1 /* 2 * Copyright 2012, Google LLC 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * * Neither the name of Google LLC nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 package com.android.tools.smali.util; 32 33 import static java.util.Collections.unmodifiableSet; 34 import static java.util.Collections.unmodifiableSortedSet; 35 import static java.util.Collections.unmodifiableList; 36 37 import javax.annotation.Nonnull; 38 import javax.annotation.Nullable; 39 import java.util.Collections; 40 import java.util.List; 41 import java.util.Set; 42 import java.util.SortedSet; 43 44 public class ImmutableUtils { nullToEmptyList(@ullable List<T> list)45 @Nonnull public static <T> List<T> nullToEmptyList(@Nullable List<T> list) { 46 if (list == null) { 47 return Collections.emptyList(); 48 } 49 return unmodifiableList(list); 50 } 51 nullToEmptySet(@ullable Set<T> set)52 @Nonnull public static <T> Set<T> nullToEmptySet(@Nullable Set<T> set) { 53 if (set == null) { 54 return Collections.emptySet(); 55 } 56 return unmodifiableSet(set); 57 } 58 nullToEmptySortedSet(@ullable SortedSet<T> set)59 @Nonnull public static <T> SortedSet<T> nullToEmptySortedSet(@Nullable SortedSet<T> set) { 60 if (set == null) { 61 return Collections.emptySortedSet(); 62 } 63 return unmodifiableSortedSet(set); 64 } 65 } 66