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.*;
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 &quot;<a href="http://bit.ly/anMa4g"
022     *          target="_blank">Emulating 'self types' using Java Generics to simplify fluent API implementation</a>&quot;
023     *          for more details.
024     * @param <A> the type of the "actual" value.
025     * 
026     * @author Yvonne Wang
027     * @author Alex Ruiz
028     */
029    public interface Assert<S, A> extends Descriptable<S>, ExtensionPoints<S, A> {
030    
031      /**
032       * Verifies that the actual value is equal to the given one.
033       * @param expected the given value to compare the actual value to.
034       * @return {@code this} assertion object.
035       * @throws AssertionError if the actual value is not equal to the given one.
036       */
037      S isEqualTo(A expected);
038    
039      /**
040       * Verifies that the actual value is not equal to the given one.
041       * @param other the given value to compare the actual value to.
042       * @return {@code this} assertion object.
043       * @throws AssertionError if the actual value is equal to the given one.
044       */
045      S isNotEqualTo(A other);
046    
047      /**
048       * Verifies that the actual value is {@code null}.
049       * @throws AssertionError if the actual value is not {@code null}.
050       */
051      void isNull();
052    
053      /**
054       * Verifies that the actual value is not {@code null}.
055       * @return {@code this} assertion object.
056       * @throws AssertionError if the actual value is {@code null}.
057       */
058      S isNotNull();
059    
060      /**
061       * Verifies that the actual value is the same as the given one.
062       * @param expected the given value to compare the actual value to.
063       * @return {@code this} assertion object.
064       * @throws AssertionError if the actual value is not the same as the given one.
065       */
066      S isSameAs(A expected);
067    
068      /**
069       * Verifies that the actual value is not the same as the given one.
070       * @param other the given value to compare the actual value to.
071       * @return {@code this} assertion object.
072       * @throws AssertionError if the actual value is the same as the given one.
073       */
074      S isNotSameAs(A other);
075    
076      /**
077       * Verifies that the actual value is present in the given array of values.
078       * @param values the given array to search the actual value in.
079       * @return {@code this} assertion object.
080       * @throws NullPointerException if the given array is {@code null}.
081       * @throws IllegalArgumentException if the given array is empty.
082       * @throws AssertionError if the actual value is not present in the given array.
083       */
084      S isIn(A... values);
085    
086      /**
087       * Verifies that the actual value is not present in the given array of values.
088       * @param values the given array to search the actual value in.
089       * @return {@code this} assertion object.
090       * @throws NullPointerException if the given array is {@code null}.
091       * @throws IllegalArgumentException if the given array is empty.
092       * @throws AssertionError if the actual value is present in the given array.
093       */
094      S isNotIn(A... values);
095    
096      /**
097       * Verifies that the actual value is present in the given collection of values.
098       * @param values the given collection to search the actual value in.
099       * @return {@code this} assertion object.
100       * @throws NullPointerException if the given collection is {@code null}.
101       * @throws IllegalArgumentException if the given collection is empty.
102       * @throws AssertionError if the actual value is not present in the given collection.
103       */
104      S isIn(Collection<?> values);
105    
106      /**
107       * Verifies that the actual value is not present in the given collection of values.
108       * @param values the given collection to search the actual value in.
109       * @return {@code this} assertion object.
110       * @throws NullPointerException if the given collection is {@code null}.
111       * @throws IllegalArgumentException if the given collection is empty.
112       * @throws AssertionError if the actual value is present in the given collection.
113       */
114      S isNotIn(Collection<?> values);
115    
116      /**
117       * Use given custom comparator instead of relying on actual type A equals method for incoming assertion checks.<br>
118       * Custom comparator is bound to assertion instance, meaning that if a new assertion is created, it will use default
119       * comparison strategy. </p> Example :
120       * 
121       * <pre>
122       * // compares invoices by payee 
123       * assertThat(invoiceList).usingComparator(invoicePayeeComparator).isEqualTo(expectedInvoiceList).
124       * 
125       * // compares invoices by date, doesNotHaveDuplicates and contains both use the given invoice date comparator
126       * assertThat(invoiceList).usingComparator(invoiceDateComparator).doesNotHaveDuplicates().contains(may2010Invoice)
127       * 
128       * // as assertThat(invoiceList) creates a new assertion, it uses standard comparison strategy (Invoice's equal method) to compare invoiceList elements to lowestInvoice.                                                      
129       * assertThat(invoiceList).contains(lowestInvoice).
130       * </pre>
131       * 
132       * Custom comparator is not parameterized with actual type A (ie. Comparator&lt;A&gt;) because if it was, we could not
133       * write the following code :
134       * 
135       * <pre>
136       * // frodo and sam are instances of Character (a Character having a Race)
137       * // raceComparator implements Comparator&lt;Character&gt; 
138       * // assertThat(frodo) returns an ObjectAssert and not a custom CharacterAssert implementing Assert&lt;CharacterAssert, Character&gt;  
139       * assertThat(frodo).usingComparator(raceComparator).isEqualTo(sam); // won't compile !
140       * 
141       * The code does not compile because assertThat(frodo) returns an ObjectAssert, thus usingComparator expects a Comparator&lt;Object&gt; 
142       * and Comparator&lt;Character&gt; is not a Comparator&lt;Object&gt; as generics are not reified.
143       * 
144       * Note that, it would have worked if assertThat(frodo) returned a CharacterAssert implementing Assert&lt;CharacterAssert, Character&gt;. 
145       * </pre>
146       * 
147       * @param customComparator the comparator to use for incoming assertion checks.
148       * @throws NullPointerException if the given comparator is {@code null}.
149       * @return {@code this} assertion object.
150       */
151      S usingComparator(Comparator<?> customComparator);
152    
153      /**
154       * Revert to standard comparison for incoming assertion checks.<br>
155       * This method should be used to disable a custom comparison strategy set by calling
156       * {@link #usingComparator(Comparator)}.
157       * @return {@code this} assertion object.
158       */
159      S usingDefaultComparator();
160      
161      /**
162       * Throws <code>{@link UnsupportedOperationException}</code> if called. It is easy to accidentally call
163       * <code>{@link #equals(Object)}</code> instead of <code>isEqualTo</code>.
164       * @throws UnsupportedOperationException if this method is called.
165       */
166      @Override boolean equals(Object obj);
167    }