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    }