| /* |
| * Copyright (C) 2018 The Android Open Source Project |
| * |
| * 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.android.server.textservices; |
| |
| import android.annotation.NonNull; |
| import android.util.SparseIntArray; |
| |
| import java.util.function.IntUnaryOperator; |
| |
| /** |
| * Simple int-to-int key-value-store that is to be lazily initialized with the given |
| * {@link IntUnaryOperator}. |
| */ |
| final class LazyIntToIntMap { |
| |
| private final SparseIntArray mMap = new SparseIntArray(); |
| |
| @NonNull |
| private final IntUnaryOperator mMappingFunction; |
| |
| /** |
| * @param mappingFunction int to int mapping rules to be (lazily) evaluated |
| */ |
| public LazyIntToIntMap(@NonNull IntUnaryOperator mappingFunction) { |
| mMappingFunction = mappingFunction; |
| } |
| |
| /** |
| * Deletes {@code key} and associated value. |
| * @param key key to be deleted |
| */ |
| public void delete(int key) { |
| mMap.delete(key); |
| } |
| |
| /** |
| * @param key key associated with the value |
| * @return value associated with the {@code key}. If this is the first time to access |
| * {@code key}, then {@code mappingFunction} passed to the constructor will be evaluated |
| */ |
| public int get(int key) { |
| final int index = mMap.indexOfKey(key); |
| if (index >= 0) { |
| return mMap.valueAt(index); |
| } |
| final int value = mMappingFunction.applyAsInt(key); |
| mMap.append(key, value); |
| return value; |
| } |
| } |