Class DiagnosingMatcher<T>

  extended by org.hamcrest.BaseMatcher<T>
      extended by org.hamcrest.DiagnosingMatcher<T>
Type Parameters:
T -
All Implemented Interfaces:
Matcher<T>, SelfDescribing
Direct Known Subclasses:
AllOf, IsInstanceOf

public abstract class DiagnosingMatcher<T>
extends BaseMatcher<T>

TODO(ngd): Document.

Constructor Summary
Method Summary
 void describeMismatch(Object item, Description mismatchDescription)
          Generate a description of why the matcher has not accepted the item.
 boolean matches(Object item)
          Evaluates the matcher for argument item.
protected abstract  boolean matches(Object item, Description mismatchDescription)
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
Methods inherited from interface org.hamcrest.SelfDescribing

Constructor Detail


public DiagnosingMatcher()
Method Detail


public final boolean matches(Object item)
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.

item - the object against which the matcher is evaluated.
true if item matches, otherwise false.
See Also:


public final 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>
describeMismatch in class BaseMatcher<T>
item - The item that the Matcher has rejected.
mismatchDescription - The description to be built or appended to.


protected abstract boolean matches(Object item,
                                   Description mismatchDescription)

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