org.apache.hadoop.streaming.StreamKeyValUtil.java Source code

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Here is the source code for org.apache.hadoop.streaming.StreamKeyValUtil.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.hadoop.streaming;

import java.io.IOException;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.util.LineReader;

public class StreamKeyValUtil {

    /**
     * Find the first occurred tab in a UTF-8 encoded string
     * @param utf a byte array containing a UTF-8 encoded string
     * @param start starting offset
     * @param length no. of bytes
     * @return position that first tab occurres otherwise -1
     */
    public static int findTab(byte[] utf, int start, int length) {
        for (int i = start; i < (start + length); i++) {
            if (utf[i] == (byte) '\t') {
                return i;
            }
        }
        return -1;
    }

    /**
     * Find the first occurred tab in a UTF-8 encoded string
     * @param utf a byte array containing a UTF-8 encoded string
     * @return position that first tab occurres otherwise -1
     */
    public static int findTab(byte[] utf) {
        return org.apache.hadoop.util.UTF8ByteArrayUtils.findNthByte(utf, 0, utf.length, (byte) '\t', 1);
    }

    /**
     * split a UTF-8 byte array into key and value 
     * assuming that the delimilator is at splitpos. 
     * @param utf utf-8 encoded string
     * @param start starting offset
     * @param length no. of bytes
     * @param key contains key upon the method is returned
     * @param val contains value upon the method is returned
     * @param splitPos the split pos
     * @param separatorLength the length of the separator between key and value
     * @throws IOException
     */
    public static void splitKeyVal(byte[] utf, int start, int length, Text key, Text val, int splitPos,
            int separatorLength) throws IOException {
        if (splitPos < start || splitPos >= (start + length))
            throw new IllegalArgumentException(
                    "splitPos must be in the range " + "[" + start + ", " + (start + length) + "]: " + splitPos);
        int keyLen = (splitPos - start);
        int valLen = (start + length) - splitPos - separatorLength;
        key.set(utf, start, keyLen);
        val.set(utf, splitPos + separatorLength, valLen);
    }

    /**
     * split a UTF-8 byte array into key and value 
     * assuming that the delimilator is at splitpos. 
     * @param utf utf-8 encoded string
     * @param start starting offset
     * @param length no. of bytes
     * @param key contains key upon the method is returned
     * @param val contains value upon the method is returned
     * @param splitPos the split pos
     * @throws IOException
     */
    public static void splitKeyVal(byte[] utf, int start, int length, Text key, Text val, int splitPos)
            throws IOException {
        splitKeyVal(utf, start, length, key, val, splitPos, 1);
    }

    /**
     * split a UTF-8 byte array into key and value 
     * assuming that the delimilator is at splitpos. 
     * @param utf utf-8 encoded string
     * @param key contains key upon the method is returned
     * @param val contains value upon the method is returned
     * @param splitPos the split pos
     * @param separatorLength the length of the separator between key and value
     * @throws IOException
     */
    public static void splitKeyVal(byte[] utf, Text key, Text val, int splitPos, int separatorLength)
            throws IOException {
        splitKeyVal(utf, 0, utf.length, key, val, splitPos, separatorLength);
    }

    /**
     * split a UTF-8 byte array into key and value 
     * assuming that the delimilator is at splitpos. 
     * @param utf utf-8 encoded string
     * @param key contains key upon the method is returned
     * @param val contains value upon the method is returned
     * @param splitPos the split pos
     * @throws IOException
     */
    public static void splitKeyVal(byte[] utf, Text key, Text val, int splitPos) throws IOException {
        splitKeyVal(utf, 0, utf.length, key, val, splitPos, 1);
    }

    /**
     * Read a utf8 encoded line from a data input stream. 
     * @param lineReader LineReader to read the line from.
     * @param out Text to read into
     * @return number of bytes read 
     * @throws IOException
     */
    public static int readLine(LineReader lineReader, Text out) throws IOException {
        out.clear();
        return lineReader.readLine(out);
    }

}