selector.g

OpenJMS是一个开源的Java Message Service API 1.0.2 规范的实现,它包含有以下特性： *. 它既支持点到点（point-to-point）（PTP）模型和发布/订

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 */
 
    package org.exolab.jms.selector.parser;


    import org.exolab.jms.selector.Context;
    import org.exolab.jms.selector.Identifiers;
    import org.exolab.jms.selector.SelectorException;
    import org.exolab.jms.selector.Type;

/**
 * Selector parser
 *
 * @version     $Revision: 1.2 $ $Date: 2005/11/12 13:47:56 $
 * @author      <a href="mailto:[e-mail]">Tim Anderson</a>
 * @see         SelectorLexer
 * @see         SelectorTreeParser
 */
}

class SelectorParser extends Parser;

options 
{
    exportVocab = Selector;         // call this vocabulary "Selector"
    k = 2;                          // two token lookahead
    buildAST = true;                // build tree
    ASTLabelType = "SelectorAST";   // cast nodes to SelectorAST
    defaultErrorHandler = false;    // abort parsing on error
}

tokens 
{
    // tokens used in tree generation
    UNARY_MINUS;
}

{
    public void initialise() {
        setASTFactory(new SelectorASTFactory());

        // construct SelectorAST nodes
        setASTNodeClass(SelectorAST.class.getName());
    }

    private void rethrow(String msg, AST node, Token token)
        throws SelectorException {
        if (node != null) {
            throw new SelectorException(((SelectorAST) node).getContext(), 
                msg);
        } else {
            Context context = new Context(token.getLine(), token.getColumn());
            throw new SelectorException(context, msg);
        }
    }
}

selector
    :   orExpression
        EOF!
    ;
    exception
    catch [NoViableAltException error] 
    {
        rethrow(error.getMessage(), error.node, error.token);
    }
    catch [MismatchedTokenException error]
    {
        rethrow(error.getMessage(), error.node, error.token);
    }

orExpression
    :   andExpression 
        ( "or"^ 
            { 
                ##.setReturnType(Type.BOOLEAN); 
            } 
            andExpression 
        )*
    ;

andExpression
    :   notExpression 
        ( "and"^ 
            { 
                ##.setReturnType(Type.BOOLEAN); 
            } 
            notExpression 
        )*
    ;

notExpression
    :   ( "not"^ 
            { 
                ##.setReturnType(Type.BOOLEAN); 
            } 
        ) ? 
        expression
    ;

expression!
    :   expr:sumExpression 
        (
            bool:booleanExpression[#expr] { #expr = #bool; }
        |   comp:comparisonExpression[#expr] { #expr = #comp; }
        )?
        {
            ## = #expr;
        }
    ;

comparisonExpression![SelectorAST lhs]
    :   (   EQUAL eq:sumExpression 
            { 
                ## = #(EQUAL, lhs, #eq); 
            }
        |   NOT_EQUAL ne:sumExpression 
            { 
                ## = #(NOT_EQUAL, lhs, #ne); 
            }
        |   LT lt:sumExpression 
            { 
                ## = #(LT, lhs, #lt); 
            }
        |   GT gt:sumExpression 
            { 
                ## = #(GT, lhs, #gt); 
            }
        |   LE le:sumExpression 
            { 
                ## = #(LE, lhs, #le); 
            }
        |   GE ge:sumExpression 
            { 
                ## = #(GE, lhs, #ge); 
            }
        )
        {
            ##.setReturnType(Type.BOOLEAN);
        }
    ;

sumExpression
    :   productExpression 
        (
            ( PLUS^ | MINUS^ ) 
            { 
                ##.setReturnType(Type.NUMERIC); 
            }
            productExpression 
        )*
    ;

productExpression
    :   unaryExpression 
        (( MULTIPLY^ | DIVIDE^ ) 
            { 
                ##.setReturnType(Type.NUMERIC); 
            }
            unaryExpression )*
    ;

unaryExpression
    :   MINUS^ 
        { 
            ##.setType(UNARY_MINUS); 
            ##.setReturnType(Type.NUMERIC);
        } 
        unaryExpression
    |   PLUS! unaryExpression
    |   term
    ;

term
    :   LPAREN orExpression RPAREN
    |   literal
    |   ident:IDENT
        {
            String name = ident.getText();
            if (Identifiers.isJMSIdentifier(name)) {
                if (Identifiers.isNumeric(name)) {
                    #ident.setReturnType(Type.NUMERIC);
                } else if (Identifiers.isString(name)) {
                    #ident.setReturnType(Type.STRING);
                } else {
                    String msg = "invalid message header identifier: " + name;
                    throw new SelectorException(#ident.getContext(), msg);
                }
            }
        }
    ;

booleanExpression[SelectorAST lhs]
    :   isExpression[lhs]
    |   ( "not"^ ) ? 
        (   betweenExpression[lhs]
        |   likeExpression[lhs]
        |   inExpression[lhs]
        )
    ;

isExpression![SelectorAST lhs]
    :   is:"is" ( not:"not" )? nul:"null"
        {
            ## = #(#is, lhs, #nul);
            if (not != null)
            {
                ## = #(#not, ##);
                ##.setReturnType(Type.BOOLEAN);
            }
            ##.setReturnType(Type.BOOLEAN);
        }
    ;

betweenExpression![SelectorAST lhs]
    :   btw:"between" sum1:sumExpression "and" sum2:sumExpression
        { 
            ## = #(#btw, lhs, #sum1, #sum2);
            ##.setReturnType(Type.BOOLEAN);
        }
    ;

inExpression![SelectorAST lhs]
    :   in:"in" LPAREN values:valueList RPAREN
        {
            ## = #(#in, lhs, LPAREN, #values, RPAREN);
            ##.setReturnType(Type.BOOLEAN);
        }
    ;

likeExpression![SelectorAST lhs]
    :   like:"like" pattern:STRING_LITERAL 
            ( esc:"escape" escape:STRING_LITERAL )?
        {