Package org.h2.expression

Class OperationN

java.lang.Object
org.h2.expression.Expression
org.h2.expression.OperationN
All Implemented Interfaces:
ExpressionWithVariableParameters, HasSQL, Typed
Direct Known Subclasses:
ConcatenationOperation, FunctionN, JsonConstructorFunction, SearchedCase
public abstract class OperationN extends Expression implements ExpressionWithVariableParameters
Operation with many arguments.

  • Field Details

    • args

      protected Expression[] args
      The array of arguments.

    • argsCount

      protected int argsCount
      The number of arguments.

    • type

      protected TypeInfo type
      The type of the result.

  • Constructor Details

    • OperationN

      protected OperationN(Expression[] args)

  • Method Details

    • addParameter

      public void addParameter(Expression param)
      Description copied from interface: ExpressionWithVariableParameters
      Adds the parameter expression.
      Specified by:
      addParameter in interface ExpressionWithVariableParameters
      Parameters:
      param - the expression

    • doneWithParameters

      public void doneWithParameters() throws DbException
      Description copied from interface: ExpressionWithVariableParameters
      This method must be called after all the parameters have been set. It checks if the parameter count is correct when required by the implementation.
      Specified by:
      doneWithParameters in interface ExpressionWithVariableParameters
      Throws:
      DbException - if the parameter count is incorrect.

    • getType

      public TypeInfo getType()
      Description copied from class: Expression
      Returns the data type. The data type may be unknown before the optimization phase.
      Specified by:
      getType in interface Typed
      Specified by:
      getType in class Expression
      Returns:
      the data type

    • 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

    • optimizeArguments

      protected boolean optimizeArguments(SessionLocal session, boolean allConst)
      Optimizes arguments.
      Parameters:
      session - the session
      allConst - whether operation is deterministic
      Returns:
      whether operation is deterministic and all arguments are constants

    • inlineSubexpressions

      protected final void inlineSubexpressions(Predicate<Expression> tester)
      Inlines subexpressions if possible.
      Parameters:
      tester - the predicate to check whether subexpression can be inlined

    • setEvaluatable

      public void setEvaluatable(TableFilter tableFilter, boolean value)
      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
      value - true if the table filter can return value

    • 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

    • 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