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java.lang.Objectorg.apache.directory.shared.ldap.util.ObjectUtils
Operations on Object
.
This class tries to handle null
input gracefully. An exception
will generally not be thrown for a null
input. Each method
documents its behaviour in more detail.
Nested 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.StringBuffer |
appendIdentityToString(java.lang.StringBuffer buffer,
java.lang.Object object)
Appends the toString that would be produced by Object if a
class did not override toString itself. |
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 int |
hashCode(java.lang.Object obj)
Gets the hash code of an object returning zero when the object is 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. |
static java.lang.String |
toString(java.lang.Object obj)
Gets the toString of an Object returning an
empty string ("") if null input. |
static java.lang.String |
toString(java.lang.Object obj,
java.lang.String nullStr)
Gets the toString of an Object returning a
specified text if null input. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
public static final ObjectUtils.Null NULL
Singleton used as a null
placeholder where
null
has another meaning.
For example, in a HashMap
the
HashMap.get(java.lang.Object)
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.
Constructor Detail |
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.
Method Detail |
public static java.lang.Object defaultIfNull(java.lang.Object object, java.lang.Object defaultValue)
Returns a default value if the object passed is null
.
ObjectUtils.defaultIfNull(null, null) = null ObjectUtils.defaultIfNull(null, "") = "" ObjectUtils.defaultIfNull(null, "zz") = "zz" ObjectUtils.defaultIfNull("abc", *) = "abc" ObjectUtils.defaultIfNull(Boolean.TRUE, *) = Boolean.TRUE
object
- the Object
to test, may be null
defaultValue
- the default value to return, may be null
object
if it is not null
,
defaultValue otherwisepublic 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
.
ObjectUtils.equals(null, null) = true ObjectUtils.equals(null, "") = false ObjectUtils.equals("", null) = false ObjectUtils.equals("", "") = true ObjectUtils.equals(Boolean.TRUE, null) = false ObjectUtils.equals(Boolean.TRUE, "true") = false ObjectUtils.equals(Boolean.TRUE, Boolean.TRUE) = true ObjectUtils.equals(Boolean.TRUE, Boolean.FALSE) = false
object1
- the first object, may be null
object2
- the second object, may be null
true
if the values of both objects are the samepublic static int hashCode(java.lang.Object obj)
Gets the hash code of an object returning zero when the object is
null
.
ObjectUtils.hashCode(null) = 0 ObjectUtils.hashCode(obj) = obj.hashCode()
obj
- the object to obtain the hash code of, may be
null
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
.
ObjectUtils.identityToString(null) = null ObjectUtils.identityToString("") = "java.lang.String@1e23" ObjectUtils.identityToString(Boolean.TRUE) = "java.lang.Boolean@7fa"
object
- the object to create a toString for, may be null
null
if
null
passed inpublic static java.lang.StringBuffer appendIdentityToString(java.lang.StringBuffer buffer, java.lang.Object object)
Appends the toString that would be produced by Object
if a
class did not override toString itself. null
will return
null
.
ObjectUtils.appendIdentityToString(*, null) = null ObjectUtils.appendIdentityToString(null, "") = "java.lang.String@1e23" ObjectUtils.appendIdentityToString(null, Boolean.TRUE) = "java.lang.Boolean@7fa" ObjectUtils.appendIdentityToString(buf, Boolean.TRUE) = buf.append("java.lang.Boolean@7fa")
buffer
- the buffer to append to, may be null
object
- the object to create a toString for, may be null
null
if
null
passed inpublic static java.lang.String toString(java.lang.Object obj)
Gets the toString
of an Object
returning an
empty string ("") if null
input.
ObjectUtils.toString(null) = "" ObjectUtils.toString("") = "" ObjectUtils.toString("bat") = "bat" ObjectUtils.toString(Boolean.TRUE) = "true"
obj
- the Object to toString
, may be null
null
inputString.valueOf(Object)
public static java.lang.String toString(java.lang.Object obj, java.lang.String nullStr)
Gets the toString
of an Object
returning a
specified text if null
input.
ObjectUtils.toString(null, null) = null ObjectUtils.toString(null, "null") = "null" ObjectUtils.toString("", "null") = "" ObjectUtils.toString("bat", "null") = "bat" ObjectUtils.toString(Boolean.TRUE, "null") = "true"
obj
- the Object to toString
, may be nullnullStr
- the String to return if null
input, may be null
null
inputString.valueOf(Object)
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