HadoopJobInfo.java

/*
 * 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.ignite.internal.processors.hadoop;

import org.apache.ignite.IgniteCheckedException;
import org.apache.ignite.IgniteLogger;
import org.apache.ignite.hadoop.HadoopMapReducePlan;
import org.jetbrains.annotations.Nullable;

/**
 * Extended job description.
 */
public interface HadoopJobInfo {
    /**
     * Gets optional configuration property for the job.
     *
     * @param name Property name.
     * @return Value or {@code null} if none.
     */
    @Nullable String property(String name);

    /**
     * Checks whether job has combiner.
     *
     * @return {@code true} If job has combiner.
     */
    boolean hasCombiner();

    /**
     * Checks whether job has reducer.
     * Actual number of reducers will be in {@link HadoopMapReducePlan#reducers()}.
     *
     * @return Number of reducer.
     */
    boolean hasReducer();

    /**
     * @return Number of reducers configured for job.
     */
    int reducers();

    /**
     * Gets job name.
     *
     * @return Job name.
     */
    String jobName();

    /**
     * Gets user name.
     *
     * @return User name.
     */
    String user();

    /**
     * Creates new job instance for the given ID.
     * {@link HadoopJobInfo} is reusable for multiple jobs while {@link HadoopJobEx} is for one job execution.
     * This method will be called once for the same ID on one node, though it can be called on the same host
     * multiple times from different processes (in case of multiple nodes on the same host or external execution).
     *
     * @param jobCls The job class.
     * @param jobId Job ID.
     * @param log Logger.
     * @param libNames Optional additional native library names.
     * @param helper HadoopHelper.
     * @return Job.
     * @throws IgniteCheckedException If failed.
     */
    public HadoopJobEx createJob(Class<? extends HadoopJobEx> jobCls,
        HadoopJobId jobId, IgniteLogger log, @Nullable String[] libNames, HadoopHelper helper)
            throws IgniteCheckedException;
}