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A Java architecture test library, to specify and assert architecture rules in plain Java - Module 'archunit'
/*
* Copyright 2014-2022 TNG Technology Consulting GmbH
*
* 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.tngtech.archunit.core.domain;
import java.lang.annotation.Annotation;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Maps;
import com.tngtech.archunit.base.MayResolveTypesViaReflection;
import com.tngtech.archunit.core.InitialConfiguration;
import static com.google.common.base.Preconditions.checkArgument;
@MayResolveTypesViaReflection(reason = "We depend on the classpath, if we proxy an annotation type")
class AnnotationProxy {
private static final InitialConfiguration propertiesFormatter = new InitialConfiguration<>();
static {
DomainPlugin.Loader.loadForCurrentPlatform().plugInAnnotationPropertiesFormatter(propertiesFormatter);
}
public static A of(Class annotationType, JavaAnnotation toProxy) {
checkArgument(annotationType.getName().equals(toProxy.getRawType().getName()),
"Requested annotation type %s is incompatible with %s of type %s",
annotationType.getSimpleName(), JavaAnnotation.class.getSimpleName(), toProxy.getRawType().getSimpleName());
return newProxy(annotationType, toProxy);
}
@SuppressWarnings("unchecked") // annotationType A will be implemented
private static A newProxy(Class annotationType, JavaAnnotation toProxy) {
return (A) Proxy.newProxyInstance(
annotationType.getClassLoader(),
new Class[]{annotationType},
new AnnotationMethodInvocationHandler(annotationType, toProxy));
}
private static class AnnotationMethodInvocationHandler implements InvocationHandler {
private final JavaAnnotation toProxy;
private final Conversions conversions;
private final Map handlersByMethod;
private AnnotationMethodInvocationHandler(Class annotationType, JavaAnnotation toProxy) {
this.toProxy = toProxy;
conversions = initConversions(annotationType);
handlersByMethod = initHandlersByMethod(annotationType, toProxy, conversions);
}
private Conversions initConversions(Class annotationType) {
JavaClassConversion javaClassConversion = new JavaClassConversion(annotationType.getClassLoader());
JavaEnumConstantConversion enumConversion = new JavaEnumConstantConversion();
JavaAnnotationConversion annotationConversion = new JavaAnnotationConversion(annotationType.getClassLoader());
return new Conversions(
javaClassConversion,
new JavaClassArrayConversion(javaClassConversion),
enumConversion,
new JavaEnumConstantArrayConversion(enumConversion),
annotationConversion,
new JavaAnnotationArrayConversion(annotationConversion));
}
private ImmutableMap initHandlersByMethod(
Class annotationType, JavaAnnotation toProxy, Conversions conversions) {
return ImmutableMap.of(
new MethodKey("annotationType"), new ConstantReturnValueHandler(annotationType),
new MethodKey("equals", Object.class.getName()), new EqualsHandler(),
new MethodKey("hashCode"), new HashCodeHandler(),
new MethodKey("toString"), new ToStringHandler(annotationType, toProxy, conversions)
);
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) {
SpecificHandler handler = handlersByMethod.get(MethodKey.of(method));
if (handler != null) {
return handler.handle(proxy, method, args);
}
Object result = toProxy.get(method.getName()).orElse(method.getDefaultValue());
return conversions.convertIfNecessary(result, method.getReturnType());
}
}
private interface Conversion {
Object convert(F input, Class returnType);
boolean canHandle(Class returnType);
}
private static class JavaClassConversion implements Conversion {
private final ClassLoader classLoader;
private JavaClassConversion(ClassLoader classLoader) {
this.classLoader = classLoader;
}
@Override
public Class convert(JavaClass input, Class returnType) {
return JavaClassDescriptor.From.javaClass(input).resolveClass(classLoader);
}
@Override
public boolean canHandle(Class returnType) {
return Class.class.isAssignableFrom(returnType);
}
}
private static class JavaClassArrayConversion implements Conversion {
private final JavaClassConversion javaClassConversion;
private JavaClassArrayConversion(JavaClassConversion javaClassConversion) {
this.javaClassConversion = javaClassConversion;
}
@Override
public Object convert(Object[] input, Class returnType) {
return convertArray(input, javaClassConversion, returnType.getComponentType());
}
@Override
public boolean canHandle(Class returnType) {
return Class[].class.isAssignableFrom(returnType);
}
}
private static class JavaEnumConstantConversion implements Conversion {
@Override
public Enum convert(JavaEnumConstant input, Class returnType) {
for (Object constant : JavaClassDescriptor.From.javaClass(input.getDeclaringClass()).resolveClass().getEnumConstants()) {
Enum anEnum = (Enum) constant;
if (anEnum.name().equals(input.name())) {
return anEnum;
}
}
throw new IllegalStateException(String.format(
"Couldn't find Enum Constant %s.%s", input.getDeclaringClass().getSimpleName(), input.name()));
}
@Override
public boolean canHandle(Class returnType) {
return returnType.isEnum();
}
}
private static class JavaEnumConstantArrayConversion implements Conversion {
private final JavaEnumConstantConversion enumConversion;
private JavaEnumConstantArrayConversion(JavaEnumConstantConversion enumConversion) {
this.enumConversion = enumConversion;
}
@Override
public Object convert(Object[] input, Class returnType) {
return convertArray(input, enumConversion, returnType.getComponentType());
}
@Override
public boolean canHandle(Class returnType) {
return returnType.getComponentType() != null && returnType.getComponentType().isEnum();
}
}
private static class JavaAnnotationConversion implements Conversion> {
private final ClassLoader classLoader;
private JavaAnnotationConversion(ClassLoader classLoader) {
this.classLoader = classLoader;
}
@Override
public Annotation convert(JavaAnnotation input, Class returnType) {
// JavaAnnotation.getType() will return the type name of a Class
@SuppressWarnings("unchecked")
Class type = (Class)
JavaClassDescriptor.From.javaClass(input.getRawType()).resolveClass(classLoader);
return AnnotationProxy.of(type, input);
}
@Override
public boolean canHandle(Class returnType) {
return returnType.isAnnotation();
}
}
private static class JavaAnnotationArrayConversion implements Conversion {
private final JavaAnnotationConversion annotationConversion;
private JavaAnnotationArrayConversion(JavaAnnotationConversion annotationConversion) {
this.annotationConversion = annotationConversion;
}
@Override
public Object convert(Object[] input, Class returnType) {
return convertArray(input, annotationConversion, returnType.getComponentType());
}
@Override
public boolean canHandle(Class returnType) {
return returnType.getComponentType() != null && returnType.getComponentType().isAnnotation();
}
}
@SuppressWarnings("unchecked") // canHandle must ensure this
private static Object[] convertArray(Object[] input, Conversion elementConversion, Class targetType) {
Object[] result = (Object[]) Array.newInstance(targetType, input.length);
for (int i = 0; i < input.length; i++) {
result[i] = elementConversion.convert((F) input[i], targetType);
}
return result;
}
private interface SpecificHandler {
Object handle(Object proxy, Method method, Object[] args);
}
private static class ConstantReturnValueHandler implements SpecificHandler {
private final Object value;
private ConstantReturnValueHandler(Object value) {
this.value = value;
}
@Override
public Object handle(Object proxy, Method method, Object[] args) {
return value;
}
}
private static class EqualsHandler implements SpecificHandler {
@Override
public Object handle(Object proxy, Method method, Object[] args) {
return proxy == args[0];
}
}
private static class HashCodeHandler implements SpecificHandler {
@Override
public Object handle(Object proxy, Method method, Object[] args) {
return System.identityHashCode(proxy);
}
}
private static class ToStringHandler implements SpecificHandler {
private final Class annotationType;
private final JavaAnnotation toProxy;
private final Conversions conversions;
private ToStringHandler(Class annotationType, JavaAnnotation toProxy, Conversions conversions) {
this.annotationType = annotationType;
this.toProxy = toProxy;
this.conversions = conversions;
}
@Override
public Object handle(Object proxy, Method method, Object[] args) {
return String.format("@%s(%s)", toProxy.getRawType().getName(), propertiesString());
}
private String propertiesString() {
Map unwrappedProperties = unwrapProxiedProperties();
return propertiesFormatter.get().formatProperties(unwrappedProperties);
}
private Map unwrapProxiedProperties() {
return Maps.transformEntries(toProxy.getProperties(), (key, value) -> {
Class returnType = getDeclaredMethod(key).getReturnType();
return conversions.convertIfNecessary(value, returnType);
});
}
private Method getDeclaredMethod(String name) {
try {
return annotationType.getDeclaredMethod(name);
} catch (NoSuchMethodException e) {
throw new RuntimeException(e);
}
}
}
private static class Conversions {
private final Set> conversions;
private Conversions(Conversion... conversions) {
this.conversions = ImmutableSet.copyOf(conversions);
}
Object convertIfNecessary(T result, Class returnType) {
if (returnType.isInstance(result)) {
return result;
}
return tryFindConversionFor(returnType).orElse(new NoOpConversion<>()).convert(result, returnType);
}
private static class NoOpConversion implements Conversion {
@Override
public T convert(T input, Class returnType) {
return input;
}
@Override
public boolean canHandle(Class returnType) {
return true;
}
}
@SuppressWarnings("unchecked") // Trust sanity of canHandle(..)
private Optional> tryFindConversionFor(Class returnType) {
for (Conversion conversion : conversions) {
if (conversion.canHandle(returnType)) {
return Optional.of((Conversion) conversion);
}
}
return Optional.empty();
}
}
private static class MethodKey {
private final String name;
private final List paramTypeNames;
private MethodKey(String name, String... paramTypeNames) {
this(name, ImmutableList.copyOf(paramTypeNames));
}
private MethodKey(String name, ImmutableList paramTypeNames) {
this.name = name;
this.paramTypeNames = paramTypeNames;
}
@Override
public int hashCode() {
return Objects.hash(name, paramTypeNames);
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null || getClass() != obj.getClass()) {
return false;
}
final MethodKey other = (MethodKey) obj;
return Objects.equals(this.name, other.name)
&& Objects.equals(this.paramTypeNames, other.paramTypeNames);
}
public static MethodKey of(Method method) {
ImmutableList.Builder paramTypeNames = ImmutableList.builder();
for (Class type : method.getParameterTypes()) {
paramTypeNames.add(type.getName());
}
return new MethodKey(method.getName(), paramTypeNames.build());
}
}
}