    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
    015    package 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     */
    029    public 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    }