/*
* Copyright (C) 2014 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.testing.compile;
import static com.google.common.base.Preconditions.checkState;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.testing.compile.Compilation.Result;
import org.junit.Rule;
import org.junit.rules.TestRule;
import org.junit.runner.Description;
import org.junit.runners.JUnit4;
import org.junit.runners.model.Statement;
import java.util.Set;
import java.util.concurrent.atomic.AtomicReference;
import javax.annotation.processing.AbstractProcessor;
import javax.annotation.processing.ProcessingEnvironment;
import javax.annotation.processing.RoundEnvironment;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.TypeElement;
import javax.lang.model.util.Elements;
import javax.lang.model.util.Types;
/**
* A {@link JUnit4} {@link Rule} that executes tests such that a instances of {@link Elements} and
* {@link Types} are available during execution.
*
* <p>To use this rule in a test, just add the following field: <pre> {@code
* @Rule public CompilationRule compilationRule = new CompilationRule();}
*
* @author Gregory Kick
*/
public final class CompilationRule implements TestRule {
private Elements elements;
private Types types;
@Override
public Statement apply(final Statement base, Description description) {
return new Statement() {
@Override public void evaluate() throws Throwable {
final AtomicReference<Throwable> thrown = new AtomicReference<Throwable>();
Result result = Compilation.compile(ImmutableList.of(new AbstractProcessor() {
@Override
public SourceVersion getSupportedSourceVersion() {
return SourceVersion.latest();
}
@Override
public Set<String> getSupportedAnnotationTypes() {
return ImmutableSet.of("*");
}
@Override
public synchronized void init(ProcessingEnvironment processingEnv) {
super.init(processingEnv);
elements = processingEnv.getElementUtils();
types = processingEnv.getTypeUtils();
}
@Override
public boolean process(Set<? extends TypeElement> annotations,
RoundEnvironment roundEnv) {
// just run the test on the last round after compilation is over
if (roundEnv.processingOver()) {
try {
base.evaluate();
} catch (Throwable e) {
thrown.set(e);
}
}
return false;
}
}),
// just compile _something_
ImmutableList.of(JavaFileObjects.forSourceLines("Dummy", "final class Dummy {}")));
checkState(result.successful(), result);
Throwable t = thrown.get();
if (t != null) {
throw t;
}
}
};
}
/**
* Returns the {@link Elements} instance associated with the current execution of the rule.
*
* @throws IllegalStateException if this method is invoked outside the execution of the rule.
*/
public Elements getElements() {
checkState(elements != null, "Not running within the rule");
return elements;
}
/**
* Returns the {@link Types} instance associated with the current execution of the rule.
*
* @throws IllegalStateException if this method is invoked outside the execution of the rule.
*/
public Types getTypes() {
checkState(elements != null, "Not running within the rule");
return types;
}
}