de.ipcon.db.oql

Class Parser

java.lang.Object

de.ipcon.db.oql.Parser

public class Parser
extends java.lang.Object

Generates a parse tree for a stream of tokens representing an OQL query. heavily inspired by the work of Nissim Karpenstein from Castor JDO.

Author:

Patric Bechtel

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Parser.QueryPart

Constructor Summary

Constructors

Constructor and Description
Parser(java.lang.String oql, QueryNameSpace nameSpace) Creates a parser which will generate a parse tree from a series of tokens.

Method Summary

Modifier and Type	Method and Description
Token	consume() Consumes the next token It also keep currentToken and nextToken updated.
Token	consume(TokenType tokenType) Consumes the next token if it has the given type, otherwise an OQLSyntaxException is thrown.
Token	getCurrentToken()
QueryNameSpace	getNameSpace() the query namespace, which holds information about roots and joins.
Token	getNextToken()
ParseTreeNode	getParseTree()
java.lang.String	getQueryString()
java.lang.String	getRootAlias()
boolean	hasParameters() Convenience Method to decide whether this Query or any of its Subquerie declare any parameters.
QueryExpressionNode	parse() Generates the parse tree for the tokens provided by the Lexer passed in the constructor.
QueryExpressionNode	parse(Token prefix)

Methods inherited from class java.lang.Object

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

Constructor Detail

Parser

public Parser(java.lang.String oql,
              QueryNameSpace nameSpace)
       throws OQLSyntaxException

Creates a parser which will generate a parse tree from a series of tokens.

Parameters:

oql - he string representation of the OQL Query

Throws:

OQLSyntaxException - thrown if the query doesn't have at least two lexical tokens

Method Detail

getQueryString

public java.lang.String getQueryString()

hasParameters

public boolean hasParameters()

Convenience Method to decide whether this Query or any of its Subquerie declare any parameters.

Returns:

true, if this query uses parameters, i.e. $1, $2, etc, false otherwise

getParseTree

public ParseTreeNode getParseTree()

getRootAlias

public java.lang.String getRootAlias()

parse

public QueryExpressionNode parse()
                          throws OQLSyntaxException

Generates the parse tree for the tokens provided by the Lexer passed in the constructor.

Throws:

OQLSyntaxException - thrown by match.

parse

public QueryExpressionNode parse(Token prefix)
                          throws OQLSyntaxException

Throws:

OQLSyntaxException

getNameSpace

public QueryNameSpace getNameSpace()

the query namespace, which holds information about roots and joins.

getCurrentToken

public Token getCurrentToken()

Returns:

the current Token which will be consumed on the next consume() call.

getNextToken

public Token getNextToken()

Returns:

the token following the current token.

consume

public Token consume(TokenType tokenType)
              throws OQLSyntaxException

Consumes the next token if it has the given type, otherwise an OQLSyntaxException is thrown. It will call consume() and thus update currentToken and nextToken.

Parameters:

tokenType - The token type to compare the current token to.

Returns:

the consumed token

Throws:

OQLSyntaxException

consume

public Token consume()
              throws OQLSyntaxException

Consumes the next token It also keep currentToken and nextToken updated.

Returns:

the consumed token

Throws:

OQLSyntaxException