1/* 2 * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26package sun.jvmstat.perfdata.monitor.protocol.file; 27 28import sun.jvmstat.monitor.*; 29import sun.jvmstat.perfdata.monitor.*; 30import java.io.*; 31import java.net.URI; 32import java.nio.ByteBuffer; 33import java.nio.channels.FileChannel; 34 35/** 36 * The concrete PerfDataBuffer implementation for the <em>file:</em> 37 * protocol for the HotSpot PerfData monitoring implemetation. 38 * <p> 39 * This class is responsible for acquiring access to the instrumentation 40 * buffer stored in a file referenced by a file URI. 41 * 42 * @author Brian Doherty 43 * @since 1.5 44 */ 45public class PerfDataBuffer extends AbstractPerfDataBuffer { 46 47 /** 48 * Create a PerfDataBuffer instance for accessing the specified 49 * instrumentation buffer. 50 * 51 * @param vmid the <em>file:</em> URI to the instrumentation buffer file 52 * 53 * @throws MonitorException 54 */ 55 public PerfDataBuffer(VmIdentifier vmid) throws MonitorException { 56 File f = new File(vmid.getURI()); 57 String mode = vmid.getMode(); 58 59 try { 60 FileChannel fc = new RandomAccessFile(f, mode).getChannel(); 61 ByteBuffer bb = null; 62 63 if (mode.compareTo("r") == 0) { 64 bb = fc.map(FileChannel.MapMode.READ_ONLY, 0L, (int)fc.size()); 65 } else if (mode.compareTo("rw") == 0) { 66 bb = fc.map(FileChannel.MapMode.READ_WRITE, 0L, (int)fc.size()); 67 } else { 68 throw new IllegalArgumentException("Invalid mode: " + mode); 69 } 70 71 fc.close(); // doesn't need to remain open 72 73 createPerfDataBuffer(bb, 0); 74 } catch (FileNotFoundException e) { 75 throw new MonitorException("Could not find " + vmid.toString()); 76 } catch (IOException e) { 77 throw new MonitorException("Could not read " + vmid.toString()); 78 } 79 } 80} 81