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    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
    18  package org.apache.log4j.helpers;
    19
    20  import org.apache.log4j.spi.AppenderAttachable;
    21  import org.apache.log4j.spi.LoggingEvent;
    22
    23  import org.apache.log4j.Appender;
    24  import java.util.Vector;
    25  import java.util.Enumeration;
    26
    27  /***
    28     A straightforward implementation of the {@link AppenderAttachable}
    29     interface.
    30
    31     @author Ceki G&uuml;lc&uuml;
    32     @since version 0.9.1 */
    33  public class AppenderAttachableImpl implements AppenderAttachable {
    34
    35    /*** Array of appenders. */
    36    protected Vector  appenderList;
    37
    38    /***
    39       Attach an appender. If the appender is already in the list in
    40       won't be added again.
    41    */
    42    public
    43    void addAppender(Appender newAppender) {
    44      // Null values for newAppender parameter are strictly forbidden.
    45      if(newAppender == null)
    46        return;
    47
    48      if(appenderList == null) {
    49        appenderList = new Vector(1);
    50      }
    51      if(!appenderList.contains(newAppender))
    52        appenderList.addElement(newAppender);
    53    }
    54
    55    /***
    56       Call the <code>doAppend</code> method on all attached appenders.  */
    57    public
    58    int appendLoopOnAppenders(LoggingEvent event) {
    59      int size = 0;
    60      Appender appender;
    61
    62      if(appenderList != null) {
    63        size = appenderList.size();
    64        for(int i = 0; i < size; i++) {
    65  	appender = (Appender) appenderList.elementAt(i);
    66  	appender.doAppend(event);
    67        }
    68      }
    69      return size;
    70    }
    71
    72
    73    /***
    74       Get all attached appenders as an Enumeration. If there are no
    75       attached appenders <code>null</code> is returned.
    76
    77       @return Enumeration An enumeration of attached appenders.
    78     */
    79    public
    80    Enumeration getAllAppenders() {
    81      if(appenderList == null)
    82        return null;
    83      else
    84        return appenderList.elements();
    85    }
    86
    87    /***
    88       Look for an attached appender named as <code>name</code>.
    89
    90       <p>Return the appender with that name if in the list. Return null
    91       otherwise.
    92
    93     */
    94    public
    95    Appender getAppender(String name) {
    96       if(appenderList == null || name == null)
    97        return null;
    98
    99       int size = appenderList.size();
    100      Appender appender;
    101      for(int i = 0; i < size; i++) {
    102        appender = (Appender) appenderList.elementAt(i);
    103        if(name.equals(appender.getName()))
    104 	  return appender;
    105      }
    106      return null;
    107   }
    108
    109
    110   /***
    111      Returns <code>true</code> if the specified appender is in the
    112      list of attached appenders, <code>false</code> otherwise.
    113
    114      @since 1.2 */
    115   public
    116   boolean isAttached(Appender appender) {
    117     if(appenderList == null || appender == null)
    118       return false;
    119
    120      int size = appenderList.size();
    121      Appender a;
    122      for(int i = 0; i < size; i++) {
    123        a  = (Appender) appenderList.elementAt(i);
    124        if(a == appender)
    125 	  return true;
    126      }
    127      return false;
    128   }
    129
    130
    131
    132   /***
    133    * Remove and close all previously attached appenders.
    134    * */
    135   public
    136   void removeAllAppenders() {
    137     if(appenderList != null) {
    138       int len = appenderList.size();
    139       for(int i = 0; i < len; i++) {
    140 	Appender a = (Appender) appenderList.elementAt(i);
    141 	a.close();
    142       }
    143       appenderList.removeAllElements();
    144       appenderList = null;
    145     }
    146   }
    147
    148
    149   /***
    150      Remove the appender passed as parameter form the list of attached
    151      appenders.  */
    152   public
    153   void removeAppender(Appender appender) {
    154     if(appender == null || appenderList == null)
    155       return;
    156     appenderList.removeElement(appender);
    157   }
    158
    159
    160  /***
    161     Remove the appender with the name passed as parameter form the
    162     list of appenders.
    163   */
    164   public
    165   void removeAppender(String name) {
    166     if(name == null || appenderList == null) return;
    167     int size = appenderList.size();
    168     for(int i = 0; i < size; i++) {
    169       if(name.equals(((Appender)appenderList.elementAt(i)).getName())) {
    170 	 appenderList.removeElementAt(i);
    171 	 break;
    172       }
    173     }
    174   }
    175
    176 }