1 /* 2 * Copyright (c) 2016, 2018, 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 26 package jdk.jfr.internal.handlers; 27 28 import java.io.IOException; 29 import java.io.ObjectInputStream; 30 import java.io.ObjectOutputStream; 31 32 import jdk.jfr.EventType; 33 import jdk.jfr.internal.EventControl; 34 import jdk.jfr.internal.JVM; 35 import jdk.jfr.internal.PlatformEventType; 36 import jdk.jfr.internal.PrivateAccess; 37 import jdk.jfr.internal.StringPool; 38 39 // Users should not be subclass for security reasons. 40 public abstract class EventHandler { 41 // Accessed by generated sub class 42 protected final PlatformEventType platformEventType; 43 44 private final EventType eventType; 45 private final EventControl eventControl; 46 47 // Accessed by generated sub class 48 EventHandler(boolean registered, EventType eventType, EventControl eventControl) { 49 this.eventType = eventType; 50 this.platformEventType = PrivateAccess.getInstance().getPlatformEventType(eventType); 51 this.eventControl = eventControl; 52 platformEventType.setRegistered(registered); 53 } 54 55 final protected StringPool createStringFieldWriter() { 56 return new StringPool(); 57 } 58 59 // Accessed by generated code in event class 60 public final boolean shouldCommit(long duration) { 61 return isEnabled() && duration >= platformEventType.getThresholdTicks(); 62 } 63 64 // Accessed by generated code in event class 65 // Accessed by generated sub class 66 public final boolean isEnabled() { 67 return platformEventType.isCommitable(); 68 } 69 70 public final EventType getEventType() { 71 return eventType; 72 } 73 74 public final PlatformEventType getPlatformEventType() { 75 return platformEventType; 76 } 77 78 public final EventControl getEventControl() { 79 return eventControl; 80 } 81 82 public static long timestamp() { 83 return JVM.counterTime(); 84 } 85 86 public static long duration(long startTime) { 87 if (startTime == 0) { 88 // User forgot to invoke begin, or instrumentation was 89 // added after the user invoked begin. 90 // Returning 0 will make it an instant event 91 return 0; 92 } 93 return timestamp() - startTime; 94 } 95 96 // Prevent a malicious user from instantiating a generated event handlers. 97 @Override 98 public final Object clone() throws java.lang.CloneNotSupportedException { 99 throw new CloneNotSupportedException(); 100 } 101 102 private final void writeObject(ObjectOutputStream out) throws IOException { 103 throw new IOException("Object cannot be serialized"); 104 } 105 106 private final void readObject(ObjectInputStream in) throws IOException { 107 throw new IOException("Class cannot be deserialized"); 108 } 109 110 public boolean isRegistered() { 111 return platformEventType.isRegistered(); 112 } 113 114 public boolean setRegistered(boolean registered) { 115 return platformEventType.setRegistered(registered); 116 } 117 }