com.basho.riak.client.query.MapReducePhase Maven / Gradle / Ivy

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/*
 * This file is provided 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 com.basho.riak.client.query;

/**
 * Shared common interface for Map/Reduce phase definitions.
 * @author russell
 * 
 * @see MapReduce#addMapPhase(com.basho.riak.client.query.functions.Function)
 * @see MapReduce#addLinkPhase(String, String)
 * @see MapReduce#addReducePhase(com.basho.riak.client.query.functions.Function)
 */
public interface MapReducePhase {

    /**
     * Possible phase typess.
     */
    public enum PhaseType {
        LINK("link"), MAP("map"), REDUCE("reduce");

        private final String phaseName;

        private PhaseType(String phaseName) {
            this.phaseName = phaseName;
        }

        public String toString() {
            return this.phaseName;
        }
    };

    /**
     * Is this phase's output to be returned or only passed as input to the next phase.
     * @return true if the results are returned, false otherwise.
     */
    Boolean isKeep();

    /**
     * The PhaseType of this {@link MapReducePhase} implementation.
     * @return a PhaseType.
     */
    PhaseType getType();
}