78 lines
2.5 KiB
Java
78 lines
2.5 KiB
Java
/*
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* Copyright (C) 2012 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.inputmethod.latin.common;
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import com.android.inputmethod.annotations.UsedForTesting;
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.Map;
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import javax.annotation.Nonnull;
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import javax.annotation.Nullable;
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/**
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* Utility methods for working with collections.
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*/
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public final class CollectionUtils {
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private CollectionUtils() {
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// This utility class is not publicly instantiable.
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}
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/**
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* Converts a sub-range of the given array to an ArrayList of the appropriate type.
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* @param array Array to be converted.
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* @param start First index inclusive to be converted.
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* @param end Last index exclusive to be converted.
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* @throws IllegalArgumentException if start or end are out of range or start > end.
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*/
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@Nonnull
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public static <E> ArrayList<E> arrayAsList(@Nonnull final E[] array, final int start,
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final int end) {
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if (start < 0 || start > end || end > array.length) {
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throw new IllegalArgumentException("Invalid start: " + start + " end: " + end
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+ " with array.length: " + array.length);
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}
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final ArrayList<E> list = new ArrayList<>(end - start);
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for (int i = start; i < end; i++) {
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list.add(array[i]);
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}
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return list;
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}
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/**
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* Tests whether c contains no elements, true if c is null or c is empty.
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* @param c Collection to test.
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* @return Whether c contains no elements.
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*/
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@UsedForTesting
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public static boolean isNullOrEmpty(@Nullable final Collection c) {
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return c == null || c.isEmpty();
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}
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/**
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* Tests whether map contains no elements, true if map is null or map is empty.
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* @param map Map to test.
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* @return Whether map contains no elements.
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*/
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@UsedForTesting
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public static boolean isNullOrEmpty(@Nullable final Map map) {
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return map == null || map.isEmpty();
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}
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}
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