Class Preconditions (2.0.0)

public final class Preconditions

Simple static methods to be called at the start of your own methods to verify correct arguments and state. This allows constructs such as


 if (count <= 0)="" {="" throw="" new="" illegalargumentexception("must="" be="" positive:="" "="" +="" count);="" }="">

to be replaced with the more compact

     checkArgument(count > 0, "must be positive: %s", count);

Note that the sense of the expression is inverted; with Preconditions you declare what you expect to be true, just as you do with an assert or a JUnit assertTrue call.

Note:This class is a copy of a very old version of Guava's Preconditions. Please use the current Guava version instead. See Also: "https://google.github.io/guava/releases/21.0/api/docs/com/google/common/base/Preconditions.html"

Inheritance

java.lang.Object > Preconditions

Inherited Members

Object.clone()

Object.equals(Object)

Object.finalize()

Object.getClass()

Object.hashCode()

Object.notify()

Object.notifyAll()

Object.toString()

Object.wait()

Object.wait(long)

Object.wait(long,int)

Static Methods

<T>checkNotNull(T reference, @Nullable Object errorMessage)

public static T <T>checkNotNull(T reference, @Nullable Object errorMessage)

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

Parameters
Name	Description
`reference`	`T` an object reference
`errorMessage`	`@org.checkerframework.checker.nullness.qual.Nullable java.lang.Object` the exception message to use if the check fails; will be converted to a string using String#valueOf(Object)

Returns
Type	Description
`T`	the non-null reference that was validated

checkArgument(boolean expression, @Nullable Object errorMessage)

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

Ensures the truth of an expression involving one or more parameters to the calling method.

Parameters
Name	Description
`expression`	`boolean` a boolean expression
`errorMessage`	`@org.checkerframework.checker.nullness.qual.Nullable java.lang.Object` the exception message to use if the check fails; will be converted to a string using String#valueOf(Object) if not null (a null will not be converted).

checkArgument(boolean expression, @Nullable String errorMessageTemplate, @Nullable Object[] errorMessageArgs)

public static void checkArgument(boolean expression, @Nullable String errorMessageTemplate, @Nullable Object[] errorMessageArgs)

Ensures the truth of an expression involving one or more parameters to the calling method.

Parameters
Name	Description
`expression`	`boolean` a boolean expression
`errorMessageTemplate`	`@org.checkerframework.checker.nullness.qual.Nullable java.lang.String` a template for the exception message should the check fail. The message is formed using String#format(String, Object...). if not null (a null will not be converted).
`errorMessageArgs`	`@org.checkerframework.checker.nullness.qual.Nullable java.lang.Object[]` the arguments to be substituted into the message template.

checkState(boolean expression, @Nullable String errorMessage)

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

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

Parameters
Name	Description
`expression`	`boolean` a boolean expression
`errorMessage`	`@org.checkerframework.checker.nullness.qual.Nullable java.lang.String` the exception message to use if the check fails; will be converted to a string using String#valueOf(Object) if not null (a null will not be converted).

checkState(boolean expression, @Nullable String errorMessageTemplate, @Nullable Object[] errorMessageArgs)

public static void checkState(boolean expression, @Nullable String errorMessageTemplate, @Nullable Object[] errorMessageArgs)

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

Parameters
Name	Description
`expression`	`boolean` a boolean expression
`errorMessageTemplate`	`@org.checkerframework.checker.nullness.qual.Nullable java.lang.String` a template for the exception message should the check fail. The message is formed using String#format(String, Object...). if not null (a null will not be converted).
`errorMessageArgs`	`@org.checkerframework.checker.nullness.qual.Nullable java.lang.Object[]` the arguments to be substituted into the message template.