it.unimi.dsi.parser.callback

Interface Callback

All Known Implementing Classes:

DebugCallbackDecorator, DefaultCallback, LinkExtractor, TextExtractor

public interface Callback

A callback for the bullet parser.

This interface is very loosely inspired to the SAX2 interface. However, it strives to be simple, and to be StringFree™.

By contract, all implementations of this interface are bound to be reusable: by calling startDocument(), a callback can be used again. It must be safe to call startDocument() any number of times.

Field Summary

Fields

Modifier and Type	Field and Description
static Callback[]	EMPTY_CALLBACK_ARRAY A singleton empty callback array.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	cdata(Element element, char[] text, int offset, int length) Receive notification of the content of a CDATA section.
boolean	characters(char[] text, int offset, int length, boolean flowBroken) Receive notification of character data inside an element.
void	configure(BulletParser parser) Configure the parser for usage with this callback.
void	endDocument() Receive notification of the end of the document.
boolean	endElement(Element element) Receive notification of the end of an element.
void	startDocument() Receive notification of the beginning of the document.
boolean	startElement(Element element, Map<Attribute,MutableString> attrMap) Receive notification of the start of an element.

Field Detail

EMPTY_CALLBACK_ARRAY

static final Callback[] EMPTY_CALLBACK_ARRAY

A singleton empty callback array.

Method Detail

configure

void configure(BulletParser parser)

Configure the parser for usage with this callback.

When a callback is registered with a parser, it needs to set up the parser so that all data required by the callback is actually parsed. The configuration must be a monotone process—you can only set properties and add attribute types to be parsed.

startDocument

void startDocument()

Receive notification of the beginning of the document.

The callback must use this method to reset its internal state so that it can be resued. It must be safe to invoke this method several times.

startElement

boolean startElement(Element element,
                   Map<Attribute,MutableString> attrMap)

Receive notification of the start of an element.

For simple elements, this is the only notification that the callback will ever receive.

Parameters:

element - the element whose opening tag was found.

attrMap - a map from Attributes to MutableStrings.

Returns:

true to keep the parser parsing, false to stop it.

endElement

boolean endElement(Element element)

Receive notification of the end of an element. Warning: unless specific decorators are used, in general a callback will just receive notifications for elements whose closing tag appears explicitly in the document.

This method will never be called for element without closing tags, even if such a tag is found.

Parameters:

element - the element whose closing tag was found.

Returns:

true to keep the parser parsing, false to stop it.

characters

boolean characters(char[] text,
                 int offset,
                 int length,
                 boolean flowBroken)

Receive notification of character data inside an element.

You must not write into text, as it could be passed around to many callbacks.

flowBroken will be true iff the flow was broken before text. This feature makes it possible to extract quickly the text in a document without looking at the elements.

Parameters:

text - an array containing the character data.

offset - the start position in the array.

length - the number of characters to read from the array.

flowBroken - whether the flow is broken at the start of text.

Returns:

true to keep the parser parsing, false to stop it.

cdata

boolean cdata(Element element,
            char[] text,
            int offset,
            int length)

Receive notification of the content of a CDATA section.

CDATA sections in an HTML document are the result of meeting a STYLE or SCRIPT element. In that case, the element will be passed as first argument.

You must not write into text, as it could be passed around to many callbacks.

Parameters:

element - the element enclosing the CDATA section, or null if the CDATA section was created with explicit markup.

text - an array containing the character data.

offset - the start position in the array.

length - the number of characters to read from the array.

Returns:

true to keep the parser parsing, false to stop it.

endDocument

void endDocument()

Receive notification of the end of the document.