src/main/java/org/apache/log4j/helpers/AppenderAttachableImpl.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;

import org.apache.log4j.Appender;
import org.apache.log4j.spi.AppenderAttachable;
import org.apache.log4j.spi.LoggingEvent;

import java.util.Enumeration;
import java.util.Vector;


/**
   A straightforward implementation of the {@link AppenderAttachable}
   interface.

   @author Ceki Gülcü
   @since version 0.9.1 */
public class AppenderAttachableImpl implements AppenderAttachable {
  /** Array of appenders. */
  protected Vector appenderList;

  /**
     Attach an appender. If the appender is already in the list in
     won't be added again.
  */
  public void addAppender(Appender newAppender) {
    // Null values for newAppender parameter are strictly forbidden.
    if (newAppender == null) {
      return;
    }

    if (appenderList == null) {
      appenderList = new Vector(1);
    }

    if (!appenderList.contains(newAppender)) {
      appenderList.addElement(newAppender);
    }
  }

  /**
     Call the <code>doAppend</code> method on all attached appenders.  */
  public int appendLoopOnAppenders(LoggingEvent event) {
    int size = 0;
    Appender appender;

    if (appenderList != null) {
      size = appenderList.size();

      for (int i = 0; i < size; i++) {
        appender = (Appender) appenderList.elementAt(i);
        appender.doAppend(event);
      }
    }

    return size;
  }

  /**
     Get all attached appenders as an Enumeration. If there are no
     attached appenders <code>null</code> is returned.

     @return Enumeration An enumeration of attached appenders.
   */
  public Enumeration getAllAppenders() {
    if (appenderList == null) {
      return null;
    } else {
      return appenderList.elements();
    }
  }

  /**
     Look for an attached appender named as <code>name</code>.

     <p>Return the appender with that name if in the list. Return null
     otherwise.

   */
  public Appender getAppender(String name) {
    if ((appenderList == null) || (name == null)) {
      return null;
    }

    int size = appenderList.size();
    Appender appender;

    for (int i = 0; i < size; i++) {
      appender = (Appender) appenderList.elementAt(i);

      if (name.equals(appender.getName())) {
        return appender;
      }
    }

    return null;
  }

  /**
     Returns <code>true</code> if the specified appender is in the
     list of attached appenders, <code>false</code> otherwise.

     @since 1.2 */
  public boolean isAttached(Appender appender) {
    if ((appenderList == null) || (appender == null)) {
      return false;
    }

    int size = appenderList.size();
    Appender a;

    for (int i = 0; i < size; i++) {
      a = (Appender) appenderList.elementAt(i);

      if (a == appender) {
        return true;
      }
    }

    return false;
  }

  /**
   * Remove and close all previously attached appenders.
   * */
  public void removeAllAppenders() {
    if (appenderList != null) {
      int len = appenderList.size();

      for (int i = 0; i < len; i++) {
        Appender a = (Appender) appenderList.elementAt(i);
        a.close();
      }

      appenderList.removeAllElements();
      appenderList = null;
    }
  }

  /**
     Remove the appender passed as parameter form the list of attached
     appenders.  */
  public void removeAppender(Appender appender) {
    if ((appender == null) || (appenderList == null)) {
      return;
    }

    appenderList.removeElement(appender);
  }

  /**
     Remove the appender with the name passed as parameter form the
     list of appenders.
   */
  public void removeAppender(String name) {
    if ((name == null) || (appenderList == null)) {
      return;
    }

    int size = appenderList.size();

    for (int i = 0; i < size; i++) {
      if (name.equals(((Appender) appenderList.elementAt(i)).getName())) {
        appenderList.removeElementAt(i);

        break;
      }
    }
  }
}