/*

 * Copyright (c) 2003, 2005, 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.visitor;

import java.lang.reflect.Type;

import java.util.List;

import java.util.Iterator;

import sun.reflect.generics.tree.*;

import sun.reflect.generics.factory.*;

/**

 * Visitor that converts AST to reified types.

 */

public class Reifier implements TypeTreeVisitor<Type> {

    private Type resultType;

    private final GenericsFactory factory;

    private Reifier(GenericsFactory f){

        factory = f;

    }

    private GenericsFactory getFactory(){ return factory;}

    /**

     * Factory method. The resulting visitor will convert an AST

     * representing generic signatures into corresponding reflective

     * objects, using the provided factory, {@code f}.

     * @param f - a factory that can be used to manufacture reflective

     * objects returned by this visitor

     * @return A visitor that can be used to reify ASTs representing

     * generic type information into reflective objects

     */

    public static Reifier make(GenericsFactory f){

        return new Reifier(f);

    }

    // Helper method. Visits an array of TypeArgument and produces

    // reified Type array.

    private Type[] reifyTypeArguments(TypeArgument[] tas) {

        Type[] ts = new Type[tas.length];

        for (int i = 0; i < tas.length; i++) {

            tas[i].accept(this);

            ts[i] = resultType;

        }

        return ts;

    }

    /**

     * Accessor for the result of the last visit by this visitor,

     * @return The type computed by this visitor based on its last

     * visit

     */

    public Type getResult() { assert resultType != null;return resultType;}

    public void visitFormalTypeParameter(FormalTypeParameter ftp){

        resultType = getFactory().makeTypeVariable(ftp.getName(),

                                                   ftp.getBounds());

    }

    public void visitClassTypeSignature(ClassTypeSignature ct){

        // This method examines the pathname stored in ct, which has the form

        // n1.n2...nk<targs>....

        // where n1 ... nk-1 might not exist OR

        // nk might not exist (but not both). It may be that k equals 1.

        // The idea is that nk is the simple class type name that has

        // any type parameters associated with it.

        //  We process this path in two phases.

        //  First, we scan until we reach nk (if it exists).

        //  If nk does not exist, this identifies a raw class n1 ... nk-1

        // which we can return.

        // if nk does exist, we begin the 2nd phase.

        // Here nk defines a parameterized type. Every further step nj (j > k)

        // down the path must also be represented as a parameterized type,

        // whose owner is the representation of the previous step in the path,

        // n{j-1}.

        // extract iterator on list of simple class type sigs

        List<SimpleClassTypeSignature> scts = ct.getPath();

        assert(!scts.isEmpty());

        Iterator<SimpleClassTypeSignature> iter = scts.iterator();

        SimpleClassTypeSignature sc = iter.next();

        StringBuilder n = new StringBuilder(sc.getName());

        boolean dollar = sc.getDollar();

        // phase 1: iterate over simple class types until

        // we are either done or we hit one with non-empty type parameters

        while (iter.hasNext() && sc.getTypeArguments().length == 0) {

            sc = iter.next();

            dollar = sc.getDollar();

            n.append(dollar?"$":".").append(sc.getName());

        }

        // Now, either sc is the last element of the list, or

        // it has type arguments (or both)

        assert(!(iter.hasNext()) || (sc.getTypeArguments().length > 0));

        // Create the raw type

        Type c = getFactory().makeNamedType(n.toString());

        // if there are no type arguments

        if (sc.getTypeArguments().length == 0) {

            //we have surely reached the end of the path

            assert(!iter.hasNext());

            resultType = c; // the result is the raw type

        } else {

            assert(sc.getTypeArguments().length > 0);

            // otherwise, we have type arguments, so we create a parameterized

            // type, whose declaration is the raw type c, and whose owner is

            // the declaring class of c (if any). This latter fact is indicated

            // by passing null as the owner.

            // First, we reify the type arguments

            Type[] pts = reifyTypeArguments(sc.getTypeArguments());

            Type owner = getFactory().makeParameterizedType(c, pts, null);

            // phase 2: iterate over remaining simple class types

            dollar =false;

            while (iter.hasNext()) {

                sc = iter.next();

                dollar = sc.getDollar();

                n.append(dollar?"$":".").append(sc.getName()); // build up raw class name

                c = getFactory().makeNamedType(n.toString()); // obtain raw class

                pts = reifyTypeArguments(sc.getTypeArguments());// reify params

                // Create a parameterized type, based on type args, raw type

                // and previous owner

                owner = getFactory().makeParameterizedType(c, pts, owner);

            }

            resultType = owner;

        }

    }

    public void visitArrayTypeSignature(ArrayTypeSignature a){

        // extract and reify component type

        a.getComponentType().accept(this);

        Type ct = resultType;

        resultType = getFactory().makeArrayType(ct);

    }

    public void visitTypeVariableSignature(TypeVariableSignature tv){

        resultType = getFactory().findTypeVariable(tv.getIdentifier());

    }

    public void visitWildcard(Wildcard w){

        resultType = getFactory().makeWildcard(w.getUpperBounds(),

                                               w.getLowerBounds());

    }

    public void visitSimpleClassTypeSignature(SimpleClassTypeSignature sct){

        resultType = getFactory().makeNamedType(sct.getName());

    }

    public void visitBottomSignature(BottomSignature b){

    }

    public void visitByteSignature(ByteSignature b){

        resultType = getFactory().makeByte();

    }

    public void visitBooleanSignature(BooleanSignature b){

        resultType = getFactory().makeBool();

    }

    public void visitShortSignature(ShortSignature s){

        resultType = getFactory().makeShort();

    }

    public void visitCharSignature(CharSignature c){

        resultType = getFactory().makeChar();

    }

    public void visitIntSignature(IntSignature i){

        resultType = getFactory().makeInt();

    }

    public void visitLongSignature(LongSignature l){

        resultType = getFactory().makeLong();

    }

    public void visitFloatSignature(FloatSignature f){

        resultType = getFactory().makeFloat();

    }

    public void visitDoubleSignature(DoubleSignature d){

        resultType = getFactory().makeDouble();

    }

    public void visitVoidDescriptor(VoidDescriptor v){

        resultType = getFactory().makeVoid();

    }

}