1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache license, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the license for the specific language governing permissions and 15 * limitations under the license. 16 */ 17 package org.apache.logging.log4j.message; 18 19 import org.apache.logging.log4j.status.StatusLogger; 20 21 /** 22 * Specialized {@link ParameterizedMessageFactory} that creates {@link SimpleMessage} objects that do not retain a 23 * reference to the parameter object. 24 * <p> 25 * Intended for use by the {@link StatusLogger}: this logger retains a queue of recently logged messages in memory, 26 * causing memory leaks in web applications. (LOG4J2-1176) 27 * </p> 28 * <p> 29 * This class is immutable. 30 * </p> 31 */ 32 public final class ParameterizedNoReferenceMessageFactory extends AbstractMessageFactory { 33 private static final long serialVersionUID = 5027639245636870500L; 34 35 /** 36 * Message implementation that only keeps a reference to the error text and the error (if any), not to the 37 * message parameters, in order to avoid memory leaks. This addresses LOG4J2-1368. 38 * @since 2.6 39 */ 40 static class StatusMessage implements Message { 41 private final String formattedMessage; 42 private final Throwable throwable; 43 44 public StatusMessage(final String formattedMessage, final Throwable throwable) { 45 this.formattedMessage = formattedMessage; 46 this.throwable = throwable; 47 } 48 49 @Override 50 public String getFormattedMessage() { 51 return formattedMessage; 52 } 53 54 @Override 55 public String getFormat() { 56 return formattedMessage; 57 } 58 59 @Override 60 public Object[] getParameters() { 61 return null; 62 } 63 64 @Override 65 public Throwable getThrowable() { 66 return throwable; 67 } 68 } 69 70 /** 71 * Constructs a message factory with default flow strings. 72 */ 73 public ParameterizedNoReferenceMessageFactory() { 74 super(); 75 } 76 77 /** 78 * Instance of ParameterizedStatusMessageFactory. 79 */ 80 public static final ParameterizedNoReferenceMessageFactory INSTANCE = new ParameterizedNoReferenceMessageFactory(); 81 82 /** 83 * Creates {@link SimpleMessage} instances containing the formatted parameterized message string. 84 * 85 * @param message The message pattern. 86 * @param params The message parameters. 87 * @return The Message. 88 * 89 * @see MessageFactory#newMessage(String, Object...) 90 */ 91 @Override 92 public Message newMessage(final String message, final Object... params) { 93 if (params == null) { 94 return new SimpleMessage(message); 95 } 96 final ParameterizedMessage msg = new ParameterizedMessage(message, params); 97 return new StatusMessage(msg.getFormattedMessage(), msg.getThrowable()); 98 } 99 }