com.snowtide.pdf
Class OutputTarget

java.lang.Object
  com.snowtide.pdf.OutputHandler
      com.snowtide.pdf.OutputTarget

public class OutputTarget
extends OutputHandler

This is a base OutputHandler implementation that provides a common output interface for Writer and StringBuffer instances, allowing PDFTextStream to easily redirect output to either type of object. Not only does using an OutputTarget simplify your code, but it also minimizes the internal buffering that PDFTextStream might otherwise perform when being used as a java.io.Reader implementation.

Note that since this class provides a baseline OutputHandler implementation that will direct all text content to the provided Writer or StringBuffer, it is the ideal place to start when building a custom OutputHandler implementation. See the XMLOutputTarget class as an example of how this can be done.

Finally, please note that OutputTarget does not make any attempt to retain the visual layout or formatting of the text extracted from PDF documents. This OutputHandler implementation is focussed on:

• Maximum performance
• Ensuring that extracted PDF text is yielded with the proper segmentation and read-ordering, for the benefit of most users whose applications are sensitive to the semantic ordering of the PDF content. This includes search, text analytics, summarization tools, and similar applications.

If your application requires PDF text extracts that retain the visual appearance of the text as it is laid out on each page, then VisualOutputTarget would be more suitable.

Example usage:

 StringBuffer sb = new StringBuffer(1024);
 OutputTarget tgt = new OutputTarget(sb);
 
 PDFTextStream stream = new PDFTextStream();
 stream.pipe(tgt);
 stream.close();
 
  // do something with the extracted text...
 processText(sb);
 

Version:

©2004-2009 Snowtide Informatics Systems, Inc.

See Also:

PDFTextStream.pipe(OutputHandler), Page.pipe(OutputHandler), Block.pipe(OutputHandler), Line.pipe(OutputHandler)

Constructor Summary

OutputTarget(java.lang.StringBuffer sb)
Creates a new OutputTarget that directs output to the given java.lang.StringBuffer instance.

OutputTarget(java.io.Writer w)
Creates a new OutputTarget that directs output to the given java.io.Writer instance.

Method Summary

void	endPage(Page page) Invoked when PDFTextStream has finished processing a page
static OutputTarget	forBuffer(java.lang.StringBuffer sb) Deprecated. use OutputTarget(StringBuffer)
static OutputTarget	forWriter(java.io.Writer w) Deprecated. use OutputTarget(Writer) instead
PDFTextStreamConfig	getConfig() Returns the PDFTextStreamConfig instance that this OutputTarget is currently using.
java.lang.Object	getObject() Returns the output object that this instance wraps; will be an instance of either java.io.Writer or java.lang.StringBuffer.
void	linebreaks(int linebreakCnt) Default implementation that writes specified number of line breaks (using the linebreak String provided by the current configuration) to the java.io.Writer or java.io.StringBuffer object that this OutputTarget wraps.
void	setConfig(PDFTextStreamConfig config) Sets the PDFTextStreamConfig instance this OutputTarget should use.
void	spaces(int spaceCnt) Default implementation that writes specified number of spaces to the java.io.Writer or java.io.StringBuffer object that this OutputTarget wraps.
void	startPage(Page page) Invoked when a page is about to be processed.
void	textUnit(TextUnit tu) Default implementation that writes the character run specified by the given TextUnit instance to the java.io.Writer or java.io.StringBuffer object that this OutputTarget wraps.
void	write(char c) Writes the provided character to the wrapped output object.
void	write(char[] buf) Writes the provided character data to the wrapped output object.
void	write(char[] buf, int start, int len) Writes the provided character data to the wrapped output object.
void	write(java.lang.String str) Writes the provided String's character data to the wrapped output object.
void	write(java.lang.StringBuffer sb) Writes the provided StringBuffer's character data to the wrapped output object.

Methods inherited from class com.snowtide.pdf.OutputHandler

endBlock, endLine, endPDF, startBlock, startLine, startPDF

Methods inherited from class java.lang.Object

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

Constructor Detail

OutputTarget

public OutputTarget(java.io.Writer w)

Creates a new OutputTarget that directs output to the given java.io.Writer instance.

OutputTarget

public OutputTarget(java.lang.StringBuffer sb)

Creates a new OutputTarget that directs output to the given java.lang.StringBuffer instance.

Method Detail

forWriter

public static OutputTarget forWriter(java.io.Writer w)

Deprecated. use OutputTarget(Writer) instead

Creates a new OutputTarget that wraps a java.io.Writer instance.

forBuffer

public static OutputTarget forBuffer(java.lang.StringBuffer sb)

Deprecated. use OutputTarget(StringBuffer)

Creates a new OutputTarget that wraps a java.lang.StringBuffer instance.

write

public void write(java.lang.String str)
           throws java.io.IOException

Writes the provided String's character data to the wrapped output object.

Throws:

java.io.IOException - - if an error occurs writing the character data; only possible in connection with an OutputTarget instance that wraps a java.io.Writer instance.

write

public void write(java.lang.StringBuffer sb)
           throws java.io.IOException

Writes the provided StringBuffer's character data to the wrapped output object.

Throws:

java.io.IOException - - if an error occurs writing the character data; only possible in connection with an OutputTarget instance that wraps a java.io.Writer instance.

write

public void write(char[] buf,
                  int start,
                  int len)
           throws java.io.IOException

Writes the provided character data to the wrapped output object.

Throws:

java.io.IOException - - if an error occurs writing the character data; only possible in connection with an OutputTarget instance that wraps a java.io.Writer instance.

write

public final void write(char[] buf)
                 throws java.io.IOException

Writes the provided character data to the wrapped output object.

Throws:

java.io.IOException - - if an error occurs writing the character data; only possible in connection with an OutputTarget instance that wraps a java.io.Writer instance.

write

public void write(char c)
           throws java.io.IOException

Writes the provided character to the wrapped output object.

Throws:

java.io.IOException - - if an error occurs writing the character; only possible in connection with an OutputTarget instance that wraps a java.io.Writer instance.

getObject

public java.lang.Object getObject()

Returns the output object that this instance wraps; will be an instance of either java.io.Writer or java.lang.StringBuffer.

textUnit

public void textUnit(TextUnit tu)

Default implementation that writes the character run specified by the given TextUnit instance to the java.io.Writer or java.io.StringBuffer object that this OutputTarget wraps.

This implementation is very straightforward; it is provided here for illustrative purposes only:

 if (tu.getCharacterSequence() == null) {
     // no mapped sequence, append direct character code conversion
     int cc = tu.getCharCode();
     if (cc >= 32) write((char)cc);
 } else {
     write(tu.getCharacterSequence());
 }
 

Overrides:

textUnit in class OutputHandler

spaces

public void spaces(int spaceCnt)

Default implementation that writes specified number of spaces to the java.io.Writer or java.io.StringBuffer object that this OutputTarget wraps.

Overrides:

spaces in class OutputHandler

Parameters:

spaceCnt - - the number of spaces that PDFTextStream recommends should be outputted

linebreaks

public void linebreaks(int linebreakCnt)

Default implementation that writes specified number of line breaks (using the linebreak String provided by the current configuration) to the java.io.Writer or java.io.StringBuffer object that this OutputTarget wraps.

Overrides:

linebreaks in class OutputHandler

Parameters:

linebreakCnt - - the number of line breaks that PDFTextStream recommends should be outputted

startPage

public void startPage(Page page)

Description copied from class: OutputHandler

Invoked when a page is about to be processed.

Overrides:

startPage in class OutputHandler

Parameters:

page - - a reference to the Page that is about to be processed

endPage

public void endPage(Page page)

Description copied from class: OutputHandler

Invoked when PDFTextStream has finished processing a page

Overrides:

endPage in class OutputHandler

Parameters:

page - - a reference to the Page that has been processed

getConfig

public PDFTextStreamConfig getConfig()

Returns the PDFTextStreamConfig instance that this OutputTarget is currently using. Please note that unless an OutputTarget instance is explicitly provided with a particular configuration via setConfig(PDFTextStreamConfig), it will synchronize its configuration with the configuration of a PDFTextStream instance any time an OutputTarget is provided to either PDFTextStream.pipe(OutputHandler) or Page.pipe(OutputHandler).

If an OutputTarget is to be used to pipe content only from Block contexts, then it will use the default PDFTextStreamConfig instance until a different configuration is set via setConfig(PDFTextStreamConfig).

setConfig

public void setConfig(PDFTextStreamConfig config)

Sets the PDFTextStreamConfig instance this OutputTarget should use. Once this OutputTarget instance's configuration is set using this function, it will cease to synchronize its configuration with the configuration provided by PDFTextStream and Page objects from which it is used to pipe content.