content: /**
   * 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.apex.examples.wordcount;
  
  import java.util.regex.Pattern;
  
  import com.datatorrent.api.Context.OperatorContext;
  import com.datatorrent.api.DefaultInputPort;
  import com.datatorrent.api.DefaultOutputPort;
  import com.datatorrent.common.util.BaseOperator;
  
  /**
   * Extracts words from input line
   *
   * @since 3.3.0
   */
  public class WordReader extends BaseOperator
  {
    // default pattern for word-separators
    private static final Pattern nonWordDefault = Pattern.compile("[\\p{Punct}\\s]+");
  
    private String nonWordStr;              // configurable regex
    private transient Pattern nonWord;      // compiled regex
  
    /**
     * Output port on which words from the current file are emitted
     */
    public final transient DefaultOutputPort<String> output = new DefaultOutputPort<>();
  
    /**
     * Input port on which lines from the current file are received
     */
    public final transient DefaultInputPort<String> input = new DefaultInputPort<String>()
    {
  
      @Override
      public void process(String line)
      {
        // line; split it into words and emit them
        final String[] words = nonWord.split(line);
        for (String word : words) {
          if (word.isEmpty()) {
            continue;
          }
          output.emit(word);
        }
      }
    };
  
    /**
     * Returns the regular expression that matches strings between words
     * @return Regular expression for strings that separate words
     */
    public String getNonWordStr()
    {
      return nonWordStr;
    }
  
    /**
     * Sets the regular expression that matches strings between words
     * @param regex New regular expression for strings that separate words
     */
    public void setNonWordStr(String regex)
    {
      nonWordStr = regex;
    }
  
    /**
     * {@inheritDoc}
     * Set nonWord to the default pattern if necessary
     */
    @Override
    public void setup(OperatorContext context)
    {
      if (null == nonWordStr) {
        nonWord = nonWordDefault;
      } else {
        nonWord = Pattern.compile(nonWordStr);
      }
    }
  
  }
  