001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.pool2.impl; 018 019import java.io.PrintWriter; 020import java.lang.ref.WeakReference; 021import java.security.AccessController; 022import java.security.PrivilegedAction; 023import java.text.DateFormat; 024import java.text.SimpleDateFormat; 025import java.util.ArrayList; 026import java.util.List; 027 028/** 029 * CallStack strategy using a {@link SecurityManager}. Obtaining the current call stack is much faster via a 030 * SecurityManger, but access to the underlying method may be restricted by the current SecurityManager. In environments 031 * where a SecurityManager cannot be created, {@link ThrowableCallStack} should be used instead. 032 * 033 * @see RuntimePermission 034 * @see SecurityManager#getClassContext() 035 * @since 2.4.3 036 */ 037public class SecurityManagerCallStack implements CallStack { 038 039 /** 040 * A custom security manager. 041 */ 042 private static class PrivateSecurityManager extends SecurityManager { 043 /** 044 * Get the class stack. 045 * 046 * @return class stack 047 */ 048 private List<WeakReference<Class<?>>> getCallStack() { 049 final Class<?>[] classes = getClassContext(); 050 final List<WeakReference<Class<?>>> stack = new ArrayList<>(classes.length); 051 for (final Class<?> klass : classes) { 052 stack.add(new WeakReference<>(klass)); 053 } 054 return stack; 055 } 056 } 057 /** 058 * A snapshot of a class stack. 059 */ 060 private static class Snapshot { 061 private final long timestampMillis = System.currentTimeMillis(); 062 private final List<WeakReference<Class<?>>> stack; 063 064 /** 065 * Create a new snapshot with a class stack. 066 * 067 * @param stack class stack 068 */ 069 private Snapshot(final List<WeakReference<Class<?>>> stack) { 070 this.stack = stack; 071 } 072 } 073 private final String messageFormat; 074 075 //@GuardedBy("dateFormat") 076 private final DateFormat dateFormat; 077 078 private final PrivateSecurityManager securityManager; 079 080 private volatile Snapshot snapshot; 081 082 /** 083 * Create a new instance. 084 * 085 * @param messageFormat message format 086 * @param useTimestamp whether to format the dates in the output message or not 087 */ 088 public SecurityManagerCallStack(final String messageFormat, final boolean useTimestamp) { 089 this.messageFormat = messageFormat; 090 this.dateFormat = useTimestamp ? new SimpleDateFormat(messageFormat) : null; 091 this.securityManager = AccessController.doPrivileged((PrivilegedAction<PrivateSecurityManager>) PrivateSecurityManager::new); 092 } 093 094 @Override 095 public void clear() { 096 snapshot = null; 097 } 098 099 @Override 100 public void fillInStackTrace() { 101 snapshot = new Snapshot(securityManager.getCallStack()); 102 } 103 104 @Override 105 public boolean printStackTrace(final PrintWriter writer) { 106 final Snapshot snapshotRef = this.snapshot; 107 if (snapshotRef == null) { 108 return false; 109 } 110 final String message; 111 if (dateFormat == null) { 112 message = messageFormat; 113 } else { 114 synchronized (dateFormat) { 115 message = dateFormat.format(Long.valueOf(snapshotRef.timestampMillis)); 116 } 117 } 118 writer.println(message); 119 for (final WeakReference<Class<?>> reference : snapshotRef.stack) { 120 writer.println(reference.get()); 121 } 122 return true; 123 } 124}