package jef.tools.reflect;
import java.io.Serializable;
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.NoSuchElementException;
import jef.common.log.LogUtil;
import jef.tools.Assert;
final class GqGenericResolver {
static final Type[] EMPTY_TYPE_ARRAY = new Type[] {};
/**
* Returns a new parameterized type, applying {@code typeArguments} to
* {@code rawType} and enclosed by {@code ownerType}.
*
* @return a {@link java.io.Serializable serializable} parameterized type.
*/
public static ParameterizedType newParameterizedTypeWithOwner(Type ownerType, Type rawType, Type... typeArguments) {
return new ParameterizedTypeImpl(ownerType, rawType, typeArguments);
}
/**
* Returns an array type whose elements are all instances of
* {@code componentType}.
*
* @return a {@link java.io.Serializable serializable} generic array type.
*/
public static GenericArrayType arrayOf(Type componentType) {
return new GenericArrayTypeImpl(componentType);
}
/**
* Returns a type that represents an unknown type that extends {@code bound}
* . For example, if {@code bound} is {@code CharSequence.class}, this
* returns {@code ? extends CharSequence}. If {@code bound} is
* {@code Object.class}, this returns {@code ?}, which is shorthand for
* {@code ?
* extends Object}.
*/
public static WildcardType subtypeOf(Type bound) {
return new WildcardTypeImpl(new Type[] { bound }, EMPTY_TYPE_ARRAY);
}
/**
* Returns a type that represents an unknown supertype of {@code bound}. For
* example, if {@code bound} is {@code String.class}, this returns {@code ?
* super String}.
*/
public static WildcardType supertypeOf(Type bound) {
return new WildcardTypeImpl(new Type[] { Object.class }, new Type[] { bound });
}
/**
* Returns a type that is functionally equal but not necessarily equal
* according to {@link Object#equals(Object) Object.equals()}. The returned
* type is {@link java.io.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 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;
}
}
static boolean equal(Object a, Object b) {
return a == b || (a != null && a.equals(b));
}
/**
* 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;
}
ParameterizedType pa = (ParameterizedType) a;
ParameterizedType pb = (ParameterizedType) b;
return 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() == 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 supertype}. 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>}.
*/
static Type getGenericSupertype(Type context, Class<?> rawType, Class<?> toResolve) {
if (toResolve == rawType) {
return context;
}
// 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;
}
/**
* Returns true if this type is an array.
*/
public static boolean isArray(Type type) {
return type instanceof GenericArrayType || (type instanceof Class && ((Class<?>) type).isArray());
}
/**
* Returns the component type of this array type.
*
* @throws ClassCastException
* if this type is not an array.
*/
public static Type getArrayComponentType(Type array) {
return array instanceof GenericArrayType ? ((GenericArrayType) array).getGenericComponentType() : ((Class<?>) array).getComponentType();
}
public static Type resolve(Type context, Class<?> contextRawType, Type toResolve) {
// this implementation is made a little more complicated in an attempt
// to avoid object-creation
while (true) {
if (toResolve instanceof TypeVariable) {
TypeVariable<?> typeVariable = (TypeVariable<?>) toResolve;
toResolve = resolveTypeVariable(context, contextRawType, typeVariable);
if (toResolve == typeVariable) {
return toResolve;
}
} else if (toResolve instanceof Class && ((Class<?>) toResolve).isArray()) {
Class<?> original = (Class<?>) toResolve;
Type componentType = original.getComponentType();
Type newComponentType = resolve(context, contextRawType, componentType);
return componentType == newComponentType ? original : arrayOf(newComponentType);
} else if (toResolve instanceof GenericArrayType) {
GenericArrayType original = (GenericArrayType) toResolve;
Type componentType = original.getGenericComponentType();
Type newComponentType = resolve(context, contextRawType, componentType);
return componentType == newComponentType ? original : arrayOf(newComponentType);
} else if (toResolve instanceof ParameterizedType) {
ParameterizedType original = (ParameterizedType) toResolve;
Type ownerType = original.getOwnerType();
Type newOwnerType = resolve(context, contextRawType, ownerType);
boolean changed = newOwnerType != ownerType;
Type[] args = original.getActualTypeArguments();
for (int t = 0, length = args.length; t < length; t++) {
Type resolvedTypeArgument = resolve(context, contextRawType, args[t]);
if (resolvedTypeArgument != args[t]) {
if (!changed) {
args = args.clone();
changed = true;
}
args[t] = resolvedTypeArgument;
}
}
return changed ? newParameterizedTypeWithOwner(newOwnerType, original.getRawType(), args) : original;
} else if (toResolve instanceof WildcardType) {
WildcardType original = (WildcardType) toResolve;
Type[] originalLowerBound = original.getLowerBounds();
Type[] originalUpperBound = original.getUpperBounds();
if (originalLowerBound.length == 1) {
Type lowerBound = resolve(context, contextRawType, originalLowerBound[0]);
if (lowerBound != originalLowerBound[0]) {
return supertypeOf(lowerBound);
}
} else if (originalUpperBound.length == 1) {
Type upperBound = resolve(context, contextRawType, originalUpperBound[0]);
if (upperBound != originalUpperBound[0]) {
return subtypeOf(upperBound);
}
}
return original;
} else {
return toResolve;
}
}
}
static Type resolveTypeVariable(Type context, Class<?> contextRawType, TypeVariable<?> unknown) {
Class<?> declaredByRaw = declaringClassOf(unknown);
// we can't reduce this further
if (declaredByRaw == null) {
return unknown;
}
Type declaredBy = getGenericSupertype(context, contextRawType, 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("Not found:" + toFind);
}
/**
* 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;
}
private static void checkNotPrimitive(Type type) {
Assert.isTrue(!(type instanceof Class<?>) || !((Class<?>) type).isPrimitive());
}
private static final class ParameterizedTypeImpl implements ParameterizedType, Serializable {
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
if (rawType instanceof Class<?>) {
Class<?> rawTypeAsClass = (Class<?>) rawType;
try {
Assert.isTrue(ownerType != null || rawTypeAsClass.getEnclosingClass() == null);
Assert.isTrue(ownerType == null || rawTypeAsClass.getEnclosingClass() != null);
} catch (RuntimeException e) {
// R][2011-09-27 21:08:14,570] [ORM._log] ownerType:null
// [ERROR][2011-09-27 21:08:14,572] [ORM._log]
// rawTypeAsClass:interface java.util.Map$Entry
// [ERROR][2011-09-27 21:08:14,573] [ORM._log]
// getEnclosingClass:interface java.util.Map
LogUtil.error("ownerType:" + ownerType);
LogUtil.error("rawTypeAsClass:" + rawTypeAsClass);
LogUtil.error("getEnclosingClass:" + rawTypeAsClass.getEnclosingClass());
throw e;
}
}
this.ownerType = ownerType == null ? null : canonicalize(ownerType);
this.rawType = canonicalize(rawType);
this.typeArguments = typeArguments.clone();
for (int t = 0; t < this.typeArguments.length; t++) {
Assert.notNull(this.typeArguments[t]);
checkNotPrimitive(this.typeArguments[t]);
this.typeArguments[t] = canonicalize(this.typeArguments[t]);
}
}
public Type[] getActualTypeArguments() {
return typeArguments.clone();
}
public Type getRawType() {
return rawType;
}
public Type getOwnerType() {
return ownerType;
}
@Override
public boolean equals(Object other) {
return other instanceof ParameterizedType && GqGenericResolver.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 final long serialVersionUID = 0;
}
private static final class GenericArrayTypeImpl implements GenericArrayType, Serializable {
private final Type componentType;
public GenericArrayTypeImpl(Type componentType) {
this.componentType = canonicalize(componentType);
}
public Type getGenericComponentType() {
return componentType;
}
@Override
public boolean equals(Object o) {
return o instanceof GenericArrayType && GqGenericResolver.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.
*/
private static final class WildcardTypeImpl implements WildcardType, Serializable {
private final Type upperBound;
private final Type lowerBound;
public WildcardTypeImpl(Type[] upperBounds, Type[] lowerBounds) {
Assert.isTrue(lowerBounds.length <= 1);
Assert.isTrue(upperBounds.length == 1);
if (lowerBounds.length == 1) {
Assert.notNull(lowerBounds[0]);
checkNotPrimitive(lowerBounds[0]);
Assert.isTrue(upperBounds[0] == Object.class);
this.lowerBound = canonicalize(lowerBounds[0]);
this.upperBound = Object.class;
} else {
Assert.notNull(upperBounds[0]);
checkNotPrimitive(upperBounds[0]);
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;
}
@Override
public boolean equals(Object other) {
return other instanceof WildcardType && GqGenericResolver.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;
}
}