Modifier and Type	Class and Description
private class	ConditionalNode.ReplaceCaseOperandVisitor A visitor that replaces all occurrences of the `caseOperand` node in a tree with dummy parameter nodes.

Modifier and Type	Field and Description
private CachedValueNode	caseOperand The case operand if this is a simple case expression.
private ValueNodeList	testConditions The list of test conditions in the WHEN clauses.
private ValueNodeList	thenElseList The list of corresponding THEN expressions to the test conditions in `testConditions`.

Access	Constructor and Description
pack-priv	ConditionalNode(CachedValueNode The case operand if this is a simple case expression, or `null` otherwise caseOperand, ValueNodeList The boolean test conditions testConditions, ValueNodeList ValueNodeList with then and else expressions thenElseList, ContextManager The context manager cm) Constructor for a ConditionalNode

Method Summary

Modifier and Type	Method and Description
pack-priv void	acceptChildren(Visitor the visitor v) Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.acceptChildren. Accept the visitor for all visitable children of this node.
private ValueNodeList	Returns: a list of dummy parameter nodes that have been inserted into the tree instead of the case operand, if such a replacement has happened; otherwise, `null` is returned bindCaseOperand(CompilerContext cc, FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates) Bind the case operand, if there is one, and check that it doesn't contain anything that's illegal in a case operand (such as calls to routines that are non-deterministic or modify SQL).
pack-priv ValueNode	Returns: The new top of the expression tree. bindExpression(FromList The FROM list for the query this expression is in, for binding columns. fromList, SubqueryList The subquery list being built as we find SubqueryNodes subqueryList, List<AggregateNode> The aggregate list being built as we find AggregateNodes aggregates) Overrides org.apache.derby.impl.sql.compile.ValueNode.bindExpression. Bind this expression.
pack-priv boolean	Returns: boolean Whether or not source.expression is a ColumnReference or a VirtualColumnNode. categorize(JBitSet JBitSet with bit map of referenced FromTables referencedTabs, boolean Whether or not to consider method calls, field references and conditional nodes when building bit map simplePredsOnly) Overrides org.apache.derby.impl.sql.compile.ValueNode.categorize. Categorize this predicate.
pack-priv boolean	constantExpression(PredicateList whereClause) Overrides org.apache.derby.impl.sql.compile.ValueNode.constantExpression. Return whether or not this expression tree represents a constant value.
pack-priv ValueNode	Returns: The modified expression eliminateNots(boolean Whether or not we are under a NotNode. underNotNode) Overrides org.apache.derby.impl.sql.compile.ValueNode.eliminateNots. Eliminate NotNodes in the current query block.
pack-priv void	generateExpression(ExpressionClassBuilder The ExpressionClassBuilder for the class we're generating acb, MethodBuilder The method the expression will go into mb) Overrides org.apache.derby.impl.sql.compile.ValueNode.generateExpression. Do code generation for this conditional expression.
pack-priv boolean	Returns: Whether or not this expression tree represents a constant expression. isConstantExpression() Overrides org.apache.derby.impl.sql.compile.ValueNode.isConstantExpression. Return whether or not this expression tree represents a constant expression.
pack-priv boolean	isEquivalent(ValueNode the node to compare this ValueNode against. o) Implements abstract org.apache.derby.impl.sql.compile.ValueNode.isEquivalent. Tests if this node is equivalent to the specified ValueNode.
pack-priv ValueNode	Returns: The modified expression preprocess(int Number of tables in the DML Statement numTables, FromList FromList from outer query block outerFromList, SubqueryList SubqueryList from outer query block outerSubqueryList, PredicateList PredicateList from outer query block outerPredicateList) Overrides org.apache.derby.impl.sql.compile.ValueNode.preprocess. Preprocess an expression tree.
pack-priv void	printSubNodes(int The depth of this node in the tree depth) Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.printSubNodes. Prints the sub-nodes of this object.
private void	recastNullNodes(DataTypeDescriptor The type to cast SQL parsed NULL's too. castType, FromList FromList to pass on to bindExpression if recast is performed fromList, SubqueryList SubqueryList to pass on to bindExpression if recast is performed subqueryList, List<AggregateNode> List of aggregates to pass on to bindExpression if recast is performed aggregates) This method makes sure any SQL NULLs will be cast to the correct type.
pack-priv ValueNode	Returns: ValueNode The remapped expression tree. remapColumnReferencesToExpressions() Overrides org.apache.derby.impl.sql.compile.ValueNode.remapColumnReferencesToExpressions. Remap all ColumnReferences in this tree to be clones of the underlying expression.

Inherited from org.apache.derby.impl.sql.compile.ValueNode:: bindExpression changeToCNF checkIsBoolean checkTopPredicatesForEqualsConditions copyFields evaluateConstantExpressions genEqualsFalseTree generate genIsNullTree genSQLJavaSQLTree getClone getColumnName getConstantValueAsObject getDataValueFactory getOrderableVariantType getSchemaName getSourceResultColumn getTableName getTablesReferenced getTransformed getTypeCompiler getTypeId getTypeServices isBinaryEqualsOperatorNode isBooleanFalse isBooleanTrue isCloneable isInListProbeNode isParameterNode isRelationalOperator isSameNodeKind optimizableEqualityNode putAndsOnTop requiresTypeFromContext selectivity setCollationInfo setCollationInfo setCollationUsingCompilationSchema setCollationUsingCompilationSchema setNullability setTransformed setType setType setType toString updatableByCursor verifyChangeToCNF verifyEliminateNots verifyPutAndsOnTop

Field Detail

caseOperand	back to summary
private CachedValueNode caseOperand The case operand if this is a simple case expression. Otherwise, it is `null`.

testConditions	back to summary
private ValueNodeList testConditions The list of test conditions in the WHEN clauses.

thenElseList	back to summary
private ValueNodeList thenElseList The list of corresponding THEN expressions to the test conditions in `testConditions`. The last element represents the ELSE clause.

Constructor Detail

ConditionalNode back to summary

ConditionalNode	back to summary
pack-priv ConditionalNode(CachedValueNode caseOperand, ValueNodeList testConditions, ValueNodeList thenElseList, ContextManager cm) Constructor for a ConditionalNode Parameters caseOperand:CachedValueNode The case operand if this is a simple case expression, or `null` otherwise testConditions:ValueNodeList The boolean test conditions thenElseList:ValueNodeList ValueNodeList with then and else expressions cm:ContextManager The context manager

pack-priv ConditionalNode(CachedValueNode caseOperand, ValueNodeList testConditions, ValueNodeList thenElseList, ContextManager cm)

Constructor for a ConditionalNode

Parameters

caseOperand:CachedValueNode: The case operand if this is a simple case expression, or null otherwise
testConditions:ValueNodeList: The boolean test conditions
thenElseList:ValueNodeList: ValueNodeList with then and else expressions
cm:ContextManager: The context manager

Method Detail

acceptChildren	back to summary
pack-priv void acceptChildren(Visitor v) throws StandardException Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.acceptChildren. Accept the visitor for all visitable children of this node. Parameters v:Visitor the visitor Annotations @Override Exceptions StandardException: on error

acceptChildren

back to summary

pack-priv void acceptChildren(Visitor v) throws StandardException

Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.acceptChildren.

Accept the visitor for all visitable children of this node.

Parameters

v:Visitor: the visitor

Annotations

@Override

Exceptions

StandardException:: on error

bindCaseOperand back to summary

bindCaseOperand	back to summary
private ValueNodeList bindCaseOperand(CompilerContext cc, FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates) throws StandardException Bind the case operand, if there is one, and check that it doesn't contain anything that's illegal in a case operand (such as calls to routines that are non-deterministic or modify SQL). Also, if the type of the case operand needs to be inferred, insert dummy parameter nodes into `testConditions` instead of the case operand, so that the type can be inferred individually for each test condition. Later, `bindExpression` will find a common type for all of them, use that type for the case operand, and reinsert the case operand into the test conditions. Returns:ValueNodeList a list of dummy parameter nodes that have been inserted into the tree instead of the case operand, if such a replacement has happened; otherwise, `null` is returned

private ValueNodeList bindCaseOperand(CompilerContext cc, FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates) throws StandardException

Bind the case operand, if there is one, and check that it doesn't contain anything that's illegal in a case operand (such as calls to routines that are non-deterministic or modify SQL).

Also, if the type of the case operand needs to be inferred, insert dummy parameter nodes into testConditions instead of the case operand, so that the type can be inferred individually for each test condition. Later, bindExpression will find a common type for all of them, use that type for the case operand, and reinsert the case operand into the test conditions.

Returns:ValueNodeList: a list of dummy parameter nodes that have been inserted into the tree instead of the case operand, if such a replacement has happened; otherwise, null is returned

bindExpression	back to summary
pack-priv ValueNode bindExpression(FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates) throws StandardException Overrides org.apache.derby.impl.sql.compile.ValueNode.bindExpression. Bind this expression. This means binding the sub-expressions, as well as figuring out what the return type is for this expression. Parameters fromList:FromList The FROM list for the query this expression is in, for binding columns. subqueryList:SubqueryList The subquery list being built as we find SubqueryNodes aggregates:List<AggregateNode> The aggregate list being built as we find AggregateNodes Returns:ValueNode The new top of the expression tree. Annotations @Override Exceptions StandardException: Thrown on error

bindExpression

back to summary

pack-priv ValueNode bindExpression(FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates) throws StandardException

Overrides org.apache.derby.impl.sql.compile.ValueNode.bindExpression.

Bind this expression. This means binding the sub-expressions, as well as figuring out what the return type is for this expression.

Parameters

fromList:FromList: The FROM list for the query this expression is in, for binding columns.
subqueryList:SubqueryList: The subquery list being built as we find SubqueryNodes
aggregates:List<AggregateNode>: The aggregate list being built as we find AggregateNodes

Returns:ValueNode

The new top of the expression tree.

Annotations

@Override

Exceptions

StandardException:: Thrown on error

categorize	back to summary
pack-priv boolean categorize(JBitSet referencedTabs, boolean simplePredsOnly) throws StandardException Overrides org.apache.derby.impl.sql.compile.ValueNode.categorize. 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. Parameters referencedTabs:JBitSet JBitSet with bit map of referenced FromTables simplePredsOnly:boolean Whether or not to consider method calls, field references and conditional nodes when building bit map Returns:boolean boolean Whether or not source.expression is a ColumnReference or a VirtualColumnNode. Annotations @Override Exceptions StandardException: Thrown on error

categorize

back to summary

pack-priv boolean categorize(JBitSet referencedTabs, boolean simplePredsOnly) throws StandardException

Overrides org.apache.derby.impl.sql.compile.ValueNode.categorize.

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.

Parameters

referencedTabs:JBitSet: JBitSet with bit map of referenced FromTables
simplePredsOnly:boolean: Whether or not to consider method calls, field references and conditional nodes when building bit map

Returns:boolean

boolean Whether or not source.expression is a ColumnReference or a VirtualColumnNode.

Annotations

@Override

Exceptions

StandardException:: Thrown on error

constantExpression back to summary

constantExpression	back to summary
pack-priv boolean constantExpression(PredicateList whereClause) Overrides org.apache.derby.impl.sql.compile.ValueNode.constantExpression. Doc from org.apache.derby.impl.sql.compile.ValueNode.constantExpression. 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. Returns:boolean True means this expression tree represents a constant value. Annotations @Override See Also `ValueNode#constantExpression`

pack-priv boolean constantExpression(PredicateList whereClause)

Overrides org.apache.derby.impl.sql.compile.ValueNode.constantExpression.

Doc from org.apache.derby.impl.sql.compile.ValueNode.constantExpression.

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.

Returns:boolean

True means this expression tree represents a constant value.

Annotations

@Override

See Also

ValueNode#constantExpression

eliminateNots	back to summary
pack-priv ValueNode eliminateNots(boolean underNotNode) throws StandardException Overrides org.apache.derby.impl.sql.compile.ValueNode.eliminateNots. Eliminate NotNodes in the current query block. We traverse the tree, inverting ANDs and ORs and eliminating NOTs as we go. We stop at ComparisonOperators and boolean expressions. We invert ComparisonOperators and replace boolean expressions with boolean expression = false. Note Since we do not recurse under ComparisonOperators, there still could be NotNodes left in the tree. Parameters underNotNode:boolean Whether or not we are under a NotNode. Returns:ValueNode The modified expression Annotations @Override Exceptions StandardException: Thrown on error

eliminateNots

back to summary

pack-priv ValueNode eliminateNots(boolean underNotNode) throws StandardException

Overrides org.apache.derby.impl.sql.compile.ValueNode.eliminateNots.

Eliminate NotNodes in the current query block. We traverse the tree, inverting ANDs and ORs and eliminating NOTs as we go. We stop at ComparisonOperators and boolean expressions. We invert ComparisonOperators and replace boolean expressions with boolean expression = false.

Note

Since we do not recurse under ComparisonOperators, there still could be NotNodes left in the tree.

Parameters

underNotNode:boolean: Whether or not we are under a NotNode.

Returns:ValueNode

The modified expression

Annotations

@Override

Exceptions

StandardException:: Thrown on error

generateExpression	back to summary
pack-priv void generateExpression(ExpressionClassBuilder acb, MethodBuilder mb) throws StandardException Overrides org.apache.derby.impl.sql.compile.ValueNode.generateExpression. Do code generation for this conditional expression. Parameters acb:ExpressionClassBuilder The ExpressionClassBuilder for the class we're generating mb:MethodBuilder The method the expression will go into Annotations @Override Exceptions StandardException: Thrown on error

generateExpression

back to summary

pack-priv void generateExpression(ExpressionClassBuilder acb, MethodBuilder mb) throws StandardException

Overrides org.apache.derby.impl.sql.compile.ValueNode.generateExpression.

Do code generation for this conditional expression.

Parameters

acb:ExpressionClassBuilder: The ExpressionClassBuilder for the class we're generating
mb:MethodBuilder: The method the expression will go into

Annotations

@Override

Exceptions

StandardException:: Thrown on error

isConstantExpression	back to summary
pack-priv boolean isConstantExpression() Overrides org.apache.derby.impl.sql.compile.ValueNode.isConstantExpression. Return whether or not this expression tree represents a constant expression. Returns:boolean Whether or not this expression tree represents a constant expression. Annotations @Override

isConstantExpression

back to summary

pack-priv boolean isConstantExpression()

Overrides org.apache.derby.impl.sql.compile.ValueNode.isConstantExpression.

Return whether or not this expression tree represents a constant expression.

Returns:boolean

Whether or not this expression tree represents a constant expression.

Annotations

@Override

isEquivalent back to summary

isEquivalent	back to summary
pack-priv boolean isEquivalent(ValueNode o) throws StandardException Implements abstract org.apache.derby.impl.sql.compile.ValueNode.isEquivalent. Doc from org.apache.derby.impl.sql.compile.ValueNode.isEquivalent. 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. Parameters o:ValueNode the node to compare this ValueNode against. Returns:boolean `true` if the two nodes are equivalent, `false` otherwise.

pack-priv boolean isEquivalent(ValueNode o) throws StandardException

Implements abstract org.apache.derby.impl.sql.compile.ValueNode.isEquivalent.

Doc from org.apache.derby.impl.sql.compile.ValueNode.isEquivalent.

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.

Parameters

o:ValueNode: the node to compare this ValueNode against.

Returns:boolean

true if the two nodes are equivalent, false otherwise.

preprocess	back to summary
pack-priv ValueNode preprocess(int numTables, FromList outerFromList, SubqueryList outerSubqueryList, PredicateList outerPredicateList) throws StandardException Overrides org.apache.derby.impl.sql.compile.ValueNode.preprocess. 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. Parameters numTables:int Number of tables in the DML Statement outerFromList:FromList FromList from outer query block outerSubqueryList:SubqueryList SubqueryList from outer query block outerPredicateList:PredicateList PredicateList from outer query block Returns:ValueNode The modified expression Annotations @Override Exceptions StandardException: Thrown on error

preprocess

back to summary

pack-priv ValueNode preprocess(int numTables, FromList outerFromList, SubqueryList outerSubqueryList, PredicateList outerPredicateList) throws StandardException

Overrides org.apache.derby.impl.sql.compile.ValueNode.preprocess.

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.

Parameters

numTables:int: Number of tables in the DML Statement
outerFromList:FromList: FromList from outer query block
outerSubqueryList:SubqueryList: SubqueryList from outer query block
outerPredicateList:PredicateList: PredicateList from outer query block

Returns:ValueNode

The modified expression

Annotations

@Override

Exceptions

StandardException:: Thrown on error

printSubNodes	back to summary
pack-priv void printSubNodes(int depth) Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.printSubNodes. Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed to work. Parameters depth:int The depth of this node in the tree Annotations @Override

printSubNodes

back to summary

pack-priv void printSubNodes(int depth)

Overrides org.apache.derby.impl.sql.compile.QueryTreeNode.printSubNodes.

Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed to work.

Parameters

depth:int: The depth of this node in the tree

Annotations

@Override

recastNullNodes	back to summary
private void recastNullNodes(DataTypeDescriptor castType, FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates) throws StandardException This method makes sure any SQL NULLs will be cast to the correct type. Parameters castType:DataTypeDescriptor The type to cast SQL parsed NULL's too. fromList:FromList FromList to pass on to bindExpression if recast is performed subqueryList:SubqueryList SubqueryList to pass on to bindExpression if recast is performed aggregates:List<AggregateNode> List of aggregates to pass on to bindExpression if recast is performed Exceptions StandardException: Thrown on error.

recastNullNodes

back to summary

private void recastNullNodes(DataTypeDescriptor castType, FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates) throws StandardException

This method makes sure any SQL NULLs will be cast to the correct type.

Parameters

castType:DataTypeDescriptor: The type to cast SQL parsed NULL's too.
fromList:FromList: FromList to pass on to bindExpression if recast is performed
subqueryList:SubqueryList: SubqueryList to pass on to bindExpression if recast is performed
aggregates:List<AggregateNode>: List of aggregates to pass on to bindExpression if recast is performed

Exceptions

StandardException:: Thrown on error.

remapColumnReferencesToExpressions	back to summary
pack-priv ValueNode remapColumnReferencesToExpressions() throws StandardException Overrides org.apache.derby.impl.sql.compile.ValueNode.remapColumnReferencesToExpressions. Remap all ColumnReferences in this tree to be clones of the underlying expression. Returns:ValueNode ValueNode The remapped expression tree. Annotations @Override Exceptions StandardException: Thrown on error

remapColumnReferencesToExpressions

back to summary

pack-priv ValueNode remapColumnReferencesToExpressions() throws StandardException

Overrides org.apache.derby.impl.sql.compile.ValueNode.remapColumnReferencesToExpressions.

Remap all ColumnReferences in this tree to be clones of the underlying expression.

Returns:ValueNode

ValueNode The remapped expression tree.

Annotations

@Override

Exceptions

StandardException:: Thrown on error

org.apache.derby.impl.sql.compile back to summary

private Class ConditionalNode.ReplaceCaseOperandVisitor

Class Inheritance

extends Object
implements Visitor

java.lang.Object
org.apache.derby.impl.sql.compile.ConditionalNode.ReplaceCaseOperandVisitor

All Implemented Interfaces

org.apache.derby.iapi.sql.compile.Visitor

A visitor that replaces all occurrences of the caseOperand node in a tree with dummy parameter nodes. It also fills a supplied list with the parameter nodes that have been inserted into the tree.

Field Summary

Modifier and Type	Field and Description
private final ValueNodeList	replacements

Constructor Summary

Access	Constructor and Description
private	ReplaceCaseOperandVisitor(ValueNodeList replacements)

Method Summary

Modifier and Type	Method and Description
public boolean	skipChildren(Visitable the node to process node) Implements org.apache.derby.iapi.sql.compile.Visitor.skipChildren. Method that is called to indicate whether we should skip all nodes below this node for traversal.
public boolean	stopTraversal() Implements org.apache.derby.iapi.sql.compile.Visitor.stopTraversal. Method that is called to see if query tree traversal should be stopped before visiting all nodes.
public Visitable	visit(Visitable the node to process node) Implements org.apache.derby.iapi.sql.compile.Visitor.visit. This is the default visit operation on a QueryTreeNode.
public boolean	visitChildrenFirst(Visitable the top node of a sub-tree about to be visited node) Implements org.apache.derby.iapi.sql.compile.Visitor.visitChildrenFirst. Method that is called to see if `visit()` should be called on the children of `node` before it is called on `node` itself.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

replacements	back to summary
private final ValueNodeList replacements

Constructor Detail

ReplaceCaseOperandVisitor	back to summary
private ReplaceCaseOperandVisitor(ValueNodeList replacements)

Method Detail

skipChildren	back to summary
public boolean skipChildren(Visitable node) throws StandardException Implements org.apache.derby.iapi.sql.compile.Visitor.skipChildren. Doc from org.apache.derby.iapi.sql.compile.Visitor.skipChildren. Method that is called to indicate whether we should skip all nodes below this node for traversal. Useful if we want to effectively ignore/prune all branches under a particular node. Differs from stopTraversal() in that it only affects subtrees, rather than the entire traversal. Parameters node:Visitable the node to process Returns:boolean true/false Annotations @Override

skipChildren

back to summary

public boolean skipChildren(Visitable node) throws StandardException

Implements org.apache.derby.iapi.sql.compile.Visitor.skipChildren.

Doc from org.apache.derby.iapi.sql.compile.Visitor.skipChildren.

Method that is called to indicate whether we should skip all nodes below this node for traversal. Useful if we want to effectively ignore/prune all branches under a particular node.

Differs from stopTraversal() in that it only affects subtrees, rather than the entire traversal.

Parameters

node:Visitable: the node to process

Returns:boolean

true/false

Annotations

@Override

stopTraversal	back to summary
public boolean stopTraversal() Implements org.apache.derby.iapi.sql.compile.Visitor.stopTraversal. Doc from org.apache.derby.iapi.sql.compile.Visitor.stopTraversal. Method that is called to see if query tree traversal should be stopped before visiting all nodes. Useful for short circuiting traversal if we already know we are done. Returns:boolean true/false Annotations @Override

stopTraversal

back to summary

public boolean stopTraversal()

Implements org.apache.derby.iapi.sql.compile.Visitor.stopTraversal.

Doc from org.apache.derby.iapi.sql.compile.Visitor.stopTraversal.

Method that is called to see if query tree traversal should be stopped before visiting all nodes. Useful for short circuiting traversal if we already know we are done.

Returns:boolean

true/false

Annotations

@Override

visit	back to summary
public Visitable visit(Visitable node) throws StandardException Implements org.apache.derby.iapi.sql.compile.Visitor.visit. Doc from org.apache.derby.iapi.sql.compile.Visitor.visit. This is the default visit operation on a QueryTreeNode. It just returns the node. This will typically suffice as the default visit operation for most visitors unless the visitor needs to count the number of nodes visited or something like that. Visitors will overload this method by implementing a version with a signature that matches a specific type of node. For example, if I want to do something special with aggregate nodes, then that Visitor will implement a visit(AggregateNode node) method which does the aggregate specific processing. Parameters node:Visitable the node to process Returns:Visitable a query tree node. Often times this is the same node that was passed in, but Visitors that replace nodes with other nodes will use this to return the new replacement node. Annotations @Override Exceptions StandardException: may be throw an error as needed by the visitor (i.e. may be a normal error if a particular node is found, e.g. if checking a group by, we don't expect to find any ColumnReferences that aren't under an AggregateNode -- the easiest thing to do is just throw an error when we find the questionable node).

visit

back to summary

public Visitable visit(Visitable node) throws StandardException

Implements org.apache.derby.iapi.sql.compile.Visitor.visit.

Doc from org.apache.derby.iapi.sql.compile.Visitor.visit.

This is the default visit operation on a QueryTreeNode. It just returns the node. This will typically suffice as the default visit operation for most visitors unless the visitor needs to count the number of nodes visited or something like that.

Visitors will overload this method by implementing a version with a signature that matches a specific type of node. For example, if I want to do something special with aggregate nodes, then that Visitor will implement a visit(AggregateNode node) method which does the aggregate specific processing.

Parameters

node:Visitable: the node to process

Returns:Visitable

a query tree node. Often times this is the same node that was passed in, but Visitors that replace nodes with other nodes will use this to return the new replacement node.

Annotations

@Override

Exceptions

StandardException:: may be throw an error as needed by the visitor (i.e. may be a normal error if a particular node is found, e.g. if checking a group by, we don't expect to find any ColumnReferences that aren't under an AggregateNode -- the easiest thing to do is just throw an error when we find the questionable node).

visitChildrenFirst back to summary

visitChildrenFirst	back to summary
public boolean visitChildrenFirst(Visitable node) Implements org.apache.derby.iapi.sql.compile.Visitor.visitChildrenFirst. Doc from org.apache.derby.iapi.sql.compile.Visitor.visitChildrenFirst. Method that is called to see if `visit()` should be called on the children of `node` before it is called on `node` itself. If this method always returns `true`, the visitor will walk the tree bottom-up. If it always returns `false`, the tree is visited top-down. Parameters node:Visitable the top node of a sub-tree about to be visited Returns:boolean `true` if `node`'s children should be visited before `node`, `false` otherwise Annotations @Override

public boolean visitChildrenFirst(Visitable node)

Implements org.apache.derby.iapi.sql.compile.Visitor.visitChildrenFirst.

Doc from org.apache.derby.iapi.sql.compile.Visitor.visitChildrenFirst.

Method that is called to see if visit() should be called on the children of node before it is called on node itself. If this method always returns true, the visitor will walk the tree bottom-up. If it always returns false, the tree is visited top-down.

Parameters

node:Visitable: the top node of a sub-tree about to be visited

Returns:boolean

true if node's children should be visited before node, false otherwise

Annotations

@Override

pack-priv Class ConditionalNode

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private Class ConditionalNode.ReplaceCaseOperandVisitor

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