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/**
 * File     : Scanner.java
 * License  :
 *   Original   - Copyright (c) 2010 - 2016 Boxfuse GmbH
 *   Derivative - Copyright (c) 2016 - 2018 cassandra-migration Contributors
 *
 *   Licensed 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 com.hhandoko.cassandra.migration.internal.util.scanner;

import com.hhandoko.cassandra.migration.api.CassandraMigrationException;
import com.hhandoko.cassandra.migration.internal.util.Location;
import com.hhandoko.cassandra.migration.internal.util.scanner.classpath.ClassPathScanner;
import com.hhandoko.cassandra.migration.internal.util.scanner.classpath.ResourceAndClassScanner;
import com.hhandoko.cassandra.migration.internal.util.scanner.filesystem.FileSystemScanner;

/**
 * Scanner for Resources and Classes.
 */
public class Scanner {
    private final ResourceAndClassScanner resourceAndClassScanner;

    private final ClassLoader classLoader;

    private final FileSystemScanner fileSystemScanner = new FileSystemScanner();

    public Scanner(ClassLoader classLoader) {
        this.classLoader = classLoader;
        this.resourceAndClassScanner = new ClassPathScanner(classLoader);
    }

    /**
     * Scans this location for resources, starting with the specified prefix and ending with the specified suffix.
     *
     * @param location The location to start searching. Subdirectories are also searched.
     * @param prefix   The prefix of the resource names to match.
     * @param suffix   The suffix of the resource names to match.
     * @return The resources that were found.
     */
    public Resource[] scanForResources(Location location, String prefix, String suffix) {
        try {
            if (location.isFileSystem()) {
                return fileSystemScanner.scanForResources(location, prefix, suffix);
            }

            return resourceAndClassScanner.scanForResources(location, prefix, suffix);
        } catch (Exception e) {
            throw new CassandraMigrationException("Unable to scan for CQL migrations in location: " + location, e);
        }
    }

    /**
     * Scans the classpath for concrete classes under the specified package implementing this interface.
     * Non-instantiable abstract classes are filtered out.
     *
     * @param location             The location (package) in the classpath to start scanning.
     *                             Subpackages are also scanned.
     * @param implementedInterface The interface the matching classes should implement.
     * @return The non-abstract classes that were found.
     * @throws Exception when the location could not be scanned.
     */
    public Class[] scanForClasses(Location location, Class implementedInterface) throws Exception {
        return resourceAndClassScanner.scanForClasses(location, implementedInterface);
    }

    /**
     * @return The class loader used for scanning.
     */
    public ClassLoader getClassLoader() {
        return classLoader;
    }
}