com.univocity.parsers.common.input
Class LookaheadCharInputReader

java.lang.Object
  com.univocity.parsers.common.input.LookaheadCharInputReader

All Implemented Interfaces:

CharInput, CharInputReader

public class LookaheadCharInputReader
extends Object
implements CharInputReader

A special implementation of CharInputReader that wraps another CharInputReader and collects a sequence of characters from the wrapped input, in order to analyze what the buffer contains ahead of the current position.

Constructor Summary

LookaheadCharInputReader(CharInputReader reader, char newLine, int whitespaceRangeStart)
Creates a lookahead input reader by wrapping a given CharInputReader implementation

Method Summary

long	charCount() Returns the number of characters returned by CharInputReader.nextChar() at any given time.
String	currentParsedContent() Returns a String with the input character sequence parsed to produce the current record.
void	enableNormalizeLineEndings(boolean escaping) Indicates to the input reader that the parser is running in "escape" mode and new lines should be returned as-is to prevent modifying the content of the parsed value.
char	getChar() Returns the last character returned by the CharInputReader.nextChar() method.
char[]	getLineSeparator() Returns the line separator by this character input reader.
String	getLookahead() Returns the current lookahead value.
String	getLookahead(char current) Returns the lookahead value prepended with the current character
String	getString(char ch, char stop, boolean trim, String nullValue, int maxLength) Attempts to collect a String from the current position until a stop character is found on the input, or a line ending is reached.
long	lineCount() Returns the number of newlines read so far.
void	lookahead(int numberOfCharacters) Fills the lookahead buffer with a given number of characters that will be extracted from the wrapped CharInputReader
void	markRecordStart() Marks the start of a new record in the input, used internally to calculate the result of CharInputReader.currentParsedContent()
boolean	matches(char[] sequence, char wildcard) Matches a sequence of characters against the current lookahead buffer.
boolean	matches(char current, char[] sequence, char wildcard) Matches a sequence of characters against the current lookahead buffer.
char	nextChar() Returns the next character in the input provided by the active Reader.
String	readComment() Collects the comment line found on the input.
void	skipLines(long lineCount) Skips characters in the input until the given number of lines is discarded.
char	skipWhitespace(char ch, char stopChar1, char stopChar2) Skips characters from the current input position, until a non-whitespace character, or a stop character is found
void	start(Reader reader) Initializes the CharInputReader implementation with a Reader which provides access to the input.
void	stop() Stops the CharInputReader from reading characters from the Reader provided in CharInputReader.start(Reader) and closes it.

Methods inherited from class java.lang.Object

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

Constructor Detail

LookaheadCharInputReader

public LookaheadCharInputReader(CharInputReader reader,
                                char newLine,
                                int whitespaceRangeStart)

Creates a lookahead input reader by wrapping a given CharInputReader implementation

Parameters:

reader - the input reader whose characters will read and stored in a limited internal buffer, in order to allow a parser to query what the characters are available ahead of the current input position.

newLine - the normalized character that represents a line ending. Used internally as a stop character.

whitespaceRangeStart - starting range of characters considered to be whitespace.

Method Detail

matches

public boolean matches(char current,
                       char[] sequence,
                       char wildcard)

Matches a sequence of characters against the current lookahead buffer.

Parameters:

current - the last character used by the parser, which should match the first character in the lookahead buffer

sequence - the expected sequence of characters after the current character, that are expected appear in the current lookahead buffer

wildcard - character used in the sequence as a wildcard (e.g. * or ?), meaning any character is acceptable in its place.

Returns:

true if the current character and the sequence characters that follows are present in the lookahead, otherwise false

matches

public boolean matches(char[] sequence,
                       char wildcard)

Matches a sequence of characters against the current lookahead buffer.

Parameters:

sequence - the expected sequence of characters that are expected appear in the current lookahead buffer

wildcard - character used in the sequence as a wildcard (e.g. * or ?), meaning any character is acceptable in its place.

Returns:

true if the given sequence of characters is present in the lookahead, otherwise false

getLookahead

public String getLookahead()

Returns the current lookahead value.

Returns:

the current lookahead value, or an empty String if the lookahead buffer is empty.

getLookahead

public String getLookahead(char current)

Returns the lookahead value prepended with the current character

Parameters:

current - the current character obtained by the parser

Returns:

a String formed by the given character followed by the lookahead value (if any).

lookahead

public void lookahead(int numberOfCharacters)

Fills the lookahead buffer with a given number of characters that will be extracted from the wrapped CharInputReader

Parameters:

numberOfCharacters - the number of characters to read from the wrapped CharInputReader, given in the constructor of this class.

start

public void start(Reader reader)

Description copied from interface: CharInputReader

Initializes the CharInputReader implementation with a Reader which provides access to the input.

Specified by:

start in interface CharInputReader

Parameters:

reader - A Reader that provides access to the input.

stop

public void stop()

Description copied from interface: CharInputReader

Stops the CharInputReader from reading characters from the Reader provided in CharInputReader.start(Reader) and closes it.

Specified by:

stop in interface CharInputReader

nextChar

public char nextChar()

Description copied from interface: CharInputReader

Returns the next character in the input provided by the active Reader.

If the input contains a sequence of newline characters (defined by Format.getLineSeparator()), this method will automatically converted them to the newline character specified in Format.getNormalizedNewline().

A subsequent call to this method will return the character after the newline sequence.

Specified by:

nextChar in interface CharInput

Specified by:

nextChar in interface CharInputReader

Returns:

the next character in the input. '\0' if there are no more characters in the input or if the CharInputReader was stopped.

charCount

public long charCount()

Description copied from interface: CharInputReader

Returns the number of characters returned by CharInputReader.nextChar() at any given time.

Specified by:

charCount in interface CharInputReader

Returns:

the number of characters returned by CharInputReader.nextChar()

lineCount

public long lineCount()

Description copied from interface: CharInputReader

Returns the number of newlines read so far.

Specified by:

lineCount in interface CharInputReader

Returns:

the number of newlines read so far.

skipLines

public void skipLines(long lineCount)

Description copied from interface: CharInputReader

Skips characters in the input until the given number of lines is discarded.

Specified by:

skipLines in interface CharInputReader

Parameters:

lineCount - the number of lines to skip from the current location in the input

enableNormalizeLineEndings

public void enableNormalizeLineEndings(boolean escaping)

Description copied from interface: CharInputReader

Indicates to the input reader that the parser is running in "escape" mode and new lines should be returned as-is to prevent modifying the content of the parsed value.

Specified by:

enableNormalizeLineEndings in interface CharInputReader

Parameters:

escaping - flag indicating that the parser is escaping values and line separators are to be returned as-is.

readComment

public String readComment()

Description copied from interface: CharInputReader

Collects the comment line found on the input.

Specified by:

readComment in interface CharInputReader

Returns:

the text found in the comment from the current position.

getLineSeparator

public char[] getLineSeparator()

Description copied from interface: CharInputReader

Returns the line separator by this character input reader. This could be the line separator defined in the Format.getLineSeparator() configuration, or the line separator sequence identified automatically when CommonParserSettings.isLineSeparatorDetectionEnabled() evaluates to true.

Specified by:

getLineSeparator in interface CharInputReader

Returns:

the line separator in use.

getChar

public final char getChar()

Description copied from interface: CharInputReader

Returns the last character returned by the CharInputReader.nextChar() method.

Specified by:

getChar in interface CharInput

Specified by:

getChar in interface CharInputReader

Returns:

the last character returned by the CharInputReader.nextChar() method.'\0' if there are no more characters in the input or if the CharInputReader was stopped.

skipWhitespace

public char skipWhitespace(char ch,
                           char stopChar1,
                           char stopChar2)

Description copied from interface: CharInputReader

Skips characters from the current input position, until a non-whitespace character, or a stop character is found

Specified by:

skipWhitespace in interface CharInputReader

Parameters:

ch - the current character of the input

stopChar1 - the first stop character (which can be a whitespace)

stopChar2 - the second character (which can be a whitespace)

Returns:

the first non-whitespace character (or delimiter) found in the input.

currentParsedContent

public String currentParsedContent()

Description copied from interface: CharInputReader

Returns a String with the input character sequence parsed to produce the current record.

Specified by:

currentParsedContent in interface CharInputReader

Returns:

the text content parsed for the current input record.

markRecordStart

public void markRecordStart()

Description copied from interface: CharInputReader

Marks the start of a new record in the input, used internally to calculate the result of CharInputReader.currentParsedContent()

Specified by:

markRecordStart in interface CharInputReader

getString

public String getString(char ch,
                        char stop,
                        boolean trim,
                        String nullValue,
                        int maxLength)

Description copied from interface: CharInputReader

Attempts to collect a String from the current position until a stop character is found on the input, or a line ending is reached. If the String can be obtained, the current position of the parser will be updated to the last consumed character. If the internal buffer needs to be reloaded, this method will return null and the current position of the buffer will remain unchanged.

Specified by:

getString in interface CharInputReader

Parameters:

ch - the current character to be considered. If equal to the stop character the nullValue will be returned

stop - the stop character that identifies the end of the content to be collected

trim - flag indicating whether or not trailing whitespaces should be discarded

nullValue - value to return when the length of the content to be returned is 0.

maxLength - the maximum length of the String to be returned. If the length exceeds this limit, null will be returned

Returns:

the String found on the input, or null if the buffer needs to reloaded or the maximum length has been exceeded.