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.codegen;
018
019import com.google.common.collect.Lists;
020import org.jetbrains.annotations.NotNull;
021
022import java.util.List;
023
024public abstract class ClassBuilderOnDemand {
025
026    private ClassBuilder classBuilder;
027
028    private final List<ClassBuilderCallback> optionalDeclarations = Lists.newArrayList();
029
030    interface ClassBuilderCallback {
031        void doSomething(@NotNull ClassBuilder classBuilder);
032    }
033
034    @NotNull
035    protected abstract ClassBuilder createClassBuilder();
036
037    public void addOptionalDeclaration(@NotNull ClassBuilderCallback callback) {
038        optionalDeclarations.add(callback);
039        if (classBuilder != null) {
040            callback.doSomething(classBuilder);
041        }
042    }
043
044    @NotNull
045    public ClassBuilder getClassBuilder() {
046        if (classBuilder == null) {
047            classBuilder = createClassBuilder();
048            for (ClassBuilderCallback callback : optionalDeclarations) {
049                callback.doSomething(classBuilder);
050            }
051        }
052        return classBuilder;
053    }
054
055    public void done() {
056        if (classBuilder != null) {
057            classBuilder.done();
058        }
059    }
060
061    public boolean isActivated() {
062        return classBuilder != null;
063    }
064}