edu.washington.cs.knowitall.logic

Class LogicExpressionParser<E>

java.lang.Object

edu.washington.cs.knowitall.logic.LogicExpressionParser<E>

Type Parameters:

E - the type of the base expressions

All Implemented Interfaces:

com.google.common.base.Function<String,LogicExpression<E>>

public abstract class LogicExpressionParser<E>
extends Object
implements com.google.common.base.Function<String,LogicExpression<E>>

A logic expression engine that operates over user specified objects.

Author:

Michael Schmitz

Field Summary

Fields

Modifier and Type	Field and Description
static Pattern	doubleQuoteStringLiteralRegex
static Pattern	regexLiteralRegex
static Pattern	singleQuoteStringLiteralRegex

Constructor Summary

Constructors

Constructor and Description
LogicExpressionParser()

Method Summary

Methods

Modifier and Type	Method and Description
LogicExpression<E>	apply(String string)
abstract Expression.Arg<E>	factory(String argument) The factory method creates an argument from the supplied token string.
LogicExpression<E>	parse(String string) Create a LogicExpression object from the supplied string.
String	readToken(String remainder) The readToken method reads a token from the remaining LogicExpression string.
List<Expression<E>>	tokenize(String input) Convert an infix string logic representation to an infix list of tokens.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.google.common.base.Function

equals

Field Detail

doubleQuoteStringLiteralRegex

public static final Pattern doubleQuoteStringLiteralRegex

singleQuoteStringLiteralRegex

public static final Pattern singleQuoteStringLiteralRegex

regexLiteralRegex

public static final Pattern regexLiteralRegex

Constructor Detail

LogicExpressionParser

public LogicExpressionParser()

Method Detail

parse

public LogicExpression<E> parse(String string)

Create a LogicExpression object from the supplied string.

Parameters:

string -

Returns:

apply

public LogicExpression<E> apply(String string)

Specified by:

apply in interface com.google.common.base.Function<String,LogicExpression<E>>

factory

public abstract Expression.Arg<E> factory(String argument)

The factory method creates an argument from the supplied token string.

Parameters:

argument - a string representation of a token

Returns:

an evaluatable representation of a token

readToken

public String readToken(String remainder)

The readToken method reads a token from the remaining LogicExpression string. A token may contain a string. If it contains parentheses, the token will last until the parentheses are balanced. And &, |, or unbalanced ) will mark the end of a token. This is a default implementation that may be overriden.

Parameters:

remainder - the remaining text to tokenize

Returns:

a token from the beginning on `remaining`

tokenize

public List<Expression<E>> tokenize(String input)
                             throws LogicException.TokenizeLogicException

Convert an infix string logic representation to an infix list of tokens.

Parameters:

input - an infix string logic representation.

factory - a delegate that converts a string representation of an argument into a token object. @return

Throws:

LogicException.TokenizeLogicException