org.apache.carbondata.hadoop.internal.segment.Segment.java Source code

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Here is the source code for org.apache.carbondata.hadoop.internal.segment.Segment.java

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/*
 * 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.carbondata.hadoop.internal.segment;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.carbondata.core.scan.filter.resolver.FilterResolverIntf;

import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.JobContext;

/**
 * Within a carbon table, each data load becomes one Segment,
 * which stores all data files belong to this load in the segment folder.
 */
public abstract class Segment {

    protected String id;

    /**
     * Path of the segment folder
     */
    private String path;

    public Segment(String id, String path) {
        this.id = id;
        this.path = path;
    }

    public String getId() {
        return id;
    }

    public String getPath() {
        return path;
    }

    /**
     * return all InputSplit of this segment, each file is a InputSplit
     * @param job job context
     * @return all InputSplit
     * @throws IOException
     */
    public List<InputSplit> getAllSplits(JobContext job) throws IOException {
        List<InputSplit> result = new ArrayList<>();
        Path p = new Path(path);
        FileSystem fs = p.getFileSystem(job.getConfiguration());

        //TODO: filter out the hidden files
        FileStatus[] files = fs.globStatus(p);
        for (FileStatus file : files) {
            // make split and add to result
        }
        return result;
    }

    /**
     * get all files, implementation may use the input filter and index to prune files
     * @param job job context
     * @param filterResolver filter
     * @return all files
     */
    public abstract List<InputSplit> getSplits(JobContext job, FilterResolverIntf filterResolver)
            throws IOException;

    /**
     * This is called after Segment is loaded and before segment is committed,
     * implementation should load indices if required
     * @param job job context
     */
    public abstract void setupForRead(JobContext job) throws IOException;

}