org.apache.commons.lang
Class ObjectUtils
java.lang.Object
|
+--org.apache.commons.lang.ObjectUtils
- public class ObjectUtils
- extends java.lang.Object
Common Object
manipulation routines.
- Version:
- $Id: ObjectUtils.java,v 1.4 2002/09/22 09:18:33 scolebourne Exp $
- Author:
- Nissim Karpenstein, Janek Bogucki, Daniel Rall, Stephen Colebourne
Inner Class Summary |
static class |
ObjectUtils.Null
Class used as a null placeholder where null has another meaning. |
Field Summary |
static ObjectUtils.Null |
NULL
Singleton used as a null placeholder where null has another meaning. |
Constructor Summary |
ObjectUtils()
ObjectUtils instances should NOT be constructed in standard programming. |
Method Summary |
static java.lang.Object |
defaultIfNull(java.lang.Object object,
java.lang.Object defaultValue)
Returns a default value if the object passed is null. |
static boolean |
equals(java.lang.Object object1,
java.lang.Object object2)
Compares two objects for equality, where either one or both
objects may be null . |
static java.lang.String |
identityToString(java.lang.Object object)
Gets the toString that would be produced by Object if a class did not
override toString itself. |
Methods inherited from class java.lang.Object |
, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait |
NULL
public static final ObjectUtils.Null NULL
- Singleton used as a null placeholder where null has another meaning.
For example, in a HashMap
the get(key) method returns null
if the Map contains null or if there is no matching key. The Null
placeholder can be used to distinguish between these two cases.
Another example is HashTable
, where null
cannot be stored.
This instance is Serializable.
ObjectUtils
public ObjectUtils()
- ObjectUtils instances should NOT be constructed in standard programming.
Instead, the class should be used as
ObjectUtils.defaultIfNull("a","b");
.
This constructor is public to permit tools that require a JavaBean instance
to operate.
defaultIfNull
public static java.lang.Object defaultIfNull(java.lang.Object object,
java.lang.Object defaultValue)
- Returns a default value if the object passed is null.
- Parameters:
object
- the object to testdefaultValue
- the default value to return- Returns:
- object if it is not null, defaultValue otherwise
equals
public static boolean equals(java.lang.Object object1,
java.lang.Object object2)
- Compares two objects for equality, where either one or both
objects may be
null
.
- Parameters:
object1
- the first objectobject2
- the second object- Returns:
true
if the values of both objects are the same
identityToString
public static java.lang.String identityToString(java.lang.Object object)
- Gets the toString that would be produced by Object if a class did not
override toString itself. Null will return null.
- Parameters:
object
- the object to create a toString for, may be null- Returns:
- the default toString text, or null if null passed in
Copyright (c) 2001-2002 - Apache Software Foundation