New JNI bindings

src/com/github/rjeschke/neetutils/dispose/ReferenceList.java

+/*
+ * Copyright (C) 2012 René Jeschke <rene_jeschke@yahoo.de>
+ *
+ * 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.github.rjeschke.neetutils.dispose;
+
+/**
+ * Specialized linked list to hold weak references or similar stuff. Adding and
+ * removing is guaranteed O(1).
+ * 
+ * @author René Jeschke <rene_jeschke@yhoo.de>
+ */
+public class ReferenceList<T>
+{
+  private Node<T> root;
+  private int size;
+
+  /**
+   * Constructor.
+   */
+  public ReferenceList()
+  {
+    // empty
+  }
+
+  /**
+   * Gets the number of items currently in this list.
+   * 
+   * @return The size.
+   */
+  public int size()
+  {
+    return this.size;
+  }
+
+  /**
+   * Checks if this list is empty.
+   * 
+   * @return <code>true</code> is this list is empty
+   */
+  public boolean isEmpty()
+  {
+    return this.size == 0;
+  }
+
+  /**
+   * Adds a value to this list (at head).
+   * 
+   * @param value
+   *          Value to add
+   * @return Node reference needed for remove
+   */
+  public Node<T> add(final T value)
+  {
+    final Node<T> node = new Node<T>(value);
+    this.size++;
+    if (this.root != null)
+    {
+      node.next = this.root;
+      this.root.previous = node;
+    }
+    this.root = node;
+
+    return node;
+  }
+
+  /**
+   * Removes the last added Node.
+   * 
+   * @return The last added Node or <code>null</code> if this list is empty.
+   */
+  public Node<T> removeLast()
+  {
+    if (this.root == null)
+    {
+      return null;
+    }
+
+    this.size--;
+    final Node<T> node = this.root;
+    if (node.next != null)
+    {
+      node.next.previous = null;
+    }
+    this.root = node.next;
+
+    node.next = node.previous = null;
+    node.inside = false;
+    return node;
+  }
+
+  /**
+   * Removes the given Node from this list. Multiple removes are prevented.
+   * 
+   * @param node
+   *          The Node to remove
+   */
+  public void remove(final Node<T> node)
+  {
+    if (!node.inside)
+    {
+      return;
+    }
+
+    this.size--;
+    if (node.previous == null)
+    {
+      this.root = node.next;
+    }
+    else
+    {
+      node.previous.next = node.next;
+      if (node.next != null)
+      {
+        node.next.previous = node.previous;
+      }
+    }
+
+    node.next = node.previous = null;
+    node.inside = false;
+  }
+
+  /**
+   * 
+   * 
+   * @author René Jeschke <rene_jeschke@yhoo.de>
+   */
+  public static class Node<T>
+  {
+    final T value;
+    boolean inside = true;
+    Node<T> previous;
+    Node<T> next;
+
+    public Node(final T value)
+    {
+      this.value = value;
+    }
+
+    public T value()
+    {
+      return this.value;
+    }
+
+    @Override
+    public String toString()
+    {
+      return "Node: " + this.value;
+    }
+  }
+}