com.drew.imaging.jpeg

Class JpegSegmentData

java.lang.Object

com.drew.imaging.jpeg.JpegSegmentData

public class JpegSegmentData
extends Object

Holds a collection of JPEG data segments. This need not necessarily be all segments within the JPEG. For example, it may be convenient to store only the non-image segments when analysing metadata.

Segments are keyed via their JpegSegmentType. Where multiple segments use the same segment type, they will all be stored and available.

Each segment type may contain multiple entries. Conceptually the model is: Map<JpegSegmentType, Collection<byte[]>>. This class provides convenience methods around that structure.

Author:

Drew Noakes https://drewnoakes.com

Constructor Summary

Constructors

Constructor and Description
JpegSegmentData()

Method Summary

Modifier and Type	Method and Description
void	addSegment(byte segmentType, byte[] segmentBytes) Adds segment bytes to the collection.
boolean	containsSegment(byte segmentType) Determines whether data is present for a given segment type.
boolean	containsSegment(JpegSegmentType segmentType) Determines whether data is present for a given segment type.
byte[]	getSegment(byte segmentType) Gets the first JPEG segment data for the specified type.
byte[]	getSegment(byte segmentType, int occurrence) Gets segment data for a specific occurrence and type.
byte[]	getSegment(JpegSegmentType segmentType) Gets the first JPEG segment data for the specified type.
byte[]	getSegment(JpegSegmentType segmentType, int occurrence) Gets segment data for a specific occurrence and type.
int	getSegmentCount(byte segmentType) Returns the count of segment data byte arrays stored for a given segment type.
int	getSegmentCount(JpegSegmentType segmentType) Returns the count of segment data byte arrays stored for a given segment type.
Iterable<byte[]>	getSegments(byte segmentType) Returns all instances of a given JPEG segment.
Iterable<byte[]>	getSegments(JpegSegmentType segmentType) Returns all instances of a given JPEG segment.
Iterable<JpegSegmentType>	getSegmentTypes() Gets the set of JPEG segment type identifiers.
void	removeSegment(byte segmentType) Removes all segments from the collection having the specified type.
void	removeSegment(JpegSegmentType segmentType) Removes all segments from the collection having the specified type.
void	removeSegmentOccurrence(byte segmentType, int occurrence) Removes a specified instance of a segment's data from the collection.
void	removeSegmentOccurrence(JpegSegmentType segmentType, int occurrence) Removes a specified instance of a segment's data from the collection.

Methods inherited from class java.lang.Object

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

Constructor Detail

JpegSegmentData

public JpegSegmentData()

Method Detail

addSegment

public void addSegment(byte segmentType,
                       byte[] segmentBytes)

Adds segment bytes to the collection.

Parameters:

segmentType - the type of the segment being added

segmentBytes - the byte array holding data for the segment being added

getSegmentTypes

public Iterable<JpegSegmentType> getSegmentTypes()

Gets the set of JPEG segment type identifiers.

getSegment

public byte[] getSegment(byte segmentType)

Gets the first JPEG segment data for the specified type.

Parameters:

segmentType - the JpegSegmentType for the desired segment

Returns:

a byte[] containing segment data or null if no data exists for that segment

getSegment

public byte[] getSegment(JpegSegmentType segmentType)

Gets the first JPEG segment data for the specified type.

Parameters:

segmentType - the JpegSegmentType for the desired segment

Returns:

a byte[] containing segment data or null if no data exists for that segment

getSegment

public byte[] getSegment(JpegSegmentType segmentType,
                         int occurrence)

Gets segment data for a specific occurrence and type. Use this method when more than one occurrence of segment data for a given type exists.

Parameters:

segmentType - identifies the required segment

occurrence - the zero-based index of the occurrence

Returns:

the segment data as a byte[], or null if no segment exists for the type & occurrence

getSegment

public byte[] getSegment(byte segmentType,
                         int occurrence)

Gets segment data for a specific occurrence and type. Use this method when more than one occurrence of segment data for a given type exists.

Parameters:

segmentType - identifies the required segment

occurrence - the zero-based index of the occurrence

Returns:

the segment data as a byte[], or null if no segment exists for the type & occurrence

getSegments

public Iterable<byte[]> getSegments(JpegSegmentType segmentType)

Returns all instances of a given JPEG segment. If no instances exist, an empty sequence is returned.

Parameters:

segmentType - a number which identifies the type of JPEG segment being queried

Returns:

zero or more byte arrays, each holding the data of a JPEG segment

getSegments

public Iterable<byte[]> getSegments(byte segmentType)

Returns all instances of a given JPEG segment. If no instances exist, an empty sequence is returned.

Parameters:

segmentType - a number which identifies the type of JPEG segment being queried

Returns:

zero or more byte arrays, each holding the data of a JPEG segment

getSegmentCount

public int getSegmentCount(JpegSegmentType segmentType)

Returns the count of segment data byte arrays stored for a given segment type.

Parameters:

segmentType - identifies the required segment

Returns:

the segment count (zero if no segments exist).

getSegmentCount

public int getSegmentCount(byte segmentType)

Returns the count of segment data byte arrays stored for a given segment type.

Parameters:

segmentType - identifies the required segment

Returns:

the segment count (zero if no segments exist).

removeSegmentOccurrence

public void removeSegmentOccurrence(JpegSegmentType segmentType,
                                    int occurrence)

Removes a specified instance of a segment's data from the collection. Use this method when more than one occurrence of segment data exists for a given type exists.

Parameters:

segmentType - identifies the required segment

occurrence - the zero-based index of the segment occurrence to remove.

removeSegmentOccurrence

public void removeSegmentOccurrence(byte segmentType,
                                    int occurrence)

Removes a specified instance of a segment's data from the collection. Use this method when more than one occurrence of segment data exists for a given type exists.

Parameters:

segmentType - identifies the required segment

occurrence - the zero-based index of the segment occurrence to remove.

removeSegment

public void removeSegment(JpegSegmentType segmentType)

Removes all segments from the collection having the specified type.

Parameters:

segmentType - identifies the required segment

removeSegment

public void removeSegment(byte segmentType)

Removes all segments from the collection having the specified type.

Parameters:

segmentType - identifies the required segment

containsSegment

public boolean containsSegment(JpegSegmentType segmentType)

Determines whether data is present for a given segment type.

Parameters:

segmentType - identifies the required segment

Returns:

true if data exists, otherwise false

containsSegment

public boolean containsSegment(byte segmentType)

Determines whether data is present for a given segment type.

Parameters:

segmentType - identifies the required segment

Returns:

true if data exists, otherwise false