001 /* 002 * Created on Jul 15, 2010 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with 005 * the License. You may obtain a copy of the License at 006 * 007 * http://www.apache.org/licenses/LICENSE-2.0 008 * 009 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on 010 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the 011 * specific language governing permissions and limitations under the License. 012 * 013 * Copyright @2010-2011 the original author or authors. 014 */ 015 package org.fest.assertions.core; 016 017 import java.util.Comparator; 018 019 /** 020 * Base contract of all assertion objects: the minimum functionality that any assertion object should provide. 021 * @param <S> the "self" type of this assertion class. Please read "<a href="http://bit.ly/anMa4g" 022 * target="_blank">Emulating 'self types' using Java Generics to simplify fluent API implementation</a>" 023 * for more details. 024 * @param <A> the type of the "actual" value. 025 * 026 * @author Yvonne Wang 027 * @author Alex Ruiz 028 * @author Nicolas François 029 */ 030 public interface Assert<S, A> extends Descriptable<S>, ExtensionPoints<S, A> { 031 032 /** 033 * Verifies that the actual value is equal to the given one. 034 * @param expected the given value to compare the actual value to. 035 * @return {@code this} assertion object. 036 * @throws AssertionError if the actual value is not equal to the given one. 037 */ 038 S isEqualTo(A expected); 039 040 /** 041 * Verifies that the actual value is not equal to the given one. 042 * @param other the given value to compare the actual value to. 043 * @return {@code this} assertion object. 044 * @throws AssertionError if the actual value is equal to the given one. 045 */ 046 S isNotEqualTo(A other); 047 048 /** 049 * Verifies that the actual value is {@code null}. 050 * @throws AssertionError if the actual value is not {@code null}. 051 */ 052 void isNull(); 053 054 /** 055 * Verifies that the actual value is not {@code null}. 056 * @return {@code this} assertion object. 057 * @throws AssertionError if the actual value is {@code null}. 058 */ 059 S isNotNull(); 060 061 /** 062 * Verifies that the actual value is the same as the given one. 063 * @param expected the given value to compare the actual value to. 064 * @return {@code this} assertion object. 065 * @throws AssertionError if the actual value is not the same as the given one. 066 */ 067 S isSameAs(A expected); 068 069 /** 070 * Verifies that the actual value is not the same as the given one. 071 * @param other the given value to compare the actual value to. 072 * @return {@code this} assertion object. 073 * @throws AssertionError if the actual value is the same as the given one. 074 */ 075 S isNotSameAs(A other); 076 077 /** 078 * Verifies that the actual value is present in the given array of values. 079 * @param values the given array to search the actual value in. 080 * @return {@code this} assertion object. 081 * @throws NullPointerException if the given array is {@code null}. 082 * @throws IllegalArgumentException if the given array is empty. 083 * @throws AssertionError if the actual value is not present in the given array. 084 */ 085 S isIn(A... values); 086 087 /** 088 * Verifies that the actual value is not present in the given array of values. 089 * @param values the given array to search the actual value in. 090 * @return {@code this} assertion object. 091 * @throws NullPointerException if the given array is {@code null}. 092 * @throws IllegalArgumentException if the given array is empty. 093 * @throws AssertionError if the actual value is present in the given array. 094 */ 095 S isNotIn(A... values); 096 097 /** 098 * Verifies that the actual value is present in the given values. 099 * @param values the given iterable to search the actual value in. 100 * @return {@code this} assertion object. 101 * @throws NullPointerException if the given collection is {@code null}. 102 * @throws IllegalArgumentException if the given collection is empty. 103 * @throws AssertionError if the actual value is not present in the given collection. 104 */ 105 S isIn(Iterable<? extends A> values); 106 107 /** 108 * Verifies that the actual value is not present in the given values. 109 * @param values the given iterable to search the actual value in. 110 * @return {@code this} assertion object. 111 * @throws NullPointerException if the given collection is {@code null}. 112 * @throws IllegalArgumentException if the given collection is empty. 113 * @throws AssertionError if the actual value is present in the given collection. 114 */ 115 S isNotIn(Iterable<? extends A> values); 116 117 /** 118 * Use given custom comparator instead of relying on actual type A equals method for incoming assertion checks.<br> 119 * Custom comparator is bound to assertion instance, meaning that if a new assertion is created, it will use default 120 * comparison strategy. </p> Example : 121 * 122 * <pre> 123 * // compares invoices by payee 124 * assertThat(invoiceList).usingComparator(invoicePayeeComparator).isEqualTo(expectedInvoiceList). 125 * 126 * // compares invoices by date, doesNotHaveDuplicates and contains both use the given invoice date comparator 127 * assertThat(invoiceList).usingComparator(invoiceDateComparator).doesNotHaveDuplicates().contains(may2010Invoice) 128 * 129 * // as assertThat(invoiceList) creates a new assertion, it uses standard comparison strategy (Invoice's equal method) to compare invoiceList elements to lowestInvoice. 130 * assertThat(invoiceList).contains(lowestInvoice). 131 * </pre> 132 * 133 * Custom comparator is not parameterized with actual type A (ie. Comparator<A>) because if it was, we could not 134 * write the following code : 135 * 136 * <pre> 137 * // frodo and sam are instances of Character (a Character having a Race) 138 * // raceComparator implements Comparator<Character> 139 * // assertThat(frodo) returns an ObjectAssert and not a custom CharacterAssert implementing Assert<CharacterAssert, Character> 140 * assertThat(frodo).usingComparator(raceComparator).isEqualTo(sam); // won't compile ! 141 * 142 * The code does not compile because assertThat(frodo) returns an ObjectAssert, thus usingComparator expects a Comparator<Object> 143 * and Comparator<Character> is not a Comparator<Object> as generics are not reified. 144 * 145 * Note that, it would have worked if assertThat(frodo) returned a CharacterAssert implementing Assert<CharacterAssert, Character>. 146 * </pre> 147 * 148 * @param customComparator the comparator to use for incoming assertion checks. 149 * @throws NullPointerException if the given comparator is {@code null}. 150 * @return {@code this} assertion object. 151 */ 152 S usingComparator(Comparator<?> customComparator); 153 154 /** 155 * Revert to standard comparison for incoming assertion checks.<br> 156 * This method should be used to disable a custom comparison strategy set by calling 157 * {@link #usingComparator(Comparator)}. 158 * @return {@code this} assertion object. 159 */ 160 S usingDefaultComparator(); 161 162 /** 163 * Throws <code>{@link UnsupportedOperationException}</code> if called. It is easy to accidentally call 164 * <code>{@link #equals(Object)}</code> instead of <code>isEqualTo</code>. 165 * @throws UnsupportedOperationException if this method is called. 166 */ 167 @Override boolean equals(Object obj); 168 }