Class MoreObjects
java.lang.Object
com.google.common.base.MoreObjects
Helper functions that operate on any
Object
, and are not already provided in Objects
.
See the Guava User Guide on writing Object
methods with MoreObjects
.
- Since:
- 18.0 (since 2.0 as
Objects
) - Author:
- Laurence Gonsalves
-
Nested Class Summary
Modifier and TypeClassDescriptionstatic final class
Support class fortoStringHelper(java.lang.Object)
. -
Method Summary
Modifier and TypeMethodDescriptionstatic <T> T
firstNonNull
(@Nullable T first, @Nullable T second) Returns the first of two given parameters that is notnull
, if either is, or otherwise throws aNullPointerException
.static MoreObjects.ToStringHelper
toStringHelper
(Class<?> clazz) Creates an instance ofMoreObjects.ToStringHelper
in the same manner astoStringHelper(Object)
, but using the simple name ofclazz
instead of using an instance'sObject.getClass()
.static MoreObjects.ToStringHelper
toStringHelper
(Object self) Creates an instance ofMoreObjects.ToStringHelper
.static MoreObjects.ToStringHelper
toStringHelper
(String className) Creates an instance ofMoreObjects.ToStringHelper
in the same manner astoStringHelper(Object)
, but usingclassName
instead of using an instance'sObject.getClass()
.
-
Method Details
-
firstNonNull
Returns the first of two given parameters that is notnull
, if either is, or otherwise throws aNullPointerException
.To find the first non-null element in an iterable, use
Iterables.find(iterable, Predicates.notNull())
. For varargs, useIterables.find(Arrays.asList(a, b, c, ...), Predicates.notNull())
, static importing as necessary.Note: if
first
is represented as anOptional
, this can be accomplished withfirst.or(second)
. That approach also allows for lazy evaluation of the fallback instance, usingfirst.or(supplier)
.Java 9 users: use
java.util.Objects.requireNonNullElse(first, second)
instead.- Returns:
first
if it is non-null; otherwisesecond
if it is non-null- Throws:
NullPointerException
- if bothfirst
andsecond
are null- Since:
- 18.0 (since 3.0 as
Objects.firstNonNull()
).
-
toStringHelper
Creates an instance ofMoreObjects.ToStringHelper
.This is helpful for implementing
Object.toString()
. Specification by example:// Returns "ClassName{}" MoreObjects.toStringHelper(this) .toString(); // Returns "ClassName{x=1}" MoreObjects.toStringHelper(this) .add("x", 1) .toString(); // Returns "MyObject{x=1}" MoreObjects.toStringHelper("MyObject") .add("x", 1) .toString(); // Returns "ClassName{x=1, y=foo}" MoreObjects.toStringHelper(this) .add("x", 1) .add("y", "foo") .toString(); // Returns "ClassName{x=1}" MoreObjects.toStringHelper(this) .omitNullValues() .add("x", 1) .add("y", null) .toString();
Note that in GWT, class names are often obfuscated.
- Parameters:
self
- the object to generate the string for (typicallythis
), used only for its class name- Since:
- 18.0 (since 2.0 as
Objects.toStringHelper()
).
-
toStringHelper
Creates an instance ofMoreObjects.ToStringHelper
in the same manner astoStringHelper(Object)
, but using the simple name ofclazz
instead of using an instance'sObject.getClass()
.Note that in GWT, class names are often obfuscated.
- Parameters:
clazz
- theClass
of the instance- Since:
- 18.0 (since 7.0 as
Objects.toStringHelper()
).
-
toStringHelper
Creates an instance ofMoreObjects.ToStringHelper
in the same manner astoStringHelper(Object)
, but usingclassName
instead of using an instance'sObject.getClass()
.- Parameters:
className
- the name of the instance type- Since:
- 18.0 (since 7.0 as
Objects.toStringHelper()
).
-