/**
* Copyright (C) 2008 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 cn.businessworks.common.inject.internal;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.base.Objects;
import com.google.common.collect.ImmutableMap;
import cn.businessworks.common.inject.ConfigurationException;
import cn.businessworks.common.inject.Key;
import cn.businessworks.common.inject.TypeLiteral;
import cn.businessworks.common.inject.util.Types;
import java.io.Serializable;
import java.lang.reflect.Array;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.GenericDeclaration;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.lang.reflect.WildcardType;
import java.util.Arrays;
import java.util.Map;
import java.util.NoSuchElementException;
/**
* Static methods for working with types that we aren't publishing in the
* public {@code Types} API.
*
* @author [email protected] (Jesse Wilson)
*/
public class MoreTypes {
public static final Type[] EMPTY_TYPE_ARRAY = new Type[] {};
private MoreTypes() {}
private static final Map<TypeLiteral<?>, TypeLiteral<?>> PRIMITIVE_TO_WRAPPER
= new ImmutableMap.Builder<TypeLiteral<?>, TypeLiteral<?>>()
.put(TypeLiteral.get(boolean.class), TypeLiteral.get(Boolean.class))
.put(TypeLiteral.get(byte.class), TypeLiteral.get(Byte.class))
.put(TypeLiteral.get(short.class), TypeLiteral.get(Short.class))
.put(TypeLiteral.get(int.class), TypeLiteral.get(Integer.class))
.put(TypeLiteral.get(long.class), TypeLiteral.get(Long.class))
.put(TypeLiteral.get(float.class), TypeLiteral.get(Float.class))
.put(TypeLiteral.get(double.class), TypeLiteral.get(Double.class))
.put(TypeLiteral.get(char.class), TypeLiteral.get(Character.class))
.put(TypeLiteral.get(void.class), TypeLiteral.get(Void.class))
.build();
/**
* Returns a key that doesn't hold any references to parent classes.
* This is necessary for anonymous keys, so ensure we don't hold a ref
* to the containing module (or class) forever.
*/
public static <T> Key<T> canonicalizeKey(Key<T> key) {
// If we know this isn't a subclass, return as-is.
// Otherwise, recreate the key to avoid the subclass
if (key.getClass() == Key.class) {
return key;
} else if (key.getAnnotation() != null) {
return Key.get(key.getTypeLiteral(), key.getAnnotation());
} else if (key.getAnnotationType() != null) {
return Key.get(key.getTypeLiteral(), key.getAnnotationType());
} else {
return Key.get(key.getTypeLiteral());
}
}
/**
* Returns an type that's appropriate for use in a key.
*
* <p>If the raw type of {@code typeLiteral} is a {@code javax.inject.Provider}, this returns a
* {@code cn.businessworks.common.inject.Provider} with the same type parameters.
*
* <p>If the type is a primitive, the corresponding wrapper type will be returned.
*
* @throws ConfigurationException if {@code type} contains a type variable
*/
public static <T> TypeLiteral<T> canonicalizeForKey(TypeLiteral<T> typeLiteral) {
Type type = typeLiteral.getType();
if (!isFullySpecified(type)) {
Errors errors = new Errors().keyNotFullySpecified(typeLiteral);
throw new ConfigurationException(errors.getMessages());
}
if (typeLiteral.getRawType() == javax.inject.Provider.class) {
ParameterizedType parameterizedType = (ParameterizedType) type;
// the following casts are generally unsafe, but cn.businessworks.common.inject.Provider extends
// javax.inject.Provider and is covariant
@SuppressWarnings("unchecked")
TypeLiteral<T> guiceProviderType = (TypeLiteral<T>) TypeLiteral.get(
Types.providerOf(parameterizedType.getActualTypeArguments()[0]));
return guiceProviderType;
}
@SuppressWarnings("unchecked")
TypeLiteral<T> wrappedPrimitives = (TypeLiteral<T>) PRIMITIVE_TO_WRAPPER.get(typeLiteral);
if (wrappedPrimitives != null) {
return wrappedPrimitives;
}
// If we know this isn't a subclass, return as-is.
if (typeLiteral.getClass() == TypeLiteral.class) {
return typeLiteral;
}
// recreate the TypeLiteral to avoid anonymous TypeLiterals from holding refs to their
// surrounding classes.
@SuppressWarnings("unchecked")
TypeLiteral<T> recreated = (TypeLiteral<T>) TypeLiteral.get(typeLiteral.getType());
return recreated;
}
/**
* Returns true if {@code type} is free from type variables.
*/
private static boolean isFullySpecified(Type type) {
if (type instanceof Class) {
return true;
} else if (type instanceof CompositeType) {
return ((CompositeType) type).isFullySpecified();
} else if (type instanceof TypeVariable){
return false;
} else {
return ((CompositeType) canonicalize(type)).isFullySpecified();
}
}
/**
* Returns a type that is functionally equal but not necessarily equal
* according to {@link Object#equals(Object) Object.equals()}. The returned
* type is {@link Serializable}.
*/
public static Type canonicalize(Type type) {
if (type instanceof Class) {
Class<?> c = (Class<?>) type;
return c.isArray() ? new GenericArrayTypeImpl(canonicalize(c.getComponentType())) : c;
} else if (type instanceof CompositeType) {
return type;
} else if (type instanceof ParameterizedType) {
ParameterizedType p = (ParameterizedType) type;
return new ParameterizedTypeImpl(p.getOwnerType(),
p.getRawType(), p.getActualTypeArguments());
} else if (type instanceof GenericArrayType) {
GenericArrayType g = (GenericArrayType) type;
return new GenericArrayTypeImpl(g.getGenericComponentType());
} else if (type instanceof WildcardType) {
WildcardType w = (WildcardType) type;
return new WildcardTypeImpl(w.getUpperBounds(), w.getLowerBounds());
} else {
// type is either serializable as-is or unsupported
return type;
}
}
public static Class<?> getRawType(Type type) {
if (type instanceof Class<?>) {
// type is a normal class.
return (Class<?>) type;
} else if (type instanceof ParameterizedType) {
ParameterizedType parameterizedType = (ParameterizedType) type;
// I'm not exactly sure why getRawType() returns Type instead of Class.
// Neal isn't either but suspects some pathological case related
// to nested classes exists.
Type rawType = parameterizedType.getRawType();
checkArgument(rawType instanceof Class,
"Expected a Class, but <%s> is of type %s", type, type.getClass().getName());
return (Class<?>) rawType;
} else if (type instanceof GenericArrayType) {
Type componentType = ((GenericArrayType)type).getGenericComponentType();
return Array.newInstance(getRawType(componentType), 0).getClass();
} else if (type instanceof TypeVariable) {
// we could use the variable's bounds, but that'll won't work if there are multiple.
// having a raw type that's more general than necessary is okay
return Object.class;
} else {
throw new IllegalArgumentException("Expected a Class, ParameterizedType, or "
+ "GenericArrayType, but <" + type + "> is of type " + type.getClass().getName());
}
}
/**
* Returns true if {@code a} and {@code b} are equal.
*/
public static boolean equals(Type a, Type b) {
if (a == b) {
// also handles (a == null && b == null)
return true;
} else if (a instanceof Class) {
// Class already specifies equals().
return a.equals(b);
} else if (a instanceof ParameterizedType) {
if (!(b instanceof ParameterizedType)) {
return false;
}
// TODO: save a .clone() call
ParameterizedType pa = (ParameterizedType) a;
ParameterizedType pb = (ParameterizedType) b;
return Objects.equal(pa.getOwnerType(), pb.getOwnerType())
&& pa.getRawType().equals(pb.getRawType())
&& Arrays.equals(pa.getActualTypeArguments(), pb.getActualTypeArguments());
} else if (a instanceof GenericArrayType) {
if (!(b instanceof GenericArrayType)) {
return false;
}
GenericArrayType ga = (GenericArrayType) a;
GenericArrayType gb = (GenericArrayType) b;
return equals(ga.getGenericComponentType(), gb.getGenericComponentType());
} else if (a instanceof WildcardType) {
if (!(b instanceof WildcardType)) {
return false;
}
WildcardType wa = (WildcardType) a;
WildcardType wb = (WildcardType) b;
return Arrays.equals(wa.getUpperBounds(), wb.getUpperBounds())
&& Arrays.equals(wa.getLowerBounds(), wb.getLowerBounds());
} else if (a instanceof TypeVariable) {
if (!(b instanceof TypeVariable)) {
return false;
}
TypeVariable<?> va = (TypeVariable) a;
TypeVariable<?> vb = (TypeVariable) b;
return va.getGenericDeclaration().equals(vb.getGenericDeclaration())
&& va.getName().equals(vb.getName());
} else {
// This isn't a type we support. Could be a generic array type, wildcard type, etc.
return false;
}
}
private static int hashCodeOrZero(Object o) {
return o != null ? o.hashCode() : 0;
}
public static String typeToString(Type type) {
return type instanceof Class ? ((Class) type).getName() : type.toString();
}
/**
* Returns the generic supertype for {@code type}. For example, given a class {@code IntegerSet},
* the result for when supertype is {@code Set.class} is {@code Set<Integer>} and the result
* when the supertype is {@code Collection.class} is {@code Collection<Integer>}.
*/
public static Type getGenericSupertype(Type type, Class<?> rawType, Class<?> toResolve) {
if (toResolve == rawType) {
return type;
}
// we skip searching through interfaces if unknown is an interface
if (toResolve.isInterface()) {
Class[] interfaces = rawType.getInterfaces();
for (int i = 0, length = interfaces.length; i < length; i++) {
if (interfaces[i] == toResolve) {
return rawType.getGenericInterfaces()[i];
} else if (toResolve.isAssignableFrom(interfaces[i])) {
return getGenericSupertype(rawType.getGenericInterfaces()[i], interfaces[i], toResolve);
}
}
}
// check our supertypes
if (!rawType.isInterface()) {
while (rawType != Object.class) {
Class<?> rawSupertype = rawType.getSuperclass();
if (rawSupertype == toResolve) {
return rawType.getGenericSuperclass();
} else if (toResolve.isAssignableFrom(rawSupertype)) {
return getGenericSupertype(rawType.getGenericSuperclass(), rawSupertype, toResolve);
}
rawType = rawSupertype;
}
}
// we can't resolve this further
return toResolve;
}
public static Type resolveTypeVariable(Type type, Class<?> rawType, TypeVariable unknown) {
Class<?> declaredByRaw = declaringClassOf(unknown);
// we can't reduce this further
if (declaredByRaw == null) {
return unknown;
}
Type declaredBy = getGenericSupertype(type, rawType, declaredByRaw);
if (declaredBy instanceof ParameterizedType) {
int index = indexOf(declaredByRaw.getTypeParameters(), unknown);
return ((ParameterizedType) declaredBy).getActualTypeArguments()[index];
}
return unknown;
}
private static int indexOf(Object[] array, Object toFind) {
for (int i = 0; i < array.length; i++) {
if (toFind.equals(array[i])) {
return i;
}
}
throw new NoSuchElementException();
}
/**
* Returns the declaring class of {@code typeVariable}, or {@code null} if it was not declared by
* a class.
*/
private static Class<?> declaringClassOf(TypeVariable typeVariable) {
GenericDeclaration genericDeclaration = typeVariable.getGenericDeclaration();
return genericDeclaration instanceof Class
? (Class<?>) genericDeclaration
: null;
}
public static class ParameterizedTypeImpl
implements ParameterizedType, Serializable, CompositeType {
private final Type ownerType;
private final Type rawType;
private final Type[] typeArguments;
public ParameterizedTypeImpl(Type ownerType, Type rawType, Type... typeArguments) {
// require an owner type if the raw type needs it
ensureOwnerType(ownerType, rawType);
this.ownerType = ownerType == null ? null : canonicalize(ownerType);
this.rawType = canonicalize(rawType);
this.typeArguments = typeArguments.clone();
for (int t = 0; t < this.typeArguments.length; t++) {
checkNotNull(this.typeArguments[t], "type parameter");
checkNotPrimitive(this.typeArguments[t], "type parameters");
this.typeArguments[t] = canonicalize(this.typeArguments[t]);
}
}
public Type[] getActualTypeArguments() {
return typeArguments.clone();
}
public Type getRawType() {
return rawType;
}
public Type getOwnerType() {
return ownerType;
}
public boolean isFullySpecified() {
if (ownerType != null && !MoreTypes.isFullySpecified(ownerType)) {
return false;
}
if (!MoreTypes.isFullySpecified(rawType)) {
return false;
}
for (Type type : typeArguments) {
if (!MoreTypes.isFullySpecified(type)) {
return false;
}
}
return true;
}
@Override public boolean equals(Object other) {
return other instanceof ParameterizedType
&& MoreTypes.equals(this, (ParameterizedType) other);
}
@Override public int hashCode() {
return Arrays.hashCode(typeArguments)
^ rawType.hashCode()
^ hashCodeOrZero(ownerType);
}
@Override public String toString() {
StringBuilder stringBuilder = new StringBuilder(30 * (typeArguments.length + 1));
stringBuilder.append(typeToString(rawType));
if (typeArguments.length == 0) {
return stringBuilder.toString();
}
stringBuilder.append("<").append(typeToString(typeArguments[0]));
for (int i = 1; i < typeArguments.length; i++) {
stringBuilder.append(", ").append(typeToString(typeArguments[i]));
}
return stringBuilder.append(">").toString();
}
private static void ensureOwnerType(Type ownerType, Type rawType) {
if (rawType instanceof Class<?>) {
Class rawTypeAsClass = (Class) rawType;
checkArgument(ownerType != null || rawTypeAsClass.getEnclosingClass() == null,
"No owner type for enclosed %s", rawType);
checkArgument(ownerType == null || rawTypeAsClass.getEnclosingClass() != null,
"Owner type for unenclosed %s", rawType);
}
}
private static final long serialVersionUID = 0;
}
public static class GenericArrayTypeImpl
implements GenericArrayType, Serializable, CompositeType {
private final Type componentType;
public GenericArrayTypeImpl(Type componentType) {
this.componentType = canonicalize(componentType);
}
public Type getGenericComponentType() {
return componentType;
}
public boolean isFullySpecified() {
return MoreTypes.isFullySpecified(componentType);
}
@Override public boolean equals(Object o) {
return o instanceof GenericArrayType
&& MoreTypes.equals(this, (GenericArrayType) o);
}
@Override public int hashCode() {
return componentType.hashCode();
}
@Override public String toString() {
return typeToString(componentType) + "[]";
}
private static final long serialVersionUID = 0;
}
/**
* The WildcardType interface supports multiple upper bounds and multiple
* lower bounds. We only support what the Java 6 language needs - at most one
* bound. If a lower bound is set, the upper bound must be Object.class.
*/
public static class WildcardTypeImpl implements WildcardType, Serializable, CompositeType {
private final Type upperBound;
private final Type lowerBound;
public WildcardTypeImpl(Type[] upperBounds, Type[] lowerBounds) {
checkArgument(lowerBounds.length <= 1, "Must have at most one lower bound.");
checkArgument(upperBounds.length == 1, "Must have exactly one upper bound.");
if (lowerBounds.length == 1) {
checkNotNull(lowerBounds[0], "lowerBound");
checkNotPrimitive(lowerBounds[0], "wildcard bounds");
checkArgument(upperBounds[0] == Object.class, "bounded both ways");
this.lowerBound = canonicalize(lowerBounds[0]);
this.upperBound = Object.class;
} else {
checkNotNull(upperBounds[0], "upperBound");
checkNotPrimitive(upperBounds[0], "wildcard bounds");
this.lowerBound = null;
this.upperBound = canonicalize(upperBounds[0]);
}
}
public Type[] getUpperBounds() {
return new Type[] { upperBound };
}
public Type[] getLowerBounds() {
return lowerBound != null ? new Type[] { lowerBound } : EMPTY_TYPE_ARRAY;
}
public boolean isFullySpecified() {
return MoreTypes.isFullySpecified(upperBound)
&& (lowerBound == null || MoreTypes.isFullySpecified(lowerBound));
}
@Override public boolean equals(Object other) {
return other instanceof WildcardType
&& MoreTypes.equals(this, (WildcardType) other);
}
@Override public int hashCode() {
// this equals Arrays.hashCode(getLowerBounds()) ^ Arrays.hashCode(getUpperBounds());
return (lowerBound != null ? 31 + lowerBound.hashCode() : 1)
^ (31 + upperBound.hashCode());
}
@Override public String toString() {
if (lowerBound != null) {
return "? super " + typeToString(lowerBound);
} else if (upperBound == Object.class) {
return "?";
} else {
return "? extends " + typeToString(upperBound);
}
}
private static final long serialVersionUID = 0;
}
private static void checkNotPrimitive(Type type, String use) {
checkArgument(!(type instanceof Class<?>) || !((Class) type).isPrimitive(),
"Primitive types are not allowed in %s: %s", use, type);
}
/** A type formed from other types, such as arrays, parameterized types or wildcard types */
private interface CompositeType {
/** Returns true if there are no type variables in this type. */
boolean isFullySpecified();
}
}
