/*
* Copyright 2003-2004 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package sun.reflect.generics.reflectiveObjects;
import java.lang.reflect.GenericDeclaration;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import sun.reflect.generics.factory.GenericsFactory;
import sun.reflect.generics.tree.FieldTypeSignature;
import sun.reflect.generics.visitor.Reifier;
/**
* Implementation of <tt>java.lang.reflect.TypeVariable</tt> interface
* for core reflection.
*/
public class TypeVariableImpl<D extends GenericDeclaration>
extends LazyReflectiveObjectGenerator implements TypeVariable<D> {
D genericDeclaration;
private String name;
// upper bounds - evaluated lazily
private Type[] bounds;
// The ASTs for the bounds. We are required to evaluate the bounds
// lazily, so we store these at least until we are first asked
// for the bounds. This also neatly solves the
// problem with F-bounds - you can't reify them before the formal
// is defined.
private FieldTypeSignature[] boundASTs;
// constructor is private to enforce access through static factory
private TypeVariableImpl(D decl, String n, FieldTypeSignature[] bs,
GenericsFactory f) {
super(f);
genericDeclaration = decl;
name = n;
boundASTs = bs;
}
// Accessors
// accessor for ASTs for bounds. Must not be called after
// bounds have been evaluated, because we might throw the ASTs
// away (but that is not thread-safe, is it?)
private FieldTypeSignature[] getBoundASTs() {
// check that bounds were not evaluated yet
assert(bounds == null);
return boundASTs;
}
/**
* Factory method.
* @param decl - the reflective object that declared the type variable
* that this method should create
* @param name - the name of the type variable to be returned
* @param bs - an array of ASTs representing the bounds for the type
* variable to be created
* @param f - a factory that can be used to manufacture reflective
* objects that represent the bounds of this type variable
* @return A type variable with name, bounds, declaration and factory
* specified
*/
public static <T extends GenericDeclaration>
TypeVariableImpl<T> make(T decl, String name,
FieldTypeSignature[] bs,
GenericsFactory f) {
return new TypeVariableImpl<T>(decl, name, bs, f);
}
/**
* Returns an array of <tt>Type</tt> objects representing the
* upper bound(s) of this type variable. Note that if no upper bound is
* explicitly declared, the upper bound is <tt>Object</tt>.
*
* <p>For each upper bound B:
* <ul>
* <li>if B is a parameterized type or a type variable, it is created,
* (see {@link #ParameterizedType} for the details of the creation
* process for parameterized types).
* <li>Otherwise, B is resolved.
* </ul>
*
* @throws <tt>TypeNotPresentException</tt> if any of the
* bounds refers to a non-existent type declaration
* @throws <tt>MalformedParameterizedTypeException</tt> if any of the
* bounds refer to a parameterized type that cannot be instantiated
* for any reason
* @return an array of Types representing the upper bound(s) of this
* type variable
*/
public Type[] getBounds() {
// lazily initialize bounds if necessary
if (bounds == null) {
FieldTypeSignature[] fts = getBoundASTs(); // get AST
// allocate result array; note that
// keeping ts and bounds separate helps with threads
Type[] ts = new Type[fts.length];
// iterate over bound trees, reifying each in turn
for ( int j = 0; j < fts.length; j++) {
Reifier r = getReifier();
fts[j].accept(r);
ts[j] = r.getResult();
}
// cache result
bounds = ts;
// could throw away bound ASTs here; thread safety?
}
return bounds.clone(); // return cached bounds
}
/**
* Returns the <tt>GenericDeclaration</tt> object representing the
* generic declaration that declared this type variable.
*
* @return the generic declaration that declared this type variable.
*
* @since 1.5
*/
public D getGenericDeclaration(){
return genericDeclaration;
}
/**
* Returns the name of this type variable, as it occurs in the source code.
*
* @return the name of this type variable, as it appears in the source code
*/
public String getName() { return name; }
public String toString() {return getName();}
@Override
public boolean equals(Object o) {
if (o instanceof TypeVariable) {
TypeVariable that = (TypeVariable) o;
GenericDeclaration thatDecl = that.getGenericDeclaration();
String thatName = that.getName();
return
(genericDeclaration == null ?
thatDecl == null :
genericDeclaration.equals(thatDecl)) &&
(name == null ?
thatName == null :
name.equals(thatName));
} else
return false;
}
@Override
public int hashCode() {
return genericDeclaration.hashCode() ^ name.hashCode();
}
}