eu.stratosphere.api.java.record.io.TextInputFormat.java Source code

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Here is the source code for eu.stratosphere.api.java.record.io.TextInputFormat.java

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/***********************************************************************************************************************
 * Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
 *
 * Licensed 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 eu.stratosphere.api.java.record.io;

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.util.Arrays;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import eu.stratosphere.configuration.Configuration;
import eu.stratosphere.types.Record;
import eu.stratosphere.types.StringValue;

/**
 * Base implementation for an input format that returns each line as a separate record that contains
 * only a single string, namely the line.
 */
public class TextInputFormat extends DelimitedInputFormat {
    private static final long serialVersionUID = 1L;

    public static final String CHARSET_NAME = "textformat.charset";

    public static final String FIELD_POS = "textformat.pos";

    public static final String DEFAULT_CHARSET_NAME = "UTF-8";

    private static final Log LOG = LogFactory.getLog(TextInputFormat.class);

    protected final StringValue theString = new StringValue();

    // all fields below here are set in configure / open, so we do not serialze them

    protected transient CharsetDecoder decoder;

    protected transient ByteBuffer byteWrapper;

    protected transient int pos;

    protected transient boolean ascii;

    /**
     * Code of \r, used to remove \r from a line when the line ends with \r\n
     */
    private static final byte CARRIAGE_RETURN = (byte) '\r';

    /**
     * Code of \n, used to identify if \n is used as delimiter
     */
    private static final byte NEW_LINE = (byte) '\n';

    // --------------------------------------------------------------------------------------------

    @Override
    public void configure(Configuration parameters) {
        super.configure(parameters);

        // get the charset for the decoding
        String charsetName = parameters.getString(CHARSET_NAME, DEFAULT_CHARSET_NAME);
        if (charsetName == null || !Charset.isSupported(charsetName)) {
            throw new RuntimeException("Unsupported charset: " + charsetName);
        }

        if (charsetName.equals("ISO-8859-1") || charsetName.equalsIgnoreCase("ASCII")) {
            this.ascii = true;
        } else {
            this.decoder = Charset.forName(charsetName).newDecoder();
            this.byteWrapper = ByteBuffer.allocate(1);
        }

        // get the field position to write in the record
        this.pos = parameters.getInteger(FIELD_POS, 0);
        if (this.pos < 0) {
            throw new RuntimeException("Illegal configuration value for the target position: " + this.pos);
        }
    }

    // --------------------------------------------------------------------------------------------

    public Record readRecord(Record reuse, byte[] bytes, int offset, int numBytes) {
        StringValue str = this.theString;

        //Check if \n is used as delimiter and the end of this line is a \r, then remove \r from the line
        if (this.getDelimiter() != null && this.getDelimiter().length == 1 && this.getDelimiter()[0] == NEW_LINE
                && offset + numBytes >= 1 && bytes[offset + numBytes - 1] == CARRIAGE_RETURN) {
            numBytes -= 1;
        }

        if (this.ascii) {
            str.setValueAscii(bytes, offset, numBytes);
        } else {
            ByteBuffer byteWrapper = this.byteWrapper;
            if (bytes != byteWrapper.array()) {
                byteWrapper = ByteBuffer.wrap(bytes, 0, bytes.length);
                this.byteWrapper = byteWrapper;
            }
            byteWrapper.limit(offset + numBytes);
            byteWrapper.position(offset);

            try {
                CharBuffer result = this.decoder.decode(byteWrapper);
                str.setValue(result);
            } catch (CharacterCodingException e) {
                byte[] copy = new byte[numBytes];
                System.arraycopy(bytes, offset, copy, 0, numBytes);
                LOG.warn("Line could not be encoded: " + Arrays.toString(copy), e);
                return null;
            }
        }

        reuse.clear();
        reuse.setField(this.pos, str);
        return reuse;
    }
}