trunk/src/java/org/apache/lenya/cms/publication/templating/ExistingSourceResolver.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */

package org.apache.lenya.cms.publication.templating;

import org.apache.excalibur.source.Source;
import org.apache.excalibur.source.SourceResolver;

/**
 * Source visitor to obtain the first existing source.
 * 
 * @version $Id$
 */
public class ExistingSourceResolver implements VisitingSourceResolver {

    private Source source;

    /**
     * Ctor.
     */
    public ExistingSourceResolver() {
        super();
    }

    /**
     * @return the first existing source.
     */
    public Source getSource() {
        return this.source;
    }

    public void visit(SourceResolver resolver, String sourceUri) {
        if (this.source == null) {
            Source source = null;
            try {
                source = resolver.resolveURI(sourceUri);
                if (source.exists()) {
                    this.source = source;
                }
            } catch (Exception e) {
                throw new RuntimeException(e);
            } finally {
                if (source != null) {
                    resolver.release(source);
                }
            }
        }
    }

}