001    /*
002     * Copyright (c) 2007-2014 Concurrent, Inc. All Rights Reserved.
003     *
004     * Project and contact information: http://www.cascading.org/
005     *
006     * This file is part of the Cascading project.
007     *
008     * Licensed under the Apache License, Version 2.0 (the "License");
009     * you may not use this file except in compliance with the License.
010     * You may obtain a copy of the License at
011     *
012     *     http://www.apache.org/licenses/LICENSE-2.0
013     *
014     * Unless required by applicable law or agreed to in writing, software
015     * distributed under the License is distributed on an "AS IS" BASIS,
016     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
017     * See the License for the specific language governing permissions and
018     * limitations under the License.
019     */
020    
021    package cascading.operation.filter;
022    
023    import java.beans.ConstructorProperties;
024    
025    import cascading.flow.FlowProcess;
026    import cascading.operation.BaseOperation;
027    import cascading.operation.Filter;
028    import cascading.operation.FilterCall;
029    import cascading.operation.OperationCall;
030    
031    /**
032     * Class Not is a {@link Filter} class that will logically 'not' (negation) the results of the constructor provided Filter
033     * instance.
034     * <p/>
035     * Logically, if {@link Filter#isRemove(cascading.flow.FlowProcess, cascading.operation.FilterCall)} returns {@code true} for the given instance,
036     * this filter will return the opposite, {@code false}.
037     *
038     * @see And
039     * @see Xor
040     * @see Not
041     */
042    public class Not extends BaseOperation implements Filter
043      {
044      /** Field filter */
045      private final Filter filter;
046    
047      /**
048       * Constructor Not creates a new Not instance.
049       *
050       * @param filter of type Filter
051       */
052      @ConstructorProperties({"filter"})
053      public Not( Filter filter )
054        {
055        this.filter = filter;
056    
057        if( filter == null )
058          throw new IllegalArgumentException( "filter may not be null" );
059        }
060    
061      public Filter getFilter()
062        {
063        return filter;
064        }
065    
066      @Override
067      public void prepare( FlowProcess flowProcess, OperationCall operationCall )
068        {
069        filter.prepare( flowProcess, operationCall );
070        }
071    
072      @Override
073      public boolean isRemove( FlowProcess flowProcess, FilterCall filterCall )
074        {
075        return !filter.isRemove( flowProcess, filterCall );
076        }
077    
078      @Override
079      public void cleanup( FlowProcess flowProcess, OperationCall operationCall )
080        {
081        filter.cleanup( flowProcess, operationCall );
082        }
083    
084      @Override
085      public boolean equals( Object object )
086        {
087        if( this == object )
088          return true;
089        if( !( object instanceof Not ) )
090          return false;
091        if( !super.equals( object ) )
092          return false;
093    
094        Not not = (Not) object;
095    
096        if( filter != null ? !filter.equals( not.filter ) : not.filter != null )
097          return false;
098    
099        return true;
100        }
101    
102      @Override
103      public int hashCode()
104        {
105        int result = super.hashCode();
106        result = 31 * result + ( filter != null ? filter.hashCode() : 0 );
107        return result;
108        }
109      }