Generifying the general Mutable, and the underlying MutableObject. This then allows for typed checking of a MutableBigDecimal for example as per LANG-276

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@788263 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/lang/mutable/Mutable.java

@@ -30,14 +30,14 @@ package org.apache.commons.lang.mutable;
  * @since 2.1
  * @version $Id$
  */
-public interface Mutable {
+public interface Mutable<T> {
 
     /**
      * Gets the value of this mutable.
      * 
      * @return the stored value
      */
-    Object getValue();
+    T getValue();
 
     /**
      * Sets the value of this mutable.
@@ -49,6 +49,6 @@ public interface Mutable {
      * @throws ClassCastException
      *             if the type is invalid
      */
-    void setValue(Object value);
+    void setValue(T value);
 
 }

src/java/org/apache/commons/lang/mutable/MutableObject.java

@@ -25,7 +25,7 @@ import java.io.Serializable;
  * @since 2.1
  * @version $Id$
  */
-public class MutableObject implements Mutable, Serializable {
+public class MutableObject<T> implements Mutable<T>, Serializable {
 
     /**
      * Required for serialization support.
@@ -35,7 +35,7 @@ public class MutableObject implements Mutable, Serializable {
     private static final long serialVersionUID = 86241875189L;
 
     /** The mutable value. */
-    private Object value;
+    private T value;
 
     /**
      * Constructs a new MutableObject with the default value of <code>null</code>.
@@ -50,7 +50,7 @@ public class MutableObject implements Mutable, Serializable {
      * @param value
      *            a value.
      */
-    public MutableObject(Object value) {
+    public MutableObject(T value) {
         super();
         this.value = value;
     }
@@ -61,7 +61,7 @@ public class MutableObject implements Mutable, Serializable {
      * 
      * @return the value
      */
-    public Object getValue() {
+    public T getValue() {
         return this.value;
     }
 
@@ -71,27 +71,27 @@ public class MutableObject implements Mutable, Serializable {
      * @param value
      *            the value to set
      */
-    public void setValue(Object value) {
+    public void setValue(T value) {
         this.value = value;
     }
 
     //-----------------------------------------------------------------------
     /**
      * Compares this object against the specified object. The result is <code>true</code> if and only if the argument
-     * is not <code>null</code> and is a <code>MutableObject</code> object that contains the same <code>Object</code>
+     * is not <code>null</code> and is a <code>MutableObject</code> object that contains the same <code>T</code>
      * value as this object.
      * 
      * @param obj
      *            the object to compare with.
      * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
      */
-    @Override
-    public boolean equals(Object obj) {
-        if (obj instanceof MutableObject) {
-            Object other = ((MutableObject) obj).value;
-            return value == other || (value != null && value.equals(other));
+    public boolean equals(MutableObject<T> obj) {
+        if(obj == null) {
+            return false;
         }
-        return false;
+
+        T other = obj.value;
+        return value == other || (value != null && value.equals(other));
     }
 
     /**