cvs commit: logging-log4j/src/java/org/apache/log4j/helpers/mcompose MessageComposer.java

[ce...@apache.org]

ceki        2004/10/28 05:44:34

  Added:       src/java/org/apache/log4j/helpers/mcompose
                        MessageComposer.java
  Log:
  MessageComposer parses input messages and performs parameter substitution.
  This is just a step in enhancing log4j as described in bug #16229
  
  http://nagoya.apache.org/bugzilla/show_bug.cgi?id=16229
  
  Revision  Changes    Path
  1.1                  logging-log4j/src/java/org/apache/log4j/helpers/mcompose/MessageComposer.java
  
  Index: MessageComposer.java
  ===================================================================
  /*
   * Copyright 1999,2004 The Apache Software Foundation.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.log4j.helpers.mcompose;
  
  
  /**
   *
   *
   * @author Ceki Gülcü
   */
  public class MessageComposer {
    static char DELIM_START = '{';
    static char DELIM_STOP = '}';
  
    public static String compose(String message, Object param) {
      int j = message.indexOf(DELIM_START);
      int len = message.length();
      char escape = 'x';
  
      // if there are no { characters or { is the last character of the messsage
      // then we just return message
      if (j == -1 || (j+1 == len)) {
        return message;
      } else {
        if(j+1 == len) {
        }
        
        char delimStop = message.charAt(j + 1);
        if (j > 0) {
          escape = message.charAt(j - 1);
        }
        if ((delimStop != DELIM_STOP) || (escape == '\\')) {
          // invalid DELIM_START/DELIM_STOP pair or espace character is
          // present
          return message;
        } else {
          StringBuffer sbuf = new StringBuffer(len + 20);
          sbuf.append(message.substring(0, j));
          sbuf.append(param);
          sbuf.append(message.substring(j + 2));
          return sbuf.toString();
        }
      }
    }
  
    public static String compose(String message, Object param1, Object param2) {
      int i = 0;
      int len = message.length();
      int j = message.indexOf(DELIM_START);
  
      StringBuffer sbuf = new StringBuffer(message.length() + 50);
  
      for (int L = 0; L < 2; L++) {
        j = message.indexOf(DELIM_START, i);
  
        if (j == -1 || (j+1 == len)) {
          // no more variables
          if (i == 0) { // this is a simple string
            return message;
          } else { // add the tail string which contains no variables and return the result.
            sbuf.append(message.substring(i, message.length()));
            return sbuf.toString();
          }
        } else {
          char delimStop = message.charAt(j + 1);
          if ((delimStop != DELIM_STOP)) {
            // invalid DELIM_START/DELIM_STOP pair
            sbuf.append(message.substring(i, message.length()));
            return sbuf.toString();
          }
          sbuf.append(message.substring(i, j));
          sbuf.append((L == 0) ? param1 : param2);
          i = j + 2;
        }
      }
      // append the characters following the second {} pair.
      sbuf.append(message.substring(i, message.length()));
      return sbuf.toString();
    }
  }
  
  
  

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