library/src/main/java/com/datatorrent/lib/math/CompareStringMap.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.math;

import com.datatorrent.api.DefaultOutputPort;
import com.datatorrent.api.annotation.Stateless;
import com.datatorrent.lib.algo.MatchStringMap;
import java.util.HashMap;

/**
 * This operator compares String tuples based on the property "key", "value", and "cmp" and all matching tuples are emitted.
 * <p>
 * If the tuple passed the test, it is emitted on the output port "compare".&nbsp; The comparison is done by parsing double value from the String.
 * This module is a pass through<br>
 * <br>
 * <b>Ports</b>:<br>
 * <b>data</b>: expects Map&lt;K,String&gt;<br>
 * <b>compare</b>: emits HashMap&lt;K,String&gt;<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>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>
 * Does the incoming HashMap have the key<br>
 * Is the value of the key a number<br>
 * <br>
 * @displayName Compare String Map
 * @category Math
 * @tags comparison, key value, string, map
 * @since 0.3.2
 */
@Stateless
public class CompareStringMap<K> extends MatchStringMap<K>
{
    /**
     * Output port that emits a hashmap of matching string tuples after comparison.
     */
    public final transient DefaultOutputPort<HashMap<K,String>> compare = match;
}