org.apache.derby.impl.sql.compile
Class CurrentUserNode

java.lang.Object
  extended byorg.apache.derby.impl.sql.compile.QueryTreeNode
      extended byorg.apache.derby.impl.sql.compile.ValueNode
          extended byorg.apache.derby.impl.sql.compile.CurrentUserNode
All Implemented Interfaces:
Visitable

public class CurrentUserNode
extends ValueNode

The CurrentUser operator is for the builtin USER, CURRENT_USER, SESSION_USER, CURRENT SCHEMA AND IDENTITY_VAL_LOCAL() operations.

Author:
jerry

Field Summary
static int CURRENT_USER
           
static int IDENTITY_VAL
           
static int SCHEMA
           
static int SESSION_USER
           
static int SYSTEM_USER
           
static int USER
           
private  int whichType
           
 
Fields inherited from class org.apache.derby.impl.sql.compile.ValueNode
clause, dataTypeServices, IN_HAVING_CLAUSE, IN_SELECT_LIST, IN_UNKNOWN_CLAUSE, IN_WHERE_CLAUSE, transformed
 
Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX, beginOffset, endOffset
 
Constructor Summary
CurrentUserNode()
           
 
Method Summary
 ValueNode bindExpression(FromList fromList, SubqueryList subqueryList, java.util.Vector aggregateVector)
          Binding this expression means setting the result DataTypeServices.
 void generateExpression(ExpressionClassBuilder acb, MethodBuilder mb)
          CurrentDatetimeOperatorNode is used in expressions.
protected  int getOrderableVariantType()
          Return the variant type for the underlying expression.
 void init(java.lang.Object whichType)
          Initialize a query tree node.
 java.lang.String toString()
          Convert this object to a String.
 
Methods inherited from class org.apache.derby.impl.sql.compile.ValueNode
bindExpression, categorize, changeToCNF, checkIsBoolean, checkReliability, checkReliability, checkTopPredicatesForEqualsConditions, constantExpression, copyFields, eliminateNots, genEqualsFalseTree, generate, generateFilter, genIsNullTree, genSQLJavaSQLTree, getClause, getClone, getColumnName, getConstantValueAsObject, getDataValueFactory, getSchemaName, getSourceResultColumn, getTableName, getTablesReferenced, getTransformed, getTypeCompiler, getTypeId, getTypeServices, init, isBinaryEqualsOperatorNode, isBooleanFalse, isBooleanTrue, isCloneable, isConstantExpression, isParameterNode, isRelationalOperator, optimizableEqualityNode, preprocess, putAndsOnTop, remapColumnReferencesToExpressions, selectivity, setClause, setDescriptor, setTransformed, setType, verifyChangeToCNF, verifyEliminateNots, verifyPutAndsOnTop
 
Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
accept, bind, convertDefaultNode, debugFlush, debugPrint, executeSchemaName, executeStatementName, formatNodeString, foundString, generate, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContextManager, getCursorInfo, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getNodeFactory, getNodeType, getNullNode, getParameterTypes, getRowEstimate, getSchemaDescriptor, getSchemaDescriptor, getSPSName, getStatementType, getTableDescriptor, getTypeCompiler, init, init, init, init, init, init, init, init, init, init, init, init, isAtomic, isInstanceOf, isSessionSchema, isSessionSchema, makeConstantAction, makeResultDescription, makeTableName, needsSavepoint, nodeHeader, optimize, parseQueryText, printLabel, printSubNodes, referencesSessionSchema, setBeginOffset, setContextManager, setEndOffset, setNodeType, setRefActionInfo, treePrint, treePrint, verifyClassExist
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

USER

public static final int USER
See Also:
Constant Field Values

CURRENT_USER

public static final int CURRENT_USER
See Also:
Constant Field Values

SESSION_USER

public static final int SESSION_USER
See Also:
Constant Field Values

SYSTEM_USER

public static final int SYSTEM_USER
See Also:
Constant Field Values

SCHEMA

public static final int SCHEMA
See Also:
Constant Field Values

IDENTITY_VAL

public static final int IDENTITY_VAL
See Also:
Constant Field Values

whichType

private int whichType
Constructor Detail

CurrentUserNode

public CurrentUserNode()
Method Detail

init

public void init(java.lang.Object whichType)
Description copied from class: QueryTreeNode
Initialize a query tree node.

Overrides:
init in class QueryTreeNode

bindExpression

public ValueNode bindExpression(FromList fromList,
                                SubqueryList subqueryList,
                                java.util.Vector aggregateVector)
                         throws StandardException
Binding this expression means setting the result DataTypeServices. In this case, the result type is based on the operation requested.

Overrides:
bindExpression in class ValueNode
Parameters:
fromList - The FROM list for the statement. This parameter is not used in this case.
subqueryList - The subquery list being built as we find SubqueryNodes. Not used in this case.
aggregateVector - The aggregate vector being built as we find AggregateNodes. Not used in this case.
Returns:
The new top of the expression tree.
Throws:
StandardException - Thrown on error

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 ValueNode
Returns:
The variant type for the underlying expression.

generateExpression

public void generateExpression(ExpressionClassBuilder acb,
                               MethodBuilder mb)
                        throws StandardException
CurrentDatetimeOperatorNode is used in expressions. The expression generated for it invokes a static method on a special Cloudscape type to get the system time and wrap it in the right java.sql type, and then wrap it into the right shape for an arbitrary value, i.e. a column holder. This is very similar to what constants do.

Overrides:
generateExpression in class ValueNode
Parameters:
acb - The ExpressionClassBuilder for the class being built
mb - The method the code to place the code
Throws:
StandardException - Thrown on error

toString

public java.lang.String toString()
Description copied from class: ValueNode
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


Apache Derby V10.0 Engine Documentation - Copyright © 1997,2004 The Apache Software Foundation or its licensors, as applicable.