org.apache.solr.internal.csv

Class CSVParser

java.lang.Object

org.apache.solr.internal.csv.CSVParser

public class CSVParser
extends java.lang.Object

Parses CSV files according to the specified configuration. Because CSV appears in many different dialects, the parser supports many configuration settings by allowing the specification of a CSVStrategy.

Parsing of a csv-string having tabs as separators, '"' as an optional value encapsulator, and comments starting with '#':

  String[][] data = 
   (new CSVParser(new StringReader("a\tb\nc\td"), new CSVStrategy('\t','"','#'))).getAllValues();
 

Parsing of a csv-string in Excel CSV format

  String[][] data =
   (new CSVParser(new StringReader("a;b\nc;d"), CSVStrategy.EXCEL_STRATEGY)).getAllValues();
 

Internal parser state is completely covered by the strategy and the reader-state.

see package documentation for more details

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) static class	CSVParser.Token Token is an internal token representation.

Field Summary

Fields

Modifier and Type	Field and Description
private CharBuffer	code
private static java.lang.String[]	EMPTY_STRING_ARRAY Immutable empty String array.
private ExtendedBufferedReader	in
private static int	INITIAL_TOKEN_LENGTH length of the initial token (content-)buffer
private java.util.ArrayList	record A record buffer for getLine().
private CSVParser.Token	reusableToken
private CSVStrategy	strategy
protected static int	TT_EOF Token (which can have content) when end of file is reached.
protected static int	TT_EORECORD Token with content when end of a line is reached.
protected static int	TT_INVALID Token has no valid content, i.e.
protected static int	TT_TOKEN Token with content, at beginning or in the middle of a line.
private CharBuffer	wsBuf

Constructor Summary

Constructors

Constructor and Description
CSVParser(java.io.InputStream input) Deprecated. use CSVParser(Reader).
CSVParser(java.io.Reader input) CSV parser using the default CSVStrategy.
CSVParser(java.io.Reader input, char delimiter) Deprecated. use CSVParser(Reader,CSVStrategy).
CSVParser(java.io.Reader input, char delimiter, char encapsulator, char commentStart) Deprecated. use CSVParser(Reader,CSVStrategy).
CSVParser(java.io.Reader input, CSVStrategy strategy) Customized CSV parser using the given CSVStrategy

Method Summary

Modifier and Type	Method and Description
private CSVParser.Token	encapsulatedTokenLexer(CSVParser.Token tkn, int c) An encapsulated token lexer Encapsulated tokens are surrounded by the given encapsulating-string.
java.lang.String[][]	getAllValues() Parses the CSV according to the given strategy and returns the content as an array of records (whereas records are arrays of single values).
java.lang.String[]	getLine() Parses from the current point in the stream til the end of the current line.
int	getLineNumber() Returns the current line number in the input stream.
CSVStrategy	getStrategy() Obtain the specified CSV Strategy.
private boolean	isEndOfFile(int c)
private boolean	isEndOfLine(int c) Greedy - accepts \n and \r\n This checker consumes silently the second control-character...
private boolean	isWhitespace(int c)
protected CSVParser.Token	nextToken() Convenience method for nextToken(null).
protected CSVParser.Token	nextToken(CSVParser.Token tkn) Returns the next token.
java.lang.String	nextValue() Parses the CSV according to the given strategy and returns the next csv-value as string.
private int	readEscape(int c)
private CSVParser.Token	simpleTokenLexer(CSVParser.Token tkn, int c) A simple token lexer Simple token are tokens which are not surrounded by encapsulators.
protected int	unicodeEscapeLexer(int c) Decodes Unicode escapes.

Methods inherited from class java.lang.Object

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

Field Detail

INITIAL_TOKEN_LENGTH

private static final int INITIAL_TOKEN_LENGTH

length of the initial token (content-)buffer

See Also:

Constant Field Values

TT_INVALID

protected static final int TT_INVALID

Token has no valid content, i.e. is in its initilized state.

See Also:

Constant Field Values

TT_TOKEN

protected static final int TT_TOKEN

Token with content, at beginning or in the middle of a line.

See Also:

Constant Field Values

TT_EOF

protected static final int TT_EOF

Token (which can have content) when end of file is reached.

See Also:

Constant Field Values

TT_EORECORD

protected static final int TT_EORECORD

Token with content when end of a line is reached.

See Also:

Constant Field Values

EMPTY_STRING_ARRAY

private static final java.lang.String[] EMPTY_STRING_ARRAY

Immutable empty String array.

in

private final ExtendedBufferedReader in

strategy

private final CSVStrategy strategy

record

private final java.util.ArrayList record

A record buffer for getLine(). Grows as necessary and is reused.

reusableToken

private final CSVParser.Token reusableToken

wsBuf

private final CharBuffer wsBuf

code

private final CharBuffer code

Constructor Detail

CSVParser

public CSVParser(java.io.InputStream input)

Deprecated. use CSVParser(Reader).

Default strategy for the parser follows the default CSVStrategy.

Parameters:

input - an InputStream containing "csv-formatted" stream

CSVParser

public CSVParser(java.io.Reader input)

CSV parser using the default CSVStrategy.

Parameters:

input - a Reader containing "csv-formatted" input

CSVParser

public CSVParser(java.io.Reader input,
                 char delimiter)

Deprecated. use CSVParser(Reader,CSVStrategy).

Customized value delimiter parser. The parser follows the default CSVStrategy except for the delimiter setting.

Parameters:

input - a Reader based on "csv-formatted" input

delimiter - a Char used for value separation

CSVParser

public CSVParser(java.io.Reader input,
                 char delimiter,
                 char encapsulator,
                 char commentStart)

Deprecated. use CSVParser(Reader,CSVStrategy).

Customized csv parser. The parser parses according to the given CSV dialect settings. Leading whitespaces are truncated, unicode escapes are not interpreted and empty lines are ignored.

Parameters:

input - a Reader based on "csv-formatted" input

delimiter - a Char used for value separation

encapsulator - a Char used as value encapsulation marker

commentStart - a Char used for comment identification

CSVParser

public CSVParser(java.io.Reader input,
                 CSVStrategy strategy)

Customized CSV parser using the given CSVStrategy

Parameters:

input - a Reader containing "csv-formatted" input

strategy - the CSVStrategy used for CSV parsing

Method Detail

getAllValues

public java.lang.String[][] getAllValues()
                                  throws java.io.IOException

Parses the CSV according to the given strategy and returns the content as an array of records (whereas records are arrays of single values).

The returned content starts at the current parse-position in the stream.

Returns:

matrix of records x values ('null' when end of file)

Throws:

java.io.IOException - on parse error or input read-failure

nextValue

public java.lang.String nextValue()
                           throws java.io.IOException

Parses the CSV according to the given strategy and returns the next csv-value as string.

Returns:

next value in the input stream ('null' when end of file)

Throws:

java.io.IOException - on parse error or input read-failure

getLine

public java.lang.String[] getLine()
                           throws java.io.IOException

Parses from the current point in the stream til the end of the current line.

Returns:

array of values til end of line ('null' when end of file has been reached)

Throws:

java.io.IOException - on parse error or input read-failure

getLineNumber

public int getLineNumber()

Returns the current line number in the input stream. ATTENTION: in case your csv has multiline-values the returned number does not correspond to the record-number

Returns:

current line number

nextToken

protected CSVParser.Token nextToken()
                             throws java.io.IOException

Convenience method for nextToken(null).

Throws:

java.io.IOException

nextToken

protected CSVParser.Token nextToken(CSVParser.Token tkn)
                             throws java.io.IOException

Returns the next token. A token corresponds to a term, a record change or an end-of-file indicator.

Parameters:

tkn - an existing Token object to reuse. The caller is responsible to initialize the Token.

Returns:

the next token found

Throws:

java.io.IOException - on stream access error

simpleTokenLexer

private CSVParser.Token simpleTokenLexer(CSVParser.Token tkn,
                                         int c)
                                  throws java.io.IOException

A simple token lexer Simple token are tokens which are not surrounded by encapsulators. A simple token might contain escaped delimiters (as \, or \;). The token is finished when one of the following conditions become true:

• end of line has been reached (TT_EORECORD)
• end of stream has been reached (TT_EOF)
• an unescaped delimiter has been reached (TT_TOKEN)

Parameters:

tkn - the current token

c - the current character

Returns:

the filled token

Throws:

java.io.IOException - on stream access error

encapsulatedTokenLexer

private CSVParser.Token encapsulatedTokenLexer(CSVParser.Token tkn,
                                               int c)
                                        throws java.io.IOException

An encapsulated token lexer Encapsulated tokens are surrounded by the given encapsulating-string. The encapsulator itself might be included in the token using a doubling syntax (as "", '') or using escaping (as in \", \'). Whitespaces before and after an encapsulated token are ignored.

Parameters:

tkn - the current token

c - the current character

Returns:

a valid token object

Throws:

java.io.IOException - on invalid state

unicodeEscapeLexer

protected int unicodeEscapeLexer(int c)
                          throws java.io.IOException

Decodes Unicode escapes. Interpretation of "\\uXXXX" escape sequences where XXXX is a hex-number.

Parameters:

c - current char which is discarded because it's the "\\" of "\\uXXXX"

Returns:

the decoded character

Throws:

java.io.IOException - on wrong unicode escape sequence or read error

readEscape

private int readEscape(int c)
                throws java.io.IOException

Throws:

java.io.IOException

getStrategy

public CSVStrategy getStrategy()

Obtain the specified CSV Strategy. This should not be modified.

Returns:

strategy currently being used

isWhitespace

private boolean isWhitespace(int c)

Returns:

true if the given char is a whitespace character

isEndOfLine

private boolean isEndOfLine(int c)
                     throws java.io.IOException

Greedy - accepts \n and \r\n This checker consumes silently the second control-character...

Returns:

true if the given character is a line-terminator

Throws:

java.io.IOException

isEndOfFile

private boolean isEndOfFile(int c)

Returns:

true if the given character indicates end of file