org.apache.fop.pdf

## Class AbstractPDFStream

- java.lang.Object
- - org.apache.fop.pdf.PDFObject
  - - org.apache.fop.pdf.AbstractPDFStream

All Implemented Interfaces:
  PDFWritable

Direct Known Subclasses:
  AbstractPDFFontStream, PDFStream, PDFXObject

    public abstract class AbstractPDFStream
    extends PDFObject

This is an abstract base class for PDF streams.

### Field Summary

### Fields inherited from class org.apache.fop.pdf.PDFObject

`log`

### Constructor Summary

Constructors
`protected` `AbstractPDFStream()`
`protected` `AbstractPDFStream(boolean encodeOnTheFly)`
`protected` `AbstractPDFStream(PDFDictionary dictionary)`
`protected` `AbstractPDFStream(PDFDictionary dictionary, boolean encodeOnTheFly)`

### Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
`protected int` `encodeAndWriteStream(OutputStream out, PDFNumber refLength)` Encodes and writes a stream directly to an OutputStream.
`protected StreamCache` `encodeStream()` Encodes the raw data stream for output to a PDF file.
`Object` `get(String key)`
`void` `getChildren(Set<PDFObject> children)`
`protected String` `getDefaultFilterName()` Returns the name of a suitable filter for this PDF object.
`protected PDFDictionary` `getDictionary()`
`PDFFilterList` `getFilterList()` Returns the associated filter list.
`protected abstract int` `getSizeHint()` Returns a value that hints at the size of the encoded stream.
`protected boolean` `multipleFiltersAllowed()` Whether multiple filters can be applied.
`int` `output(OutputStream stream)` Overload the base object method so we don't have to copy byte arrays around so much Write the PDF represention of this object
`protected abstract void` `outputRawStreamData(OutputStream out)` Sends the raw stream data to the target OutputStream.
`protected int` `outputStreamData(StreamCache encodedStream, OutputStream out)` Output just the stream data enclosed by stream/endstream markers
`protected void` `populateStreamDict(Object lengthEntry)` Populates the dictionary with all necessary entries for the stream.
`protected void` `prepareImplicitFilters()` Prepares implicit filters (such as the DCTFilter for JPEG images).
`void` `put(String key, Object value)` Puts the given object in the dictionary associated to this stream.
`void` `registerChildren()`
`void` `setDocument(PDFDocument doc)` Sets the parent PDFDocument.
`protected void` `setupFilterList()` Sets up the default filters for this stream if they haven't been set from outside.
`boolean` `supportsObjectStream()`

### Methods inherited from class org.apache.fop.pdf.PDFObject

`contentEquals, encode, encodeBinaryToHexString, encodeString, encodeText, formatObject, getDocument, getDocumentSafely, getGeneration, getObjectID, getObjectNumber, getParent, hasObjectNumber, makeReference, outputInline, referencePDF, setObjectNumber, setObjectNumber, setObjectNumber, setParent, toPDF, toPDFString`

### Methods inherited from class java.lang.Object

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

### Constructor Detail

#### AbstractPDFStream

    protected AbstractPDFStream()

#### AbstractPDFStream

    protected AbstractPDFStream(PDFDictionary dictionary)

#### AbstractPDFStream

    protected AbstractPDFStream(boolean encodeOnTheFly)

#### AbstractPDFStream

    protected AbstractPDFStream(PDFDictionary dictionary,
                                boolean encodeOnTheFly)

### Method Detail

#### getDictionary

    protected final PDFDictionary getDictionary()

#### get

    public Object get(String key)

#### put

    public void put(String key,
                    Object value)

Puts the given object in the dictionary associated to this stream.

Parameters:
  `key` - the key in the dictionary
  `value` - the value to store

#### setupFilterList

    protected void setupFilterList()

Sets up the default filters for this stream if they haven't been set from outside.

#### getDefaultFilterName

    protected String getDefaultFilterName()

Returns the name of a suitable filter for this PDF object.

Returns:
  the default filter
See Also:
  `PDFFilterList`

#### getFilterList

    public PDFFilterList getFilterList()

Returns the associated filter list.

Returns:
  the filter list

#### getSizeHint

    protected abstract int getSizeHint()
                                throws IOException

Returns a value that hints at the size of the encoded stream. This is used to optimize buffer allocation so fewer buffer reallocations are necessary.

Returns:
  an estimated size (0 if no hint can be given)
Throws:
  `IOException` - in case of an I/O problem

#### outputRawStreamData

    protected abstract void outputRawStreamData(OutputStream out)
                                         throws IOException

Sends the raw stream data to the target OutputStream.

Parameters:
  `out` - OutputStream to write to
Throws:
  `IOException` - In case of an I/O problem

#### outputStreamData

    protected int outputStreamData(StreamCache encodedStream,
                                   OutputStream out)
                            throws IOException

Output just the stream data enclosed by stream/endstream markers

Parameters:
  `encodedStream` - already encoded/filtered stream to write
  `out` - OutputStream to write to
Returns:
  int number of bytes written
Throws:
  `IOException` - in case of an I/O problem

#### encodeStream

    protected StreamCache encodeStream()
                                throws IOException

Encodes the raw data stream for output to a PDF file.

Returns:
  the encoded stream
Throws:
  `IOException` - in case of an I/O problem

#### encodeAndWriteStream

    protected int encodeAndWriteStream(OutputStream out,
                                       PDFNumber refLength)
                                throws IOException

Encodes and writes a stream directly to an OutputStream. The length of the stream, in this case, is set on a PDFNumber object that has to be prepared beforehand.

Parameters:
  `out` - OutputStream to write to
  `refLength` - PDFNumber object to receive the stream length
Returns:
  number of bytes written (header and trailer included)
Throws:
  `IOException` - in case of an I/O problem

#### output

    public int output(OutputStream stream)
               throws IOException

Overload the base object method so we don't have to copy byte arrays around so much Write the PDF represention of this object

Overrides:
  `output` in class `PDFObject`
Parameters:
  `stream` - the stream to write the PDF to
Returns:
  the number of bytes written
Throws:
  `IOException` - if there is an error writing to the stream

#### setDocument

    public void setDocument(PDFDocument doc)

Description copied from class: `PDFObject`
Sets the parent PDFDocument.

Overrides:
  `setDocument` in class `PDFObject`
Parameters:
  `doc` - the PDFDocument.

#### populateStreamDict

    protected void populateStreamDict(Object lengthEntry)

Populates the dictionary with all necessary entries for the stream. Override this method if you need additional entries.

Parameters:
  `lengthEntry` - value for the /Length entry

#### prepareImplicitFilters

    protected void prepareImplicitFilters()

Prepares implicit filters (such as the DCTFilter for JPEG images). You must make sure that the appropriate filters are in the filter list at the right places.

#### multipleFiltersAllowed

    protected boolean multipleFiltersAllowed()

Whether multiple filters can be applied.

Returns:
  true if multiple filters allowed

#### getChildren

    public void getChildren(Set<PDFObject> children)

Overrides:
  `getChildren` in class `PDFObject`

#### registerChildren

    public void registerChildren()

#### supportsObjectStream

    public boolean supportsObjectStream()

Overrides:
  `supportsObjectStream` in class `PDFObject`