Class SimplePredicate

All Implemented Interfaces:
HasSQL, Typed
Direct Known Subclasses:
BooleanTest, NullPredicate, TypePredicate

public abstract class SimplePredicate extends Condition
Base class for simple predicates.
  • Field Details

    • left

      The left hand side of the expression.
    • not

      final boolean not
      Whether it is a "not" condition (e.g. "is not null").
    • whenOperand

      final boolean whenOperand
      Where this is the when operand of the simple case.
  • Constructor Details

    • SimplePredicate

      SimplePredicate(Expression left, boolean not, boolean whenOperand)
  • Method Details

    • optimize

      public Expression optimize(SessionLocal session)
      Description copied from class: Expression
      Try to optimize the expression.
      Specified by:
      optimize in class Expression
      Parameters:
      session - the session
      Returns:
      the optimized expression
    • setEvaluatable

      public void setEvaluatable(TableFilter tableFilter, boolean b)
      Description copied from class: Expression
      Tell the expression columns whether the table filter can return values now. This is used when optimizing the query.
      Specified by:
      setEvaluatable in class Expression
      Parameters:
      tableFilter - the table filter
      b - true if the table filter can return value
    • needParentheses

      public final boolean needParentheses()
      Description copied from class: Expression
      Returns whether this expressions needs to be wrapped in parentheses when it is used as an argument of other expressions.
      Overrides:
      needParentheses in class Expression
      Returns:
      true if it is
    • updateAggregate

      public void updateAggregate(SessionLocal session, int stage)
      Description copied from class: Expression
      Update an aggregate value. This method is called at statement execution time. It is usually called once for each row, but if the expression is used multiple times (for example in the column list, and as part of the HAVING expression) it is called multiple times - the row counter needs to be used to make sure the internal state is only updated once.
      Specified by:
      updateAggregate in class Expression
      Parameters:
      session - the session
      stage - select stage
    • mapColumns

      public void mapColumns(ColumnResolver resolver, int level, int state)
      Description copied from class: Expression
      Map the columns of the resolver to expression columns.
      Specified by:
      mapColumns in class Expression
      Parameters:
      resolver - the column resolver
      level - the subquery nesting level
      state - current state for nesting checks, initial value is Expression.MAP_INITIAL
    • isEverything

      public boolean isEverything(ExpressionVisitor visitor)
      Description copied from class: Expression
      Check if this expression and all sub-expressions can fulfill a criteria. If any part returns false, the result is false.
      Specified by:
      isEverything in class Expression
      Parameters:
      visitor - the visitor
      Returns:
      if the criteria can be fulfilled
    • getCost

      public int getCost()
      Description copied from class: Expression
      Estimate the cost to process the expression. Used when optimizing the query, to calculate the query plan with the lowest estimated cost.
      Specified by:
      getCost in class Expression
      Returns:
      the estimated cost
    • getSubexpressionCount

      public int getSubexpressionCount()
      Description copied from class: Expression
      Returns count of subexpressions.
      Overrides:
      getSubexpressionCount in class Expression
      Returns:
      count of subexpressions
    • getSubexpression

      public Expression getSubexpression(int index)
      Description copied from class: Expression
      Returns subexpression with specified index.
      Overrides:
      getSubexpression in class Expression
      Parameters:
      index - 0-based index
      Returns:
      subexpression with specified index, may be null
    • isWhenConditionOperand

      public final boolean isWhenConditionOperand()
      Description copied from class: Expression
      Returns whether this expression is a right side of condition in a when operand.
      Overrides:
      isWhenConditionOperand in class Expression
      Returns:
      true if it is, false otherwise