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    
017    package org.jetbrains.jet.util;
018    
019    import jet.Function0;
020    import jet.Function1;
021    import org.jetbrains.annotations.NotNull;
022    import org.jetbrains.jet.storage.NotNullLazyValue;
023    
024    import static org.jetbrains.jet.storage.LockBasedStorageManager.NO_LOCKS;
025    
026    public class StorageUtil {
027        private static final Function1 EMPTY_CONSUMER = new Function1<Object, Void>() {
028                    @Override
029                    public Void invoke(Object t) {
030                        return null;
031                    }
032                };
033    
034    
035        public static <T> NotNullLazyValue<T> createRecursionIntolerantLazyValueWithDefault(
036                @NotNull final T defaultValue,
037                @NotNull Function0<T> compute
038        ) {
039            //noinspection unchecked
040            return NO_LOCKS.createLazyValueWithPostCompute(
041                    compute,
042                    new Function1<Boolean, T>() {
043                        @Override
044                        public T invoke(Boolean firstTime) {
045                            if (firstTime) throw new ReenteringLazyValueComputationException();
046                            return defaultValue;
047                        }
048                    },
049                    EMPTY_CONSUMER
050            );
051        }
052    }