001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.juneau.junit.bct;
018
019/**
020 * Functional interface for computing the size of objects in test assertions.
021 *
022 * <p>
023 * Sizers are used by {@link BeanConverter#size(Object)} to determine the size of collection-like
024 * objects when validating test assertions. This provides a flexible way to compute sizes for custom
025 * types without needing to convert them to lists first.
026 *
027 * <h5 class='section'>Usage Example:</h5>
028 * <p class='bjava'>
029 *    <jc>// Register a sizer for a custom collection type</jc>
030 *    <jk>var</jk> <jv>converter</jv> = BasicBeanConverter.<jsm>builder</jsm>()
031 *       .defaultSettings()
032 *       .addSizer(MyCustomCollection.<jk>class</jk>, (<jp>coll</jp>, <jp>conv</jp>) -> <jp>coll</jp>.count())
033 *       .build();
034 *
035 *    <jc>// Use in assertions</jc>
036 *    <jk>int</jk> <jv>size</jv> = <jv>converter</jv>.size(<jv>myCustomCollection</jv>);
037 * </p>
038 *
039 * <h5 class='section'>See Also:</h5>
040 * <ul class='seealso'>
041 *    <li class='jic'>{@link BeanConverter}
042 * </ul>
043 *
044 * @param <T> The type of object this sizer handles.
045 */
046@FunctionalInterface
047public interface Sizer<T> {
048
049   /**
050    * Computes the size of the given object.
051    *
052    * @param o The object to compute the size of. Will not be <jk>null</jk>.
053    * @param bc The bean converter for accessing additional conversion utilities if needed.
054    * @return The size of the object.
055    */
056   int size(T o, BeanConverter bc);
057}