1 import org.checkerframework.checker.nullness.qual.EnsuresNonNullIf; 2 import org.checkerframework.checker.nullness.qual.NonNull; 3 import org.checkerframework.checker.nullness.qual.Nullable; 4 5 package com.google.common.base; 6 7 class Strings { 8 @EnsuresNonNullIf(result = false, expression = "#1") 9 static boolean isNullOrEmpty(@Nullable String str); 10 } 11 12 class Preconditions { 13 static <T extends @NonNull Object> T checkNotNull(T reference, @Nullable Object errorMessage); 14 } 15
