001// *************************************************************************************************************************** 002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file * 003// * distributed with this work for additional information regarding copyright ownership. The ASF licenses this file * 004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance * 005// * with the License. You may obtain a copy of the License at * 006// * * 007// * http://www.apache.org/licenses/LICENSE-2.0 * 008// * * 009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an * 010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the * 011// * specific language governing permissions and limitations under the License. * 012// *************************************************************************************************************************** 013package org.apache.juneau.mstat; 014 015import java.util.*; 016import java.util.concurrent.*; 017import java.util.stream.*; 018 019/** 020 * An in-memory cache of stack traces. 021 * 022 * <p> 023 * Used for preventing duplication of stack traces in log files and replacing them with small hashes. 024 */ 025public class ExceptionStore { 026 027 private final ConcurrentHashMap<Integer,ExceptionStats> sdb = new ConcurrentHashMap<>(); 028 private final ConcurrentHashMap<Integer,ExceptionInfo> idb = new ConcurrentHashMap<>(); 029 private final ExceptionHasher hasher; 030 private final long cacheTimeout; 031 032 /** 033 * Constructor. 034 */ 035 public ExceptionStore() { 036 this(-1, null); 037 } 038 039 040 041 /** 042 * Constructor. 043 * 044 * @param cacheTimeout 045 * The amount of time in milliseconds to cache stack trace info in this database before discarding. 046 * <br>If <c>-1</c>, never discard. 047 * @param stopClass 048 * When this class is encountered in a stack trace, stop calculating the hash. 049 * <br>Can be <jk>null</jk>. 050 */ 051 public ExceptionStore(long cacheTimeout, Class<?> stopClass) { 052 this.hasher = new ExceptionHasher(stopClass); 053 this.cacheTimeout = cacheTimeout; 054 } 055 056 /** 057 * Adds the specified throwable to this database. 058 * 059 * @param e The exception to add. 060 * @return This object (for method chaining). 061 */ 062 public ExceptionStore add(Throwable e) { 063 find(e).increment(); 064 return this; 065 } 066 067 /** 068 * Retrieves the stack trace information for the specified exception. 069 * 070 * @param e The exception. 071 * @return A clone of the stack trace info, never <jk>null</jk>. 072 */ 073 public ExceptionStats getStackTraceInfo(Throwable e) { 074 return find(e).clone(); 075 } 076 077 /** 078 * Clears out the stack trace cache. 079 */ 080 public void reset() { 081 sdb.clear(); 082 } 083 084 /** 085 * Returns the list of all stack traces in this database. 086 * 087 * @return The list of all stack traces in this database, cloned and sorted by count descending. 088 */ 089 public List<ExceptionStats> getClonedStats() { 090 return sdb.values().stream().map(x -> x.clone()).sorted().collect(Collectors.toList()); 091 } 092 093 private ExceptionStats find(Throwable e) { 094 095 if (e == null) 096 return null; 097 098 int hash = hasher.hash(e); 099 100 ExceptionStats stc = sdb.get(hash); 101 if (stc != null && ! stc.isExpired()) 102 return stc; 103 104 stc = ExceptionStats 105 .create() 106 .hash(Integer.toHexString(hash)) 107 .timeout(cacheTimeout == -1 ? Long.MAX_VALUE : System.currentTimeMillis() + cacheTimeout) 108 .message(e.getMessage()) 109 .exceptionClass(e.getClass().getName()) 110 .stackTrace(hasher.getStackTrace(e)) 111 .causedBy(e.getCause() == null ? null : findInfo(e.getCause())); 112 113 sdb.put(hash, stc); 114 115 return sdb.get(hash); 116 } 117 118 private ExceptionInfo findInfo(Throwable e) { 119 120 int hash = hasher.hash(e); 121 122 ExceptionInfo ei = sdb.get(hash); 123 if (ei == null) { 124 ei = ExceptionInfo 125 .create() 126 .hash(Integer.toHexString(hash)) 127 .message(e.getMessage()) 128 .exceptionClass(e.getClass().getName()) 129 .stackTrace(hasher.getStackTrace(e)) 130 .causedBy(e.getCause() == null ? null : findInfo(e.getCause())); 131 idb.put(hash, ei); 132 } 133 134 return ei; 135 } 136}