com.google.streamhtmlparser.impl

Class GenericParser

java.lang.Object

com.google.streamhtmlparser.impl.GenericParser

All Implemented Interfaces:

Parser

Direct Known Subclasses:

HtmlParserImpl, JavascriptParserImpl

public class GenericParser
extends Object
implements Parser

An implementation of the Parser interface that is common to both HtmlParser and JavascriptParser.

Provides methods for parsing input and ensuring that all in-state, entering-a-state and exiting-a-state callbacks are invoked as appropriate.

This class started as abstract but it was found better for testing to make it instantiatable so that the parsing logic can be tested with dummy state transitions.

Field Summary

Fields

Modifier and Type	Field and Description
protected int	columnNumber
protected com.google.streamhtmlparser.impl.InternalState	currentState
protected com.google.streamhtmlparser.impl.InternalState	initialState
protected Map<com.google.streamhtmlparser.impl.InternalState,ExternalState>	intToExtStateTable
protected int	lineNumber
protected com.google.streamhtmlparser.impl.ParserStateTable	parserStateTable

Fields inherited from interface com.google.streamhtmlparser.Parser

STATE_ERROR

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	GenericParser(GenericParser aGenericParser) Constructs a generic parser that is an exact copy of the one given.
protected	GenericParser(com.google.streamhtmlparser.impl.ParserStateTable parserStateTable, Map<com.google.streamhtmlparser.impl.InternalState,ExternalState> intToExtStateTable, com.google.streamhtmlparser.impl.InternalState initialState)

Method Summary

Methods

Modifier and Type	Method and Description
int	getColumnNumber() Returns the current column number.
int	getLineNumber() Returns the current line number.
ExternalState	getState() Return the current state of the parser.
protected com.google.streamhtmlparser.impl.InternalState	handleEnterState(com.google.streamhtmlparser.impl.InternalState currentState, com.google.streamhtmlparser.impl.InternalState expectedNextState, char input) Invoked when the parser enters a new state.
protected com.google.streamhtmlparser.impl.InternalState	handleExitState(com.google.streamhtmlparser.impl.InternalState currentState, com.google.streamhtmlparser.impl.InternalState expectedNextState, char input) Invoked when the parser exits a state.
protected com.google.streamhtmlparser.impl.InternalState	handleInState(com.google.streamhtmlparser.impl.InternalState currentState, char input) Invoked for each character read when no state change occured.
void	parse(char input) Main loop for parsing of input.
void	parse(String input) Tell the parser to process the provided String.
protected void	record(char input) Perform some processing on the given character.
void	reset() Reset the parser back to its initial default state.
void	setColumnNumber(int columnNumber) Sets the current column number which is returned during error messages.
void	setLineNumber(int lineNumber) Sets the current line number which is returned during error messages.
protected void	setNextState(com.google.streamhtmlparser.impl.InternalState nextState)

Methods inherited from class java.lang.Object

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

Field Detail

parserStateTable

protected final com.google.streamhtmlparser.impl.ParserStateTable parserStateTable

intToExtStateTable

protected final Map<com.google.streamhtmlparser.impl.InternalState,ExternalState> intToExtStateTable

initialState

protected final com.google.streamhtmlparser.impl.InternalState initialState

currentState

protected com.google.streamhtmlparser.impl.InternalState currentState

lineNumber

protected int lineNumber

columnNumber

protected int columnNumber

Constructor Detail

GenericParser

protected GenericParser(com.google.streamhtmlparser.impl.ParserStateTable parserStateTable,
             Map<com.google.streamhtmlparser.impl.InternalState,ExternalState> intToExtStateTable,
             com.google.streamhtmlparser.impl.InternalState initialState)

GenericParser

protected GenericParser(GenericParser aGenericParser)

Constructs a generic parser that is an exact copy of the one given. Note that here too, data structures that do not change are shallow-copied (parser state table and state mappings).

Parameters:

aGenericParser - the GenericParser to copy

Method Detail

parse

public void parse(String input)
           throws ParseException

Tell the parser to process the provided String. This is just a convenience method that wraps over Parser.parse(char).

Specified by:

parse in interface Parser

Parameters:

input - the String to parse

Throws:

ParseException - if an unrecoverable error occurred during parsing

parse

public void parse(char input)
           throws ParseException

Main loop for parsing of input.

Absent any callbacks defined, this function simply determines the next state to switch to based on the ParserStateTable which is derived from a state-machine configuration file in the original C++ parser.

However some states have specific callbacks defined which when receiving specific characters may decide to overwrite the next state to go to. Hence the next state is a function both of the main state table in ParserStateTable as well as specific run-time information from the callback functions.

Also note that the callbacks are called in a proper sequence, first the exit-state one then the enter-state one and finally the in-state one. Changing the order may result in a functional change.

Specified by:

parse in interface Parser

Parameters:

input - the input character to parse (process)

Throws:

ParseException - if an unrecoverable error occurred during parsing

getState

public ExternalState getState()

Return the current state of the parser.

Specified by:

getState in interface Parser

Returns:

current state of the parser

reset

public void reset()

Reset the parser back to its initial default state.

Specified by:

reset in interface Parser

setLineNumber

public void setLineNumber(int lineNumber)

Sets the current line number which is returned during error messages.

Specified by:

setLineNumber in interface Parser

Parameters:

lineNumber - the line number to set in the parser

getLineNumber

public int getLineNumber()

Returns the current line number.

Specified by:

getLineNumber in interface Parser

setColumnNumber

public void setColumnNumber(int columnNumber)

Sets the current column number which is returned during error messages.

Specified by:

setColumnNumber in interface Parser

Parameters:

columnNumber - the column number to set in the parser

getColumnNumber

public int getColumnNumber()

Returns the current column number.

Specified by:

getColumnNumber in interface Parser

setNextState

protected void setNextState(com.google.streamhtmlparser.impl.InternalState nextState)
                     throws ParseException

Throws:

ParseException

handleEnterState

protected com.google.streamhtmlparser.impl.InternalState handleEnterState(com.google.streamhtmlparser.impl.InternalState currentState,
                                                              com.google.streamhtmlparser.impl.InternalState expectedNextState,
                                                              char input)
                                                                   throws ParseException

Invoked when the parser enters a new state.

Parameters:

currentState - the current state of the parser

expectedNextState - the next state according to the state table definition

input - the last character parsed

Returns:

the state to change to, could be the same as the expectedNextState provided

Throws:

ParseException - if an unrecoverable error occurred during parsing

handleExitState

protected com.google.streamhtmlparser.impl.InternalState handleExitState(com.google.streamhtmlparser.impl.InternalState currentState,
                                                             com.google.streamhtmlparser.impl.InternalState expectedNextState,
                                                             char input)
                                                                  throws ParseException

Invoked when the parser exits a state.

Parameters:

currentState - the current state of the parser

expectedNextState - the next state according to the state table definition

input - the last character parsed

Returns:

the state to change to, could be the same as the expectedNextState provided

Throws:

ParseException - if an unrecoverable error occurred during parsing

handleInState

protected com.google.streamhtmlparser.impl.InternalState handleInState(com.google.streamhtmlparser.impl.InternalState currentState,
                                                           char input)
                                                                throws ParseException

Invoked for each character read when no state change occured.

Parameters:

currentState - the current state of the parser

input - the last character parsed

Returns:

the state to change to, could be the same as the expectedNextState provided

Throws:

ParseException - if an unrecoverable error occurred during parsing

record

protected void record(char input)

Perform some processing on the given character. Derived classes may override this method in order to perform additional logic on every processed character beyond the logic defined in state transitions.

Parameters:

input - the input character to operate on