/*
    * 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.logging.log4j.core.filter;
  
  import org.apache.logging.log4j.Level;
  import org.apache.logging.log4j.Marker;
  import org.apache.logging.log4j.core.Filter;
  import org.apache.logging.log4j.core.LifeCycle;
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.Logger;
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  import org.apache.logging.log4j.core.config.plugins.PluginElement;
  import org.apache.logging.log4j.core.config.plugins.PluginFactory;
  import org.apache.logging.log4j.message.Message;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  
  /**
   * Composes and invokes one or more filters.
   */
  @Plugin(name = "filters", type = "Core", printObject = true)
  public final class CompositeFilter implements Iterable<Filter>, Filter, LifeCycle {
  
      private final List<Filter> filters;
      private final boolean hasFilters;
  
      private boolean isStarted;
  
      private CompositeFilter() {
          this.filters = new ArrayList<Filter>();
          this.hasFilters = false;
      }
  
      private CompositeFilter(List<Filter> filters) {
          if (filters == null) {
              this.filters = Collections.unmodifiableList(new ArrayList<Filter>());
              this.hasFilters = false;
              return;
          }
          this.filters = Collections.unmodifiableList(filters);
          this.hasFilters = this.filters.size() > 0;
      }
  
      public CompositeFilter addFilter(Filter filter) {
          List<Filter> filters = new ArrayList<Filter>(this.filters);
          filters.add(filter);
          return new CompositeFilter(Collections.unmodifiableList(filters));
      }
  
      public CompositeFilter removeFilter(Filter filter) {
          List<Filter> filters = new ArrayList<Filter>(this.filters);
          filters.remove(filter);
          return new CompositeFilter(Collections.unmodifiableList(filters));
      }
  
      public Iterator<Filter> iterator() {
          return filters.iterator();
      }
  
      public List<Filter> getFilters() {
          return filters;
      }
  
      public boolean hasFilters() {
          return hasFilters;
      }
  
      public int size() {
          return filters.size();
      }
  
      public void start() {
          for (Filter filter : filters) {
              if (filter instanceof LifeCycle) {
                  ((LifeCycle) filter).start();
              }
          }
          isStarted = true;
      }
  
      public void stop() {
         for (Filter filter : filters) {
             if (filter instanceof LifeCycle) {
                 ((LifeCycle) filter).stop();
             }
         }
         isStarted = false;
     }
 
     public boolean isStarted() {
         return isStarted;
     }
 
     /**
      * Returns the result that should be returned when the filter does not match the event.
      * 
      * @return the Result that should be returned when the filter does not match the event.
      */
     public Result getOnMismatch() {
         return Result.NEUTRAL;
     }
 
     /**
      * Returns the result that should be returned when the filter matches the event.
      * 
      * @return the Result that should be returned when the filter matches the event.
      */
     public Result getOnMatch() {
         return Result.NEUTRAL;
     }
 
     /**
      * Filter an event.
      * 
      * @param logger
      *            The Logger.
      * @param level
      *            The event logging Level.
      * @param marker
      *            The Marker for the event or null.
      * @param msg
      *            String text to filter on.
      * @param params
      *            An array of parameters or null.
      * @return the Result.
      */
     public Result filter(Logger logger, Level level, Marker marker, String msg, Object... params) {
         Result result = Result.NEUTRAL;
         for (Filter filter : filters) {
             result = filter.filter(logger, level, marker, msg, params);
             if (result == Result.ACCEPT || result == Result.DENY) {
                 return result;
             }
         }
         return result;
     }
 
     /**
      * Filter an event.
      * 
      * @param logger
      *            The Logger.
      * @param level
      *            The event logging Level.
      * @param marker
      *            The Marker for the event or null.
      * @param msg
      *            Any Object.
      * @param t
      *            A Throwable or null.
      * @return the Result.
      */
     public Result filter(Logger logger, Level level, Marker marker, Object msg, Throwable t) {
         Result result = Result.NEUTRAL;
         for (Filter filter : filters) {
             result = filter.filter(logger, level, marker, msg, t);
             if (result == Result.ACCEPT || result == Result.DENY) {
                 return result;
             }
         }
         return result;
     }
 
     /**
      * Filter an event.
      * 
      * @param logger
      *            The Logger.
      * @param level
      *            The event logging Level.
      * @param marker
      *            The Marker for the event or null.
      * @param msg
      *            The Message
      * @param t
      *            A Throwable or null.
      * @return the Result.
      */
     public Result filter(Logger logger, Level level, Marker marker, Message msg, Throwable t) {
         Result result = Result.NEUTRAL;
         for (Filter filter : filters) {
             result = filter.filter(logger, level, marker, msg, t);
             if (result == Result.ACCEPT || result == Result.DENY) {
                 return result;
             }
         }
         return result;
     }
 
     /**
      * Filter an event.
      * 
      * @param event
      *            The Event to filter on.
      * @return the Result.
      */
     public Result filter(LogEvent event) {
         Result result = Result.NEUTRAL;
         for (Filter filter : filters) {
             result = filter.filter(event);
             if (result == Result.ACCEPT || result == Result.DENY) {
                 return result;
             }
         }
         return result;
     }
 
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder();
         for (Filter filter : filters) {
             if (sb.length() == 0) {
                 sb.append("{");
             } else {
                 sb.append(", ");
             }
             sb.append(filter.toString());
         }
         if (sb.length() > 0) {
             sb.append("}");
         }
         return sb.toString();
     }
 
     /**
      * Create a CompositeFilter.
      * 
      * @param filters
      *            An array of Filters to call.
      * @return The CompositeFilter.
      */
     @PluginFactory
     public static CompositeFilter createFilters(@PluginElement("filters") Filter[] filters) {
         List<Filter> f = filters == null || filters.length == 0 ? new ArrayList<Filter>() : Arrays.asList(filters);
         return new CompositeFilter(f);
     }
 
 }