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.utils;
014
015import static org.apache.juneau.internal.StringUtils.*;
016
017import java.io.*;
018import java.text.*;
019
020import org.apache.juneau.*;
021import org.apache.juneau.http.*;
022
023/**
024 * An encapsulated MessageFormat-style string and arguments.
025 * 
026 * <p>
027 * Useful for delayed serialization of arguments for logging.
028 * Message string will not be constructed until the <code>toString()</code> method is called.
029 */
030public class StringMessage implements CharSequence, Writable {
031
032   private final String pattern;
033   private final Object[] args;
034   private String results;
035
036   /**
037    * Constructor.
038    * 
039    * @param pattern {@link MessageFormat}-style pattern.
040    * @param args Message arguments.
041    */
042   public StringMessage(String pattern, Object...args) {
043      this.pattern = pattern;
044      this.args = args;
045   }
046
047   @Override /* Writable */
048   public Writer writeTo(Writer w) throws IOException {
049      w.write(toString());
050      return w;
051   }
052
053   @Override /* Writable */
054   public MediaType getMediaType() {
055      // TODO Auto-generated method stub
056      return null;
057   }
058
059   @Override /* CharSequence */
060   public char charAt(int index) {
061      return toString().charAt(index);
062   }
063
064   @Override /* CharSequence */
065   public int length() {
066      return toString().length();
067   }
068
069   @Override /* CharSequence */
070   public CharSequence subSequence(int start, int end) {
071      return toString().subSequence(start, end);
072   }
073
074   @Override /* Object */
075   public String toString() {
076      if (results == null)
077         results = format(pattern, args);
078      return results;
079   }
080}