2006-04-17 Andrew John Hughes <gnu_andrew@member.fsf.org>

	* java/lang/annotation/Annotation.java:
	Documented.

2 files changed, 91 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 7ec2e90eb..30b567d22 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2006-04-17  Andrew John Hughes  <gnu_andrew@member.fsf.org>
+
+	* java/lang/annotation/Annotation.java:
+	Documented.
+	
 2006-04-14  Tom Tromey  <tromey@redhat.com>
 
 	* javax/swing/tree/DefaultTreeSelectionModel.java (getListeners):
diff --git a/java/lang/annotation/Annotation.java b/java/lang/annotation/Annotation.java
index e07449260..cc334ec3b 100644
--- a/java/lang/annotation/Annotation.java
+++ b/java/lang/annotation/Annotation.java
@@ -38,12 +38,98 @@ exception statement from your version. */
 package java.lang.annotation;
 
 /**
+ * This is the common interface for all annotations.  Note that classes
+ * that implement this class manually are not classed as annotations, and
+ * that this interface does not define an annotation type in itself.
+ *
+ * @author Tom Tromey (tromey@redhat.com)
+ * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
  * @since 1.5
  */
 public interface Annotation
 {
+
+  /**
+   * Returns the type of this annotation.
+   *
+   * @return the class of which this annotation is an instance.
+   */
   Class<? extends Annotation> annotationType();
+
+  /**
+   * <p>
+   * Returns true if the supplied object is equivalent to this annotation.
+   * For this property to hold, the following must be true of <code>o</code>:
+   * </p>
+   * <ul>
+   * <li>The object is also an instance of the same annotation type.</li>
+   * <li>The members of the supplied annotation are equal to those of this
+   * annotation, according to the following:
+   * <ul>
+   * <li>If the members are <code>float</code>s, then, for floats
+   * <code>x</code> and <code>y</code>, 
+   * <code>Float.valueOf(x).equals(Float.valueOf(y)</code> must return
+   * true.  This differs from the usual (<code>==</code>) comparison
+   * in that <code>NaN</code> is considered equal to itself and positive
+   * and negative zero are seen as different.</li>
+   * <li>Likewise, if the members are <code>double</code>s, then, for doubles
+   * <code>x</code> and <code>y</code>, 
+   * <code>Double.valueOf(x).equals(Double.valueOf(y)</code> must return
+   * true.  This differs from the usual (<code>==</code>) comparison
+   * in that <code>NaN</code> is considered equal to itself and positive
+   * and negative zero are seen as different.</li>
+   * <li>Strings, classes, enumerations and annotations are considered
+   * equal according to the <code>equals()</code> implementation for these
+   * types.</li>
+   * <li>Arrays are considered equal according to <code>Arrays.equals()</code>
+   * </li>
+   * <li>Any remaining types are considered equal using <code>==</code>.</li>
+   * </li>
+   * </ul>
+   *
+   * @param o the object to compare with this annotation.
+   * @return true if the supplied object is an annotation with equivalent
+   *         members.
+   */
   boolean equals(Object o);
+
+  /**
+   * <p>
+   * Returns the hash code of the annotation.  This is computed as the
+   * sum of the hash codes of the annotation's members.
+   * </p>
+   * <p>
+   * The hash code of a member of the annotation is the result of XORing
+   * the hash code of its value with the result of multiplying the hash code
+   * of its name by 127.  Formally, if the value is <code>v</code> and the
+   * name is <code>n</code>, the hash code of the member is
+   * v.hashCode() XOR (127 * String.hashCode(n)).  <code>v.hashCode()</code>
+   * is defined as follows:
+   * </p>
+   * <ul>
+   * <li>The hash code of a primitive value (i.e. <code>byte</code>,
+   * <code>char</code>, <code>double</code>, <code>float</code>,
+   * <code>int</code>, <code>long</code>, <code>short</code> and
+   * <code>boolean</code>) is the hash code obtained from its corresponding
+   * wrapper class using <code>valueOf(v).hashCode()</code>, where
+   * <code>v</code> is the primitive value.</li>
+   * <li>The hash code of an enumeration, string, class or other annotation
+   * is obtained using <code>v.hashCode()</code>.</li>
+   * <li>The hash code of an array is computed using
+   * <code>Arrays.hashCode(v)</code>.</li>
+   * </ul>
+   *
+   * @return the hash code of the annotation, computed as the sum of its
+   *         member hashcodes.
+   */
   int hashCode();
+
+  /**
+   * Returns a textual representation of the annotation.  This is
+   * implementation-dependent, but is expected to include the classname
+   * and the names and values of each member.
+   *
+   * @return a textual representation of the annotation.
+   */
   String toString();
 }