library/src/main/java/com/datatorrent/lib/algo/AllAfterMatchStringValueMap.java

/*
 * Copyright (c) 2013 DataTorrent, Inc. ALL Rights Reserved.
 *
 * Licensed 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 com.datatorrent.lib.algo;

import java.util.HashMap;
import java.util.Map;

import com.datatorrent.api.DefaultInputPort;
import com.datatorrent.api.DefaultOutputPort;

import com.datatorrent.lib.util.BaseMatchOperator;

/**
 * This operator takes Maps, whose values are numeric strings, as input tuples. 
 * It then performs a numeric comparison on the values corresponding to one of the keys in the input tuple maps. 
 * All tuples processed by the operator before the first successful comparison are not output by the operator,
 * all tuples processed by the operator after and including a successful comparison are output by the operator.
 *
 * <p>
 * A compare metric is done on input tuple based on the property "key",
 * "value", and "cmp". All tuples are emitted (inclusive) once a match is made.
 * The comparison is done by getting double value from the Number.
 * </p>
 * <p>
 * This module is a pass through<br>
 * <br>
 * <b>Ports</b>:<br>
 * <b>data</b>: expects Map<K, String><br>
 * <b>allafter</b>: emits HashMap<K, String> if compare function returns true<br>
 * <br>
 * <b>Properties</b>:<br>
 * <b>key</b>: The key on which compare is done<br>
 * <b>value</b>: The value to compare with<br>
 * <b>cmp</b>: The compare function. Supported values are "lte", "lt", "eq",
 * "neq", "gt", "gte". Default is "eq"<br>
 * <br>
 * <b>Specific compile time checks</b>:<br>
 * Key must be non empty<br>
 * Value must be able to convert to a "double"<br>
 * Compare string, if specified, must be one of "lte", "lt", "eq", "neq", "gt",
 * "gte"<br>
 * <br>
 * <b>Specific run time checks</b>:<br>
 * The key exists in the HashMap<br>
 * Value converts to Double successfully<br>
 * </p>
 *
 * @displayName Emit All After Match (String)
 * @category Algorithmic
 * @tags filter, compare, numeric, key value, string
 *
 * @since 0.3.2
 */
public class AllAfterMatchStringValueMap<K> extends
    BaseMatchOperator<K, String>
{
  /**
   * Input port on which tuples are received.
   */
  public final transient DefaultInputPort<Map<K, String>> data = new DefaultInputPort<Map<K, String>>()
  {
    /**
     * Process HashMap<K,String> and emit all tuples at and after match
     */
    @Override
    public void process(Map<K, String> tuple)
    {
      if (doemit) {
        allafter.emit(cloneTuple(tuple));
        return;
      }
      String val = tuple.get(getKey());
      if (val == null) { // error tuple
        return;
      }
      double tvalue = 0;
      boolean error = false;
      try {
        tvalue = Double.valueOf(val);
      } catch (NumberFormatException e) {
        error = true;
      }
      if (!error) {
        if (compareValue(tvalue)) {
          doemit = true;
          allafter.emit(cloneTuple(tuple));
        }
      }
    }
  };

  /**
   * The output port on which all tuples after a match are emitted.
   */
  public final transient DefaultOutputPort<HashMap<K, String>> allafter = new DefaultOutputPort<HashMap<K, String>>();
  boolean doemit = false;

  /**
   * Resets the matched variable
   *
   * @param windowId
   */
  @Override
  public void beginWindow(long windowId)
  {
    doemit = false;
  }
}