/*
* Copyright (C) 2005 The Guava Authors
*
* 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.testing;
import com.google.common.annotations.Beta;
import com.google.common.base.Objects;
import com.google.common.collect.ClassToInstanceMap;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.MutableClassToInstanceMap;
import com.google.common.reflect.AbstractInvocationHandler;
import com.google.common.reflect.Reflection;
import com.google.common.reflect.TypeToken;
import junit.framework.Assert;
import junit.framework.AssertionFailedError;
import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Proxy;
import java.lang.reflect.Type;
import java.util.Arrays;
import java.util.List;
import java.util.Set;
import java.util.concurrent.ConcurrentMap;
import javax.annotation.Nullable;
/**
* A test utility that verifies that your methods and constructors throw {@link
* NullPointerException} or {@link UnsupportedOperationException} whenever null
* is passed to a parameter that isn't annotated with {@link Nullable}.
*
* <p>The tested methods and constructors are invoked -- each time with one
* parameter being null and the rest not null -- and the test fails if no
* expected exception is thrown. {@code NullPointerTester} uses best effort to
* pick non-null default values for many common JDK and Guava types, and also
* for interfaces and public classes that have public parameter-less
* constructors. When the non-null default value for a particular parameter type
* cannot be provided by {@code NullPointerTester}, the caller can provide a
* custom non-null default value for the parameter type via {@link #setDefault}.
*
* @author Kevin Bourrillion
* @since 10.0
*/
@Beta
public final class NullPointerTester {
private final ClassToInstanceMap<Object> defaults =
MutableClassToInstanceMap.create();
private final List<Member> ignoredMembers = Lists.newArrayList();
/**
* Sets a default value that can be used for any parameter of type
* {@code type}. Returns this object.
*/
public <T> NullPointerTester setDefault(Class<T> type, T value) {
defaults.put(type, value);
return this;
}
/**
* Ignore {@code method} in the tests that follow. Returns this object.
*
* @since 13.0
*/
public NullPointerTester ignore(Method method) {
ignoredMembers.add(method);
return this;
}
/**
* Runs {@link #testConstructor} on every constructor in class {@code c} that
* has at least {@code minimalVisibility}.
*/
public void testConstructors(Class<?> c, Visibility minimalVisibility) {
for (Constructor<?> constructor : c.getDeclaredConstructors()) {
if (minimalVisibility.isVisible(constructor) && !isIgnored(constructor)) {
testConstructor(constructor);
}
}
}
/**
* Runs {@link #testConstructor} on every public constructor in class {@code
* c}.
*/
public void testAllPublicConstructors(Class<?> c) {
testConstructors(c, Visibility.PUBLIC);
}
/**
* Runs {@link #testMethod} on every static method of class {@code c} that has
* at least {@code minimalVisibility}, including those "inherited" from
* superclasses of the same package.
*/
public void testStaticMethods(Class<?> c, Visibility minimalVisibility) {
for (Method method : minimalVisibility.getStaticMethods(c)) {
if (!isIgnored(method)) {
testMethod(null, method);
}
}
}
/**
* Runs {@link #testMethod} on every public static method of class {@code c},
* including those "inherited" from superclasses of the same package.
*/
public void testAllPublicStaticMethods(Class<?> c) {
testStaticMethods(c, Visibility.PUBLIC);
}
/**
* Runs {@link #testMethod} on every instance method of the class of
* {@code instance} with at least {@code minimalVisibility}, including those
* inherited from superclasses of the same package.
*/
public void testInstanceMethods(
Object instance, Visibility minimalVisibility) {
Class<?> c = instance.getClass();
for (Method method : minimalVisibility.getInstanceMethods(c)) {
if (!isIgnored(method)) {
testMethod(instance, method);
}
}
}
/**
* Runs {@link #testMethod} on every public instance method of the class of
* {@code instance}, including those inherited from superclasses of the same
* package.
*/
public void testAllPublicInstanceMethods(Object instance) {
testInstanceMethods(instance, Visibility.PUBLIC);
}
/**
* Verifies that {@code method} produces a {@link NullPointerException}
* or {@link UnsupportedOperationException} whenever <i>any</i> of its
* non-{@link Nullable} parameters are null.
*
* @param instance the instance to invoke {@code method} on, or null if
* {@code method} is static
*/
public void testMethod(Object instance, Method method) {
Class<?>[] types = method.getParameterTypes();
for (int nullIndex = 0; nullIndex < types.length; nullIndex++) {
testMethodParameter(instance, method, nullIndex);
}
}
/**
* Verifies that {@code ctor} produces a {@link NullPointerException} or
* {@link UnsupportedOperationException} whenever <i>any</i> of its
* non-{@link Nullable} parameters are null.
*/
public void testConstructor(Constructor<?> ctor) {
Class<?>[] types = ctor.getParameterTypes();
for (int nullIndex = 0; nullIndex < types.length; nullIndex++) {
testConstructorParameter(ctor, nullIndex);
}
}
/**
* Verifies that {@code method} produces a {@link NullPointerException} or
* {@link UnsupportedOperationException} when the parameter in position {@code
* paramIndex} is null. If this parameter is marked {@link Nullable}, this
* method does nothing.
*
* @param instance the instance to invoke {@code method} on, or null if
* {@code method} is static
*/
public void testMethodParameter(
final Object instance, final Method method, int paramIndex) {
method.setAccessible(true);
testFunctorParameter(instance, new Functor() {
@Override public Type[] getParameterTypes() {
Type[] unresolved = method.getGenericParameterTypes();
if (isStatic(method)) {
return unresolved;
} else {
TypeToken<?> type = TypeToken.of(instance.getClass());
Type[] resolved = new Type[unresolved.length];
for (int i = 0; i < unresolved.length; i++) {
resolved[i] = type.resolveType(unresolved[i]).getType();
}
return resolved;
}
}
@Override public Annotation[][] getParameterAnnotations() {
return method.getParameterAnnotations();
}
@Override public void invoke(Object object, Object[] params)
throws InvocationTargetException, IllegalAccessException {
method.invoke(object, params);
}
@Override public String toString() {
return method.toString();
}
}, paramIndex, method.getDeclaringClass());
}
/**
* Verifies that {@code ctor} produces a {@link NullPointerException} or
* {@link UnsupportedOperationException} when the parameter in position {@code
* paramIndex} is null. If this parameter is marked {@link Nullable}, this
* method does nothing.
*/
public void testConstructorParameter(
final Constructor<?> ctor, int paramIndex) {
ctor.setAccessible(true);
testFunctorParameter(null, new Functor() {
@Override public Type[] getParameterTypes() {
return ctor.getGenericParameterTypes();
}
@Override public Annotation[][] getParameterAnnotations() {
return ctor.getParameterAnnotations();
}
@Override public void invoke(Object instance, Object[] params)
throws InvocationTargetException, IllegalAccessException,
InstantiationException {
ctor.newInstance(params);
}
}, paramIndex, ctor.getDeclaringClass());
}
/** Visibility of any method or constructor. */
public enum Visibility {
PACKAGE {
@Override boolean isVisible(int modifiers) {
return !Modifier.isPrivate(modifiers);
}
},
PROTECTED {
@Override boolean isVisible(int modifiers) {
return Modifier.isPublic(modifiers) || Modifier.isProtected(modifiers);
}
},
PUBLIC {
@Override boolean isVisible(int modifiers) {
return Modifier.isPublic(modifiers);
}
};
abstract boolean isVisible(int modifiers);
/**
* Returns {@code true} if {@code member} is visible under {@code this}
* visibility.
*/
final boolean isVisible(Member member) {
return isVisible(member.getModifiers());
}
final Iterable<Method> getStaticMethods(Class<?> cls) {
ImmutableList.Builder<Method> builder = ImmutableList.builder();
for (Method method : getVisibleMethods(cls)) {
if (isStatic(method)) {
builder.add(method);
}
}
return builder.build();
}
final Iterable<Method> getInstanceMethods(Class<?> cls) {
ConcurrentMap<Signature, Method> map = Maps.newConcurrentMap();
for (Method method : getVisibleMethods(cls)) {
if (!isStatic(method)) {
map.putIfAbsent(new Signature(method), method);
}
}
return map.values();
}
private ImmutableList<Method> getVisibleMethods(Class<?> cls) {
// Don't use cls.getPackage() because it does nasty things like reading
// a file.
String visiblePackage = Reflection.getPackageName(cls);
ImmutableList.Builder<Method> builder = ImmutableList.builder();
for (Class<?> type : TypeToken.of(cls).getTypes().classes().rawTypes()) {
if (!Reflection.getPackageName(type).equals(visiblePackage)) {
break;
}
for (Method method : type.getDeclaredMethods()) {
if (!method.isSynthetic() && isVisible(method)) {
builder.add(method);
}
}
}
return builder.build();
}
}
// TODO(benyu): Use labs/reflect/Signature if it graduates.
private static final class Signature {
private final String name;
private final ImmutableList<Class<?>> parameterTypes;
Signature(Method method) {
this(method.getName(), ImmutableList.copyOf(method.getParameterTypes()));
}
Signature(String name, ImmutableList<Class<?>> parameterTypes) {
this.name = name;
this.parameterTypes = parameterTypes;
}
@Override public boolean equals(Object obj) {
if (obj instanceof Signature) {
Signature that = (Signature) obj;
return name.equals(that.name)
&& parameterTypes.equals(that.parameterTypes);
}
return false;
}
@Override public int hashCode() {
return Objects.hashCode(name, parameterTypes);
}
}
/**
* Verifies that {@code func} produces a {@link NullPointerException} or
* {@link UnsupportedOperationException} when the parameter in position {@code
* paramIndex} is null. If this parameter is marked {@link Nullable}, this
* method does nothing.
*
* @param instance the instance to invoke {@code func} on, or null if
* {@code func} is static
*/
private void testFunctorParameter(Object instance, Functor func,
int paramIndex, Class<?> testedClass) {
if (parameterIsPrimitiveOrNullable(func, paramIndex)) {
return; // there's nothing to test
}
Object[] params = buildParamList(func, paramIndex);
try {
func.invoke(instance, params);
Assert.fail("No exception thrown from " + func +
Arrays.toString(params) + " for " + testedClass);
} catch (InvocationTargetException e) {
Throwable cause = e.getCause();
if (cause instanceof NullPointerException ||
cause instanceof UnsupportedOperationException) {
return;
}
AssertionFailedError error = new AssertionFailedError(
"wrong exception thrown from " + func + ": " + cause);
error.initCause(cause);
throw error;
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
} catch (InstantiationException e) {
throw new RuntimeException(e);
}
}
private static boolean parameterIsPrimitiveOrNullable(
Functor func, int paramIndex) {
if (TypeToken.of(func.getParameterTypes()[paramIndex]).getRawType()
.isPrimitive()) {
return true;
}
Annotation[] annotations = func.getParameterAnnotations()[paramIndex];
for (Annotation annotation : annotations) {
if (annotation instanceof Nullable) {
return true;
}
}
return false;
}
private Object[] buildParamList(Functor func, int indexOfParamToSetToNull) {
Type[] types = func.getParameterTypes();
Object[] params = new Object[types.length];
for (int i = 0; i < types.length; i++) {
if (i != indexOfParamToSetToNull) {
TypeToken<?> type = TypeToken.of(types[i]);
params[i] = getDefaultValue(type);
if (!parameterIsPrimitiveOrNullable(func, i)) {
Assert.assertTrue("No default value found for " + type.getRawType(),
params[i] != null);
}
}
}
return params;
}
private <T> T getDefaultValue(TypeToken<T> type) {
// We assume that all defaults are generics-safe, even if they aren't,
// we take the risk.
@SuppressWarnings("unchecked")
T defaultValue = (T) defaults.getInstance(type.getRawType());
if (defaultValue != null) {
return defaultValue;
}
@SuppressWarnings("unchecked") // All null values are generics-safe
T nullValue = (T) ArbitraryInstances.get(type.getRawType());
if (nullValue != null) {
return nullValue;
}
if (type.getRawType() == Class.class) {
// If parameter is Class<? extends Foo>, we return Foo.class
@SuppressWarnings("unchecked")
T defaultClass = (T) getFirstTypeParameter(type.getType()).getRawType();
return defaultClass;
}
if (type.getRawType() == TypeToken.class) {
// If parameter is TypeToken<? extends Foo>, we return TypeToken<Foo>.
@SuppressWarnings("unchecked")
T defaultType = (T) getFirstTypeParameter(type.getType());
return defaultType;
}
if (type.getRawType().isInterface()) {
return newDefaultReturningProxy(type);
}
return null;
}
private static TypeToken<?> getFirstTypeParameter(Type type) {
if (type instanceof ParameterizedType) {
return TypeToken.of(
((ParameterizedType) type).getActualTypeArguments()[0]);
} else {
return TypeToken.of(Object.class);
}
}
@SuppressWarnings("unchecked") // T implemented with dynamic proxy.
private <T> T newDefaultReturningProxy(final TypeToken<T> type) {
Set<Class<? super T>> interfaceClasses =
type.getTypes().interfaces().rawTypes();
return (T) Proxy.newProxyInstance(
interfaceClasses.iterator().next().getClassLoader(),
interfaceClasses.toArray(new Class<?>[interfaceClasses.size()]),
new AbstractInvocationHandler() {
@Override protected Object handleInvocation(
Object proxy, Method method, Object[] args) {
return getDefaultValue(
type.resolveType(method.getGenericReturnType()));
}
@Override public String toString() {
return "NullPointerTester proxy for " + type;
}
});
}
private interface Functor {
Type[] getParameterTypes();
Annotation[][] getParameterAnnotations();
void invoke(Object o, Object[] params)
throws InvocationTargetException, IllegalAccessException,
InstantiationException;
}
private static boolean isStatic(Member member) {
return Modifier.isStatic(member.getModifiers());
}
private boolean isIgnored(Member member) {
return member.isSynthetic() || ignoredMembers.contains(member);
}
}