Package org.apache.juneau.assertions

Class AssertionPredicate<T>

java.lang.Object

org.apache.juneau.assertions.AssertionPredicate<T>

Type Parameters:

T - the type of input being tested.

All Implemented Interfaces:

Predicate<T>

Direct Known Subclasses:

AssertionPredicate.And, AssertionPredicate.Not, AssertionPredicate.Or

public class AssertionPredicate<T>
extends Object
implements Predicate<T>

Wrapper around a Predicate that allows for an error message for when the predicate fails.

Typically used wherever predicates are allowed for testing of Assertion objects such as...

• FluentObjectAssertion.is(Predicate)
• FluentArrayAssertion.is(Predicate...)
• FluentPrimitiveArrayAssertion.is(Predicate...)
• FluentListAssertion.isEach(Predicate...)

See AssertionPredicates for a set of predefined predicates for common use cases.

Example:

// Asserts that a bean passes a custom test. // AssertionError with specified message is thrown otherwise. Predicate<MyBean> predicate = new AssertionPredicate<MyBean>( x -> x.getFoo().equals("bar"), "Foo did not equal bar. Bean was=''{0}''", VALUE ); assertObject(myBean).is(predicate);

See Also:

• Overview > juneau-assertions > Overview

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	AssertionPredicate.And<T>	Encapsulates multiple predicates into a single AND operation.
static class	AssertionPredicate.Not<T>	Negates an assertion.
static class	AssertionPredicate.Or<T>	Encapsulates multiple predicates into a single OR operation.

Field Summary

Fields

Modifier and Type	Field	Description
static final Function<Object,String>	VALUE	Argument placeholder for tested value.

Constructor Summary

Constructors

Constructor	Description
AssertionPredicate(Predicate<T> inner, String message, Object... args)	Constructor.

Method Summary

Modifier and Type	Method	Description
protected String	getFailureMessage()	Returns the error message from the last call to this assertion.
boolean	test(T t)

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.function.Predicate

and, negate, or

Field Details

VALUE

public static final Function<Object,String> VALUE

Argument placeholder for tested value.

Constructor Details

AssertionPredicate

public AssertionPredicate(Predicate<T> inner,
 String message,
 Object... args)

Constructor.

Parameters:

inner - The predicate test.

message - The error message if predicate fails.
Supports MessageFormat-style arguments.

args - Optional message arguments.
Can contain VALUE to specify the value itself as an argument.
Can contain functions to apply to the tested value.

Method Details

test

public boolean test(T t)

Specified by:

test in interface Predicate<T>

getFailureMessage

protected String getFailureMessage()

Returns the error message from the last call to this assertion.

Returns:

The error message, or null if there was no failure.