    001    // Copyright 2006, 2010 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.ioc;
    016
    017    import org.apache.tapestry5.ioc.internal.util.InternalUtils;
    018
    019    /**
    020     * A wrapper that allows objects of a target type to be ordered. Each Orderable object is given a unique id and a set of
    021     * pre-requisites (objects which should be ordered earlier) and post-requisites (objects which should be ordered
    022     * later).
    023     *
    024     * @param <T>
    025     */
    026    public class Orderable<T>
    027    {
    028        private final String id;
    029
    030        private final T target;
    031
    032        private final String[] constraints;
    033
    034        /**
    035         * @param id     unique identifier for the target object
    036         * @param target the object to be ordered; this may also be null (in which case the id represents a placeholder)
    037         */
    038
    039        public Orderable(String id, T target, String... constraints)
    040        {
    041            assert InternalUtils.isNonBlank(id);
    042            this.id = id;
    043            this.target = target;
    044            this.constraints = constraints;
    045        }
    046
    047        public String getId()
    048        {
    049            return id;
    050        }
    051
    052        public T getTarget()
    053        {
    054            return target;
    055        }
    056
    057        public String[] getConstraints()
    058        {
    059            return constraints;
    060        }
    061
    062        @Override
    063        public String toString()
    064        {
    065            StringBuilder buffer = new StringBuilder("Orderable[");
    066
    067            buffer.append(id);
    068
    069            for (String c : constraints)
    070            {
    071                buffer.append(" ");
    072                buffer.append(c);
    073            }
    074
    075            buffer.append(" ");
    076            buffer.append(target.toString());
    077            buffer.append("]");
    078
    079            return buffer.toString();
    080        }
    081    }