Package org.apache.tika.detect

Class DetectHelper

java.lang.Object

org.apache.tika.detect.DetectHelper

public class DetectHelper
extends Object

Utility methods for content detection.

Constructor Summary

Constructors

Constructor	Description
DetectHelper()

Method Summary

Modifier and Type	Method	Description
static int	getDetectionContentLength(Metadata metadata)	Gets the number of bytes buffered for detection.
static TikaInputStream	getStreamForDetectionOnly(InputStream stream, int maxLength)	Creates a TikaInputStream suitable for detection-only purposes by reading up to maxLength bytes from the input stream into a byte array.
static TikaInputStream	getStreamForDetectionOnly(InputStream stream, int maxLength, Metadata metadata)	Creates a TikaInputStream suitable for detection-only purposes by reading up to maxLength bytes from the input stream into a byte array.
static boolean	isContentTruncatedForDetection(Metadata metadata)	Checks if the given metadata indicates that the content was truncated for detection.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

DetectHelper

public DetectHelper()

Method Details

getStreamForDetectionOnly

public static TikaInputStream getStreamForDetectionOnly(InputStream stream,
 int maxLength,
 Metadata metadata)
                                                 throws IOException

Creates a TikaInputStream suitable for detection-only purposes by reading up to maxLength bytes from the input stream into a byte array.

If the input stream contains more bytes than maxLength, the resulting metadata will have TikaCoreProperties.TRUNCATED_CONTENT_FOR_DETECTION set to true, signaling to detectors that they are working with truncated content and should adjust their behavior accordingly.

This is useful when you want to perform detection on a limited portion of a large file without spooling the entire file to disk.

NOTEThe downside is that you may lose precision in detection! This should only be used if you are performing detection only with no parsing.

Parameters:

stream - the input stream to read from (will NOT be closed)

maxLength - the maximum number of bytes to read

metadata - the metadata object where truncation flag will be set if applicable

Returns:

a TikaInputStream backed by the buffered bytes

Throws:

IOException - if an I/O error occurs

getStreamForDetectionOnly

public static TikaInputStream getStreamForDetectionOnly(InputStream stream,
 int maxLength)
                                                 throws IOException

Creates a TikaInputStream suitable for detection-only purposes by reading up to maxLength bytes from the input stream into a byte array.

This overload creates a new Metadata object internally. If you need to check whether the content was truncated, use getStreamForDetectionOnly(InputStream, int, Metadata) instead.

Parameters:

stream - the input stream to read from (will NOT be closed)

maxLength - the maximum number of bytes to read

Returns:

a TikaInputStream backed by the buffered bytes

Throws:

IOException - if an I/O error occurs

isContentTruncatedForDetection

public static boolean isContentTruncatedForDetection(Metadata metadata)

Checks if the given metadata indicates that the content was truncated for detection.

Parameters:

metadata - the metadata to check

Returns:

true if the content was truncated, false otherwise

getDetectionContentLength

public static int getDetectionContentLength(Metadata metadata)

Gets the number of bytes buffered for detection.

Parameters:

metadata - the metadata to check

Returns:

the number of bytes buffered, or -1 if not set