uk.ac.starlink.ttools.votlint

Class ValueParser

java.lang.Object

uk.ac.starlink.ttools.votlint.ValueParser

public abstract class ValueParser
extends Object

Object which knows how to interpret the values associated with a FIELD or PARAM object. This interpretation takes the form only of checking whether it is encoded legally, writing some message to the context if it is not, and throwing away the result (if it was ever calculated in the first place).

Since:

7 Apr 2005

Author:

Mark Taylor (Starlink)

Method Summary

Modifier and Type	Method and Description
abstract void	checkStream(InputStream in, long irow) Checks the value of a table element which is encoded in a BINARY stream.
abstract void	checkString(String text, long irow) Checks the value of a string which contains the value.
void	error(VotLintCode code, String msg, long irow) Writes an error message to the user.
abstract Class<?>	getContentClass() Returns the class of values which would be used in Java to represent an object parsed by this parser, although this class does not actually return such values.
VotLintContext	getContext() Returns this parser's context.
abstract int	getElementCount() Returns the number of items of class getContentClass() which correspond to values parsed by this parser.
void	info(VotLintCode code, String msg, long irow) Writes an info message to the user.
static ValueParser	makeParser(ElementHandler handler, String name, String datatype, String arraysize, String xtype) Constructs a ValueParsers for a given element.
static byte[]	readStreamBytes(InputStream in, int nbyte, VotLintContext context) Reads and returns a fixed number of bytes from a stream.
void	setContext(VotLintContext context) Sets this parser's context.
static void	slurpStream(InputStream in, int nbyte, VotLintContext context) Uncritically reads in a fixed number of bytes from a stream.
void	warning(VotLintCode code, String msg, long irow) Writes a warning message to the user.

Methods inherited from class java.lang.Object

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

Method Detail

checkString

public abstract void checkString(String text,
                                 long irow)

Checks the value of a string which contains the value. This is presumably either the content of the value attribute of a PARAM element or the contents of a TD element.

Parameters:

text - value string

irow - row index at which error occurred, or negative if unknown/inapplicable

checkStream

public abstract void checkStream(InputStream in,
                                 long irow)
                          throws IOException

Checks the value of a table element which is encoded in a BINARY stream.

Parameters:

in - input stream

irow - row index at which error occurred, or negative if unknown/inapplicable

Throws:

IOException

getContentClass

public abstract Class<?> getContentClass()

Returns the class of values which would be used in Java to represent an object parsed by this parser, although this class does not actually return such values. This should be the same class that ValueInfo.getContentClass() would return for this object if a StarTable was being built.

Returns:

value class

getElementCount

public abstract int getElementCount()

Returns the number of items of class getContentClass() which correspond to values parsed by this parser. This should be the same as the product of shape elements returned by ValueInfo.getShape(). If the number is indeterminate, -1 should be returned.

Returns:

number of elements per value

setContext

public void setContext(VotLintContext context)

Sets this parser's context. This method should be called shortly after construction.

Parameters:

context - lint context

getContext

public VotLintContext getContext()

Returns this parser's context.

Returns:

lint context

info

public void info(VotLintCode code,
                 String msg,
                 long irow)

Writes an info message to the user.

Parameters:

code - message identifier

msg - message text

irow - row index associated with message, or -1 for unknown/inapplicable

warning

public void warning(VotLintCode code,
                    String msg,
                    long irow)

Writes a warning message to the user.

Parameters:

code - message identifier

msg - message text

irow - row index associated with message, or -1 for unknown/inapplicable

error

public void error(VotLintCode code,
                  String msg,
                  long irow)

Writes an error message to the user.

Parameters:

code - message identifier

msg - message text

irow - row index associated with message, or -1 for unknown/inapplicable

makeParser

public static ValueParser makeParser(ElementHandler handler,
                                     String name,
                                     String datatype,
                                     String arraysize,
                                     String xtype)

Constructs a ValueParsers for a given element.

Parameters:

handler - element handler

name - name attribute value

datatype - datatype attribute value

arraysize - arraysize attribute value

xtype - xtype (extended type) attribute value

Returns:

a suitable ValueParser, or null if one can't be constructed

slurpStream

public static void slurpStream(InputStream in,
                               int nbyte,
                               VotLintContext context)
                        throws IOException

Uncritically reads in a fixed number of bytes from a stream. An error is reported if the stream ends mid-read.

Parameters:

in - input stream

nbyte - number of bytes to read

context - error reporting context

Throws:

IOException

readStreamBytes

public static byte[] readStreamBytes(InputStream in,
                                     int nbyte,
                                     VotLintContext context)
                              throws IOException

Reads and returns a fixed number of bytes from a stream. An error is reported if the stream ends mid-read.

Parameters:

in - input stream

nbyte - number of bytes to read

context - error reporting context

Returns:

full buffer of size nbyte

Throws:

IOException - if read could not complete