+
+    public void add(T t)
+    {
+        map.put(t, t);
+    }
+
+    public boolean contains(T t)
+    {
+        return map.containsKey(t);
+    }
+
+    public void remove(T t)
+    {
+        map.remove(t);
+    }
+
+    public Iterable<T> getItems()
+    {
+        return new LinkedList<T>(map.keySet());
+    }
+}