001// Copyright 2010, 2011 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// 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
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.func;
016
017/**
018 * Used when filtering a collection of objects of a given type; the predicate is passed
019 * each object in turn, and returns true to include the object in the result collection.
020 * <p>
021 * The {@link F} class includes a number of Predicate factory methods.
022 * <p>
023 * This was converted from a abstract base class to an interface in 5.3.
024 * 
025 * @since 5.2.0
026 * @see Flow#filter(Predicate)
027 * @see Flow#remove(Predicate)
028 */
029public interface Predicate<T>
030{
031    /**
032     * This method is overridden in subclasses to define which objects the Predicate will accept
033     * and which it will reject.
034     * 
035     * @param element
036     *            the element from the flow to be evaluated by the Predicate
037     */
038    boolean accept(T element);
039}