Primitive utilities : Data Type Introduction « Data Type « Java Tutorial

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 * JBoss, Home of Professional Open Source
 * Copyright 2005, JBoss Inc., and individual contributors as indicated
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

/**
 * Primitive utilities.
 * 
 * @version <tt>$Revision: 1958 $</tt>
 * @author <a href="mailto:jason@planet57.com">Jason Dillon</a>
 */
public final class Primitives {
  /**
   * Get a Boolean from a boolean, equivalent to the java 1.4 method
   * Boolean.valueOf(boolean)
   * 
   * @param value
   *          the boolean
   * @return the Boolean equivalent
   */
  public static Boolean valueOf(boolean value) {
    if (value)
      return Boolean.TRUE;
    else
      return Boolean.FALSE;
  }

  /**
   * Test the equality of two doubles by converting their values into IEEE 754
   * floating-point "double format" long values.
   * 
   * @param a
   *          Double to check equality with.
   * @param b
   *          Double to check equality with.
   * @return True if a equals b.
   */
  public static boolean equals(final double a, final double b) {
    return Double.doubleToLongBits(a) == Double.doubleToLongBits(b);
  }

  /**
   * Test the equality of two doubles by converting their values into IEEE 754
   * floating-point "single precision" bit layouts.
   * 
   * @param a
   *          Float to check equality with.
   * @param b
   *          Float to check equality with.
   * @return True if a equals b.
   */
  public static boolean equals(final float a, final float b) {
    return Float.floatToIntBits(a) == Float.floatToIntBits(b);
  }

  /**
   * Test the equality of a given sub-section of two byte arrays.
   * 
   * @param a
   *          The first byte array.
   * @param abegin
   *          The begining index of the first byte array.
   * @param b
   *          The second byte array.
   * @param bbegin
   *          The begining index of the second byte array.
   * @param length
   *          The length of the sub-section.
   * @return True if sub-sections are equal.
   */
  public static boolean equals(final byte a[], final int abegin, final byte b[], final int bbegin,
      final int length) {
    try {
      int i = length;
      while (--i >= 0) {
        if (a[abegin + i] != b[bbegin + i]) {
          return false;
        }
      }
    } catch (ArrayIndexOutOfBoundsException e) {
      return false;
    }

    return true;
  }

  /**
   * Test the equality of two byte arrays.
   * 
   * @param a
   *          The first byte array.
   * @param b
   *          The second byte array.
   * @return True if the byte arrays are equal.
   */
  public static boolean equals(final byte a[], final byte b[]) {
    if (a == b)
      return true;
    if (a == null || b == null)
      return false;
    if (a.length != b.length)
      return false;

    try {
      for (int i = 0; i < a.length; i++) {
        if (a[i] != b[i]) {
          return false;
        }
      }
    } catch (ArrayIndexOutOfBoundsException e) {
      return false;
    }

    return true;
  }

}