ObjectsCompat
class ObjectsCompat
This class consists of static utility methods for operating on objects.
Summary
Public functions |
|
|---|---|
java-static Boolean |
Returns |
java-static Int |
Generates a hash code for a sequence of input values. |
java-static Int |
Returns the hash code of a non- |
java-static T |
<T> requireNonNull(obj: T?)Checks that the specified object reference is not |
java-static T |
<T> requireNonNull(obj: T?, message: String)Checks that the specified object reference is not |
java-static String? |
Returns the result of calling |
Public functions
equals
java-static fun equals(a: Any?, b: Any?): Boolean
Returns true if the arguments are equal to each other and false otherwise.
Consequently, if both arguments are null, true is returned and if exactly one argument is null,
false is returned. Otherwise, equality is determined by using the equals method of the first argument.
| Returns | |
|---|---|
Boolean |
|
| See also | |
|---|---|
equals |
hash
java-static fun hash(values: Array<Any!>?): Int
Generates a hash code for a sequence of input values. The hash code is generated as if all the input values were placed into an array, and that array were hashed by calling hashCode.
This method is useful for implementing hashCode on objects containing multiple fields. For example, if an object that has three fields, x, y, and z, one could write:
Warning: When a single object reference is supplied, the returned value does not equal the hash code of that object reference. This value can be computed by calling @Override public int hashCode() { return ObjectsCompat.hash(x, y, z); }
hashCode.
| Returns | |
|---|---|
Int |
a hash value of the sequence of input values |
| See also | |
|---|---|
hashCode |
hashCode
java-static fun hashCode(o: Any?): Int
Returns the hash code of a non-null argument and 0 for a null argument.
| Parameters | |
|---|---|
o: Any? |
an object |
| Returns | |
|---|---|
Int |
the hash code of a non- |
| See also | |
|---|---|
hashCode |
requireNonNull
java-static fun <T> requireNonNull(obj: T?): T
Checks that the specified object reference is not null. This method is designed primarily for doing parameter validation in methods and constructors, as demonstrated below:
public Foo(Bar bar) { this.bar = Objects.requireNonNull(bar); }
| Parameters | |
|---|---|
<T> |
the type of the reference |
obj: T? |
the object reference to check for nullity |
| Returns | |
|---|---|
T |
|
| Throws | |
|---|---|
java.lang.NullPointerException |
if |
requireNonNull
java-static fun <T> requireNonNull(obj: T?, message: String): T
Checks that the specified object reference is not null and throws a customized NullPointerException if it is. This method is designed primarily for doing parameter validation in methods and constructors with multiple parameters, as demonstrated below:
public Foo(Bar bar, Baz baz) { this.bar = Objects.requireNonNull(bar, "bar must not be null"); this.baz = Objects.requireNonNull(baz, "baz must not be null"); }
| Parameters | |
|---|---|
<T> |
the type of the reference |
obj: T? |
the object reference to check for nullity |
message: String |
detail message to be used in the event that a |
| Returns | |
|---|---|
T |
|
| Throws | |
|---|---|
java.lang.NullPointerException |
if |
toString
java-static fun toString(o: Any?, nullDefault: String?): String?
Returns the result of calling toString on the first argument if the first argument is not null and returns the second argument otherwise.
| Returns | |
|---|---|
String? |
the result of calling |