001/* 002 * (C) Copyright 2006-2009 Nuxeo SAS (http://nuxeo.com/) and contributors. 003 * 004 * All rights reserved. This program and the accompanying materials 005 * are made available under the terms of the GNU Lesser General Public License 006 * (LGPL) version 2.1 which accompanies this distribution, and is available at 007 * http://www.gnu.org/licenses/lgpl.html 008 * 009 * This library is distributed in the hope that it will be useful, 010 * but WITHOUT ANY WARRANTY; without even the implied warranty of 011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 012 * Lesser General Public License for more details. 013 * 014 * Contributors: 015 * Nuxeo - initial API and implementation 016 * 017 * $Id$ 018 */ 019package org.nuxeo.runtime.management.counters; 020 021import java.util.Iterator; 022import java.util.LinkedList; 023 024/** 025 * Fixed length Stack that is used to store values of a counter over time 026 * 027 * @author Tiry (tdelprat@nuxeo.com) 028 */ 029public class CounterHistoryStack implements Iterable<long[]> { 030 031 protected final LinkedList<long[]> list = new LinkedList<long[]>(); 032 033 protected final int maxSize; 034 035 public CounterHistoryStack(int size) { 036 maxSize = size; 037 } 038 039 public synchronized void push(long[] item) { 040 list.push(item); 041 if (list.size() > maxSize) { 042 list.remove(list.size() - 1); 043 } 044 } 045 046 @Override 047 public Iterator<long[]> iterator() { 048 return list.iterator(); 049 } 050 051 @Override 052 public String toString() { 053 StringBuffer sb = new StringBuffer(); 054 055 for (long[] entry : this) { 056 sb.append(entry[0]); 057 sb.append(" => "); 058 sb.append(entry[1]); 059 sb.append("\n"); 060 } 061 return sb.toString(); 062 } 063 064 public long[] get(int idx) { 065 return list.get(idx); 066 } 067 068 public LinkedList<long[]> getAsList() { 069 return list; 070 } 071}