nl.tweeenveertig.openstack.instructions.SegmentationPlan Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of joss Show documentation

Java Client library for OpenStack Storage (Swift)

There is a newer version: 0.7.0

package nl.tweeenveertig.openstack.instructions;

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

/**
* The Segmentation plan provides a way to access the underlying data as separate InputStreams
* for the purpose of uploading in several segments.
*/
public abstract class SegmentationPlan {

    protected Long segmentationSize;

    protected Long currentSegment = 0L;

    public Long getSegmentNumber() {
        return this.currentSegment;
    }

    public SegmentationPlan(Long segmentationSize) {
        this.segmentationSize = segmentationSize;
    }

    public InputStream getNextSegment() throws IOException {
        if (done()) {
            return null;
        }
        InputStream segment = createSegment();
        this.currentSegment++;
        return segment;
    }

    /**
    * Checks whether all segments have been done
    * @return true if the segment can be read
    */
    protected boolean done() {
        return currentSegment * segmentationSize > getFileLength();
    }

    /**
    * Returns the file length of the object
    * @return file length of the object
    */
    protected abstract Long getFileLength();

    /**
    * Creates an InputStream from the current segment
    * @return the inputstream
    * @throws IOException thrown if error occurs
    */
    protected abstract InputStream createSegment() throws IOException;

    /**
    * Closes the underlying File, if appropriate
    * @throws IOException thrown if error occurs
    */
    public abstract void close() throws IOException;

}