Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> apache >> derby >> impl >> sql >> [ compile overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

---

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

java.lang.Object
  org.apache.derby.impl.sql.compile.QueryTreeNode
      org.apache.derby.impl.sql.compile.ValueNode
          org.apache.derby.impl.sql.compile.ConstantNode
              org.apache.derby.impl.sql.compile.UserTypeConstantNode

All Implemented Interfaces:

org.apache.derby.iapi.sql.compile.Visitable

---

public class UserTypeConstantNode

extends ConstantNode

User type constants. These are created by built-in types that use user types as their implementation. This could also potentially be used by an optimizer that wanted to store plans for frequently-used parameter values. This is also used to represent nulls in user types, which occurs when NULL is inserted into or supplied as the update value for a usertype column.

---

Field Summary
(package private)  java.lang.Object	value

 

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

UserTypeConstantNode()

 

Method Summary
ValueNode	bindExpression(FromList fromList, SubqueryList subqueryList, java.util.Vector aggregateVector)           Bind this expression.
boolean	constantExpression(PredicateList whereClause)           Return whether or not this expression tree represents a constant value.
(package private)  void	generateConstant(ExpressionClassBuilder acb, org.apache.derby.iapi.services.compiler.MethodBuilder mb)           Should never be called for UserTypeConstantNode because we have our own generateExpression().
void	generateExpression(ExpressionClassBuilder acb, org.apache.derby.iapi.services.compiler.MethodBuilder mb)           For a UserTypeConstantNode, we have to store away the object somewhere and have a way to get it back at runtime.
ValueNode	getClone()           Return a clone of this node.
java.lang.Object	getConstantValueAsObject()           Return an Object representing the bind time value of this expression tree.
java.lang.Object	getObjectValue()           Return the object value of this user defined type.
protected  int	getOrderableVariantType()           Return the variant type for the underlying expression.
org.apache.derby.iapi.types.DataValueDescriptor	getStorableValue()           Return the value of this user defined type as a Storable
org.apache.derby.iapi.types.DataValueDescriptor	getValue()           Get the value in this ConstantNode
void	init(java.lang.Object arg1)           Initializer for a typed null node or a date, time, or timestamp value
void	init(java.lang.Object typeId, java.lang.Object nullable, java.lang.Object maximumWidth)           Initializer for non-numeric types
boolean	isCloneable()           Return whether or not this expression tree is cloneable.
boolean	isConstantExpression()           Return whether or not this expression tree represents a constant expression.
boolean	isNull()           Return whether or not this node represents a typed null constant.
void	setObjectValue(java.lang.Object newValue)           Sets the object value of this user defined type
(package private)  void	setValue(org.apache.derby.iapi.types.DataValueDescriptor value)           Set the value in this ConstantNode.
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, copyFields, eliminateNots, genEqualsFalseTree, generate, generateFilter, genIsNullTree, genSQLJavaSQLTree, getClause, getColumnName, getDataValueFactory, getSchemaName, getSourceResultColumn, getTableName, getTablesReferenced, getTransformed, getTypeCompiler, getTypeId, getTypeServices, init, isBinaryEqualsOperatorNode, isBooleanFalse, isBooleanTrue, isParameterNode, isRelationalOperator, optimizableEqualityNode, preprocess, putAndsOnTop, remapColumnReferencesToExpressions, selectivity, setClause, setDescriptor, setTransformed, setType, updatableByCursor, 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, isAtomic, isInstanceOf, isSessionSchema, isSessionSchema, makeConstantAction, makeResultDescription, makeTableName, needsSavepoint, nodeHeader, optimize, parseQueryText, printLabel, printSubNodes, referencesSessionSchema, resolveTableToSynonym, 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

value

java.lang.Object value

Constructor Detail

UserTypeConstantNode

public UserTypeConstantNode()

Method Detail

init

public void init(java.lang.Object arg1)
          throws org.apache.derby.iapi.error.StandardException

Initializer for a typed null node or a date, time, or timestamp value

Overrides:

init in class QueryTreeNode

---

getObjectValue

public java.lang.Object getObjectValue()

Return the object value of this user defined type.

---

isNull

public boolean isNull()

Return whether or not this node represents a typed null constant.

Overrides:

isNull in class ConstantNode

---

getStorableValue

public org.apache.derby.iapi.types.DataValueDescriptor getStorableValue()
                                                                 throws org.apache.derby.iapi.error.StandardException

Return the value of this user defined type as a Storable

---

setObjectValue

public void setObjectValue(java.lang.Object newValue)

Sets the object value of this user defined type

---

getConstantValueAsObject

public java.lang.Object getConstantValueAsObject()

Return an Object representing the bind time value of this expression tree. If the expression tree does not evaluate to a constant at bind time then we return null. This is useful for bind time resolution of VTIs. RESOLVE: What do we do for primitives?

Overrides:

getConstantValueAsObject in class ValueNode

---

generateExpression

public void generateExpression(ExpressionClassBuilder acb,
                               org.apache.derby.iapi.services.compiler.MethodBuilder mb)
                        throws org.apache.derby.iapi.error.StandardException

For a UserTypeConstantNode, we have to store away the object somewhere and have a way to get it back at runtime. These objects are serializable. This gives us at least two options: 1) serialize it out into a byte array field, and serialize it back in when needed, from the field. 2) have an array of objects in the prepared statement and a #, to find the object directly. Because it is serializable, it will store with the rest of the executable just fine. Choice 2 gives better performance -- the ser/deser cost is paid on database access for the statement, not for each execution of it. However, it requires some infrastructure support from prepared statements. For now, we take choice 3, and make some assumptions about available methods on the user type. This choice has the shortcoming that it will not work for arbitrary user types. REVISIT and implement choice 2 when a general solution is needed.

A null is generated as a Null value cast to the type of the constant node.

Overrides:

generateExpression in class ConstantNode

---

generateConstant

void generateConstant(ExpressionClassBuilder acb,
                      org.apache.derby.iapi.services.compiler.MethodBuilder mb)
                throws org.apache.derby.iapi.error.StandardException

Should never be called for UserTypeConstantNode because we have our own generateExpression().

Specified by:

generateConstant in class ConstantNode

---

init

public void init(java.lang.Object typeId,
                 java.lang.Object nullable,
                 java.lang.Object maximumWidth)
          throws org.apache.derby.iapi.error.StandardException

Initializer for non-numeric types

Overrides:

init in class QueryTreeNode

---

setValue

void setValue(org.apache.derby.iapi.types.DataValueDescriptor value)

Set the value in this ConstantNode.

---

getValue

public org.apache.derby.iapi.types.DataValueDescriptor getValue()

Get the value in this ConstantNode

---

toString

public java.lang.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

---

isCloneable

public boolean isCloneable()

Return whether or not this expression tree is cloneable.

Overrides:

isCloneable in class ValueNode

---

getClone

public ValueNode getClone()

Return a clone of this node.

Overrides:

getClone in class ValueNode

---

bindExpression

public ValueNode bindExpression(FromList fromList,
                                SubqueryList subqueryList,
                                java.util.Vector aggregateVector)

Bind this expression. This means binding the sub-expressions, as well as figuring out what the return type is for this expression. In this case, there are no sub-expressions, and the return type is already known, so this is just a stub.

Overrides:

bindExpression in class ValueNode

---

isConstantExpression

public boolean isConstantExpression()

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

Overrides:

isConstantExpression in class ValueNode

---

constantExpression

public 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

---

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 VARIANT - immutable

Overrides:

getOrderableVariantType in class ValueNode

---

Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> apache >> derby >> impl >> sql >> [ compile overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

---