gobblin.util.ForkOperatorUtils.java Source code

Introduction

Here is the source code for gobblin.util.ForkOperatorUtils.java

Source

/*
 * 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 gobblin.util;

import org.apache.hadoop.fs.Path;

import com.google.common.base.Preconditions;
import com.google.common.base.Strings;

import gobblin.configuration.ConfigurationKeys;
import gobblin.configuration.State;
import gobblin.configuration.WorkUnitState;

/**
 * Utility class for use with the {@link gobblin.fork.ForkOperator} class.
 *
 * @author Yinan Li
 */
public class ForkOperatorUtils {

    /**
     * Get a new property key from an original one with branch index (if applicable).
     *
     * @param key      property key
     * @param numBranches number of branches (non-negative)
     * @param branchId    branch id (non-negative)
     * @return a new property key
     */
    public static String getPropertyNameForBranch(String key, int numBranches, int branchId) {
        Preconditions.checkArgument(numBranches >= 0, "The number of branches is expected to be non-negative");
        Preconditions.checkArgument(branchId >= 0, "The branchId is expected to be non-negative");
        return numBranches > 1 ? key + "." + branchId : key;
    }

    /**
     * Get a new property key from an original one with branch index (if applicable).
     *
     * @param key    property key
     * @param branch branch index
     * @return a new property key
     */
    public static String getPropertyNameForBranch(String key, int branch) {
        // A branch index of -1 means there is no fork and branching
        return branch >= 0 ? key + "." + branch : key;
    }

    /**
     * Get a new property key from an original one based on the branch id. The method assumes the branch id specified by
     * the {@link ConfigurationKeys#FORK_BRANCH_ID_KEY} parameter in the given WorkUnitState. The fork id key specifies
     * which fork this parameter belongs to. Note this method will only provide the aforementioned functionality for
     * {@link gobblin.converter.Converter}s. To get the same functionality in {@link gobblin.writer.DataWriter}s use
     * the {@link gobblin.writer.DataWriterBuilder#forBranch(int)} to construct a writer with a specific branch id.
     *
     * @param workUnitState contains the fork id key
     * @param key           property key
     * @return a new property key
     */
    public static String getPropertyNameForBranch(WorkUnitState workUnitState, String key) {
        Preconditions.checkNotNull(workUnitState, "Cannot get a property from a null WorkUnit");
        Preconditions.checkNotNull(key, "Cannot get a the value for a null key");

        if (!workUnitState.contains(ConfigurationKeys.FORK_BRANCH_ID_KEY)) {
            return key;
        }
        return workUnitState.getPropAsInt(ConfigurationKeys.FORK_BRANCH_ID_KEY) >= 0
                ? key + "." + workUnitState.getPropAsInt(ConfigurationKeys.FORK_BRANCH_ID_KEY)
                : key;
    }

    /**
     * Get a new path with the given branch name as a sub directory.
     *
     * @param numBranches number of branches (non-negative)
     * @param branchId    branch id (non-negative)
     * @return a new path
     */
    public static String getPathForBranch(State state, String path, int numBranches, int branchId) {
        Preconditions.checkNotNull(state);
        Preconditions.checkNotNull(path);
        Preconditions.checkArgument(numBranches >= 0, "The number of branches is expected to be non-negative");
        Preconditions.checkArgument(branchId >= 0, "The branch id is expected to be non-negative");

        return numBranches > 1
                ? path + Path.SEPARATOR + state.getProp(ConfigurationKeys.FORK_BRANCH_NAME_KEY + "." + branchId,
                        ConfigurationKeys.DEFAULT_FORK_BRANCH_NAME + branchId)
                : path;
    }

    /**
     * Get the fork branch ID of a branch of a given task.
     *
     * @param taskId task ID
     * @param index  branch index
     * @return a fork branch ID
     */
    public static String getForkId(String taskId, int index) {
        return taskId + "." + index;
    }
}