/**
 * Example Object. Store many shorts into a vector and use 1-norm distance on
 * them.
 * @author Arnoldo Jose Muller Molina.
 * @since 0.7
 */

public class OBVectorExample implements OBShort {

    /**
     * Total number of elements to store.
     */
    private static final int VECTOR_SIZE = 100;

    /**
     * 1) Actual data.
     */
    private short[] data;

    /**
     * 2) Default constructor is required by OBSearch.
     */
    public OBVectorExample() {
        data = new short[VECTOR_SIZE];
    }

    /**
     * Additional constructors can be created to make your life easier.
     * (OBSearch does not use them)
     */
    public OBVectorExample(short[] data) {
        assert data.length == VECTOR_SIZE;
        this.data = data;
    }

    /**
     * 3) 1-norm distance function. A casting error can happen here, but we
     * don't check it for efficiency reasons.
     * @param object
     *            The object to compare.
     * @return The distance between this and object.
     * @throws OBException
     *             if something goes wrong. But nothing should be wrong in this
     *             function.
     */
    public final short distance(final OBShort object) throws OBException {
        OBVectorExample o = (OBVectorExample) object;
        short res = 0;
        int i = 0;
        while (i < VECTOR_SIZE) {
            res += Math.abs(data[i] - o.data[i]);
            i++;
        }
        return res;
    }

    /**
     * 4) Load method. Loads the data into this object. This is analogous to
     * object de-serialization.
     * @param in
     *            Byte Stream with all the data that has to be loaded into this
     *            object.
     */
    public final void load(final TupleInput in) throws OBException {
        int i = 0;
        while (i < VECTOR_SIZE) {
            // read a short from the stream and
            // store it into our array.
            data[i] = in.readShort();
            i++;
        }
    }

    /**
     * 5) Store method. Write the contents of the object into out. Analogous to
     * Java's object serialization.
     * @param out
     *            Stream where we will store this object.
     */
    public final void store(TupleOutput out) {
        int i = 0;
        while (i < VECTOR_SIZE) {
            // write each short into
            // the stream
            out.writeShort(data[i]);
            i++;
        }
    }

    /**
     * 6) Equals method. Implementation of the equals method is required. A
     * casting error can happen here, but we don't check it for efficiency
     * reasons.
     * @param object
     *            The object to compare.
     * @return true if this and object are equal.
     */
    public final boolean equals(final Object object) {
        OBVectorExample o = (OBVectorExample) object;
        return Arrays.equals(data, o.data);
    }

    /**
     * 7) Hash code method. This method is required too.
     * @return The hash code of the data array.
     */
    public final int hashCode() {
        // TODO: this value should be cached.
        return Arrays.hashCode(data);
    }

}