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.logging.log4j.message; 018 019import org.apache.logging.log4j.status.StatusLogger; 020 021/** 022 * Specialized {@link ParameterizedMessageFactory} that creates {@link SimpleMessage} objects that do not retain a 023 * reference to the parameter object. 024 * <p> 025 * Intended for use by the {@link StatusLogger}: this logger retains a queue of recently logged messages in memory, 026 * causing memory leaks in web applications. (LOG4J2-1176) 027 * </p> 028 * <p> 029 * This class is immutable. 030 * </p> 031 */ 032public final class ParameterizedNoReferenceMessageFactory extends AbstractMessageFactory { 033 private static final long serialVersionUID = 5027639245636870500L; 034 035 /** 036 * Message implementation that only keeps a reference to the error text and the error (if any), not to the 037 * message parameters, in order to avoid memory leaks. This addresses LOG4J2-1368. 038 * @since 2.6 039 */ 040 static class StatusMessage implements Message { 041 private final String formattedMessage; 042 private final Throwable throwable; 043 044 public StatusMessage(final String formattedMessage, final Throwable throwable) { 045 this.formattedMessage = formattedMessage; 046 this.throwable = throwable; 047 } 048 049 @Override 050 public String getFormattedMessage() { 051 return formattedMessage; 052 } 053 054 @Override 055 public String getFormat() { 056 return formattedMessage; 057 } 058 059 @Override 060 public Object[] getParameters() { 061 return null; 062 } 063 064 @Override 065 public Throwable getThrowable() { 066 return throwable; 067 } 068 } 069 070 /** 071 * Constructs a message factory with default flow strings. 072 */ 073 public ParameterizedNoReferenceMessageFactory() { 074 super(); 075 } 076 077 /** 078 * Instance of ParameterizedStatusMessageFactory. 079 */ 080 public static final ParameterizedNoReferenceMessageFactory INSTANCE = new ParameterizedNoReferenceMessageFactory(); 081 082 /** 083 * Creates {@link SimpleMessage} instances containing the formatted parameterized message string. 084 * 085 * @param message The message pattern. 086 * @param params The message parameters. 087 * @return The Message. 088 * 089 * @see MessageFactory#newMessage(String, Object...) 090 */ 091 @Override 092 public Message newMessage(final String message, final Object... params) { 093 if (params == null) { 094 return new SimpleMessage(message); 095 } 096 final ParameterizedMessage msg = new ParameterizedMessage(message, params); 097 return new StatusMessage(msg.getFormattedMessage(), msg.getThrowable()); 098 } 099}