org.hamcrest.core
Class DescribedAs<T>

java.lang.Object
  org.hamcrest.BaseMatcher<T>
      org.hamcrest.core.DescribedAs<T>

All Implemented Interfaces:

Matcher<T>, SelfDescribing

public class DescribedAs<T>
extends BaseMatcher<T>

Provides a custom description to another matcher.

Constructor Summary

DescribedAs(String descriptionTemplate, Matcher<T> matcher, Object[] values)

Method Summary

static <T> Matcher<T>	describedAs(String description, Matcher<T> matcher, Object... values) Wraps an existing matcher, overriding its description with that specified.
void	describeMismatch(Object item, Description description) Generate a description of why the matcher has not accepted the item.
void	describeTo(Description description) Generates a description of the object.
boolean	matches(Object o) 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

DescribedAs

public DescribedAs(String descriptionTemplate,
                   Matcher<T> matcher,
                   Object[] values)

Method Detail

matches

public boolean matches(Object o)

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:

o - 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 description)

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.

description - The description to be built or appended to.

describedAs

public static <T> Matcher<T> describedAs(String description,
                                         Matcher<T> matcher,
                                         Object... values)

Wraps an existing matcher, overriding its description with that specified. All other functions are delegated to the decorated matcher, including its mismatch description.

For example:

describedAs("a big decimal equal to %0", equalTo(myBigDecimal), myBigDecimal.toPlainString())

Parameters:

description - the new description for the wrapped matcher

matcher - the matcher to wrap

values - optional values to insert into the tokenised description