1   /**
2    * Logback: the reliable, generic, fast and flexible logging framework.
3    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
4    *
5    * This program and the accompanying materials are dual-licensed under
6    * either the terms of the Eclipse Public License v1.0 as published by
7    * the Eclipse Foundation
8    *
9    *   or (per the licensee's choosing)
10   *
11   * under the terms of the GNU Lesser General Public License version 2.1
12   * as published by the Free Software Foundation.
13   */
14  package ch.qos.logback.core.spi;
15  
16  import java.util.Iterator;
17  
18  import ch.qos.logback.core.Appender;
19  import ch.qos.logback.core.util.COWArrayList;
20  
21  /**
22   * A {@link COWArrayList} based implementation of the {@link AppenderAttachable}
23   * interface.
24   *
25   * @author Ceki Gülcü
26   */
27  public class AppenderAttachableImpl<E> implements AppenderAttachable<E> {
28  
29      @SuppressWarnings("unchecked")
30      final private COWArrayList<Appender<E>> appenderList = new COWArrayList<Appender<E>>(new Appender[0]);
31  
32      /**
33       * Attach an appender. If the appender is already in the list in won't be added
34       * again.
35       */
36      public void addAppender(Appender<E> newAppender) {
37          if (newAppender == null) {
38              throw new IllegalArgumentException("Null argument disallowed");
39          }
40          appenderList.addIfAbsent(newAppender);
41      }
42  
43      /**
44       * Call the <code>doAppend</code> method on all attached appenders.
45       */
46      public int appendLoopOnAppenders(E e) {
47          int size = 0;
48          final Appender<E>[] appenderArray = appenderList.asTypedArray();
49          final int len = appenderArray.length;
50          for (int i = 0; i < len; i++) {
51              appenderArray[i].doAppend(e);
52              size++;
53          }
54          return size;
55      }
56  
57      /**
58       * Get all attached appenders as an Enumeration. If there are no attached
59       * appenders <code>null</code> is returned.
60       *
61       * @return Iterator An iterator of attached appenders.
62       */
63      public Iterator<Appender<E>> iteratorForAppenders() {
64          return appenderList.iterator();
65      }
66  
67      /**
68       * Look for an attached appender named as <code>name</code>.
69       * 
70       * <p>
71       * Return the appender with that name if in the list. Return null otherwise.
72       */
73      public Appender<E> getAppender(String name) {
74          if (name == null) {
75              return null;
76          }
77          for (Appender<E> appender : appenderList) {
78              if (name.equals(appender.getName())) {
79                  return appender;
80              }
81          }
82          return null;
83      }
84  
85      /**
86       * Returns <code>true</code> if the specified appender is in the list of
87       * attached appenders, <code>false</code> otherwise.
88       *
89       * @since 1.2
90       */
91      public boolean isAttached(Appender<E> appender) {
92          if (appender == null) {
93              return false;
94          }
95          for (Appender<E> a : appenderList) {
96              if (a == appender)
97                  return true;
98          }
99          return false;
100     }
101 
102     /**
103      * Remove and processPriorToRemoval all previously attached appenders.
104      */
105     public void detachAndStopAllAppenders() {
106         for (Appender<E> a : appenderList) {
107             a.stop();
108         }
109         appenderList.clear();
110     }
111 
112     /**
113      * Remove the appender passed as parameter form the list of attached appenders.
114      */
115     public boolean detachAppender(Appender<E> appender) {
116         if (appender == null) {
117             return false;
118         }
119         boolean result;
120         result = appenderList.remove(appender);
121         return result;
122     }
123 
124     /**
125      * Remove the appender with the name passed as parameter form the list of
126      * appenders.
127      */
128     public boolean detachAppender(String name) {
129         if (name == null) {
130             return false;
131         }
132         boolean removed = false;
133         for (Appender<E> a : appenderList.asTypedArray()) {
134             if (name.equals((a).getName())) {
135                 removed = appenderList.remove(a);
136                 break;
137             }
138         }
139         return removed;
140     }
141 }