/*

 * Copyright (c) 2014, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.tools.javac.comp;

import java.util.Collection;

import java.util.HashMap;

import com.sun.tools.javac.code.Symbol.TypeSymbol;

import com.sun.tools.javac.util.Context;

/** This class contains the type environments used by Enter, MemberEnter,

 *  Attr, DeferredAttr, and Lower.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 */

class TypeEnvs {

    private static final long serialVersionUID = 571524752489954631L;

    protected static final Context.Key<TypeEnvs> typeEnvsKey = new Context.Key<>();

    public static TypeEnvs instance(Context context) {

        TypeEnvs instance = context.get(typeEnvsKey);

        if (instance == null)

            instance = new TypeEnvs(context);

        return instance;

    }

    private HashMap<TypeSymbol,Env<AttrContext>> map;

    protected TypeEnvs(Context context) {

        map = new HashMap<>();

        context.put(typeEnvsKey, this);

    }

    Env<AttrContext> get(TypeSymbol sym) { return map.get(sym); }

    Env<AttrContext> put(TypeSymbol sym, Env<AttrContext> env) { return map.put(sym, env); }

    Env<AttrContext> remove(TypeSymbol sym) { return map.remove(sym); }

    Collection<Env<AttrContext>> values() { return map.values(); }

    void clear() { map.clear(); }

}