Package com.google.common.base
Class MoreObjects
- java.lang.Object
-
- com.google.common.base.MoreObjects
-
@GwtCompatible public final class MoreObjects extends java.lang.Object
Helper functions that operate on anyObject
, and are not already provided inObjects
.See the Guava User Guide on writing
Object
methods withMoreObjects
.- Since:
- 18.0 (since 2.0 as
Objects
) - Author:
- Laurence Gonsalves
-
-
Nested Class Summary
Nested Classes Modifier and Type Class Description static class
MoreObjects.ToStringHelper
Support class fortoStringHelper(java.lang.Object)
.
-
Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static <T> T
firstNonNull(T first, T second)
Returns the first of two given parameters that is notnull
, if either is, or otherwise throws aNullPointerException
.static MoreObjects.ToStringHelper
toStringHelper(java.lang.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(java.lang.Object self)
Creates an instance ofMoreObjects.ToStringHelper
.static MoreObjects.ToStringHelper
toStringHelper(java.lang.String className)
Creates an instance ofMoreObjects.ToStringHelper
in the same manner astoStringHelper(Object)
, but usingclassName
instead of using an instance'sObject.getClass()
.
-
-
-
Method Detail
-
firstNonNull
public static <T> T firstNonNull(@CheckForNull T first, @CheckForNull T second)
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:
java.lang.NullPointerException
- if bothfirst
andsecond
are null- Since:
- 18.0 (since 3.0 as
Objects.firstNonNull()
).
-
toStringHelper
public static MoreObjects.ToStringHelper toStringHelper(java.lang.Object self)
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
public static MoreObjects.ToStringHelper toStringHelper(java.lang.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()
.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
public static MoreObjects.ToStringHelper toStringHelper(java.lang.String className)
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()
).
-
-