Class UnaryOperatorNode

java.lang.Object
org.apache.derby.impl.sql.compile.QueryTreeNode
org.apache.derby.impl.sql.compile.ValueNode
org.apache.derby.impl.sql.compile.OperatorNode
org.apache.derby.impl.sql.compile.UnaryOperatorNode
All Implemented Interfaces:
Visitable
Direct Known Subclasses:
AggregateNode, DB2LengthOperatorNode, ExtractOperatorNode, LengthOperatorNode, SimpleStringOperatorNode, UnaryArithmeticOperatorNode, UnaryComparisonOperatorNode, UnaryDateTimestampOperatorNode, UnaryLogicalOperatorNode, WindowFunctionNode
class UnaryOperatorNode extends OperatorNode
A UnaryOperatorNode represents a built-in unary operator as defined by the ANSI/ISO SQL standard. This covers operators like +, -, NOT, and IS NULL. Java operators are not represented here: the JSQL language allows Java methods to be called from expressions, but not Java operators.

  • Field Details

    • operator

      String operator

    • methodName

      String methodName

    • resultInterfaceType

      String resultInterfaceType

    • receiverInterfaceType

      String receiverInterfaceType

    • operand

      ValueNode operand
      WARNING: operand may be NULL for COUNT(*).

    • K_XMLPARSE

      static final int K_XMLPARSE
      See Also:

    • K_XMLSERIALIZE

      static final int K_XMLSERIALIZE
      See Also:

    • K_BASE

      static final int K_BASE
      See Also:

    • kind

      final int kind
      This class is used to hold logically different objects for space efficiency. kind represents the logical object type. See also ValueNode.isSameNodeKind(ValueNode).

    • UnaryOperators

      static final String[] UnaryOperators

    • UnaryMethodNames

      static final String[] UnaryMethodNames

    • UnaryResultTypes

      static final String[] UnaryResultTypes

    • UnaryArgTypes

      static final String[] UnaryArgTypes

    • targetType

      private DataTypeDescriptor targetType
      Target type for XMLSerialize operator.

    • preserveWhitespace

      private boolean preserveWhitespace
      Whether or not an XMLParse operator should preserve whitespace.

  • Constructor Details

    • UnaryOperatorNode

      UnaryOperatorNode(ValueNode operand, String operator, String methodNameOrAddedArgs, ContextManager cm) throws StandardException
      When UnaryOperatorNode is used as an base class, this constructor is used as super.
      Throws:
      StandardException

    • UnaryOperatorNode

      UnaryOperatorNode(ValueNode operand, ContextManager cm)
      When UnaryOperatorNode is used as an base class, this constructor is used as super.

    • UnaryOperatorNode

      UnaryOperatorNode(ValueNode operand, int kind, DataTypeDescriptor targetType, boolean preserveWhiteSpace, ContextManager cm)
      Constructor for a UnaryOperatorNode when used as a concrete class.
      Parameters:
      operand - The operand of the node
      kind - The kind of operator
      targetType - The DTD of the target type
      preserveWhiteSpace - true if white space is to be preserved (relevant for kind == XMLPARSE only)
      cm - The context manager

  • Method Details

    • setOperator

      void setOperator(String operator)
      Set the operator.
      Parameters:
      operator - The operator.

    • getOperatorString

      String getOperatorString()
      Get the operator of this unary operator.
      Returns:
      The operator of this unary operator.

    • setMethodName

      void setMethodName(String methodName)
      Set the methodName.
      Parameters:
      methodName - The methodName.

    • toString

      public String toString()
      Convert this object to a String. See comments in QueryTreeNode.java for how this should be done for tree printing.
      Overrides:
      toString in class ValueNode
      Returns:
      This object as a String

    • printSubNodes

      void printSubNodes(int depth)
      Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed to work.
      Overrides:
      printSubNodes in class QueryTreeNode
      Parameters:
      depth - The depth of this node in the tree

    • getOperand

      ValueNode getOperand()
      Get the operand of this unary operator.
      Returns:
      The operand of this unary operator.

    • getParameterOperand

      ParameterNode getParameterOperand() throws StandardException
      Get the parameter operand of this unary operator. For the example below, for abs unary operator node, we want to get ? select * from t1 where -? = max_cni(abs(-?), sqrt(+?)) This gets called when ParameterNode is needed to get parameter specific information like getDefaultValue(), getParameterNumber() etc
      Returns:
      The parameter operand of this unary operator else null.
      Throws:
      StandardException

    • bindExpression

      ValueNode bindExpression(FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates) throws StandardException
      Bind this expression. This means binding the sub-expressions, as well as figuring out what the return type is for this expression. This method is the implementation for XMLPARSE and XMLSERIALIZE. Sub-classes need to implement their own bindExpression() method for their own specific rules.
      Overrides:
      bindExpression in class ValueNode
      Parameters:
      fromList - The FROM list for the query this expression is in, for binding columns.
      subqueryList - The subquery list being built as we find SubqueryNodes
      aggregates - The aggregate list being built as we find AggregateNodes
      Returns:
      The new top of the expression tree.
      Throws:
      StandardException - Thrown on error

    • bindOperand

      protected void bindOperand(FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates) throws StandardException
      Bind the operand for this unary operator. Binding the operator may change the operand node. Sub-classes bindExpression() methods need to call this method to bind the operand.
      Throws:
      StandardException

    • bindXMLParse

      private void bindXMLParse() throws StandardException
      Bind an XMLPARSE operator. Makes sure the operand type is correct, and sets the result type.
      Throws:
      StandardException - Thrown on error

    • bindXMLSerialize

      private void bindXMLSerialize() throws StandardException
      Bind an XMLSERIALIZE operator. Makes sure the operand type and target type are both correct, and sets the result type.
      Throws:
      StandardException - Thrown on error

    • preprocess

      ValueNode preprocess(int numTables, FromList outerFromList, SubqueryList outerSubqueryList, PredicateList outerPredicateList) throws StandardException
      Preprocess an expression tree. We do a number of transformations here (including subqueries, IN lists, LIKE and BETWEEN) plus subquery flattening. NOTE: This is done before the outer ResultSetNode is preprocessed.
      Overrides:
      preprocess in class ValueNode
      Parameters:
      numTables - Number of tables in the DML Statement
      outerFromList - FromList from outer query block
      outerSubqueryList - SubqueryList from outer query block
      outerPredicateList - PredicateList from outer query block
      Returns:
      The modified expression
      Throws:
      StandardException - Thrown on error

    • categorize

      boolean categorize(JBitSet referencedTabs, boolean simplePredsOnly) throws StandardException
      Categorize this predicate. Initially, this means building a bit map of the referenced tables for each predicate. If the source of this ColumnReference (at the next underlying level) is not a ColumnReference or a VirtualColumnNode then this predicate will not be pushed down. For example, in: select * from (select 1 from s) a (x) where x = 1 we will not push down x = 1. NOTE: It would be easy to handle the case of a constant, but if the inner SELECT returns an arbitrary expression, then we would have to copy that tree into the pushed predicate, and that tree could contain subqueries and method calls. RESOLVE - revisit this issue once we have views.
      Overrides:
      categorize in class ValueNode
      Parameters:
      referencedTabs - JBitSet with bit map of referenced FromTables
      simplePredsOnly - Whether or not to consider method calls, field references and conditional nodes when building bit map
      Returns:
      boolean Whether or not source.expression is a ColumnReference or a VirtualColumnNode.
      Throws:
      StandardException - Thrown on error

    • remapColumnReferencesToExpressions

      ValueNode remapColumnReferencesToExpressions() throws StandardException
      Remap all ColumnReferences in this tree to be clones of the underlying expression.
      Overrides:
      remapColumnReferencesToExpressions in class ValueNode
      Returns:
      ValueNode The remapped expression tree.
      Throws:
      StandardException - Thrown on error

    • isConstantExpression

      boolean isConstantExpression()
      Return whether or not this expression tree represents a constant expression.
      Overrides:
      isConstantExpression in class ValueNode
      Returns:
      Whether or not this expression tree represents a constant expression.

    • constantExpression

      boolean constantExpression(PredicateList whereClause)
      Description copied from class: ValueNode
      Return whether or not this expression tree represents a constant value. In this case, "constant" means that it will always evaluate to the same thing, even if it includes columns. A column is constant if it is compared to a constant expression.
      Overrides:
      constantExpression in class ValueNode
      Returns:
      True means this expression tree represents a constant value.
      See Also:

    • bindParameter

      void bindParameter() throws StandardException
      By default unary operators don't accept ? parameters as operands. This can be over-ridden for particular unary operators. We throw an exception if the parameter doesn't have a datatype assigned to it yet.
      Throws:
      StandardException - Thrown if ? parameter doesn't have a type bound to it yet. ? parameter where it isn't allowed.

    • generateExpression

      void generateExpression(ExpressionClassBuilder acb, MethodBuilder mb) throws StandardException
      Do code generation for this unary operator.
      Overrides:
      generateExpression in class ValueNode
      Parameters:
      acb - The ExpressionClassBuilder for the class we're generating
      mb - The method the expression will go into
      Throws:
      StandardException - Thrown on error

    • getReceiverInterfaceName

      String getReceiverInterfaceName() throws StandardException
      Determine the type the binary method is called on. By default, based on the receiver. Override in nodes that use methods on super-interfaces of the receiver's interface, such as comparisons.
      Throws:
      StandardException - Thrown on error

    • getOrderableVariantType

      protected int getOrderableVariantType() throws StandardException
      Return the variant type for the underlying expression. The variant type can be: VARIANT - variant within a scan (method calls and non-static field access) SCAN_INVARIANT - invariant within a scan (column references from outer tables) QUERY_INVARIANT - invariant within the life of a query (constant expressions) CONSTANT - immutable
      Overrides:
      getOrderableVariantType in class ValueNode
      Returns:
      The variant type for the underlying expression.
      Throws:
      StandardException - thrown on error

    • acceptChildren

      void acceptChildren(Visitor v) throws StandardException
      Accept the visitor for all visitable children of this node.
      Overrides:
      acceptChildren in class QueryTreeNode
      Parameters:
      v - the visitor
      Throws:
      StandardException - on error

    • addXmlOpMethodParams

      int addXmlOpMethodParams(ExpressionClassBuilder acb, MethodBuilder mb, LocalField resultField) throws StandardException
      Add some additional arguments to our method call for XML related operations like XMLPARSE and XMLSERIALIZE.
      Parameters:
      acb - the builder for the class in which the method lives
      mb - The MethodBuilder that will make the call.
      resultField - the field that contains the previous result
      Returns:
      Number of parameters added.
      Throws:
      StandardException

    • isEquivalent

      boolean isEquivalent(ValueNode o) throws StandardException
      Description copied from class: ValueNode
      Tests if this node is equivalent to the specified ValueNode. Two ValueNodes are considered equivalent if they will evaluate to the same value during query execution.

      This method provides basic expression matching facility for the derived class of ValueNode and it is used by the language layer to compare the node structural form of the two expressions for equivalence at bind phase.

      Note that it is not comparing the actual row values at runtime to produce a result; hence, when comparing SQL NULLs, they are considered to be equivalent and not unknown.

      One usage case of this method in this context is to compare the select column expression against the group by expression to check if they are equivalent. e.g.:

      SELECT c1+c2 FROM t1 GROUP BY c1+c2

      In general, node equivalence is determined by the derived class of ValueNode. But they generally abide to the rules below:

      • The two ValueNodes must be of the same node type to be considered equivalent. e.g.: CastNode vs. CastNode - equivalent (if their args also match), ColumnReference vs CastNode - not equivalent.
      • If node P contains other ValueNode(s) and so on, those node(s) must also be of the same node type to be considered equivalent.
      • If node P takes a parameter list, then the number of arguments and its arguments for the two nodes must also match to be considered equivalent. e.g.: CAST(c1 as INTEGER) vs CAST(c1 as SMALLINT), they are not equivalent.
      • When comparing SQL NULLs in this context, they are considered to be equivalent.
      • If this does not apply or it is determined that the two nodes are not equivalent then the derived class of this method should return false; otherwise, return true.
      Specified by:
      isEquivalent in class ValueNode
      Parameters:
      o - the node to compare this ValueNode against.
      Returns:
      true if the two nodes are equivalent, false otherwise.
      Throws:
      StandardException

    • isSameNodeKind

      boolean isSameNodeKind(ValueNode o)
      Description copied from class: ValueNode
      Some node classes represent several logical node types (to reduce footprint), which we call kinds. This means that implementations of ValueNode.isEquivalent(ValueNode) cannot always just use instanceof to check if the other node represents the same kind. Hence this method needs to be overridden by all node classes that represent several kinds. This default implementation does not look at kinds. It is only called from implementations of isEquivalent.
      Overrides:
      isSameNodeKind in class ValueNode
      Parameters:
      o - The other value node whose kind we want to compare with.
      Returns:
      true if this and o represent the same logical node type, i.e. kind.