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ActiveMQ example source code file (VMIndexLinkedList.java)
The ActiveMQ VMIndexLinkedList.java source code/** * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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.apache.activemq.kaha.impl.index; import org.apache.activemq.kaha.StoreEntry; /** * A linked list used by IndexItems * * */ public final class VMIndexLinkedList implements Cloneable, IndexLinkedList { private transient IndexItem root; private transient int size; /** * Constructs an empty list. * @param header */ public VMIndexLinkedList(IndexItem header) { this.root = header; this.root.next=this.root.prev=this.root; } public void setRoot(IndexItem newRoot) { this.root=newRoot; } public synchronized IndexItem getRoot() { return root; } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#getFirst() */ public synchronized IndexItem getFirst() { if (size == 0) { return null; } return root.next; } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#getLast() */ public synchronized IndexItem getLast() { if (size == 0) { return null; } return root.prev; } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#removeFirst() */ public synchronized StoreEntry removeFirst() { if (size == 0) { return null; } StoreEntry result = root.next; remove(root.next); return result; } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#removeLast() */ public synchronized Object removeLast() { if (size == 0) { return null; } StoreEntry result = root.prev; remove(root.prev); return result; } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#addFirst(org.apache.activemq.kaha.impl.IndexItem) */ public synchronized void addFirst(IndexItem item) { addBefore(item, root.next); } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#addLast(org.apache.activemq.kaha.impl.IndexItem) */ public synchronized void addLast(IndexItem item) { addBefore(item, root); } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#size() */ public synchronized int size() { return size; } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#isEmpty() */ public synchronized boolean isEmpty() { return size == 0; } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#add(org.apache.activemq.kaha.impl.IndexItem) */ public synchronized boolean add(IndexItem item) { addBefore(item, root); return true; } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#clear() */ public synchronized void clear() { root.next=root.prev=root; size = 0; } // Positional Access Operations /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#get(int) */ public synchronized IndexItem get(int index) { return entry(index); } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#add(int, * org.apache.activemq.kaha.impl.IndexItem) */ public synchronized void add(int index, IndexItem element) { addBefore(element, index == size ? root : entry(index)); } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#remove(int) */ public synchronized Object remove(int index) { IndexItem e = entry(index); remove(e); return e; } /** * Return the indexed entry. */ private IndexItem entry(int index) { if (index < 0 || index >= size) { throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + size); } IndexItem e = root; if (index < size / 2) { for (int i = 0; i <= index; i++) { e = e.next; } } else { for (int i = size; i > index; i--) { e = e.prev; } } return e; } // Search Operations /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#indexOf(org.apache.activemq.kaha.impl.IndexItem) */ public synchronized int indexOf(StoreEntry o) { int index = 0; for (IndexItem e = root.next; e != root; e = e.next) { if (o == e) { return index; } index++; } return -1; } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#getNextEntry(org.apache.activemq.kaha.impl.IndexItem) */ public synchronized IndexItem getNextEntry(IndexItem entry) { return entry.next != root ? entry.next : null; } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#getPrevEntry(org.apache.activemq.kaha.impl.IndexItem) */ public synchronized IndexItem getPrevEntry(IndexItem entry) { return entry.prev != root ? entry.prev : null; } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#addBefore(org.apache.activemq.kaha.impl.IndexItem, * org.apache.activemq.kaha.impl.IndexItem) */ public synchronized void addBefore(IndexItem insert, IndexItem e) { insert.next = e; insert.prev = e.prev; insert.prev.next = insert; insert.next.prev = insert; size++; } /* * (non-Javadoc) * * @see org.apache.activemq.kaha.impl.IndexLinkedList#remove(org.apache.activemq.kaha.impl.IndexItem) */ public synchronized void remove(IndexItem e) { if (e == root || e.equals(root)) { return; } e.prev.next = e.next; e.next.prev = e.prev; size--; } /** * @return clone */ public synchronized Object clone() { IndexLinkedList clone = new VMIndexLinkedList(this.root); for (IndexItem e = root.next; e != root; e = e.next) { clone.add(e); } return clone; } public synchronized StoreEntry getEntry(StoreEntry current) { return current; } /** * Update the indexes of a StoreEntry * * @param current */ public synchronized StoreEntry refreshEntry(StoreEntry current) { return current; } } Other ActiveMQ examples (source code examples)Here is a short list of links related to this ActiveMQ VMIndexLinkedList.java source code file: |
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