Package org.apache.commons.lang3

Class ObjectUtils

java.lang.Object

org.apache.commons.lang3.ObjectUtils

public class ObjectUtils
extends Object

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 behavior in more detail.

#ThreadSafe#

Since:

1.0

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ObjectUtils.Null	Class used as a null placeholder where null has another meaning.

Field Summary

Fields

Modifier and Type	Field	Description
static final ObjectUtils.Null	NULL	Singleton used as a null placeholder where null has another meaning.

Constructor Summary

Constructors

Constructor	Description
ObjectUtils()	Deprecated. TODO Make private in 4.0.

Method Summary

Modifier and Type	Method	Description
static boolean	allNotNull(Object... values)	Tests if all values in the array are not nulls.
static boolean	allNull(Object... values)	Tests if all values in the given array are null.
static boolean	anyNotNull(Object... values)	Tests if any value in the given array is not null.
static boolean	anyNull(Object... values)	Tests if any value in the given array is null.
static <T> T	clone(T obj)	Clones an object.
static <T> T	cloneIfPossible(T obj)	Clones an object if possible.
static <T extends Comparable<? super T>> int	compare(T c1, T c2)	Null safe comparison of Comparables.
static <T extends Comparable<? super T>> int	compare(T c1, T c2, boolean nullGreater)	Null safe comparison of Comparables.
static boolean	CONST(boolean v)	Returns the provided value unchanged.
static byte	CONST(byte v)	Returns the provided value unchanged.
static char	CONST(char v)	Returns the provided value unchanged.
static double	CONST(double v)	Returns the provided value unchanged.
static float	CONST(float v)	Returns the provided value unchanged.
static int	CONST(int v)	Returns the provided value unchanged.
static long	CONST(long v)	Returns the provided value unchanged.
static short	CONST(short v)	Returns the provided value unchanged.
static <T> T	CONST(T v)	Returns the provided value unchanged.
static byte	CONST_BYTE(int v)	Returns the provided value unchanged.
static short	CONST_SHORT(int v)	Returns the provided value unchanged.
static <T> T	defaultIfNull(T object, T defaultValue)	Returns a default value if the object passed is null.
static boolean	equals(Object object1, Object object2)	Deprecated. this method has been replaced by java.util.Objects.equals(Object, Object) in Java 7 and will be removed from future releases.
static <T> T	firstNonNull(T... values)	Returns the first value in the array which is not null.
static <T> Class<T>	getClass(T object)	Delegates to Object.getClass() using generics.
static <T> T	getFirstNonNull(Supplier<T>... suppliers)	Executes the given suppliers in order and returns the first return value where a value other than null is returned.
static <T> T	getIfNull(T object, Supplier<T> defaultSupplier)	Returns the given object is it is non-null, otherwise returns the Supplier's Supplier.get() value.
static int	hashCode(Object obj)	Deprecated. this method has been replaced by java.util.Objects.hashCode(Object) in Java 7 and will be removed in future releases
static String	hashCodeHex(Object object)	Returns the hexadecimal hash code for the given object per Objects.hashCode(Object).
static int	hashCodeMulti(Object... objects)	Deprecated. this method has been replaced by java.util.Objects.hash(Object...) in Java 7 and will be removed in future releases.
static String	identityHashCodeHex(Object object)	Returns the hexadecimal hash code for the given object per System.identityHashCode(Object).
static void	identityToString(Appendable appendable, Object object)	Appends the toString that would be produced by Object if a class did not override toString itself.
static String	identityToString(Object object)	Gets the toString that would be produced by Object if a class did not override toString itself.
static void	identityToString(StringBuffer buffer, Object object)	Appends the toString that would be produced by Object if a class did not override toString itself.
static void	identityToString(StringBuilder builder, Object object)	Appends the toString that would be produced by Object if a class did not override toString itself.
static void	identityToString(StrBuilder builder, Object object)	Deprecated. as of 3.6, because StrBuilder was moved to commons-text, use one of the other identityToString methods instead
static boolean	isArray(Object object)	Tests whether the given object is an Object array or a primitive array in a null-safe manner.
static boolean	isEmpty(Object object)	Tests if an Object is empty or null.
static boolean	isNotEmpty(Object object)	Tests if an Object is not empty and not null.
static <T extends Comparable<? super T>> T	max(T... values)	Null safe comparison of Comparables.
static <T> T	median(Comparator<T> comparator, T... items)	Find the "best guess" middle value among comparables.
static <T extends Comparable<? super T>> T	median(T... items)	Find the "best guess" middle value among comparables.
static <T extends Comparable<? super T>> T	min(T... values)	Null safe comparison of Comparables.
static <T> T	mode(T... items)	Find the most frequently occurring item.
static boolean	notEqual(Object object1, Object object2)	Compares two objects for inequality, where either one or both objects may be null.
static <T> T	requireNonEmpty(T obj)	Checks that the specified object reference is not null or empty per isEmpty(Object).
static <T> T	requireNonEmpty(T obj, String message)	Checks that the specified object reference is not null or empty per isEmpty(Object).
static String	toString(Object obj)	Deprecated. this method has been replaced by java.util.Objects.toString(Object) in Java 7 and will be removed in future releases.
static String	toString(Object obj, String nullStr)	Deprecated. this method has been replaced by java.util.Objects.toString(Object, String) in Java 7 and will be removed in future releases.
static String	toString(Supplier<Object> obj, Supplier<String> supplier)	Gets the toString of an Supplier's Supplier.get() returning a specified text if null input.
static <T> String	toString(T obj, Supplier<String> supplier)	Gets the toString of an Object returning a specified text if null input.
static void	wait(Object obj, Duration duration)	Calls Object.wait(long, int) for the given Duration.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

NULL

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(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 Details

ObjectUtils

@Deprecated
public ObjectUtils()

Deprecated.

TODO Make private in 4.0.

ObjectUtils instances should NOT be constructed in standard programming. Instead, the static methods on the class should be used, such as ObjectUtils.defaultIfNull("a","b");.

This constructor is public to permit tools that require a JavaBean instance to operate.

Method Details

allNotNull

public static boolean allNotNull(Object... values)

Tests if all values in the array are not nulls.

If any value is null or the array is null then false is returned. If all elements in array are not null or the array is empty (contains no elements) true is returned.

 ObjectUtils.allNotNull(*)             = true
 ObjectUtils.allNotNull(*, *)          = true
 ObjectUtils.allNotNull(null)          = false
 ObjectUtils.allNotNull(null, null)    = false
 ObjectUtils.allNotNull(null, *)       = false
 ObjectUtils.allNotNull(*, null)       = false
 ObjectUtils.allNotNull(*, *, null, *) = false
 

Parameters:

values - the values to test, may be null or empty

Returns:

false if there is at least one null value in the array or the array is null, true if all values in the array are not nulls or array contains no elements.

Since:

3.5

allNull

public static boolean allNull(Object... values)

Tests if all values in the given array are null.

If all the values are null or the array is null or empty, then true is returned, otherwise false is returned.

 ObjectUtils.allNull(*)                = false
 ObjectUtils.allNull(*, null)          = false
 ObjectUtils.allNull(null, *)          = false
 ObjectUtils.allNull(null, null, *, *) = false
 ObjectUtils.allNull(null)             = true
 ObjectUtils.allNull(null, null)       = true
 

Parameters:

values - the values to test, may be null or empty

Returns:

true if all values in the array are nulls, false if there is at least one non-null value in the array.

Since:

3.11

anyNotNull

public static boolean anyNotNull(Object... values)

Tests if any value in the given array is not null.

If all the values are null or the array is null or empty then false is returned. Otherwise true is returned.

 ObjectUtils.anyNotNull(*)                = true
 ObjectUtils.anyNotNull(*, null)          = true
 ObjectUtils.anyNotNull(null, *)          = true
 ObjectUtils.anyNotNull(null, null, *, *) = true
 ObjectUtils.anyNotNull(null)             = false
 ObjectUtils.anyNotNull(null, null)       = false
 

Parameters:

values - the values to test, may be null or empty

Returns:

true if there is at least one non-null value in the array, false if all values in the array are nulls. If the array is null or empty false is also returned.

Since:

3.5

anyNull

public static boolean anyNull(Object... values)

Tests if any value in the given array is null.

If any of the values are null or the array is null, then true is returned, otherwise false is returned.

 ObjectUtils.anyNull(*)             = false
 ObjectUtils.anyNull(*, *)          = false
 ObjectUtils.anyNull(null)          = true
 ObjectUtils.anyNull(null, null)    = true
 ObjectUtils.anyNull(null, *)       = true
 ObjectUtils.anyNull(*, null)       = true
 ObjectUtils.anyNull(*, *, null, *) = true
 

Parameters:

values - the values to test, may be null or empty

Returns:

true if there is at least one null value in the array, false if all the values are non-null. If the array is null or empty, true is also returned.

Since:

3.11

clone

public static <T> T clone(T obj)

Clones an object.

Type Parameters:

T - the type of the object

Parameters:

obj - the object to clone, null returns null

Returns:

the clone if the object implements Cloneable otherwise null

Throws:

CloneFailedException - if the object is cloneable and the clone operation fails

Since:

3.0

cloneIfPossible

public static <T> T cloneIfPossible(T obj)

Clones an object if possible.

This method is similar to clone(Object), but will return the provided instance as the return value instead of null if the instance is not cloneable. This is more convenient if the caller uses different implementations (e.g. of a service) and some of the implementations do not allow concurrent processing or have state. In such cases the implementation can simply provide a proper clone implementation and the caller's code does not have to change.

Type Parameters:

T - the type of the object

Parameters:

obj - the object to clone, null returns null

Returns:

the clone if the object implements Cloneable otherwise the object itself

Throws:

CloneFailedException - if the object is cloneable and the clone operation fails

Since:

3.0

compare

public static <T extends Comparable<? super T>> int compare(T c1,
 T c2)

Null safe comparison of Comparables. null is assumed to be less than a non-null value.

TODO Move to ComparableUtils.

Type Parameters:

T - type of the values processed by this method

Parameters:

c1 - the first comparable, may be null

c2 - the second comparable, may be null

Returns:

a negative value if c1 < c2, zero if c1 = c2 and a positive value if c1 > c2

compare

public static <T extends Comparable<? super T>> int compare(T c1,
 T c2,
 boolean nullGreater)

Null safe comparison of Comparables.

TODO Move to ComparableUtils.

Type Parameters:

T - type of the values processed by this method

Parameters:

c1 - the first comparable, may be null

c2 - the second comparable, may be null

nullGreater - if true null is considered greater than a non-null value or if false null is considered less than a Non-null value

Returns:

a negative value if c1 < c2, zero if c1 = c2 and a positive value if c1 > c2

See Also:

• Comparator.compare(Object, Object)

CONST

public static boolean CONST(boolean v)

Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,

     public final static boolean MAGIC_FLAG = ObjectUtils.CONST(true);
 

This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.

Parameters:

v - the boolean value to return

Returns:

the boolean v, unchanged

Since:

3.2

CONST

public static byte CONST(byte v)

Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,

     public final static byte MAGIC_BYTE = ObjectUtils.CONST((byte) 127);
 

This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.

Parameters:

v - the byte value to return

Returns:

the byte v, unchanged

Since:

3.2

CONST

public static char CONST(char v)

Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,

     public final static char MAGIC_CHAR = ObjectUtils.CONST('a');
 

This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.

Parameters:

v - the char value to return

Returns:

the char v, unchanged

Since:

3.2

CONST

public static double CONST(double v)

Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,

     public final static double MAGIC_DOUBLE = ObjectUtils.CONST(1.0);
 

This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.

Parameters:

v - the double value to return

Returns:

the double v, unchanged

Since:

3.2

CONST

public static float CONST(float v)

Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,

     public final static float MAGIC_FLOAT = ObjectUtils.CONST(1.0f);
 

This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.

Parameters:

v - the float value to return

Returns:

the float v, unchanged

Since:

3.2

CONST

public static int CONST(int v)

Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,

     public final static int MAGIC_INT = ObjectUtils.CONST(123);
 

This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.

Parameters:

v - the int value to return

Returns:

the int v, unchanged

Since:

3.2

CONST

public static long CONST(long v)

Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,

     public final static long MAGIC_LONG = ObjectUtils.CONST(123L);
 

This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.

Parameters:

v - the long value to return

Returns:

the long v, unchanged

Since:

3.2

CONST

public static short CONST(short v)

Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,

     public final static short MAGIC_SHORT = ObjectUtils.CONST((short) 123);
 

This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.

Parameters:

v - the short value to return

Returns:

the short v, unchanged

Since:

3.2

CONST

public static <T> T CONST(T v)

Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,

     public final static String MAGIC_STRING = ObjectUtils.CONST("abc");
 

This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.

Type Parameters:

T - the Object type

Parameters:

v - the genericized Object value to return (typically a String).

Returns:

the genericized Object v, unchanged (typically a String).

Since:

3.2

CONST_BYTE

public static byte CONST_BYTE(int v)

Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,

     public final static byte MAGIC_BYTE = ObjectUtils.CONST_BYTE(127);
 

This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.

Parameters:

v - the byte literal (as an int) value to return

Returns:

the byte v, unchanged

Throws:

IllegalArgumentException - if the value passed to v is larger than a byte, that is, smaller than -128 or larger than 127.

Since:

3.2

CONST_SHORT

public static short CONST_SHORT(int v)

Returns the provided value unchanged. This can prevent javac from inlining a constant field, e.g.,

     public final static short MAGIC_SHORT = ObjectUtils.CONST_SHORT(127);
 

This way any jars that refer to this field do not have to recompile themselves if the field's value changes at some future date.

Parameters:

v - the short literal (as an int) value to return

Returns:

the byte v, unchanged

Throws:

IllegalArgumentException - if the value passed to v is larger than a short, that is, smaller than -32768 or larger than 32767.

Since:

3.2

defaultIfNull

public static <T> T defaultIfNull(T object,
 T 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
 

Type Parameters:

T - the type of the object

Parameters:

object - the Object to test, may be null

defaultValue - the default value to return, may be null

Returns:

object if it is not null, defaultValue otherwise TODO Rename to getIfNull in 4.0

equals

@Deprecated
public static boolean equals(Object object1,
 Object object2)

Deprecated.

this method has been replaced by java.util.Objects.equals(Object, Object) in Java 7 and will be removed from future releases.

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
 

Parameters:

object1 - the first object, may be null

object2 - the second object, may be null

Returns:

true if the values of both objects are the same

firstNonNull

@SafeVarargs
public static <T> T firstNonNull(T... values)

Returns the first value in the array which is not null. If all the values are null or the array is null or empty then null is returned.

 ObjectUtils.firstNonNull(null, null)      = null
 ObjectUtils.firstNonNull(null, "")        = ""
 ObjectUtils.firstNonNull(null, null, "")  = ""
 ObjectUtils.firstNonNull(null, "zz")      = "zz"
 ObjectUtils.firstNonNull("abc", *)        = "abc"
 ObjectUtils.firstNonNull(null, "xyz", *)  = "xyz"
 ObjectUtils.firstNonNull(Boolean.TRUE, *) = Boolean.TRUE
 ObjectUtils.firstNonNull()                = null
 

Type Parameters:

T - the component type of the array

Parameters:

values - the values to test, may be null or empty

Returns:

the first value from values which is not null, or null if there are no non-null values

Since:

3.0

getClass

public static <T> Class<T> getClass(T object)

Delegates to Object.getClass() using generics.

Type Parameters:

T - The argument type or null.

Parameters:

object - The argument.

Returns:

The argument's Class or null.

Since:

3.13.0

getFirstNonNull

@SafeVarargs
public static <T> T getFirstNonNull(Supplier<T>... suppliers)

Executes the given suppliers in order and returns the first return value where a value other than null is returned. Once a non-null value is obtained, all following suppliers are not executed anymore. If all the return values are null or no suppliers are provided then null is returned.

 ObjectUtils.firstNonNullLazy(null, () -> null) = null
 ObjectUtils.firstNonNullLazy(() -> null, () -> "") = ""
 ObjectUtils.firstNonNullLazy(() -> "", () -> throw new IllegalStateException()) = ""
 ObjectUtils.firstNonNullLazy(() -> null, () -> "zz) = "zz"
 ObjectUtils.firstNonNullLazy() = null
 

Type Parameters:

T - the type of the return values

Parameters:

suppliers - the suppliers returning the values to test. null values are ignored. Suppliers may return null or a value of type T

Returns:

the first return value from suppliers which is not null, or null if there are no non-null values

Since:

3.10

getIfNull

public static <T> T getIfNull(T object,
 Supplier<T> defaultSupplier)

Returns the given object is it is non-null, otherwise returns the Supplier's Supplier.get() value.

The caller responsible for thread-safety and exception handling of default value supplier.

 ObjectUtils.getIfNull(null, () -> null)     = null
 ObjectUtils.getIfNull(null, null)              = null
 ObjectUtils.getIfNull(null, () -> "")       = ""
 ObjectUtils.getIfNull(null, () -> "zz")     = "zz"
 ObjectUtils.getIfNull("abc", *)                = "abc"
 ObjectUtils.getIfNull(Boolean.TRUE, *)         = Boolean.TRUE
 

Type Parameters:

T - the type of the object

Parameters:

object - the Object to test, may be null

defaultSupplier - the default value to return, may be null

Returns:

object if it is not null, defaultValueSupplier.get() otherwise

Since:

3.10

hashCode

@Deprecated
public static int hashCode(Object obj)

Deprecated.

this method has been replaced by java.util.Objects.hashCode(Object) in Java 7 and will be removed in future releases

Gets the hash code of an object returning zero when the object is null.

 ObjectUtils.hashCode(null)   = 0
 ObjectUtils.hashCode(obj)    = obj.hashCode()
 

Parameters:

obj - the object to obtain the hash code of, may be null

Returns:

the hash code of the object, or zero if null

Since:

2.1

hashCodeHex

public static String hashCodeHex(Object object)

Returns the hexadecimal hash code for the given object per Objects.hashCode(Object).

Short hand for Integer.toHexString(Objects.hashCode(object)).

Parameters:

object - object for which the hashCode is to be calculated

Returns:

Hash code in hexadecimal format.

Since:

3.13.0

hashCodeMulti

@Deprecated
public static int hashCodeMulti(Object... objects)

Deprecated.

this method has been replaced by java.util.Objects.hash(Object...) in Java 7 and will be removed in future releases.

Gets the hash code for multiple objects.

This allows a hash code to be rapidly calculated for a number of objects. The hash code for a single object is the not same as hashCode(Object). The hash code for multiple objects is the same as that calculated by an ArrayList containing the specified objects.

 ObjectUtils.hashCodeMulti()                 = 1
 ObjectUtils.hashCodeMulti((Object[]) null)  = 1
 ObjectUtils.hashCodeMulti(a)                = 31 + a.hashCode()
 ObjectUtils.hashCodeMulti(a,b)              = (31 + a.hashCode()) * 31 + b.hashCode()
 ObjectUtils.hashCodeMulti(a,b,c)            = ((31 + a.hashCode()) * 31 + b.hashCode()) * 31 + c.hashCode()
 

Parameters:

objects - the objects to obtain the hash code of, may be null

Returns:

the hash code of the objects, or zero if null

Since:

3.0

identityHashCodeHex

public static String identityHashCodeHex(Object object)

Returns the hexadecimal hash code for the given object per System.identityHashCode(Object).

Short hand for Integer.toHexString(System.identityHashCode(object)).

Parameters:

object - object for which the hashCode is to be calculated

Returns:

Hash code in hexadecimal format.

Since:

3.13.0

identityToString

public static void identityToString(Appendable appendable,
 Object object)
                             throws IOException

Appends the toString that would be produced by Object if a class did not override toString itself. null will throw a NullPointerException for either of the two parameters.

 ObjectUtils.identityToString(appendable, "")            = appendable.append("java.lang.String@1e23")
 ObjectUtils.identityToString(appendable, Boolean.TRUE)  = appendable.append("java.lang.Boolean@7fa")
 ObjectUtils.identityToString(appendable, Boolean.TRUE)  = appendable.append("java.lang.Boolean@7fa")
 

Parameters:

appendable - the appendable to append to

object - the object to create a toString for

Throws:

IOException - if an I/O error occurs.

Since:

3.2

identityToString

public static String identityToString(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"
 

Parameters:

object - the object to create a toString for, may be null

Returns:

the default toString text, or null if null passed in

identityToString

@Deprecated
public static void identityToString(StrBuilder builder,
 Object object)

Deprecated.

as of 3.6, because StrBuilder was moved to commons-text, use one of the other identityToString methods instead

Appends the toString that would be produced by Object if a class did not override toString itself. null will throw a NullPointerException for either of the two parameters.

 ObjectUtils.identityToString(builder, "")            = builder.append("java.lang.String@1e23")
 ObjectUtils.identityToString(builder, Boolean.TRUE)  = builder.append("java.lang.Boolean@7fa")
 ObjectUtils.identityToString(builder, Boolean.TRUE)  = builder.append("java.lang.Boolean@7fa")
 

Parameters:

builder - the builder to append to

object - the object to create a toString for

Since:

3.2

identityToString

public static void identityToString(StringBuffer buffer,
 Object object)

Appends the toString that would be produced by Object if a class did not override toString itself. null will throw a NullPointerException for either of the two parameters.

 ObjectUtils.identityToString(buf, "")            = buf.append("java.lang.String@1e23")
 ObjectUtils.identityToString(buf, Boolean.TRUE)  = buf.append("java.lang.Boolean@7fa")
 ObjectUtils.identityToString(buf, Boolean.TRUE)  = buf.append("java.lang.Boolean@7fa")
 

Parameters:

buffer - the buffer to append to

object - the object to create a toString for

Since:

2.4

identityToString

public static void identityToString(StringBuilder builder,
 Object object)

Appends the toString that would be produced by Object if a class did not override toString itself. null will throw a NullPointerException for either of the two parameters.

 ObjectUtils.identityToString(builder, "")            = builder.append("java.lang.String@1e23")
 ObjectUtils.identityToString(builder, Boolean.TRUE)  = builder.append("java.lang.Boolean@7fa")
 ObjectUtils.identityToString(builder, Boolean.TRUE)  = builder.append("java.lang.Boolean@7fa")
 

Parameters:

builder - the builder to append to

object - the object to create a toString for

Since:

3.2

isArray

public static boolean isArray(Object object)

Tests whether the given object is an Object array or a primitive array in a null-safe manner.

A null object Object will return false.

 ObjectUtils.isArray(null)             = false
 ObjectUtils.isArray("")               = false
 ObjectUtils.isArray("ab")             = false
 ObjectUtils.isArray(new int[]{})      = true
 ObjectUtils.isArray(new int[]{1,2,3}) = true
 ObjectUtils.isArray(1234)             = false
 

Parameters:

object - the object to check, may be null

Returns:

true if the object is an array, false otherwise

Since:

3.13.0

isEmpty

public static boolean isEmpty(Object object)

Tests if an Object is empty or null. The following types are supported:

• CharSequence: Considered empty if its length is zero.
• Array: Considered empty if its length is zero.
• Collection: Considered empty if it has zero elements.
• Map: Considered empty if it has zero key-value mappings.
• Optional: Considered empty if Optional.isPresent() returns false, regardless of the "emptiness" of the contents.

 ObjectUtils.isEmpty(null)             = true
 ObjectUtils.isEmpty("")               = true
 ObjectUtils.isEmpty("ab")             = false
 ObjectUtils.isEmpty(new int[]{})      = true
 ObjectUtils.isEmpty(new int[]{1,2,3}) = false
 ObjectUtils.isEmpty(1234)             = false
 ObjectUtils.isEmpty(1234)             = false
 ObjectUtils.isEmpty(Optional.of(""))  = false
 ObjectUtils.isEmpty(Optional.empty()) = true
 

Parameters:

object - the Object to test, may be null

Returns:

true if the object has a supported type and is empty or null, false otherwise

Since:

3.9

isNotEmpty

public static boolean isNotEmpty(Object object)

Tests if an Object is not empty and not null. The following types are supported:

• CharSequence: Considered empty if its length is zero.
• Array: Considered empty if its length is zero.
• Collection: Considered empty if it has zero elements.
• Map: Considered empty if it has zero key-value mappings.
• Optional: Considered empty if Optional.isPresent() returns false, regardless of the "emptiness" of the contents.

 ObjectUtils.isNotEmpty(null)             = false
 ObjectUtils.isNotEmpty("")               = false
 ObjectUtils.isNotEmpty("ab")             = true
 ObjectUtils.isNotEmpty(new int[]{})      = false
 ObjectUtils.isNotEmpty(new int[]{1,2,3}) = true
 ObjectUtils.isNotEmpty(1234)             = true
 ObjectUtils.isNotEmpty(Optional.of(""))  = true
 ObjectUtils.isNotEmpty(Optional.empty()) = false
 

Parameters:

object - the Object to test, may be null

Returns:

true if the object has an unsupported type or is not empty and not null, false otherwise

Since:

3.9

max

@SafeVarargs
public static <T extends Comparable<? super T>> T max(T... values)

Null safe comparison of Comparables.

TODO Move to ComparableUtils.

Type Parameters:

T - type of the values processed by this method

Parameters:

values - the set of comparable values, may be null

Returns:

• If any objects are non-null and unequal, the greater object.
• If all objects are non-null and equal, the first.
• If any of the comparables are null, the greater of the non-null objects.
• If all the comparables are null, null is returned.

median

@SafeVarargs
public static <T> T median(Comparator<T> comparator,
 T... items)

Find the "best guess" middle value among comparables. If there is an even number of total values, the lower of the two middle values will be returned.

Type Parameters:

T - type of values processed by this method

Parameters:

comparator - to use for comparisons

items - to compare

Returns:

T at middle position

Throws:

NullPointerException - if items or comparator is null

IllegalArgumentException - if items is empty or contains null values

Since:

3.0.1

median

@SafeVarargs
public static <T extends Comparable<? super T>> T median(T... items)

Find the "best guess" middle value among comparables. If there is an even number of total values, the lower of the two middle values will be returned.

Type Parameters:

T - type of values processed by this method

Parameters:

items - to compare

Returns:

T at middle position

Throws:

NullPointerException - if items is null

IllegalArgumentException - if items is empty or contains null values

Since:

3.0.1

min

@SafeVarargs
public static <T extends Comparable<? super T>> T min(T... values)

Null safe comparison of Comparables.

TODO Move to ComparableUtils.

Type Parameters:

T - type of the values processed by this method

Parameters:

values - the set of comparable values, may be null

Returns:

• If any objects are non-null and unequal, the lesser object.
• If all objects are non-null and equal, the first.
• If any of the comparables are null, the lesser of the non-null objects.
• If all the comparables are null, null is returned.

mode

@SafeVarargs
public static <T> T mode(T... items)

Find the most frequently occurring item.

Type Parameters:

T - type of values processed by this method

Parameters:

items - to check

Returns:

most populous T, null if non-unique or no items supplied

Since:

3.0.1

notEqual

public static boolean notEqual(Object object1,
 Object object2)

Compares two objects for inequality, where either one or both objects may be null.

 ObjectUtils.notEqual(null, null)                  = false
 ObjectUtils.notEqual(null, "")                    = true
 ObjectUtils.notEqual("", null)                    = true
 ObjectUtils.notEqual("", "")                      = false
 ObjectUtils.notEqual(Boolean.TRUE, null)          = true
 ObjectUtils.notEqual(Boolean.TRUE, "true")        = true
 ObjectUtils.notEqual(Boolean.TRUE, Boolean.TRUE)  = false
 ObjectUtils.notEqual(Boolean.TRUE, Boolean.FALSE) = true
 

Parameters:

object1 - the first object, may be null

object2 - the second object, may be null

Returns:

false if the values of both objects are the same

requireNonEmpty

public static <T> T requireNonEmpty(T obj)

Checks that the specified object reference is not null or empty per isEmpty(Object). Use this method for validation, for example:

 public Foo(Bar bar) {
     this.bar = Objects.requireNonEmpty(bar);
 }
 

Type Parameters:

T - the type of the reference.

Parameters:

obj - the object reference to check for nullity.

Returns:

obj if not null.

Throws:

NullPointerException - if obj is null.

IllegalArgumentException - if obj is empty per isEmpty(Object).

Since:

3.12.0

See Also:

• isEmpty(Object)

requireNonEmpty

public static <T> T requireNonEmpty(T obj,
 String message)

Checks that the specified object reference is not null or empty per isEmpty(Object). Use this method for validation, for example:

 public Foo(Bar bar) {
     this.bar = Objects.requireNonEmpty(bar, "bar");
 }
 

Type Parameters:

T - the type of the reference.

Parameters:

obj - the object reference to check for nullity.

message - the exception message.

Returns:

obj if not null.

Throws:

NullPointerException - if obj is null.

IllegalArgumentException - if obj is empty per isEmpty(Object).

Since:

3.12.0

See Also:

• isEmpty(Object)

toString

@Deprecated
public static String toString(Object obj)

Deprecated.

this method has been replaced by java.util.Objects.toString(Object) in Java 7 and will be removed in future releases. Note however that said method will return "null" for null references, while this method returns an empty String. To preserve behavior use java.util.Objects.toString(myObject, "")

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"
 

Parameters:

obj - the Object to toString, may be null

Returns:

the passed in Object's toString, or "" if null input

Since:

2.0

See Also:

• Objects.toString(Object)
• Objects.toString(Object, String)
• StringUtils.defaultString(String)
• String.valueOf(Object)

toString

@Deprecated
public static String toString(Object obj,
 String nullStr)

Deprecated.

this method has been replaced by java.util.Objects.toString(Object, String) in Java 7 and will be removed in future releases.

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"
 

Parameters:

obj - the Object to toString, may be null

nullStr - the String to return if null input, may be null

Returns:

the passed in Object's toString, or nullStr if null input

Since:

2.0

See Also:

• Objects.toString(Object)
• Objects.toString(Object, String)
• StringUtils.defaultString(String,String)
• String.valueOf(Object)

toString

public static String toString(Supplier<Object> obj,
 Supplier<String> supplier)

Gets the toString of an Supplier's Supplier.get() returning a specified text if null input.

 ObjectUtils.toString(() -> obj, () -> expensive())
 

 ObjectUtils.toString(() -> null, () -> expensive())         = result of expensive()
 ObjectUtils.toString(() -> null, () -> expensive())         = result of expensive()
 ObjectUtils.toString(() -> "", () -> expensive())           = ""
 ObjectUtils.toString(() -> "bat", () -> expensive())        = "bat"
 ObjectUtils.toString(() -> Boolean.TRUE, () -> expensive()) = "true"
 

Parameters:

obj - the Object to toString, may be null

supplier - the Supplier of String used on null input, may be null

Returns:

the passed in Object's toString, or nullStr if null input

Since:

3.14.0

toString

public static <T> String toString(T obj,
 Supplier<String> supplier)

Gets the toString of an Object returning a specified text if null input.

 ObjectUtils.toString(obj, () -> expensive())
 

 ObjectUtils.toString(null, () -> expensive())         = result of expensive()
 ObjectUtils.toString(null, () -> expensive())         = result of expensive()
 ObjectUtils.toString("", () -> expensive())           = ""
 ObjectUtils.toString("bat", () -> expensive())        = "bat"
 ObjectUtils.toString(Boolean.TRUE, () -> expensive()) = "true"
 

Type Parameters:

T - the obj type (used to provide better source compatibility in 3.14.0).

Parameters:

obj - the Object to toString, may be null

supplier - the Supplier of String used on null input, may be null

Returns:

the passed in Object's toString, or nullStr if null input

Since:

3.11

wait

public static void wait(Object obj,
 Duration duration)
                 throws InterruptedException

Calls Object.wait(long, int) for the given Duration.

Parameters:

obj - The receiver of the wait call.

duration - How long to wait.

Throws:

IllegalArgumentException - if the timeout duration is negative.

IllegalMonitorStateException - if the current thread is not the owner of the obj's monitor.

InterruptedException - if any thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.

Since:

3.12.0

See Also:

• Object.wait(long, int)