/*
* Copyright (c) 2003, 2004, Oracle and/or its affiliates. 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package sun.reflect.generics.reflectiveObjects;
import java.lang.reflect.Type;
import java.lang.reflect.WildcardType;
import sun.reflect.generics.factory.GenericsFactory;
import sun.reflect.generics.tree.FieldTypeSignature;
import sun.reflect.generics.visitor.Reifier;
import java.util.Arrays;
/**
* Implementation of WildcardType interface for core reflection.
*/
public class WildcardTypeImpl extends LazyReflectiveObjectGenerator
implements WildcardType {
// upper bounds - evaluated lazily
private Type[] upperBounds;
// lower bounds - evaluated lazily
private Type[] lowerBounds;
// 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[] upperBoundASTs;
private FieldTypeSignature[] lowerBoundASTs;
// constructor is private to enforce access through static factory
private WildcardTypeImpl(FieldTypeSignature[] ubs,
FieldTypeSignature[] lbs,
GenericsFactory f) {
super(f);
upperBoundASTs = ubs;
lowerBoundASTs = lbs;
}
/**
* Factory method.
* @param ubs - an array of ASTs representing the upper bounds for the type
* variable to be created
* @param lbs - an array of ASTs representing the lower 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 wildcard type
* @return a wild card type with the requested bounds and factory
*/
public static WildcardTypeImpl make(FieldTypeSignature[] ubs,
FieldTypeSignature[] lbs,
GenericsFactory f) {
return new WildcardTypeImpl(ubs, lbs, f);
}
// Accessors
// accessor for ASTs for upper bounds. Must not be called after upper
// bounds have been evaluated, because we might throw the ASTs
// away (but that is not thread-safe, is it?)
private FieldTypeSignature[] getUpperBoundASTs() {
// check that upper bounds were not evaluated yet
assert(upperBounds == null);
return upperBoundASTs;
}
// accessor for ASTs for lower bounds. Must not be called after lower
// bounds have been evaluated, because we might throw the ASTs
// away (but that is not thread-safe, is it?)
private FieldTypeSignature[] getLowerBoundASTs() {
// check that lower bounds were not evaluated yet
assert(lowerBounds == null);
return lowerBoundASTs;
}
/**
* 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>
*
* @return an array of Types representing the upper bound(s) of this
* type variable
* @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
*/
public Type[] getUpperBounds() {
// lazily initialize bounds if necessary
if (upperBounds == null) {
FieldTypeSignature[] fts = getUpperBoundASTs(); // 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
upperBounds = ts;
// could throw away upper bound ASTs here; thread safety?
}
return upperBounds.clone(); // return cached bounds
}
/**
* Returns an array of <tt>Type</tt> objects representing the
* lower bound(s) of this type variable. Note that if no lower bound is
* explicitly declared, the lower bound is the type of <tt>null</tt>.
* In this case, a zero length array is returned.
*
* <p>For each lower 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>
*
* @return an array of Types representing the lower bound(s) of this
* type variable
* @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
*/
public Type[] getLowerBounds() {
// lazily initialize bounds if necessary
if (lowerBounds == null) {
FieldTypeSignature[] fts = getLowerBoundASTs(); // 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
lowerBounds = ts;
// could throw away lower bound ASTs here; thread safety?
}
return lowerBounds.clone(); // return cached bounds
}
public String toString() {
Type[] lowerBounds = getLowerBounds();
Type[] bounds = lowerBounds;
StringBuilder sb = new StringBuilder();
if (lowerBounds.length > 0)
sb.append("? super ");
else {
Type[] upperBounds = getUpperBounds();
if (upperBounds.length > 0 && !upperBounds[0].equals(Object.class) ) {
bounds = upperBounds;
sb.append("? extends ");
} else
return "?";
}
assert bounds.length > 0;
boolean first = true;
for(Type bound: bounds) {
if (!first)
sb.append(" & ");
first = false;
if (bound instanceof Class)
sb.append(((Class)bound).getName() );
else
sb.append(bound.toString());
}
return sb.toString();
}
@Override
public boolean equals(Object o) {
if (o instanceof WildcardType) {
WildcardType that = (WildcardType) o;
return
Arrays.equals(this.getLowerBounds(),
that.getLowerBounds()) &&
Arrays.equals(this.getUpperBounds(),
that.getUpperBounds());
} else
return false;
}
@Override
public int hashCode() {
Type [] lowerBounds = getLowerBounds();
Type [] upperBounds = getUpperBounds();
return Arrays.hashCode(lowerBounds) ^ Arrays.hashCode(upperBounds);
}
}