/*
* 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 com.google.common.annotations.GwtIncompatible;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.truth.codegen.CompilingClassLoader;
import com.google.common.truth.codegen.CompilingClassLoader.CompilerException;
import com.google.common.truth.codegen.IteratingWrapperClassBuilder;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Type;
import java.util.concurrent.ExecutionException;
import javax.annotation.CheckReturnValue;
/**
* A verb that iterates over data and applies the predicate iteratively
*/
@GwtIncompatible("Code generation and loading.")
public class IteratingVerb<T> {
private static final String CANNOT_WRAP_MSG = "Cannot build an iterating wrapper around ";
private static LoadingCache<SubjectFactory<?,?>, Class<?>> WRAPPER_CACHE =
CacheBuilder.newBuilder().build(
new CacheLoader<SubjectFactory<?,?>, Class<?>>() {
@Override public Class<?> load(SubjectFactory<?,?> subjectFactory) throws Exception {
return compileWrapperClass(subjectFactory);
}
});
private final Iterable<T> data;
private final FailureStrategy failureStrategy;
public IteratingVerb(Iterable<T> data, FailureStrategy fs) {
this.failureStrategy = fs;
this.data = data;
}
@CheckReturnValue
public <S extends Subject<S,T>, SF extends SubjectFactory<S, T>> S thatEach(SF factory) {
return wrap(failureStrategy, factory, data);
}
private <S extends Subject<S,T>, SF extends SubjectFactory<S, T>>
S wrap(FailureStrategy fs, SF factory, Iterable<T> data) {
Type t = factory.getSubjectClass();
Class<?> wrapperClass;
try {
wrapperClass = WRAPPER_CACHE.get(factory);
return instantiate(wrapperClass, t, fs, factory, data);
} catch (ExecutionException e) {
throw new RuntimeException(CANNOT_WRAP_MSG + t, e);
}
}
@SuppressWarnings("unchecked")
private <SF, S> S instantiate(Class<?> wrapperType, Type t, FailureStrategy fs,
SF factory, Iterable<T> data) {
try {
Constructor<S> c = (Constructor<S>)wrapperType.getConstructors()[0];
return c.newInstance(fs, factory, data);
} catch (SecurityException e) {
throw new RuntimeException(CANNOT_WRAP_MSG + t, e);
} catch (InstantiationException e) {
throw new RuntimeException(CANNOT_WRAP_MSG + t, e);
} catch (IllegalAccessException e) {
throw new RuntimeException(CANNOT_WRAP_MSG + t, e);
} catch (InvocationTargetException e) {
throw new RuntimeException(CANNOT_WRAP_MSG + t, e);
}
}
private static Class<?> compileWrapperClass(SubjectFactory<?, ?> subjectFactory) {
IteratingWrapperClassBuilder builder = new IteratingWrapperClassBuilder(subjectFactory);
String out = builder.build().toString();
ClassLoader classLoader;
try {
classLoader = new CompilingClassLoader(
subjectFactory.getSubjectClass().getClassLoader(), builder.className, out, null);
} catch (CompilerException e) {
throw new Error("Could not compile class " + builder.className + " with source:\n" + out , e);
}
try {
Class<?> wrapper = classLoader.loadClass(builder.className);
return wrapper;
} catch (ClassNotFoundException e) {
throw new Error("Could not load class " + subjectFactory.getSubjectClass().getSimpleName(), e);
}
}
}