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

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+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.spi.AppenderAttachable;
+import org.apache.log4j.spi.LoggingEvent;
+
+import org.apache.log4j.Appender;
+import java.util.Vector;
+import java.util.Enumeration;
+
+/**
+   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;
+      }
+    }
+  }
+
+}