com.cloudera.sqoop.lib.BlobRef.java Source code

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Here is the source code for com.cloudera.sqoop.lib.BlobRef.java

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/**
 * Licensed to Cloudera, Inc. under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  Cloudera, Inc. 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 com.cloudera.sqoop.lib;

import java.io.ByteArrayInputStream;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.regex.Matcher;

import org.apache.hadoop.io.BytesWritable;
import com.cloudera.sqoop.io.LobFile;

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

/**
 * BlobRef is a wrapper that holds a BLOB either directly, or a
 * reference to a file that holds the BLOB data.
 */
public class BlobRef extends LobRef<byte[], BytesWritable, InputStream> {

    public static final Log LOG = LogFactory.getLog(BlobRef.class.getName());

    public BlobRef() {
        super();
    }

    public BlobRef(byte[] bytes) {
        super(new BytesWritable(bytes));
    }

    /**
     * Initialize a BlobRef to an external BLOB.
     * @param file the filename to the BLOB. May be relative to the job dir.
     * @param offset the offset (in bytes) into the LobFile for this record.
     * @param length the length of the record in bytes.
     */
    public BlobRef(String file, long offset, long length) {
        super(file, offset, length);
    }

    @Override
    protected InputStream getExternalSource(LobFile.Reader reader) throws IOException {
        return reader.readBlobRecord();
    }

    @Override
    protected InputStream getInternalSource(BytesWritable data) {
        return new ByteArrayInputStream(data.getBytes(), 0, data.getLength());
    }

    @Override
    protected byte[] getInternalData(BytesWritable data) {
        return Arrays.copyOf(data.getBytes(), data.getLength());
    }

    @Override
    protected BytesWritable deepCopyData(BytesWritable data) {
        return new BytesWritable(Arrays.copyOf(data.getBytes(), data.getLength()));
    }

    @Override
    public void readFieldsInternal(DataInput in) throws IOException {
        // For internally-stored BLOBs, the data is a BytesWritable
        // containing the actual data.

        BytesWritable data = getDataObj();

        if (null == data) {
            data = new BytesWritable();
        }
        data.readFields(in);
        setDataObj(data);
    }

    @Override
    public void writeInternal(DataOutput out) throws IOException {
        getDataObj().write(out);
    }

    /**
     * Create a BlobRef based on parsed data from a line of text.
     * This only operates correctly on external blobs; inline blobs are simply
     * returned as null. You should store BLOB data in SequenceFile format
     * if reparsing is necessary.
     * @param inputString the text-based input data to parse.
     * @return a new BlobRef containing a reference to an external BLOB, or
     * an empty BlobRef if the data to be parsed is actually inline.
     */
    public static BlobRef parse(String inputString) {
        // If inputString is of the form 'externalLob(lf,%s,%d,%d)', then this is
        // an external BLOB stored at the LobFile indicated by '%s' with the next
        // two arguments representing its offset and length in the file.
        // Otherwise, it is an inline BLOB, which we don't support parsing of.

        Matcher m = EXTERNAL_MATCHER.get();
        m.reset(inputString);
        if (m.matches()) {
            // This is a LobFile. Extract the filename, offset and len from the
            // matcher.
            return new BlobRef(m.group(1), Long.valueOf(m.group(2)), Long.valueOf(m.group(3)));
        } else {
            // This is inline BLOB string data.
            LOG.warn("Reparsing inline BLOB data is not supported; use SequenceFiles.");
            return new BlobRef();
        }
    }
}