| java.lang.Object | ||
| ↳ | com.pdftron.filters.Filter | |
| ↳ | com.pdftron.filters.CustomFilter | |
 Known Direct Subclasses
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Class Overview
CustomFilter allows for customizing the reading and writing process. It is useful, for example, for users to write their own encryption and decryption methods.
Note that this is an abstract class.
Summary
| Constants | |||||||||||
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| int | APPEND_MODE | Filter is in append mode. | |||||||||
| int | READ_MODE | Filter is in read mode. | |||||||||
| int | SEEK_CUR | The offset is relative to the current position of the filter. | |||||||||
| int | SEEK_END | The offset is relative to the end of the filter. | |||||||||
| int | SEEK_SET | The offset is relative to the beginning of the filter. | |||||||||
| String | TAG | ||||||||||
| int | WRITE_MODE | Filter is in write mode. | |||||||||
| Public Constructors | |||||||||||
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CustomFilter(int mode, Object user_object)
The constructor.
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| Public Methods | |||||||||||
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| abstract void |
close()
Frees the native memory of the object.
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| void |
destroy()
Frees the native memory of the object.
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| String |
getName()
Gets the name of the filter.
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| Object |
getUserObject()
Gets the user data from
CustomFilter(int, Object). | ||||||||||
| abstract long | onCreateInputIterator(Object user_object) | ||||||||||
| abstract void | onDestroy(Object user_object) | ||||||||||
| abstract long |
onFlush(Object user_object)
The abstract function in which the output data is flushed.
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| abstract long |
onRead(byte[] buf, Object user_object)
The abstract function in which the input data are read.
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| abstract long |
onSeek(long offset, int origin, Object user_object)
The abstract function in which the position indicator of the filter is
set.
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| abstract long |
onTell(Object user_object)
The abstract function in which the position indicator of the filter is
queried.
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| long |
onTruncate(long new_size, Object user_object)
The abstract function the size of the filter is set
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| abstract long |
onWrite(byte[] buf, Object user_object)
The abstract function in which the data are output.
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[Expand]
Inherited Methods | |||||||||||
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From class
com.pdftron.filters.Filter
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From class
java.lang.Object
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From interface
java.lang.AutoCloseable
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Constants
public static final int APPEND_MODE
Filter is in append mode.
public static final int READ_MODE
Filter is in read mode.
public static final int SEEK_CUR
The offset is relative to the current position of the filter.
public static final int SEEK_END
The offset is relative to the end of the filter.
public static final int SEEK_SET
The offset is relative to the beginning of the filter.
public static final String TAG
public static final int WRITE_MODE
Filter is in write mode.
Public Constructors
public CustomFilter (int mode, Object user_object)
The constructor.
Parameters
| mode | The mode of the filter. Possible values are READ_MODE
, WRITE_MODE, and APPEND_MODE. |
|---|---|
| user_object | The user data that can will be passed back in the abstract functions. |
Throws
| PDFNetException |
|---|
Public Methods
public abstract void close ()
Frees the native memory of the object. This can be explicity called to control the deallocation of native memory and avoid situations where the garbage collector does not free the object in a timely manner.
public void destroy ()
Frees the native memory of the object. This can be explicitly called to control the deallocation of native memory and avoid situations where the garbage collector does not free the object in a timely manner.
Throws
| PDFNetException |
|---|
public String getName ()
public abstract long onCreateInputIterator (Object user_object)
public abstract void onDestroy (Object user_object)
public abstract long onFlush (Object user_object)
The abstract function in which the output data is flushed.
Parameters
| user_object | The user data from passed in via
CustomFilter(int, Object). |
|---|
Returns
- If successful, the value is 0; otherwise, it is non-zero.
public abstract long onRead (byte[] buf, Object user_object)
The abstract function in which the input data are read.
Parameters
| buf | The buffer to contain the data to read, which has already been allocated. |
|---|---|
| user_object | The user data from passed in via CustomFilter(int, Object). |
Returns
- The number of bytes read. It should return 0 if it fails or reaches the end of the input stream.
public abstract long onSeek (long offset, int origin, Object user_object)
The abstract function in which the position indicator of the filter is set.
Parameters
| offset | Number of bytes to offset from origin. A positive value implies the indicator is moved forward, and a negative value implies the indicator is moved backward. |
|---|---|
| origin | Position from where offset is added. It is specified by one of
the following: SEEK_SET,
SEEK_CUR, SEEK_END. |
| user_object | The user data from passed in via
CustomFilter(int, Object). |
Returns
- The new position of the indicator set. If successful, the value is 0; otherwise, it is non-zero.
public abstract long onTell (Object user_object)
The abstract function in which the position indicator of the filter is queried.
Parameters
| user_object | The user data from passed in via
CustomFilter(int, Object). |
|---|
Returns
- The position of the indicator.
public long onTruncate (long new_size, Object user_object)
The abstract function the size of the filter is set
Parameters
| new_size | number of bytes to resize the filter to. |
|---|---|
| user_object | The user data from passed in via
CustomFilter(int, Object). |
Returns
- The new size of the filter.
public abstract long onWrite (byte[] buf, Object user_object)
The abstract function in which the data are output.
Parameters
| buf | The buffer to contain the data to write out. |
|---|---|
| user_object | The user data from passed in via
CustomFilter(int, Object). |
Returns
- The number of bytes successfully written.