| /* |
| * 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 com.intellij.util.io.DataExternalizer; |
| import org.jetbrains.annotations.NotNull; |
| import org.jetbrains.annotations.Nullable; |
| |
| import java.io.DataInput; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| |
| /** |
| * A specialization of FileBasedIndexExtension allowing to create a mapping [DataObject -> List of files containing this object] |
| * |
| */ |
| public abstract class ScalarIndexExtension<K> extends FileBasedIndexExtension<K, Void>{ |
| |
| public static final DataExternalizer<Void> VOID_DATA_EXTERNALIZER = new VoidDataExternalizer(); |
| |
| @NotNull |
| @Override |
| public final DataExternalizer<Void> getValueExternalizer() { |
| return VOID_DATA_EXTERNALIZER; |
| } |
| |
| private static class VoidDataExternalizer implements DataExternalizer<Void> { |
| |
| @Override |
| public void save(@NotNull final DataOutput out, final Void value) throws IOException { |
| } |
| |
| @Override |
| @Nullable |
| public Void read(@NotNull final DataInput in) throws IOException { |
| return null; |
| } |
| } |
| } |