    001/*
    002 * Copyright (c) 2007-2017 Xplenty, 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
    021package cascading.operation.regex;
    022
    023import java.beans.ConstructorProperties;
    024import java.util.regex.Pattern;
    025
    026import cascading.flow.FlowProcess;
    027import cascading.operation.Function;
    028import cascading.operation.FunctionCall;
    029import cascading.operation.OperationCall;
    030import cascading.tuple.Fields;
    031import cascading.tuple.Tuple;
    032import cascading.util.Pair;
    033
    034/**
    035 * Class RegexSplitter will split an incoming argument value by the given regex delimiter patternString.
    036 * <p/>
    037 * RegexSplitter only expects one field value. If more than one argument value is passed, only the
    038 * first is handled, the remainder are ignored.
    039 * <p/>
    040 * Note a {@code null} valued argument passed to the parser will be converted to an empty string ({@code ""}) before
    041 * the regex is applied.
    042 * <p/>
    043 * Any Object value will be coerced to a String type if type information is provided. See the
    044 * {@link cascading.tuple.type.CoercibleType} interface to control how custom Object types are converted to String
    045 * values.
    046 */
    047public class RegexSplitter extends RegexOperation<Pair<Pattern, Tuple>> implements Function<Pair<Pattern, Tuple>>
    048  {
    049  private final int length;
    050
    051  /**
    052   * Constructor RegexSplitter creates a new RegexSplitter instance.
    053   *
    054   * @param patternString of type String
    055   */
    056  @ConstructorProperties({"patternString"})
    057  public RegexSplitter( String patternString )
    058    {
    059    super( 1, patternString );
    060    length = fieldDeclaration.isUnknown() ? -1 : fieldDeclaration.size();
    061    }
    062
    063  /**
    064   * Constructor RegexOperation creates a new RegexOperation instance, where the delimiter is the tab character.
    065   *
    066   * @param fieldDeclaration of type Fields
    067   */
    068  @ConstructorProperties({"fieldDeclaration"})
    069  public RegexSplitter( Fields fieldDeclaration )
    070    {
    071    super( 1, fieldDeclaration, "\t" );
    072    length = fieldDeclaration.isUnknown() ? -1 : fieldDeclaration.size();
    073    }
    074
    075  /**
    076   * Constructor RegexSplitter creates a new RegexSplitter instance.
    077   *
    078   * @param fieldDeclaration of type Fields
    079   * @param patternString    of type String
    080   */
    081  @ConstructorProperties({"fieldDeclaration", "patternString"})
    082  public RegexSplitter( Fields fieldDeclaration, String patternString )
    083    {
    084    super( 1, fieldDeclaration, patternString );
    085    length = fieldDeclaration.isUnknown() ? -1 : fieldDeclaration.size();
    086    }
    087
    088  @Override
    089  public void prepare( FlowProcess flowProcess, OperationCall<Pair<Pattern, Tuple>> operationCall )
    090    {
    091    operationCall.setContext( new Pair<Pattern, Tuple>( getPattern(), new Tuple() ) );
    092    }
    093
    094  @Override
    095  public void operate( FlowProcess flowProcess, FunctionCall<Pair<Pattern, Tuple>> functionCall )
    096    {
    097    String value = functionCall.getArguments().getString( 0 );
    098
    099    if( value == null )
    100      value = "";
    101
    102    Tuple output = functionCall.getContext().getRhs();
    103
    104    output.clear();
    105
    106    String[] split = functionCall.getContext().getLhs().split( value, length );
    107
    108    for( int i = 0; i < split.length; i++ )
    109      output.add( split[ i ] );
    110
    111    functionCall.getOutputCollector().add( output );
    112    }
    113  }