Class Objects
Object
.
See the Guava User Guide on
writing
Object
methods with Objects
.
- Since:
- 2.0
-
Nested Class Summary
Nested Classes -
Method Summary
Modifier and TypeMethodDescriptionstatic boolean
Determines whether two possibly-null objects are equal.static <T> T
firstNonNull
(T first, T second) Deprecated.UseMoreObjects.firstNonNull(T, T)
instead.static int
Generates a hash code for multiple values.static Objects.ToStringHelper
toStringHelper
(Class<?> clazz) Deprecated.UseMoreObjects.toStringHelper(Class)
instead.static Objects.ToStringHelper
toStringHelper
(Object self) Deprecated.UseMoreObjects.toStringHelper(Object)
instead.static Objects.ToStringHelper
toStringHelper
(String className) Deprecated.UseMoreObjects.toStringHelper(String)
instead.
-
Method Details
-
equal
Determines whether two possibly-null objects are equal. Returns:true
ifa
andb
are both null.true
ifa
andb
are both non-null and they are equal according toObject.equals(Object)
.false
in all other situations.
This assumes that any non-null objects passed to this function conform to the
equals()
contract.Note for Java 7 and later: This method should be treated as deprecated; use
Objects.equals(java.lang.Object, java.lang.Object)
instead. -
hashCode
Generates a hash code for multiple values. The hash code is generated by callingArrays.hashCode(Object[])
. Note that array arguments to this method, with the exception of a single Object array, do not get any special handling; their hash codes are based on identity and not contents.This is useful for implementing
Object.hashCode()
. For example, in an object that has three properties,x
,y
, andz
, one could write:public int hashCode() { return Objects.hashCode(getX(), getY(), getZ()); }
Warning: When a single object is supplied, the returned hash code does not equal the hash code of that object.
Note for Java 7 and later: This method should be treated as deprecated; use
Objects.hash(java.lang.Object...)
instead. -
toStringHelper
Deprecated.UseMoreObjects.toStringHelper(Object)
instead. This method is scheduled for removal in Guava 21.0.Creates an instance ofObjects.ToStringHelper
.This is helpful for implementing
Object.toString()
. Specification by example:// Returns "ClassName{}" Objects.toStringHelper(this) .toString(); // Returns "ClassName{x=1}" Objects.toStringHelper(this) .add("x", 1) .toString(); // Returns "MyObject{x=1}" Objects.toStringHelper("MyObject") .add("x", 1) .toString(); // Returns "ClassName{x=1, y=foo}" Objects.toStringHelper(this) .add("x", 1) .add("y", "foo") .toString(); // Returns "ClassName{x=1}" Objects.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:
- 2.0
-
toStringHelper
Deprecated.UseMoreObjects.toStringHelper(Class)
instead. This method is scheduled for removal in Guava 21.0.Creates an instance ofObjects.ToStringHelper
in the same manner astoStringHelper(Object)
, but using the 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:
- 7.0 (source-compatible since 2.0)
-
toStringHelper
Deprecated.UseMoreObjects.toStringHelper(String)
instead. This method is scheduled for removal in Guava 21.0.Creates an instance ofObjects.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:
- 7.0 (source-compatible since 2.0)
-
firstNonNull
Deprecated.UseMoreObjects.firstNonNull(T, T)
instead. This method is scheduled for removal in Guava 21.0.Returns the first of two given parameters that is notnull
, if either is, or otherwise throws aNullPointerException
.Note: if
first
is represented as anOptional
, this can be accomplished with first.or(second). That approach also allows for lazy evaluation of the fallback instance, using first.or(Supplier).- Returns:
first
iffirst
is notnull
, orsecond
iffirst
isnull
andsecond
is notnull
- Throws:
NullPointerException
- if bothfirst
andsecond
werenull
- Since:
- 3.0
-
MoreObjects.ToStringHelper
instead.