Merge branch 'Jalview-JS/develop' into develop

[jalview.git] / srcjar_unused / org / apache / log4j / spi / Filter.java

diff --git a/srcjar_unused/org/apache/log4j/spi/Filter.java b/srcjar_unused/org/apache/log4j/spi/Filter.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.spi;
+
+
+
+/**
+   Users should extend this class to implement customized logging
+   event filtering. Note that {@link org.apache.log4j.Category} and {@link
+   org.apache.log4j.AppenderSkeleton}, the parent class of all standard
+   appenders, have built-in filtering rules. It is suggested that you
+   first use and understand the built-in rules before rushing to write
+   your own custom filters.
+
+   <p>This abstract class assumes and also imposes that filters be
+   organized in a linear chain. The {@link #decide
+   decide(LoggingEvent)} method of each filter is called sequentially,
+   in the order of their addition to the chain.
+
+   <p>The {@link #decide decide(LoggingEvent)} method must return one
+   of the integer constants {@link #DENY}, {@link #NEUTRAL} or {@link
+   #ACCEPT}.
+
+   <p>If the value {@link #DENY} is returned, then the log event is
+   dropped immediately without consulting with the remaining
+   filters. 
+
+   <p>If the value {@link #NEUTRAL} is returned, then the next filter
+   in the chain is consulted. If there are no more filters in the
+   chain, then the log event is logged. Thus, in the presence of no
+   filters, the default behaviour is to log all logging events.
+
+   <p>If the value {@link #ACCEPT} is returned, then the log
+   event is logged without consulting the remaining filters. 
+
+   <p>The philosophy of log4j filters is largely inspired from the
+   Linux ipchains. 
+
+   <p>Note that filtering is only supported by the {@link
+   org.apache.log4j.xml.DOMConfigurator DOMConfigurator}. The {@link
+   org.apache.log4j.PropertyConfigurator PropertyConfigurator} does not
+   support filters.
+
+   @author Ceki G&uuml;lc&uuml;
+   @since 0.9.0 */
+public abstract class Filter implements OptionHandler {
+
+  /**
+     Points to the next filter in the filter chain.
+
+     @deprecated As of 1.2.12, use {@link #getNext} and {@link #setNext} instead
+   */
+  public Filter next;
+
+  /**
+     The log event must be dropped immediately without consulting
+     with the remaining filters, if any, in the chain.  */
+  public static final int DENY    = -1;
+  
+  /**
+     This filter is neutral with respect to the log event. The
+     remaining filters, if any, should be consulted for a final decision.
+  */
+  public static final int NEUTRAL = 0;
+
+  /**
+     The log event must be logged immediately without consulting with
+     the remaining filters, if any, in the chain.  */
+  public static final int ACCEPT  = 1;
+
+
+  /**
+     Usually filters options become active when set. We provide a
+     default do-nothing implementation for convenience.
+  */
+  public
+  void activateOptions() {
+  }
+
+
+
+  /**     
+     <p>If the decision is <code>DENY</code>, then the event will be
+     dropped. If the decision is <code>NEUTRAL</code>, then the next
+     filter, if any, will be invoked. If the decision is ACCEPT then
+     the event will be logged without consulting with other filters in
+     the chain.
+
+     @param event The LoggingEvent to decide upon.
+     @return decision The decision of the filter.  */
+  abstract
+  public
+  int decide(LoggingEvent event);
+
+  /**
+   * Set the next filter pointer.
+   */ 
+  public void setNext(Filter next) {
+    this.next = next;
+  }
+ 
+  /**
+   * Return the pointer to the next filter;
+   */ 
+  public Filter getNext() {
+        return next;
+  }
+
+}