| /* |
| * Copyright 2000-2013 JetBrains s.r.o. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.intellij.psi.util; |
| |
| import com.intellij.openapi.diagnostic.Logger; |
| import com.intellij.util.ArrayUtil; |
| import org.jetbrains.annotations.NotNull; |
| import org.jetbrains.annotations.Nullable; |
| |
| import java.util.Collection; |
| |
| public interface CachedValueProvider<T> { |
| @Nullable |
| Result<T> compute(); |
| |
| class Result<T> { |
| private static final Logger LOG = Logger.getInstance("#com.intellij.psi.util.CachedValueProvider.Result"); |
| private final T myValue; |
| private final Object[] myDependencyItems; |
| |
| public Result(@Nullable T value, @NotNull Object... dependencyItems) { |
| myValue = value; |
| myDependencyItems = dependencyItems; |
| |
| if (dependencyItems.length == 0) { |
| LOG.error("No dependencies provided which causes CachedValue to be never recalculated again. " + |
| "If this is intentional, please use ModificationTracker.NEVER_CHANGED"); |
| } |
| for (int i = 0; i < dependencyItems.length; i++) { |
| if (dependencyItems[i] == null) { |
| LOG.error("Null dependencies are not allowed, index=" + i); |
| } |
| } |
| } |
| |
| public T getValue() { |
| return myValue; |
| } |
| |
| @NotNull |
| public Object[] getDependencyItems() { |
| return myDependencyItems; |
| } |
| |
| public static <T> Result<T> createSingleDependency(@Nullable T value, @NotNull Object dependency) { |
| return create(value, dependency); |
| } |
| |
| public static <T> Result<T> create(@Nullable T value, @NotNull Object... dependencies) { |
| return new Result<T>(value, dependencies); |
| } |
| |
| public static <T> Result<T> create(@Nullable T value, @NotNull Collection<?> dependencies) { |
| return new Result<T>(value, ArrayUtil.toObjectArray(dependencies)); |
| } |
| |
| } |
| } |