FeatureMatcher (JUnit API 文档)

java.lang.Object
- org.hamcrest.BaseMatcher<T>
- - org.hamcrest.TypeSafeDiagnosingMatcher<T>
  - - org.hamcrest.FeatureMatcher<T,U>

Type Parameters:
T - The type of the object to be matched
U - The type of the feature to be matched
All Implemented Interfaces:
Matcher<T>, SelfDescribing
```
public abstract class FeatureMatcher<T,U>
extends TypeSafeDiagnosingMatcher<T>
```
Supporting class for matching a feature of an object. Implement featureValueOf() in a subclass to pull out the feature to be matched against.

Constructor Summary
Constructors
Constructor Description
FeatureMatcher(Matcher<? super U> subMatcher, String featureDescription, String featureName)
Constructor

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`describeTo(Description description)`	Generates a description of the object.
`protected abstract U`	`featureValueOf(T actual)`	Implement this to extract the interesting feature.
`protected boolean`	`matchesSafely(T actual, Description mismatch)`	Subclasses should implement this.

Methods inherited from class org.hamcrest.TypeSafeDiagnosingMatcher
describeMismatch, matches

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
  - FeatureMatcher
```
public FeatureMatcher(Matcher<? super U> subMatcher,
                      String featureDescription,
                      String featureName)
```
    Constructor
    Parameters:
    subMatcher - The matcher to apply to the feature
    featureDescription - Descriptive text to use in describeTo
    featureName - Identifying text for mismatch message
- Method Detail
  - featureValueOf
```
protected abstract U featureValueOf(T actual)
```
    Implement this to extract the interesting feature.
    Parameters:
    actual - the target object
    Returns:
    the feature to be matched
  - matchesSafely
```
protected boolean matchesSafely(T actual,
                                Description mismatch)
```
    Description copied from class: TypeSafeDiagnosingMatcher
    Subclasses should implement this. The item will already have been checked for the specific type and will never be null.
    Specified by:
    matchesSafely in class TypeSafeDiagnosingMatcher<T>
  - describeTo
```
public final 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.