    001/*
    002 * Copyright (c) 2016-2017 Chris K Wensel. All Rights Reserved.
    003 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved.
    004 *
    005 * Project and contact information: http://www.cascading.org/
    006 *
    007 * This file is part of the Cascading project.
    008 *
    009 * Licensed under the Apache License, Version 2.0 (the "License");
    010 * you may not use this file except in compliance with the License.
    011 * You may obtain a copy of the License at
    012 *
    013 *     http://www.apache.org/licenses/LICENSE-2.0
    014 *
    015 * Unless required by applicable law or agreed to in writing, software
    016 * distributed under the License is distributed on an "AS IS" BASIS,
    017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    018 * See the License for the specific language governing permissions and
    019 * limitations under the License.
    020 */
    021
    022package cascading.operation.regex;
    023
    024import java.beans.ConstructorProperties;
    025import java.util.regex.Pattern;
    026
    027import cascading.flow.FlowProcess;
    028import cascading.operation.Function;
    029import cascading.operation.FunctionCall;
    030import cascading.operation.OperationCall;
    031import cascading.tuple.Fields;
    032import cascading.tuple.Tuple;
    033import cascading.tuple.TupleEntry;
    034import cascading.util.Pair;
    035
    036/**
    037 * Class RegexSplitter will split an incoming argument value by the given regex delimiter patternString.
    038 * <p/>
    039 * RegexSplitter only expects one field value. If more than one argument value is passed, only the
    040 * first is handled, the remainder are ignored.
    041 * <p/>
    042 * Note a {@code null} valued argument passed to the parser will be converted to an empty string ({@code ""}) before
    043 * the regex is applied.
    044 * <p/>
    045 * Any Object value will be coerced to a String type if type information is provided. See the
    046 * {@link cascading.tuple.type.CoercibleType} interface to control how custom Object types are converted to String
    047 * values.
    048 */
    049public class RegexSplitter extends RegexOperation<Pair<Pattern, TupleEntry>> implements Function<Pair<Pattern, TupleEntry>>
    050  {
    051  private int length;
    052
    053  /**
    054   * Constructor RegexSplitter creates a new RegexSplitter instance.
    055   *
    056   * @param patternString of type String
    057   */
    058  @ConstructorProperties({"patternString"})
    059  public RegexSplitter( String patternString )
    060    {
    061    super( 1, patternString );
    062    length = fieldDeclaration.isUnknown() ? -1 : fieldDeclaration.size();
    063    }
    064
    065  /**
    066   * Constructor RegexOperation creates a new RegexOperation instance, where the delimiter is the tab character.
    067   *
    068   * @param fieldDeclaration of type Fields
    069   */
    070  @ConstructorProperties({"fieldDeclaration"})
    071  public RegexSplitter( Fields fieldDeclaration )
    072    {
    073    super( 1, fieldDeclaration, "\t" );
    074    }
    075
    076  /**
    077   * Constructor RegexSplitter creates a new RegexSplitter instance.
    078   *
    079   * @param fieldDeclaration of type Fields
    080   * @param patternString    of type String
    081   */
    082  @ConstructorProperties({"fieldDeclaration", "patternString"})
    083  public RegexSplitter( Fields fieldDeclaration, String patternString )
    084    {
    085    super( 1, fieldDeclaration, patternString );
    086    length = fieldDeclaration.isUnknown() ? -1 : fieldDeclaration.size();
    087    }
    088
    089  @Override
    090  public void prepare( FlowProcess flowProcess, OperationCall<Pair<Pattern, TupleEntry>> operationCall )
    091    {
    092    length = operationCall.getDeclaredFields().isUnknown() ? -1 : operationCall.getDeclaredFields().size();
    093
    094    TupleEntry tupleEntry = new TupleEntry( operationCall.getDeclaredFields(), Tuple.size( Math.max( 1, length ) ) );
    095
    096    operationCall.setContext( new Pair<>( getPattern(), tupleEntry ) );
    097    }
    098
    099  @Override
    100  public void operate( FlowProcess flowProcess, FunctionCall<Pair<Pattern, TupleEntry>> functionCall )
    101    {
    102    String value = functionCall.getArguments().getString( 0 );
    103
    104    if( value == null )
    105      value = "";
    106
    107    TupleEntry output = functionCall.getContext().getRhs();
    108
    109    String[] split = functionCall.getContext().getLhs().split( value, length );
    110
    111    if( length == -1 )
    112      {
    113      output.getTuple().clear();
    114
    115      for( String element : split )
    116        output.getTuple().add( element );
    117      }
    118    else
    119      {
    120      output.setCanonicalValues( split );
    121      }
    122
    123    functionCall.getOutputCollector().add( output );
    124    }
    125  }