| /* |
| * Copyright 2000-2014 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.util.indexing; |
| |
| import org.jetbrains.annotations.NotNull; |
| import org.jetbrains.annotations.Nullable; |
| |
| import java.util.Collections; |
| import java.util.Map; |
| |
| /** |
| * Simplifies API and ensures that data key will always be equal to virtual file id |
| * |
| * @author Eugene Zhuravlev |
| * Date: Feb 18, 2009 |
| */ |
| public abstract class SingleEntryIndexer<V> implements DataIndexer<Integer, V, FileContent>{ |
| private final boolean myAcceptNullValues; |
| |
| protected SingleEntryIndexer(boolean acceptNullValues) { |
| myAcceptNullValues = acceptNullValues; |
| } |
| |
| @Override |
| @NotNull |
| public final Map<Integer, V> map(@NotNull FileContent inputData) { |
| if (inputData == null) { |
| return Collections.emptyMap(); |
| } |
| final V value = computeValue(inputData); |
| if (value == null && !myAcceptNullValues) { |
| return Collections.emptyMap(); |
| } |
| final int key = Math.abs(FileBasedIndex.getFileId(inputData.getFile())); |
| return Collections.singletonMap(key, value); |
| } |
| |
| protected abstract @Nullable V computeValue(@NotNull FileContent inputData); |
| } |