11d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert/* 21d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Copyright (C) 2007 The Guava Authors 31d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 41d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Licensed under the Apache License, Version 2.0 (the "License"); 51d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * you may not use this file except in compliance with the License. 61d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * You may obtain a copy of the License at 71d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 81d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * http://www.apache.org/licenses/LICENSE-2.0 91d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 101d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Unless required by applicable law or agreed to in writing, software 111d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * distributed under the License is distributed on an "AS IS" BASIS, 121d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 131d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * See the License for the specific language governing permissions and 141d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * limitations under the License. 151d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 161d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 171d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertpackage com.google.common.collect; 181d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 191d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport com.google.common.annotations.Beta; 201d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport com.google.common.annotations.GwtCompatible; 211d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 221d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport javax.annotation.Nullable; 231d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 241d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert/** 251d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * A constraint on the keys and values that may be added to a {@code Map} or 261d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * {@code Multimap}. For example, {@link MapConstraints#notNull()}, which 271d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * prevents a map from including any null keys or values, could be implemented 281d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * like this: <pre> {@code 291d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 301d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * public void checkKeyValue(Object key, Object value) { 311d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * if (key == null || value == null) { 321d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * throw new NullPointerException(); 331d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * } 341d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * }}</pre> 351d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 360888a09821a98ac0680fad765217302858e70fa4Paul Duffin * <p>In order to be effective, constraints should be deterministic; that is, they 371d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * should not depend on state that can change (such as external state, random 381d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * variables, and time) and should only depend on the value of the passed-in key 391d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * and value. A non-deterministic constraint cannot reliably enforce that all 401d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * the collection's elements meet the constraint, since the constraint is only 411d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * enforced when elements are added. 421d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * 431d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * @author Mike Bostock 441d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * @see MapConstraints 451d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * @see Constraint 461d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * @since 3.0 471d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 481d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert@GwtCompatible 491d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert@Beta 501d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertpublic interface MapConstraint<K, V> { 511d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert /** 521d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Throws a suitable {@code RuntimeException} if the specified key or value is 531d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * illegal. Typically this is either a {@link NullPointerException}, an 541d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * {@link IllegalArgumentException}, or a {@link ClassCastException}, though 551d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * an application-specific exception class may be used if appropriate. 561d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 571d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert void checkKeyValue(@Nullable K key, @Nullable V value); 581d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 591d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert /** 601d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Returns a brief human readable description of this constraint, such as 611d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * "Not null". 621d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert */ 630888a09821a98ac0680fad765217302858e70fa4Paul Duffin @Override 641d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert String toString(); 651d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert} 66