SequenceFileActionManagerServiceFacade.java

package eu.dnetlib.iis.wf.export.actionmanager.api;

import java.io.IOException;
import java.util.List;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.io.SequenceFile.CompressionType;
import org.apache.hadoop.io.SequenceFile.Writer;
import org.apache.hadoop.io.Text;

import eu.dnetlib.actionmanager.actions.AtomicAction;
import eu.dnetlib.actionmanager.rmi.ActionManagerException;

/**
 * Sequence file based action manager service facade.
 * 
 * @author mhorst
 *
 */
public class SequenceFileActionManagerServiceFacade implements ActionManagerServiceFacade {

    private final SequenceFile.Writer writer;

    // ------------------------------- CONSTRUCTORS ----------------------------------------

    /**
     * @param hadoopConf hadoop configuration
     * @param outputDirRoot root output directory
     * @param outputDirName output subdirectory name
     */
    public SequenceFileActionManagerServiceFacade(Configuration hadoopConf, String outputDirRoot, String outputDirName)
            throws IOException {
        this.writer = SequenceFile.createWriter(hadoopConf,
                Writer.file(new Path(new Path(outputDirRoot, outputDirName), "part-m-00000")),
                Writer.keyClass(Text.class), Writer.valueClass(Text.class), Writer.compression(CompressionType.BLOCK));
    }
    
    /**
     * @param writer writer instantiated outside facade
     */
    public SequenceFileActionManagerServiceFacade(SequenceFile.Writer writer) {
        this.writer = writer;
    }

    // ------------------------------- LOGIC ----------------------------------------

    @Override
    public void storeActions(List<AtomicAction> actions) throws ActionManagerException {
        if (actions != null) {
            for (AtomicAction action : actions) {
                try {
                    Text keyOut = new Text();
                    Text valueOut = new Text();
                    keyOut.set(action.getRowKey());
                    valueOut.set(action.toString());
                    writer.append(keyOut, valueOut);
                } catch (IOException e) {
                    throw new ActionManagerException("exception occurred when writing action: " + action.toString(), e);
                }
            }
        }
    }

    @Override
    public void close() {
        IOUtils.closeStream(writer);
    }

}