org.zuinnote.hadoop.bitcoin.format.BitcoinTransactionRecordReader.java Source code

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Here is the source code for org.zuinnote.hadoop.bitcoin.format.BitcoinTransactionRecordReader.java

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/**
* Copyright 2016 ZuInnoTe (Jrn Franke) <zuinnote@gmail.com>
*
* 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 org.zuinnote.hadoop.bitcoin.format;

import org.zuinnote.hadoop.bitcoin.format.exception.HadoopCryptoLedgerConfigurationException;
import org.zuinnote.hadoop.bitcoin.format.exception.BitcoinBlockReadException;

import java.io.IOException;
import java.io.InputStream;

import java.security.NoSuchAlgorithmException;

import org.apache.hadoop.io.BytesWritable;

import org.apache.hadoop.mapred.FileSplit;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.Reporter;

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

public class BitcoinTransactionRecordReader extends AbstractBitcoinRecordReader<BytesWritable, BitcoinTransaction> {
    private static final Log LOG = LogFactory.getLog(BitcoinBlockRecordReader.class.getName());

    private int currentTransactionCounterInBlock = 0;
    private BitcoinBlock currentBitcoinBlock;

    public BitcoinTransactionRecordReader(FileSplit split, JobConf job, Reporter reporter)
            throws IOException, HadoopCryptoLedgerConfigurationException, BitcoinBlockReadException {
        super(split, job, reporter);
    }

    /**
    *
    * Create an empty key
    *
    * @return key
    */
    public BytesWritable createKey() {
        return new BytesWritable();
    }

    /**
    *
    * Create an empty value
    *
    * @return value
    */
    public BitcoinTransaction createValue() {
        return new BitcoinTransaction();
    }

    /**
    *
    * Read a next block. 
    *
    * @param key is a 68 byte array (hashMerkleRoot, prevHashBlock, transActionCounter)
    * @param value is a deserialized Java object of class BitcoinBlock
    *
    * @return true if next block is available, false if not
    */
    public boolean next(BytesWritable key, BitcoinTransaction value) throws IOException {
        // read all the blocks, if necessary a block overlapping a split
        while (getFilePosition() <= getEnd()) { // did we already went beyond the split (remote) or do we have no further data left?
            if ((currentBitcoinBlock == null)
                    || (currentBitcoinBlock.getTransactions().size() == currentTransactionCounterInBlock)) {
                try {
                    currentBitcoinBlock = getBbr().readBlock();
                    currentTransactionCounterInBlock = 0;
                } catch (BitcoinBlockReadException e) {
                    // log
                    LOG.error(e);
                }
            }

            if (currentBitcoinBlock == null)
                return false;
            BitcoinTransaction currentTransaction = currentBitcoinBlock.getTransactions()
                    .get(currentTransactionCounterInBlock);
            // the unique identifier that is linked in other transaction is usually its hash
            byte[] newKey = new byte[0];
            try {
                newKey = BitcoinUtil.getTransactionHash(currentTransaction);
            } catch (NoSuchAlgorithmException nsae) {
                LOG.error("Cannot calculate transaction hash. Algorithm not available. Exception: "
                        + nsae.toString());
            }
            key.set(newKey, 0, newKey.length);
            value.set(currentTransaction);
            currentTransactionCounterInBlock++;
            return true;
        }
        return false;
    }

}