001// Copyright 2005 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.tapestry.util;
016
017import org.apache.hivemind.Location;
018import org.apache.hivemind.Resource;
019import org.apache.hivemind.util.Defense;
020
021/**
022 * Implementation of {@link org.apache.hivemind.Location} that is used to describe a location within
023 * a resource. This is used when the location within the resource can't be expressed as a line and
024 * column. One example is for setting the location of an annotation. This is useful for line-precise
025 * exception reporting of errors related to annotations.
026 * 
027 * @author Howard Lewis Ship
028 * @since 4.0
029 */
030public class DescribedLocation implements Location
031{
032    private final Resource _resource;
033
034    private final String _description;
035
036    public DescribedLocation(Resource resource, String description)
037    {
038        Defense.notNull(resource, "resource");
039        Defense.notNull(description, "description");
040
041        _resource = resource;
042        _description = description;
043    }
044
045    /**
046     * Returns the description provided in the constructor.
047     */
048
049    public String toString()
050    {
051        return _description;
052    }
053
054    /**
055     * Returns the resource provided in the constructor.
056     */
057
058    public Resource getResource()
059    {
060        return _resource;
061    }
062
063    /**
064     * Always returns 0.
065     */
066
067    public int getLineNumber()
068    {
069        return 0;
070    }
071
072    /**
073     * Always returns 0.
074     */
075
076    public int getColumnNumber()
077    {
078        return 0;
079    }
080
081    /**
082     * A DescribedLocation is equal to another only if their resources are equal, and their
083     * descriptions are equal.
084     */
085    public boolean equals(Object other)
086    {
087        if (other instanceof DescribedLocation)
088        {
089            DescribedLocation otherLocation = (DescribedLocation) other;
090
091            return _resource.equals(otherLocation._resource)
092                    && _description.equals(otherLocation._description);
093        }
094
095        return false;
096    }
097}