public void
    compilefilter(DapVariable var, DapSequence seq, CEAST expr)
            throws DapException
    {
        if(expr == null)
            return;
        if(expr.sort == CEAST.Sort.SEGMENT) {
            // This must be a simple segment and it must appear in seq
            if(expr.subnodes != null)
                throw new DapException("compilefilter: Non-simple segment:" + expr.name);
            // Look for the name in the top-level field of seq
            DapVariable field = seq.findByName(expr.name);
            if(field == null)
                throw new DapException("compilefilter: Unknown filter variable:" + expr.name);
            expr.field = field;
        } else if(expr.sort == CEAST.Sort.EXPR) {
            if(expr.lhs != null)
                compilefilter(var, seq, expr.lhs);
            if(expr.rhs != null)
                compilefilter(var, seq, expr.rhs);
            // If both lhs and rhs are non-null,
            // canonicalize any comparison so that it is var op const
            if(expr.lhs != null && expr.rhs != null) {
                boolean leftvar = (expr.lhs.sort == CEAST.Sort.SEGMENT);
                boolean rightvar = (expr.rhs.sort == CEAST.Sort.SEGMENT);

                if(rightvar && !leftvar) { // swap operands
                    CEAST tmp = expr.lhs;
                    expr.lhs = expr.rhs;
                    expr.rhs = tmp;
                    // fix operator
                    switch (expr.op) {
                    case LT:  //x<y -> y>x
                        expr.op = CEAST.Operator.GT;
                        break;
                    case LE: //x<=y -> y>=x
                        expr.op = CEAST.Operator.GE;
                        break;
                    case GT:  //x>y -> y<x
                        expr.op = CEAST.Operator.LT;
                        break;
                    case GE:   //x>=y -> y<=x
                        expr.op = CEAST.Operator.LE;
                        break;
                    default:
                        break; // leave as is
                    }
                }
            }
        } else if(expr.sort == CEAST.Sort.CONSTANT) {
            return;
        } else
            throw new DapException("compilefilter: Unexpected node type:" + expr.sort);
    }
public void
    compilefilter(DapVariable var, DapSequence seq, CEAST expr)
            throws DapException
    {
        if(expr == null)
            return;
        if(expr.sort == CEAST.Sort.SEGMENT) {
            
            if(expr.subnodes != null)
                throw new DapException("compilefilter: Non-simple segment:" + expr.name);
            
            DapVariable field = seq.findByName(expr.name);
            if(field == null)
                throw new DapException("compilefilter: Unknown filter variable:" + expr.name);
            expr.field = field;
        } else if(expr.sort == CEAST.Sort.EXPR) {
            if(expr.lhs != null)
                compilefilter(var, seq, expr.lhs);
            if(expr.rhs != null)
                compilefilter(var, seq, expr.rhs);
            
            
            if(expr.lhs != null && expr.rhs != null) {
                boolean leftvar = (expr.lhs.sort == CEAST.Sort.SEGMENT);
                boolean rightvar = (expr.rhs.sort == CEAST.Sort.SEGMENT);

                if(rightvar && !leftvar) { 
                    CEAST tmp = expr.lhs;
                    expr.lhs = expr.rhs;
                    expr.rhs = tmp;
                    
                    switch (expr.op) {
                    case LT:  
                        expr.op = CEAST.Operator.GT;
                        break;
                    case LE: 
                        expr.op = CEAST.Operator.GE;
                        break;
                    case GT:  
                        expr.op = CEAST.Operator.LT;
                        break;
                    case GE:   
                        expr.op = CEAST.Operator.LE;
                        break;
                    default:
                        break; 
                    }
                }
            }
        } else if(expr.sort == CEAST.Sort.CONSTANT) {
            return;
        } else
            throw new DapException("compilefilter: Unexpected node type:" + expr.sort);
    }
public void compilefilter ( DapVariable var , DapSequence seq , CEAST expr ) throws DapException { if ( expr == null ) return ; if ( expr . sort == CEAST . Sort . SEGMENT ) { // This must be a simple segment and it must appear in seq if ( expr . subnodes != null ) throw new DapException ( "compilefilter: Non-simple segment:" + expr . name ) ; // Look for the name in the top-level field of seq DapVariable field = seq . findByName ( expr . name ) ; if ( field == null ) throw new DapException ( "compilefilter: Unknown filter variable:" + expr . name ) ; expr . field = field ; } else if ( expr . sort == CEAST . Sort . EXPR ) { if ( expr . lhs != null ) compilefilter ( var , seq , expr . lhs ) ; if ( expr . rhs != null ) compilefilter ( var , seq , expr . rhs ) ; // If both lhs and rhs are non-null, // canonicalize any comparison so that it is var op const if ( expr . lhs != null && expr . rhs != null ) { boolean leftvar = ( expr . lhs . sort == CEAST . Sort . SEGMENT ) ; boolean rightvar = ( expr . rhs . sort == CEAST . Sort . SEGMENT ) ; if ( rightvar && ! leftvar ) { // swap operands CEAST tmp = expr . lhs ; expr . lhs = expr . rhs ; expr . rhs = tmp ; // fix operator switch ( expr . op ) { case LT : //x<y -> y>x expr . op = CEAST . Operator . GT ; break ; case LE : //x<=y -> y>=x expr . op = CEAST . Operator . GE ; break ; case GT : //x>y -> y<x expr . op = CEAST . Operator . LT ; break ; case GE : //x>=y -> y<=x expr . op = CEAST . Operator . LE ; break ; default : break ; // leave as is } } } } else if ( expr . sort == CEAST . Sort . CONSTANT ) { return ; } else throw new DapException ( "compilefilter: Unexpected node type:" + expr . sort ) ; }
Convert field references in a filter
Convert field references in a filter