/
AbstractVerb.java
124 lines (105 loc) · 4.03 KB
/
AbstractVerb.java
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/*
* Copyright (c) 2011 Google, Inc.
*
* 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 com.google.common.truth;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.truth.StringUtil.format;
import javax.annotation.Nullable;
public abstract class AbstractVerb<T extends AbstractVerb<T>> {
private final FailureStrategy failureStrategy;
public AbstractVerb(FailureStrategy failureStrategy) {
this.failureStrategy = checkNotNull(failureStrategy);
}
protected FailureStrategy getFailureStrategy() {
return hasFailureMessage()
? new MessagePrependingFailureStrategy(failureStrategy, this)
: failureStrategy;
}
/**
* Triggers the failure strategy with an empty failure message
*/
public void fail() {
getFailureStrategy().fail("");
}
/**
* Triggers the failure strategy with the given failure message
*/
public void fail(@Nullable String format, Object... args) {
getFailureStrategy().fail(format(format, args));
}
/**
* Overrides the failure message of the subsequent subject's propositions.
*
* @see com.google.common.truth.delegation.DelegationTest
* @param failureMessage a descriptive message. {@code null} to remove any current message.
* @return A custom verb which will show the descriptive message along with the normal failure
* text.
*/
public abstract T withFailureMessage(@Nullable String failureMessage);
@Nullable
protected abstract String getFailureMessage();
// TODO(kak): This should probably be abstract...
protected boolean hasFailureMessage() {
return false;
}
/**
* The recommended method of extension of Truth to new types, which is
* documented in {@link com.google.common.truth.delegation.DelegationTest }.
*
* @see com.google.common.truth.delegation.DelegationTest
* @param factory
* a SubjectFactory<S, T> implementation
* @returns A custom verb for the type returned by the SubjectFactory
*/
public <S extends Subject<S, T>, T, SF extends SubjectFactory<S, T>> DelegatedVerb<S, T> about(
SF factory) {
return new DelegatedVerb<S, T>(getFailureStrategy(), factory);
}
/**
* A special Verb implementation which wraps a SubjectFactory
*/
public static class DelegatedVerb<S extends Subject<S, T>, T> {
private final SubjectFactory<S, T> factory;
private final FailureStrategy failureStrategy;
public DelegatedVerb(FailureStrategy failureStrategy, SubjectFactory<S, T> factory) {
this.factory = checkNotNull(factory);
this.failureStrategy = checkNotNull(failureStrategy);
}
public S that(T target) {
return factory.getSubject(failureStrategy, target);
}
}
protected static class MessagePrependingFailureStrategy extends FailureStrategy {
private final FailureStrategy delegate;
private final AbstractVerb<?> verb;
protected MessagePrependingFailureStrategy(FailureStrategy delegate, AbstractVerb<?> verb) {
this.delegate = checkNotNull(delegate);
this.verb = checkNotNull(verb);
}
@Override
public void fail(String message) {
delegate.fail(verb.getFailureMessage() + ": " + message);
}
@Override
public void fail(String message, Throwable cause) {
delegate.fail(verb.getFailureMessage() + ": " + message, cause);
}
@Override
public void failComparing(String message, CharSequence expected, CharSequence actual) {
delegate.fail(
verb.getFailureMessage() + ": " + StringUtil.messageFor(message, expected, actual));
}
}
}