org.hamcrest.core

Class Is<T>

java.lang.Object

org.hamcrest.BaseMatcher<T>

org.hamcrest.core.Is<T>

All Implemented Interfaces:

Matcher<T>, SelfDescribing

public class Is<T>
extends BaseMatcher<T>

Decorates another Matcher, retaining the behavior but allowing tests to be slightly more expressive. For example: assertThat(cheese, equalTo(smelly)) vs. assertThat(cheese, is(equalTo(smelly)))

Constructor Summary

Constructors

Constructor and Description
Is(Matcher<T> matcher)

Method Summary

Methods

Modifier and Type	Method and Description
void	describeMismatch(Object item, Description mismatchDescription) Generate a description of why the matcher has not accepted the item.
void	describeTo(Description description) Generates a description of the object.
static <T> Matcher<? super T>	is(Class<T> type) This is a shortcut to the frequently used is(instanceOf(SomeClass.class)).
static <T> Matcher<T>	is(Matcher<T> matcher) Decorates another Matcher, retaining the behavior but allowing tests to be slightly more expressive.
static <T> Matcher<? super T>	is(T value) This is a shortcut to the frequently used is(equalTo(x)).
boolean	matches(Object arg) Evaluates the matcher for argument item.

Methods inherited from class org.hamcrest.BaseMatcher

_dont_implement_Matcher___instead_extend_BaseMatcher_, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

Is

public Is(Matcher<T> matcher)

Method Detail

matches

public boolean matches(Object arg)

Description copied from interface: Matcher

Evaluates the matcher for argument item.

This method matches against Object, instead of the generic type T. This is because the caller of the Matcher does not know at runtime what the type is (because of type erasure with Java generics). It is down to the implementations to check the correct type.

Parameters:

arg - the object against which the matcher is evaluated.

Returns:

true if item matches, otherwise false.

See Also:

BaseMatcher

describeTo

public void describeTo(Description description)

Description copied from interface: SelfDescribing

Generates a description of the object. The description may be part of a a description of a larger object of which this is just a component, so it should be worded appropriately.

Parameters:

description - The description to be built or appended to.

describeMismatch

public void describeMismatch(Object item,
                    Description mismatchDescription)

Description copied from interface: Matcher

Generate a description of why the matcher has not accepted the item. The description will be part of a larger description of why a matching failed, so it should be concise. This method assumes that matches(item) is false, but will not check this.

Specified by:

describeMismatch in interface Matcher<T>

Overrides:

describeMismatch in class BaseMatcher<T>

Parameters:

item - The item that the Matcher has rejected.

mismatchDescription - The description to be built or appended to.

is

public static <T> Matcher<T> is(Matcher<T> matcher)

Decorates another Matcher, retaining the behavior but allowing tests to be slightly more expressive. For example: assertThat(cheese, equalTo(smelly)) vs. assertThat(cheese, is(equalTo(smelly)))

is

public static <T> Matcher<? super T> is(T value)

This is a shortcut to the frequently used is(equalTo(x)). For example: assertThat(cheese, is(equalTo(smelly))) vs. assertThat(cheese, is(smelly))

is

public static <T> Matcher<? super T> is(Class<T> type)

This is a shortcut to the frequently used is(instanceOf(SomeClass.class)). For example: assertThat(cheese, is(instanceOf(Cheddar.class))) vs. assertThat(cheese, is(Cheddar.class))