org.apache.druid.indexer.path.HadoopGlobPathSplitter.java Source code

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Here is the source code for org.apache.druid.indexer.path.HadoopGlobPathSplitter.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.druid.indexer.path;

import com.google.common.base.Functions;
import com.google.common.collect.Iterables;

import java.util.ArrayList;
import java.util.List;

//Note: This class has been created to workaround https://issues.apache.org/jira/browse/MAPREDUCE-5061
public class HadoopGlobPathSplitter {

    /**
     * Splits given hadoop glob path by commas.
     * e.g. splitGlob("/a,/b") -> ["/a","/b"]
     * splitGlob("/a/{c,d}") -> ["/a/c", "/a/d"]
     */
    public static Iterable<String> splitGlob(String path) {
        return Iterables.transform(splitGlob(new CharStream(path)), Functions.toStringFunction());
    }

    private static List<StringBuilder> splitGlob(CharStream path) {
        List<StringBuilder> result = new ArrayList<>();

        List<StringBuilder> current = new ArrayList<>();
        current.add(new StringBuilder());

        while (path.hasMore()) {
            char c = path.next();
            switch (c) {
            case '{':
                List<StringBuilder> childResult = splitGlob(path);
                List<StringBuilder> oldCurrent = current;
                current = new ArrayList<>();

                for (StringBuilder sb1 : oldCurrent) {
                    for (StringBuilder sb2 : childResult) {
                        StringBuilder sb3 = new StringBuilder();
                        sb3.append(sb1);
                        sb3.append(sb2);
                        current.add(sb3);
                    }
                }
                break;
            case '}':
                result.addAll(current);
                return result;
            case ',':
                result.addAll(current);
                current = new ArrayList<>();
                current.add(new StringBuilder());
                break;
            default:
                for (StringBuilder sb : current) {
                    sb.append(c);
                }
            }
        }

        result.addAll(current);
        return result;
    }
}

class CharStream {
    private String string;
    private int offset;

    public CharStream(String string) {
        super();
        this.string = string;
        this.offset = 0;
    }

    public boolean hasMore() {
        return offset < string.length();
    }

    public char next() {
        return string.charAt(offset++);
    }
}