001/*
002 * Copyright 2010-2013 JetBrains s.r.o.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.jetbrains.jet.lang.types;
018
019import org.jetbrains.annotations.Nullable;
020
021public interface TypeSubstitution {
022    TypeSubstitution EMPTY = new TypeSubstitution() {
023        @Override
024        public TypeProjection get(TypeConstructor key) {
025            return null;
026        }
027
028        @Override
029        public boolean isEmpty() {
030            return true;
031        }
032
033        @Override
034        public String toString() {
035            return "Empty TypeSubstitution";
036        }
037    };
038
039    @Nullable
040    TypeProjection get(TypeConstructor key);
041    boolean isEmpty();
042}