io.flutter.util

Class Preconditions

java.lang.Object

io.flutter.util.Preconditions

public final class Preconditions
extends Object

Static convenience methods that help a method or constructor check whether it was invoked correctly (that is, whether its preconditions were met).

Method Summary

Modifier and Type	Method and Description
static <T> T	checkNotNull(T reference) Ensures that an object reference passed as a parameter to the calling method is not null.
static void	checkState(boolean expression) Ensures the truth of an expression involving the state of the calling instance.
static void	checkState(boolean expression, Object errorMessage) Ensures the truth of an expression involving the state of the calling instance.

Methods inherited from class java.lang.Object

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

Method Detail

checkNotNull

public static <T> T checkNotNull(T reference)

Ensures that an object reference passed as a parameter to the calling method is not null.

Parameters:

reference - an object reference

Returns:

the non-null reference that was validated

Throws:

NullPointerException - if reference is null

checkState

public static void checkState(boolean expression)

Ensures the truth of an expression involving the state of the calling instance.

Parameters:

expression - a boolean expression that must be checked to be true

Throws:

IllegalStateException - if expression is false

checkState

public static void checkState(boolean expression,
                              @Nullable
                              Object errorMessage)

Ensures the truth of an expression involving the state of the calling instance.

Parameters:

expression - a boolean expression that must be checked to be true

errorMessage - the exception message to use if the check fails; will be converted to a string using String.valueOf(Object)

Throws:

IllegalStateException - if expression is false