    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
    015package org.apache.tapestry5.ioc;
    016
    017import 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 */
    026public 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}