| /* |
| * Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved. |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v. 2.0, which is available at |
| * http://www.eclipse.org/legal/epl-2.0. |
| * |
| * This Source Code may also be made available under the following Secondary |
| * Licenses when the conditions for such availability set forth in the |
| * Eclipse Public License v. 2.0 are satisfied: GNU General Public License, |
| * version 2 with the GNU Classpath Exception, which is available at |
| * https://www.gnu.org/software/classpath/license.html. |
| * |
| * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 |
| */ |
| |
| package org.jvnet.tiger_types; |
| |
| import java.lang.reflect.Array; |
| import java.lang.reflect.GenericArrayType; |
| import java.lang.reflect.GenericDeclaration; |
| import java.lang.reflect.Method; |
| import java.lang.reflect.ParameterizedType; |
| import java.lang.reflect.Type; |
| import java.lang.reflect.TypeVariable; |
| import java.lang.reflect.WildcardType; |
| |
| /** |
| * Type arithmetic functions. |
| * |
| * @author Kohsuke Kawaguchi |
| */ |
| public class Types { |
| private static final TypeVisitor<Type,Class> baseClassFinder = new TypeVisitor<Type,Class>() { |
| public Type onClass(Class c, Class sup) { |
| // t is a raw type |
| if(sup==c) |
| return sup; |
| |
| Type r; |
| |
| Type sc = c.getGenericSuperclass(); |
| if(sc!=null) { |
| r = visit(sc,sup); |
| if(r!=null) return r; |
| } |
| |
| for( Type i : c.getGenericInterfaces() ) { |
| r = visit(i,sup); |
| if(r!=null) return r; |
| } |
| |
| return null; |
| } |
| |
| public Type onParameterizdType(ParameterizedType p, Class sup) { |
| Class raw = (Class) p.getRawType(); |
| if(raw==sup) { |
| // p is of the form sup<...> |
| return p; |
| } else { |
| // recursively visit super class/interfaces |
| Type r = raw.getGenericSuperclass(); |
| if(r!=null) |
| r = visit(bind(r,raw,p),sup); |
| if(r!=null) |
| return r; |
| for( Type i : raw.getGenericInterfaces() ) { |
| r = visit(bind(i,raw,p),sup); |
| if(r!=null) return r; |
| } |
| return null; |
| } |
| } |
| |
| public Type onGenericArray(GenericArrayType g, Class sup) { |
| // not clear what I should do here |
| return null; |
| } |
| |
| public Type onVariable(TypeVariable v, Class sup) { |
| return visit(v.getBounds()[0],sup); |
| } |
| |
| public Type onWildcard(WildcardType w, Class sup) { |
| // not clear what I should do here |
| return null; |
| } |
| |
| /** |
| * Replaces the type variables in {@code t} by its actual arguments. |
| * |
| * @param decl |
| * provides a list of type variables. See {@link GenericDeclaration#getTypeParameters()} |
| * @param args |
| * actual arguments. See {@link ParameterizedType#getActualTypeArguments()} |
| */ |
| private Type bind( Type t, GenericDeclaration decl, ParameterizedType args ) { |
| return binder.visit(t,new BinderArg(decl,args.getActualTypeArguments())); |
| } |
| }; |
| |
| private static class BinderArg { |
| final TypeVariable[] params; |
| final Type[] args; |
| |
| BinderArg(TypeVariable[] params, Type[] args) { |
| this.params = params; |
| this.args = args; |
| assert params.length==args.length; |
| } |
| |
| public BinderArg( GenericDeclaration decl, Type[] args ) { |
| this(decl.getTypeParameters(),args); |
| } |
| |
| Type replace( TypeVariable v ) { |
| for(int i=0; i<params.length; i++) |
| if(params[i].equals(v)) |
| return args[i]; |
| return v; // this is a free variable |
| } |
| } |
| private static final TypeVisitor<Type,BinderArg> binder = new TypeVisitor<Type,BinderArg>() { |
| public Type onClass(Class c, BinderArg args) { |
| return c; |
| } |
| |
| public Type onParameterizdType(ParameterizedType p, BinderArg args) { |
| Type[] params = p.getActualTypeArguments(); |
| |
| boolean different = false; |
| for( int i=0; i<params.length; i++ ) { |
| Type t = params[i]; |
| params[i] = visit(t,args); |
| different |= t!=params[i]; |
| } |
| |
| Type newOwner = p.getOwnerType(); |
| if(newOwner!=null) |
| newOwner = visit(newOwner,args); |
| different |= p.getOwnerType()!=newOwner; |
| |
| if(!different) return p; |
| |
| return new ParameterizedTypeImpl( (Class<?>)p.getRawType(), params, newOwner ); |
| } |
| |
| public Type onGenericArray(GenericArrayType g, BinderArg types) { |
| Type c = visit(g.getGenericComponentType(),types); |
| if(c==g.getGenericComponentType()) return g; |
| |
| return new GenericArrayTypeImpl(c); |
| } |
| |
| public Type onVariable(TypeVariable v, BinderArg types) { |
| return types.replace(v); |
| } |
| |
| public Type onWildcard(WildcardType w, BinderArg types) { |
| // TODO: this is probably still incorrect |
| // bind( "? extends T" ) with T= "? extends Foo" should be "? extends Foo", |
| // not "? extends (? extends Foo)" |
| Type[] lb = w.getLowerBounds(); |
| Type[] ub = w.getUpperBounds(); |
| boolean diff = false; |
| |
| for( int i=0; i<lb.length; i++ ) { |
| Type t = lb[i]; |
| lb[i] = visit(t,types); |
| diff |= (t!=lb[i]); |
| } |
| |
| for( int i=0; i<ub.length; i++ ) { |
| Type t = ub[i]; |
| ub[i] = visit(t,types); |
| diff |= (t!=ub[i]); |
| } |
| |
| if(!diff) return w; |
| |
| return new WildcardTypeImpl(lb,ub); |
| } |
| }; |
| |
| /** |
| * Gets the parameterization of the given base type. |
| * |
| * <p> |
| * For example, given the following |
| * <pre><xmp> |
| * interface Foo<T> extends List<List<T>> {} |
| * interface Bar extends Foo<String> {} |
| * </xmp></pre> |
| * This method works like this: |
| * <pre><xmp> |
| * getBaseClass( Bar, List ) = List<List<String> |
| * getBaseClass( Bar, Foo ) = Foo<String> |
| * getBaseClass( Foo<? extends Number>, Collection ) = Collection<List<? extends Number>> |
| * getBaseClass( ArrayList<? extends BigInteger>, List ) = List<? extends BigInteger> |
| * </xmp></pre> |
| * |
| * @param type |
| * The type that derives from {@code baseType} |
| * @param baseType |
| * The class whose parameterization we are interested in. |
| * @return |
| * The use of {@code baseType} in {@code type}. |
| * or null if the type is not assignable to the base type. |
| */ |
| public static Type getBaseClass(Type type, Class baseType) { |
| return baseClassFinder.visit(type,baseType); |
| } |
| |
| /** |
| * Gets the display name of the type object |
| * |
| * @return |
| * a human-readable name that the type represents. |
| */ |
| public static String getTypeName(Type type) { |
| if (type instanceof Class) { |
| Class c = (Class) type; |
| if(c.isArray()) |
| return getTypeName(c.getComponentType())+"[]"; |
| return c.getName(); |
| } |
| return type.toString(); |
| } |
| |
| /** |
| * Checks if {@code sub} is a sub-type of {@code sup}. |
| */ |
| public static boolean isSubClassOf(Type sub, Type sup) { |
| return erasure(sup).isAssignableFrom(erasure(sub)); |
| } |
| |
| |
| /** |
| * Implements the logic for {@link #erasure(Type)}. |
| */ |
| private static final TypeVisitor<Class,Void> eraser = new TypeVisitor<Class,Void>() { |
| public Class onClass(Class c,Void v) { |
| return c; |
| } |
| |
| public Class onParameterizdType(ParameterizedType p,Void v) { |
| // TODO: why getRawType returns Type? not Class? |
| return visit(p.getRawType(),null); |
| } |
| |
| public Class onGenericArray(GenericArrayType g,Void v) { |
| return Array.newInstance( |
| visit(g.getGenericComponentType(),null), |
| 0 ).getClass(); |
| } |
| |
| public Class onVariable(TypeVariable t,Void v) { |
| return visit(t.getBounds()[0],null); |
| } |
| |
| public Class onWildcard(WildcardType w,Void v) { |
| return visit(w.getUpperBounds()[0],null); |
| } |
| }; |
| |
| /** |
| * Returns the {@link Class} representation of the given type. |
| * |
| * This corresponds to the notion of the erasure in JSR-14. |
| * |
| * <p> |
| * It made me realize how difficult it is to define the common navigation |
| * layer for two different underlying reflection library. The other way |
| * is to throw away the entire parameterization and go to the wrapper approach. |
| */ |
| public static <T> Class<T> erasure(Type t) { |
| return eraser.visit(t,null); |
| } |
| |
| /** |
| * Returns the {@link Type} object that represents {@code clazz<T1,T2,T3>}. |
| */ |
| public static ParameterizedType createParameterizedType( Class rawType, Type... arguments ) { |
| return new ParameterizedTypeImpl(rawType,arguments,null); |
| } |
| |
| /** |
| * Checks if the type is an array type. |
| */ |
| public static boolean isArray(Type t) { |
| if (t instanceof Class) { |
| Class c = (Class) t; |
| return c.isArray(); |
| } |
| if(t instanceof GenericArrayType) |
| return true; |
| return false; |
| } |
| |
| /** |
| * Checks if the type is an array type but not byte[]. |
| */ |
| public static boolean isArrayButNotByteArray(Type t) { |
| if (t instanceof Class) { |
| Class c = (Class) t; |
| return c.isArray() && c!=byte[].class; |
| } |
| if(t instanceof GenericArrayType) { |
| t = ((GenericArrayType)t).getGenericComponentType(); |
| return t!=Byte.TYPE; |
| } |
| return false; |
| } |
| |
| /** |
| * Gets the component type of the array. |
| * |
| * @param t |
| * must be an array. |
| */ |
| public static Type getComponentType(Type t) { |
| if (t instanceof Class) { |
| Class c = (Class) t; |
| return c.getComponentType(); |
| } |
| if(t instanceof GenericArrayType) |
| return ((GenericArrayType)t).getGenericComponentType(); |
| |
| throw new IllegalArgumentException(); |
| } |
| |
| /** |
| * Gets the i-th type argument from a parameterized type. |
| * |
| * <p> |
| * Unlike {@link #getTypeArgument(Type, int, Type)}, this method |
| * throws {@link IllegalArgumentException} if the given type is |
| * not parameterized. |
| */ |
| public static Type getTypeArgument(Type type, int i) { |
| Type r = getTypeArgument(type, i, null); |
| if(r==null) |
| throw new IllegalArgumentException(); |
| return r; |
| } |
| |
| /** |
| * Gets the i-th type argument from a parameterized type. |
| * |
| * <p> |
| * For example, {@code getTypeArgument([Map<Integer,String>],0)=Integer} |
| * If the given type is not a parameterized type, returns the specified |
| * default value. |
| * |
| * <p> |
| * This is convenient for handling raw types and parameterized types uniformly. |
| * |
| * @throws IndexOutOfBoundsException |
| * If i is out of range. |
| */ |
| public static Type getTypeArgument(Type type, int i, Type defaultValue) { |
| if (type instanceof ParameterizedType) { |
| ParameterizedType p = (ParameterizedType) type; |
| return fix(p.getActualTypeArguments()[i]); |
| } else |
| return defaultValue; |
| } |
| |
| /** |
| * Checks if the given type is a primitive type. |
| */ |
| public static boolean isPrimitive(Type type) { |
| if (type instanceof Class) { |
| Class c = (Class) type; |
| return c.isPrimitive(); |
| } |
| return false; |
| } |
| |
| public static boolean isOverriding(Method method, Class base) { |
| // this isn't actually correct, |
| // as the JLS considers |
| // class Derived extends Base<Integer> { |
| // Integer getX() { ... } |
| // } |
| // class Base<T> { |
| // T getX() { ... } |
| // } |
| // to be overrided. Handling this correctly needs a careful implementation |
| |
| String name = method.getName(); |
| Class[] params = method.getParameterTypes(); |
| |
| while(base!=null) { |
| try { |
| if(null != base.getDeclaredMethod(name,params)) |
| return true; |
| } catch (NoSuchMethodException e) { |
| // recursively go into the base class |
| } |
| |
| base = base.getSuperclass(); |
| } |
| |
| return false; |
| } |
| |
| /** |
| * JDK 5.0 has a bug of createing {@link GenericArrayType} where it shouldn't. |
| * fix that manually to work around the problem. |
| * |
| * See bug 6202725. |
| */ |
| private static Type fix(Type t) { |
| if(!(t instanceof GenericArrayType)) |
| return t; |
| |
| GenericArrayType gat = (GenericArrayType) t; |
| if(gat.getGenericComponentType() instanceof Class) { |
| Class c = (Class) gat.getGenericComponentType(); |
| return Array.newInstance(c,0).getClass(); |
| } |
| |
| return t; |
| } |
| |
| } |