src/share/classes/java/lang/Number.java

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 1994, 2001, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1994, 2011, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this

@@ -24,85 +24,97 @@
  */
 
 package java.lang;
 
 /**
- * The abstract class <code>Number</code> is the superclass of classes
- * <code>BigDecimal</code>, <code>BigInteger</code>,
- * <code>Byte</code>, <code>Double</code>, <code>Float</code>,
- * <code>Integer</code>, <code>Long</code>, and <code>Short</code>.
- * <p>
- * Subclasses of <code>Number</code> must provide methods to convert
- * the represented numeric value to <code>byte</code>, <code>double</code>,
- * <code>float</code>, <code>int</code>, <code>long</code>, and
- * <code>short</code>.
+ * The abstract class {@code Number} is the superclass of platform
+ * classes representing numeric values that are convertible to the
+ * primitive types {@code byte}, {@code double}, {@code float}, {@code
+ * int}, {@code long}, and {@code short}.
+ *
+ * The specific semantics of the conversion from the numeric value of
+ * a particular {@code Number} implementation to a given primitive
+ * type is defined by the {@code Number} implementation in question.
+ *
+ * For platform classes, the conversion is often analogous to a
+ * narrowing primitive conversion or a widening primitive conversion
+ * as defining in <cite>The Java&trade; Language Specification</cite>
+ * for converting between primitive types.  Therefore, conversions may
+ * lose information about the overall magnitude of a numeric value, may
+ * lose precision, and may even return a result of a different sign
+ * than the input.
+ *
+ * See the documentation of a given {@code Number} implementation for
+ * conversion details.
  *
  * @author      Lee Boynton
  * @author      Arthur van Hoff
- * @see     java.lang.Byte
- * @see     java.lang.Double
- * @see     java.lang.Float
- * @see     java.lang.Integer
- * @see     java.lang.Long
- * @see     java.lang.Short
+ * @jls 5.1.2 Widening Primitive Conversions
+ * @jls 5.1.3 Narrowing Primitive Conversions
  * @since   JDK1.0
  */
 public abstract class Number implements java.io.Serializable {
     /**
-     * Returns the value of the specified number as an <code>int</code>.
-     * This may involve rounding or truncation.
+     * Returns the value of the specified number as an {@code int},
+     * which may involve rounding or truncation.
      *
      * @return  the numeric value represented by this object after conversion
-     *          to type <code>int</code>.
+     *          to type {@code int}.
      */
     public abstract int intValue();
 
     /**
-     * Returns the value of the specified number as a <code>long</code>.
-     * This may involve rounding or truncation.
+     * Returns the value of the specified number as a {@code long},
+     * which may involve rounding or truncation.
      *
      * @return  the numeric value represented by this object after conversion
-     *          to type <code>long</code>.
+     *          to type {@code long}.
      */
     public abstract long longValue();
 
     /**
-     * Returns the value of the specified number as a <code>float</code>.
-     * This may involve rounding.
+     * Returns the value of the specified number as a {@code float},
+     * which may involve rounding.
      *
      * @return  the numeric value represented by this object after conversion
-     *          to type <code>float</code>.
+     *          to type {@code float}.
      */
     public abstract float floatValue();
 
     /**
-     * Returns the value of the specified number as a <code>double</code>.
-     * This may involve rounding.
+     * Returns the value of the specified number as a {@code double},
+     * which may involve rounding.
      *
      * @return  the numeric value represented by this object after conversion
-     *          to type <code>double</code>.
+     *          to type {@code double}.
      */
     public abstract double doubleValue();
 
     /**
-     * Returns the value of the specified number as a <code>byte</code>.
-     * This may involve rounding or truncation.
+     * Returns the value of the specified number as a {@code byte},
+     * which may involve rounding or truncation.
+     *
+     * <p>This implementation returns the result of {@link #intValue} cast
+     * to a {@code byte}.
      *
      * @return  the numeric value represented by this object after conversion
-     *          to type <code>byte</code>.
+     *          to type {@code byte}.
      * @since   JDK1.1
      */
     public byte byteValue() {
         return (byte)intValue();
     }
 
     /**
-     * Returns the value of the specified number as a <code>short</code>.
-     * This may involve rounding or truncation.
+     * Returns the value of the specified number as a {@code short},
+     * which may involve rounding or truncation.
+     *
+     * <p>This implementation returns the result of {@link #intValue} cast
+     * to a {@code short}.
      *
      * @return  the numeric value represented by this object after conversion
-     *          to type <code>short</code>.
+     *          to type {@code short}.
      * @since   JDK1.1
      */
     public short shortValue() {
         return (short)intValue();
     }