eu.stratosphere.arraymodel.io.StringInputFormat.java Source code

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Here is the source code for eu.stratosphere.arraymodel.io.StringInputFormat.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.arraymodel.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.api.common.io.DelimitedInputFormat;
import eu.stratosphere.configuration.Configuration;
import eu.stratosphere.types.StringValue;
import eu.stratosphere.types.Value;

/**
 * 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 StringInputFormat extends DelimitedInputFormat<Value[]> {

    private static final long serialVersionUID = 1L;

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

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

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

    protected final StringValue theString = new StringValue();

    protected CharsetDecoder decoder;

    protected ByteBuffer byteWrapper;

    protected boolean ascii;

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

    @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);
        }
    }

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

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

        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.clear();
            byteWrapper.position(offset);
            byteWrapper.limit(offset + numBytes);

            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 false;
            }
        }

        target[0] = str;
        return true;
    }
}