public void test_fillInStackTrace() {
        CrawlerSystemException exception = new CrawlerSystemException("Fill stack trace test");

        StackTraceElement[] originalStackTrace = exception.getStackTrace();
        assertNotNull(originalStackTrace);
        assertTrue(originalStackTrace.length > 0);

        // Fill in stack trace again
        Throwable filled = exception.fillInStackTrace();
        assertSame(exception, filled);

/*
 * Copyright 2012-2025 CodeLibs Project and the Others.
 *
 * 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,

    }

    /**
     * Sets the output file extension.
     * @param outputExtension The output file extension to set.
     */
    public void setOutputExtension(final String outputExtension) {
        this.outputExtension = outputExtension;
    }

    /**
     * Sets the temporary directory for file operations.
     * @param tempDir The temporary directory to set.
     */

    }
}
```

### File System Crawling

```java
import org.codelibs.fess.crawler.client.fs.FileSystemClient;

// Configure for file system crawling
container.singleton("fsClient", FileSystemClient.class);

// Add file URL
crawler.addUrl("file:///path/to/directory");
crawler.urlFilter.addInclude("file:///path/to/directory/.*");
```

## Configuration

/*
 * Copyright 2012-2025 CodeLibs Project and the Others.
 *
 * 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,

                }
            } else if (!file.mkdirs()) {
                throw new CrawlerSystemException("Could not create " + file.getAbsolutePath());
            }
            targetFile = file;
        }

        File file = new File(targetFile, paths[paths.length - 1]);
        if (file.exists()) {
            for (int i = 0; i < maxDuplicatedPath; i++) {
                file = new File(targetFile, paths[paths.length - 1] + "_" + i);

/*
 * Copyright 2012-2025 CodeLibs Project and the Others.
 *
 * 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,

 * and ignored. Otherwise, they will be re-thrown as {@link CrawlerSystemException}.
 * </p>
 *
 */
public abstract class AbstractIntervalController implements IntervalController {

    /**
     * Indicates whether exceptions during the delay process should be ignored.
     * If set to true, exceptions will be caught and ignored. If set to false,

/*
 * Copyright 2012-2025 CodeLibs Project and the Others.
 *
 * 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,

/*
 * Copyright 2012-2025 CodeLibs Project and the Others.
 *
 * 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,