因为condition.accept
我收到错误“无法解析方法'accept(cs4321.project2.Operators.SelectExpressionVisitor)”。我不知道为什么,因为我正确地遵循了Expressionaccept
方法的语法。
public class SelectExpressionVisitor implements ExpressionVisitor {
private Tuple tuple;
private Map<String, Integer> colToTupleIndexMap;
private boolean tupleFollowsCondition;
public SelectExpressionVisitor(Tuple tuple) {
this.tuple = tuple;
colToTupleIndexMap = DatabaseCatalog.getInstance()
.colToTupleIndexMap;
tupleFollowsCondition = false;
}
public Tuple getSelectTuple(Expression condition) {
condition.accept(this);
if(tupleFollowsCondition) {
return tuple;
}
return null;
}
}