import org.codelibs.fess.crawler.exception.ExtractException;

/**
 * Gets a text from .xls file.
 *
 * @author shinsuke
 *
 */
public class MsExcelExtractor extends AbstractExtractor {

    /**
     * Creates a new MsExcelExtractor instance.
     */
    public MsExcelExtractor() {
        super();
    }

    /**
     * Extracts text from the Excel input stream.
     * @param in The input stream.

        }
    }

    /**
     * Test that MsExcelExtractor properly closes resources on successful extraction.
     */
    public void test_MsExcelExtractor_closesResourcesOnSuccess() throws IOException {
        final MsExcelExtractor extractor = container.getComponent("msExcelExtractor");
        final AtomicBoolean streamClosed = new AtomicBoolean(false);

- Resource closure on failed extraction
- Improved error messages with context
- Input validation using `validateInputStream()`

**Covered Extractors**:
- MsWordExtractor
- MsExcelExtractor
- MsPowerPointExtractor
- TextExtractor

**Test Count**: 8 tests

**Key Scenarios**:
- ✅ Successful extraction closes resources properly
- ✅ Failed extraction includes descriptive error messages

**Extractor**: Weight-based selection (tries in descending weight order)

### Key Extractors

`TikaExtractor` (1000+ formats), `PdfExtractor`, `MsWordExtractor`, `MsExcelExtractor`, `MsPowerPointExtractor`, `ZipExtractor`, `HtmlExtractor`, etc.

**Registration**:
```java
extractorFactory.addExtractor("text/html", htmlExtractor, 2);  // Weight 2

	</component>
	<component name="msWordExtractor"
		class="org.codelibs.fess.crawler.extractor.impl.MsWordExtractor" />
	<component name="msExcelExtractor"
		class="org.codelibs.fess.crawler.extractor.impl.MsExcelExtractor" />
	<component name="msPowerPointExtractor"
		class="org.codelibs.fess.crawler.extractor.impl.MsPowerPointExtractor" />
	<component name="msPublisherExtractor"