Int64Data.java

// <editor-fold defaultstate="collapsed" desc="license">
/*
 * Copyright (c) 2014, Karl H. Beckers
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * * Neither the name of the <ORGANIZATION> nor the names of its contributors
 *   may be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 **/
// </editor-fold>
package net.jarre_de_the.griffin.types.data;

import java.io.IOException;
import java.io.RandomAccessFile;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Implementation of the INT64. The GFF INT64 is an 8 byte signed integer with possible values from -9223372036854775808
 * to 9223372036854775807.
 * <p>
 * @author charly4711
 */
public class Int64Data extends AbstractFixedLengthData<Long, Int64Data>
        implements NumberData<Long>, Cloneable {

    /**
     * The length of a INT64 in bytes.
     */
    public static final int LENGTH = 8;
    private static final Logger LOGGER = LoggerFactory.getLogger(Int64Data.class);
    private long value = 0L;

    /*
     *
     * constructors
     *
     */
    protected Int64Data() {
    }

    /**
     * Creates a new instance of {@code Int64Data} and sets a defined value.
     * <p>
     * @param l The value to set. The Java primitive long corresponds well with the INT64 by being both 64 bit and
     *          signed.
     * @see #setValue(long l)
     */
    public Int64Data(long l) {
        setValue(l);
    }

    /*
     *
     * read from file
     *
     */
    /**
     * Creates a new instance of {@code Int64Data} based on the data read from the file passed. Note that the contents
     * are read from whatever position the file pointer is at.
     * <p>
     * @param in An open {@code RandomAccessFile}.
     * @return
     * @throws java.io.IOException If there are any I/O related problems with file access to in.
     */
    public static Int64Data read(RandomAccessFile in)
            throws IOException {
        return new Int64Data((long)read(in, Long.class));
    }

    /*
     *
     * setter
     *
     */
    /**
     * Sets this instance's value.
     * <p>
     * @param l The value to set.
     */
    private void setValue(long l) {
        this.value = l;
    }

    /*
     *
     * getter
     *
     */
    /**
     * Returns the instance64's value as a long.
     * <p>
     * @return The numeric value of this instance.
     */
    @Override
    public Long getValueAsNumber() {
        LOGGER.debug("Retrieving long to long from: " + value);
        return value;
    }

    @Override
    public Long getValue() {
        return value;
    }

    /**
     * Returns the value of this instance as a byte array in the same order it would be stored in a GFF file.
     * <p>
     * @return This instance's value as a bit field split into 8 bytes.
     */
    @Override
    public byte[] getValueAsByteArray() {
        return super.getValueAsByteArray(value);
    }

    /*
     *
     * utility
     *
     */
    @Override
    public int length() {
        return LENGTH;
    }

    /**
     * Overrides the {@code java.lang.Object} method to ensure we always get back an instance of {@code Int64Data}
     * rather than just {@code Object}.
     * <p>
     * @return A deep copy of this object.
     * @throws java.lang.CloneNotSupportedException
     */
    @Override
    public Int64Data clone() throws CloneNotSupportedException {
        LOGGER.debug("Cloning object");
        Int64Data clone = (Int64Data) super.clone();
        clone.setValue(value);

        return clone;
    }

    /**
     * Overrides the {@code java.lang.Object} method to make test for equality possible for this class.
     * <p>
     * @param compare The Object to compare this object with.
     * @return True if the objects have the same value, false if not.
     */
    @Override
    public boolean equals(Object compare) {
        if (compare == this) {
            return true;
        }

        if (!(compare instanceof Int64Data)) {
            return false;
        }

        Int64Data dw = (Int64Data) compare;
        if (dw.getValueAsNumber().equals(this.getValueAsNumber())) {
            return true;
        }

        return false;
    }

    /**
     * Overrides the {@code java.lang.Object} method to ensure we have a hash code consistent with the test for
     * equality. Because we have a full 8 byte long value but can only return a 4 byte int, we need to lose some date.
     * We do the same as the {@code java.lang.Long}, i. e. return an exclusive OR of the two halves of the long value.
     * <p>
     * <blockquote> {@code (int)(this.getLongValue()^(this.getLongValue()>>>32))}
     * </blockquote>
     * <p>
     * @return The hash returned is based on the value.
     */
    @Override
    public int hashCode() {
        LOGGER.debug("Creating int hashCode from long value");
        long l = value;
        return (int) (l ^ (l >>> 32));
    }

    @Override
    public String toString() {
        return Long.toString(getValueAsNumber());
    }
}