BoundedMatcher.java
/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.test.espresso.matcher;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import org.hamcrest.BaseMatcher;
import org.hamcrest.Description;
/**
* Some matcher sugar that lets you create a matcher for a given type but only process items of a
* specific subtype of that matcher.
*
* <p>Use {@link BoundedDiagnosingMatcher} for better diagnostic messages when a mismatch happens.
*
* @param <T> The desired type of the Matcher.
* @param <S> the subtype of T that your matcher applies safely to.
*/
public abstract class BoundedMatcher<T, S extends T> extends BaseMatcher<T> {
private final Class<?> expectedType;
private final Class<?>[] interfaceTypes;
public BoundedMatcher(Class<? extends S> expectedType) {
this.expectedType = checkNotNull(expectedType);
this.interfaceTypes = new Class<?>[0];
}
public BoundedMatcher(
Class<?> expectedType, Class<?> interfaceType1, Class<?>... otherInterfaces) {
this.expectedType = checkNotNull(expectedType);
checkNotNull(otherInterfaces);
int interfaceCount = otherInterfaces.length + 1;
this.interfaceTypes = new Class<?>[interfaceCount];
interfaceTypes[0] = checkNotNull(interfaceType1);
checkArgument(interfaceType1.isInterface());
int interfaceTypeIdx = 1;
for (Class<?> intfType : otherInterfaces) {
interfaceTypes[interfaceTypeIdx] = checkNotNull(intfType);
checkArgument(intfType.isInterface());
interfaceTypeIdx++;
}
}
protected abstract boolean matchesSafely(S item);
@Override
@SuppressWarnings({"unchecked"})
public final boolean matches(Object item) {
if (item == null) {
return false;
}
if (expectedType.isInstance(item)) {
for (Class<?> intfType : interfaceTypes) {
if (!intfType.isInstance(item)) {
return false;
}
}
return matchesSafely((S) item);
}
return false;
}
@Override
@SuppressWarnings({"unchecked"})
public void describeMismatch(Object item, Description description) {
if (item == null) {
description.appendText("item was null");
return;
}
if (!expectedType.isInstance(item)) {
description.appendText("item does not extend ").appendText(expectedType.getName());
return;
}
for (Class<?> intfType : interfaceTypes) {
if (!intfType.isInstance(item)) {
description.appendText("item does not implement ").appendText(intfType.getName());
return;
}
}
}
}