
/*
 * Janino - An embedded Java[TM] compiler
 *
 * Copyright (c) 2001-2010 Arno Unkrig. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
 * following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
 *       following disclaimer.
 *    2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
 *       following disclaimer in the documentation and/or other materials provided with the distribution.
 *    3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote
 *       products derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.codehaus.commons.compiler.util.resource;

import java.io.File;

import org.codehaus.commons.nullanalysis.Nullable;

/**
 * This class specializes the {@link org.codehaus.commons.compiler.util.resource.ResourceFinder} for finding resources
 * in {@link java.io.File}s.
 * <p>
 *   It finds {@link FileResource}s instead of simple {@link Resource}s.
 * </p>
 */
public abstract
class FileResourceFinder extends ListableResourceFinder {

    @Override @Nullable public final Resource
    findResource(String resourceName) {
        File file = this.findResourceAsFile(resourceName);
        if (file == null) return null;
        return new FileResource(file);
    }

    /**
     * Converts a given resource resource name into a {@link File}.
     */
    @Nullable protected abstract File
    findResourceAsFile(String resourceName);
}
