local.tomas.expr.compiler
Class ExpressionCompiler

java.lang.Object
  local.tomas.expr.compiler.ExpressionCompiler

public class ExpressionCompiler
extends Object

The ExpressionCompiler creates Expressions from strings.

Author:

tomas

Field Summary

protected Locale	locale Locale for compilation
protected int	nextToken Next token in compilation.
static int	PRESERVE_NEWLINES_IN_STRINGS Option to preserve newline characters within strings.
protected String[]	tokenStream Token stream compiled.

Constructor Summary

ExpressionCompiler(String expr, Locale locale, int options)
Constructor.

Method Summary

protected Class<? extends BinaryTerm>	additionOperator(String string) Get expression class for addition operator.
protected Class<? extends BinaryTerm>	comparisonOperator(String string) Get expression class for comparison operator.
protected String	currentToken() Get current token
protected String	followingToken() Get following token without moving the token cursor.
protected Class<? extends FunctionCall>	function(String name) Get expression class for function with at least two arguments.
protected List<String>	getTokenStream(String expr, int options) Convert string to token stream.
protected Class<? extends BinaryTerm>	multiplicationOperator(String string) Get expression class for multiplication operator.
protected Class<? extends FunctionCall>	noArgFunction(String name) Get expression class for argument-less function.
protected Expression	parse() Parse expression string.
static Expression	parse(String expr, Locale locale, int options) Parse an expression.
protected Expression	parseAddition() Parse addition term.
protected Expression	parseAnd() Parse AND term.
protected Expression	parseAtom() Parse atomic expression.
protected Expression	parseComparison() Parse comparison term.
protected Expression	parseMultiplication() Parse multiplication term.
protected Expression	parseOr() Parse OR term.
protected Expression	parseUnaryTerm() Parse unary term.
protected Expression	resolveName(String name)
protected Class<? extends UnaryTerm>	unaryFunction(String name) Get expression class for function with a single argument.
protected Class<? extends UnaryTerm>	unaryPostfix(String string) Get expression class for unary postfix operator.
protected Class<? extends UnaryTerm>	unaryPrefix(String string) Get expression class for unary postfix operator.

Methods inherited from class java.lang.Object

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

Field Detail

PRESERVE_NEWLINES_IN_STRINGS

public static final int PRESERVE_NEWLINES_IN_STRINGS

Option to preserve newline characters within strings.

See Also:

Constant Field Values

locale

protected Locale locale

Locale for compilation

tokenStream

protected String[] tokenStream

Token stream compiled.

nextToken

protected int nextToken

Next token in compilation.

Constructor Detail

ExpressionCompiler

public ExpressionCompiler(String expr,
                          Locale locale,
                          int options)
                   throws ExpressionException

Constructor.

Parameters:

expr - expression to compile

locale - locale used for compilation

options - compilation options like PRESERVE_NEWLINES_IN_STRINGS or'ed together

Throws:

ExpressionException

Method Detail

getTokenStream

protected List<String> getTokenStream(String expr,
                                      int options)
                               throws ExpressionException

Convert string to token stream.

Parameters:

expr - expression string

options - compilation options like PRESERVER_NEWLINES_IN_STRINGS or'ed together

Returns:

list of tokens

Throws:

ExpressionException

currentToken

protected String currentToken()

Get current token

Returns:

current token

followingToken

protected String followingToken()

Get following token without moving the token cursor.

Returns:

following token

parse

protected Expression parse()
                    throws ExpressionException

Parse expression string.

Returns:

expression parsed

Throws:

ExpressionException

parseOr

protected Expression parseOr()
                      throws ExpressionException

Parse OR term.

Returns:

expression parsed

Throws:

ExpressionException

parseAnd

protected Expression parseAnd()
                       throws ExpressionException

Parse AND term.

Returns:

epression parsed

Throws:

ExpressionException

parseComparison

protected Expression parseComparison()
                              throws ExpressionException

Parse comparison term.

Returns:

expression parsed

Throws:

ExpressionException

comparisonOperator

protected Class<? extends BinaryTerm> comparisonOperator(String string)

Get expression class for comparison operator.

Parameters:

string - comparison operator

Returns:

subclass of BinaryTerm or null if string is not a comparison operator

parseAddition

protected Expression parseAddition()
                            throws ExpressionException

Parse addition term.

Returns:

expression parsed

Throws:

ExpressionException

additionOperator

protected Class<? extends BinaryTerm> additionOperator(String string)

Get expression class for addition operator.

Parameters:

string - addition operator

Returns:

subclass of BinaryTerm or null if string is not an addition operator

parseMultiplication

protected Expression parseMultiplication()
                                  throws ExpressionException

Parse multiplication term.

Returns:

expression parsed

Throws:

ExpressionException

multiplicationOperator

protected Class<? extends BinaryTerm> multiplicationOperator(String string)

Get expression class for multiplication operator.

Parameters:

string - operator

Returns:

subclass of BinaryTerm or null if string is not a multiplication operator

parseUnaryTerm

protected Expression parseUnaryTerm()
                             throws ExpressionException

Parse unary term.

Returns:

expression parsed

Throws:

ExpressionException

unaryPostfix

protected Class<? extends UnaryTerm> unaryPostfix(String string)

Get expression class for unary postfix operator.

Parameters:

string - operator

Returns:

subclass of UnaryTerm or null if string is not a unary postfix operator

unaryPrefix

protected Class<? extends UnaryTerm> unaryPrefix(String string)

Get expression class for unary postfix operator.

Parameters:

string - operator

Returns:

subclass of UnaryTerm or null if string is not a unary prefix operator

parseAtom

protected Expression parseAtom()
                        throws ExpressionException

Parse atomic expression.

Returns:

expression parsed

Throws:

ExpressionException

resolveName

protected Expression resolveName(String name)
                          throws ExpressionException

Throws:

ExpressionException

noArgFunction

protected Class<? extends FunctionCall> noArgFunction(String name)

Get expression class for argument-less function.

Parameters:

name - function name

Returns:

subclass of FunctionCall or null if name is not an argument-less function

unaryFunction

protected Class<? extends UnaryTerm> unaryFunction(String name)

Get expression class for function with a single argument.

Parameters:

name - function name

Returns:

subclass of FunctionCall or null if name is not function with a single argument

function

protected Class<? extends FunctionCall> function(String name)

Get expression class for function with at least two arguments.

Parameters:

name - function name

Returns:

subclass of FunctionCall or null if name is not function with at least two arguments

parse

public static Expression parse(String expr,
                               Locale locale,
                               int options)
                        throws ExpressionException

Parse an expression.

Parameters:

expr - string representation of an expression

locale - locale used for compilation

options - compilation options or'ed together

Returns:

expression parsed

Throws:

ExpressionException