org.apache.derby.impl.sql.compile

Class GetCurrentConnectionNode

java.lang.Object

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

org.apache.derby.impl.sql.compile.JavaValueNode

org.apache.derby.impl.sql.compile.GetCurrentConnectionNode

All Implemented Interfaces:

Node, Visitable

public final class GetCurrentConnectionNode
extends JavaValueNode

This node represents a unary getCurrentConnection operator RESOLVE - parameter will always be null for now. Someday we may want to allow user to specify which of their connections they want. Assume that we will use a String.

Field Summary

Fields inherited from class org.apache.derby.impl.sql.compile.JavaValueNode

forCallStatement, jsqlType

Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode

AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX

Constructor Summary

Constructors

Constructor and Description
GetCurrentConnectionNode() Constructor for a GetCurrentConnectionNode

Method Summary

Modifier and Type	Method and Description
JavaValueNode	bindExpression(FromList fromList, SubqueryList subqueryList, java.util.List aggregateVector) Bind this operator
(package private) void	bindParameter() Bind a ?
boolean	categorize(JBitSet referencedTabs, boolean simplePredsOnly) Categorize this predicate.
void	checkReliability(ValueNode sqlNode) Check the reliability type of this java value.
void	generateExpression(ExpressionClassBuilder acb, MethodBuilder mb) General logic shared by Core compilation and by the Replication Filter compiler.
protected int	getOrderableVariantType() Return the variant type for the underlying expression.
void	preprocess(int numTables, FromList outerFromList, SubqueryList outerSubqueryList, PredicateList outerPredicateList) Preprocess an expression tree.
JavaValueNode	remapColumnReferencesToExpressions() Remap all ColumnReferences in this tree to be clones of the underlying expression.

Methods inherited from class org.apache.derby.impl.sql.compile.JavaValueNode

castToPrimitive, generate, generateReceiver, generateReceiver, getCollationType, getConstantValueAsObject, getDataType, getJavaTypeName, getJSQLType, getPrimitiveTypeName, getReceiverExpression, isPrimitiveType, mapToTypeID, markForCallStatement, markReturnValueDiscarded, mustCastToPrimitive, returnValueDiscarded, returnValueToSQLDomain, setCollationType, setJavaTypeName, valueReturnedToSQLDomain

Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode

accept, acceptChildren, bindOffsetFetch, bindRowMultiSet, bindUserCatalogType, bindUserType, checkReliability, checkReliability, convertDefaultNode, createTypeDependency, debugFlush, debugPrint, disablePrivilegeCollection, formatNodeString, foundString, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContextManager, getCursorInfo, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getNodeFactory, getNodeType, getNullNode, getParameterTypes, getSchemaDescriptor, getSchemaDescriptor, getStatementType, getTableDescriptor, getTypeCompiler, init, init, init, init, init, init, init, init, init, init, init, init, init, init, isAtomic, isInstanceOf, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, makeTableName, nodeHeader, orReliability, parseStatement, printLabel, printSubNodes, referencesSessionSchema, resolveTableToSynonym, setBeginOffset, setContextManager, setEndOffset, setNodeType, setRefActionInfo, stackPrint, toString, treePrint, treePrint, verifyClassExist

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

GetCurrentConnectionNode

public GetCurrentConnectionNode()

Constructor for a GetCurrentConnectionNode

Method Detail

bindExpression

public JavaValueNode bindExpression(FromList fromList,
                                    SubqueryList subqueryList,
                                    java.util.List aggregateVector)
                             throws StandardException

Bind this operator

Specified by:

bindExpression in class JavaValueNode

Parameters:

fromList - The query's FROM list

subqueryList - The subquery list being built as we find SubqueryNodes

aggregateVector - The aggregate vector being built as we find AggregateNodes

Returns:

the new node, usually this

Throws:

StandardException - Thrown on error

See Also:

ValueNode.bindExpression(org.apache.derby.impl.sql.compile.FromList, org.apache.derby.impl.sql.compile.SubqueryList, java.util.List)

preprocess

public void 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.

Specified by:

preprocess in class JavaValueNode

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

Throws:

StandardException - Thrown on error

See Also:

ValueNode.preprocess(int, org.apache.derby.impl.sql.compile.FromList, org.apache.derby.impl.sql.compile.SubqueryList, org.apache.derby.impl.sql.compile.PredicateList)

categorize

public boolean categorize(JBitSet referencedTabs,
                          boolean simplePredsOnly)

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.

Specified by:

categorize in class JavaValueNode

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.

See Also:

ValueNode.categorize(org.apache.derby.iapi.util.JBitSet, boolean)

remapColumnReferencesToExpressions

public JavaValueNode remapColumnReferencesToExpressions()

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

Specified by:

remapColumnReferencesToExpressions in class JavaValueNode

Returns:

JavaValueNode The remapped expression tree.

See Also:

ValueNode.remapColumnReferencesToExpressions()

bindParameter

void bindParameter()

Bind a ? parameter operand of the char_length function.

getOrderableVariantType

protected int getOrderableVariantType()

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)

Overrides:

getOrderableVariantType in class JavaValueNode

Returns:

The variant type for the underlying expression.

generateExpression

public void generateExpression(ExpressionClassBuilder acb,
                               MethodBuilder mb)
                        throws StandardException

Description copied from class: JavaValueNode

General logic shared by Core compilation and by the Replication Filter compiler. Every child of ValueNode must implement one of these methods.

Specified by:

generateExpression in class JavaValueNode

Parameters:

acb - The ExpressionClassBuilder for the class being built

mb - The method the code to place the code

Throws:

StandardException - Thrown on error

See Also:

ConstantNode.generateExpression(org.apache.derby.impl.sql.compile.ExpressionClassBuilder, org.apache.derby.iapi.services.compiler.MethodBuilder)

checkReliability

public void checkReliability(ValueNode sqlNode)
                      throws StandardException

Check the reliability type of this java value.

Overrides:

checkReliability in class JavaValueNode

Throws:

StandardException - Thrown on error

See Also:

CompilerContext