ParameterNode (Apache Derby V10.14 Internals)

java.lang.Object
- org.apache.derby.impl.sql.compile.QueryTreeNode
- - org.apache.derby.impl.sql.compile.ValueNode
  - - org.apache.derby.impl.sql.compile.ParameterNode

All Implemented Interfaces:

Visitable
```
public class ParameterNode
extends ValueNode
```
This node type represents a ? parameter.

Field Summary

Fields
Modifier and Type	Field	Description
`private DataValueDescriptor`	`defaultValue`
`private JSQLType`	`jsqlType`	This ParameterNode may turn up as an argument to a replicated Work Unit.
`private int`	`orderableVariantType`
`private int`	`parameterNumber`
`private ValueNode`	`returnOutputParameter`	By default, we assume we are just a normal, harmless little ole parameter.
`private DataTypeDescriptor[]`	`userParameterTypes`	Pointer to the array in the CompilerContext that holds array of types for all the user-visible paramerers..
`private ValueNode`	`valToGenerate`	If this parameter node was created as part of a "probe predicate" for an InListOperatorNode then it does not actually correspond to a specific value--we just created it as a start-key place-holder for IN-list values at execution time.

Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_CYCLE, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX

Fields inherited from class org.apache.derby.impl.sql.compile.ValueNode
transformed

Constructor Summary

Constructors
Constructor Description

ParameterNode(int parameterNumber, DataValueDescriptor defaultValue, ContextManager cm)
Constructor for a ParameterNode.

Constructors
Constructor	Description
`ParameterNode(int parameterNumber, DataValueDescriptor defaultValue, ContextManager cm)`	Constructor for a ParameterNode.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`(package private) ValueNode`	`bindExpression(FromList fromList, SubqueryList subqueryList, java.util.List<AggregateNode> aggregates)`	Bind this expression.
`(package private) boolean`	`constantExpression(PredicateList whereClause)`	Return whether or not this expression tree represents a constant value.
`(package private) void`	`generateExpression(ExpressionClassBuilder acb, MethodBuilder mb)`	For a ParameterNode, we generate for the return value: () ( (BaseActivation) this.getParameter(parameterNumber) )
`(package private) static void`	`generateParameterValueSet(ExpressionClassBuilder acb, int numberOfParameters, java.util.List<ParameterNode> parameterList)`	Generate the code to create the ParameterValueSet, if necessary, when constructing the activation.
`(package private) DataValueDescriptor`	`getDefaultValue()`	Get the default value for the parameter.
`JSQLType`	`getJSQLType()`	Get the JSQLType associated with this parameter.
`protected int`	`getOrderableVariantType()`	Return the variant type for the underlying expression.
`(package private) int`	`getParameterNumber()`	Get the parameter number
`(package private) TypeId`	`getTypeId()`	Get the TypeId from this ValueNode.
`(package private) boolean`	`isConstantExpression()`	Return whether or not this expression tree represents a constant expression.
`(package private) boolean`	`isEquivalent(ValueNode o)`	Tests if this node is equivalent to the specified ValueNode.
`(package private) boolean`	`isParameterNode()`	Returns TRUE if this is a parameter node.
`(package private) boolean`	`isReturnOutputParam()`	Is this as a return output parameter (e.g. ?
`(package private) boolean`	`requiresTypeFromContext()`	Returns TRUE if the type of this node will be determined from the context in which it is getting used.
`(package private) void`	`setDescriptors(DataTypeDescriptor[] descriptors)`	Set the descriptor array
`void`	`setJSQLType(JSQLType type)`	Set the JSQLType of this parameter.
`(package private) void`	`setOrderableVariantType(int type)`	In a special circumstance, we want to consider parameters as constants.
`(package private) void`	`setReturnOutputParam(ValueNode valueNode)`	Mark this as a return output parameter (e.g. ?
`(package private) void`	`setType(DataTypeDescriptor descriptor)`	Set the DataTypeServices for this parameter
`protected void`	`setValueToGenerate(ValueNode vn)`	Save the received ValueNode locally so that we can generate it (in place of "this") at generation time.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode
accept, acceptChildren, addTag, addUDTUsagePriv, addUDTUsagePriv, bindOffsetFetch, bindRowMultiSet, bindUserCatalogType, bindUserType, checkReliability, checkReliability, convertDefaultNode, copyTagsFrom, createTypeDependency, debugFlush, debugPrint, disablePrivilegeCollection, formatNodeString, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContext, getContextManager, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getLongProperty, getNullNode, getOffsetOrderedNodes, getOptimizerFactory, getOptimizerTracer, getParameterTypes, getSchemaDescriptor, getSchemaDescriptor, getStatementType, getTableDescriptor, getTypeCompiler, getUDTDesc, isAtomic, isPrivilegeCollectionRequired, isSessionSchema, isSessionSchema, makeConstantAction, makeTableName, makeTableName, nodeHeader, optimizerTracingIsOn, orReliability, parseSearchCondition, parseStatement, printLabel, printSubNodes, referencesSessionSchema, resolveTableToSynonym, setBeginOffset, setEndOffset, setRefActionInfo, stackPrint, taggedWith, treePrint, treePrint, verifyClassExist

Methods inherited from class org.apache.derby.impl.sql.compile.ValueNode
bindExpression, categorize, changeToCNF, checkIsBoolean, checkTopPredicatesForEqualsConditions, copyFields, eliminateNots, evaluateConstantExpressions, genEqualsFalseTree, generate, genIsNullTree, genSQLJavaSQLTree, getClone, getColumnName, getConstantValueAsObject, getDataValueFactory, getSchemaName, getSourceResultColumn, getTableName, getTablesReferenced, getTransformed, getTypeCompiler, getTypeServices, isBinaryEqualsOperatorNode, isBooleanFalse, isBooleanTrue, isCloneable, isInListProbeNode, isRelationalOperator, isSameNodeKind, optimizableEqualityNode, preprocess, putAndsOnTop, remapColumnReferencesToExpressions, selectivity, setCollationInfo, setCollationInfo, setCollationUsingCompilationSchema, setCollationUsingCompilationSchema, setNullability, setTransformed, setType, setType, toString, updatableByCursor, verifyChangeToCNF, verifyEliminateNots, verifyPutAndsOnTop

- Field Detail
  - parameterNumber
```
private int parameterNumber
```
  - userParameterTypes
```
private DataTypeDescriptor[] userParameterTypes
```
    Pointer to the array in the CompilerContext that holds array of types for all the user-visible paramerers.. When each parameter is bound, it fills in its type descriptor in this array. Note that the array is allocated in the parser, but the individual elements are not filled in until their corresponding parameters are bound. This array is not read in this class, but is read from the CompilerContext on completion of compiling the statement. In some case a parameter node may exist but is not a visble user parameter, in this case typeServices will be null so that setting its type will not modify the user's set.
  - defaultValue
```
private DataValueDescriptor defaultValue
```
  - jsqlType
```
private JSQLType jsqlType
```
    This ParameterNode may turn up as an argument to a replicated Work Unit. If so, the remote system will have figured out the type of this node. That's what this variable is for.
  - orderableVariantType
```
private int orderableVariantType
```
  - returnOutputParameter
```
private ValueNode returnOutputParameter
```
    By default, we assume we are just a normal, harmless little ole parameter. But sometimes we may be a return parameter (e.g. ? = CALL myMethod()).
  - valToGenerate
```
private ValueNode valToGenerate
```
    If this parameter node was created as part of a "probe predicate" for an InListOperatorNode then it does not actually correspond to a specific value--we just created it as a start-key place-holder for IN-list values at execution time. In order to serve that purpose we need to generate some value that can be used as the place-holder. Since this parameter node is "fake" and does not correspond to an actual parameter, we can't really generate it; so the following field holds some legitimate ValueNode--either a constant node or a "real" parameter node--that we can generate to serve as the place-holder.
- Constructor Detail
  - ParameterNode
```
ParameterNode(int parameterNumber,
              DataValueDescriptor defaultValue,
              ContextManager cm)
```
    Constructor for a ParameterNode.
    
    Parameters:
    
    parameterNumber - The number of this parameter, (unique per query starting at 0)
    
    defaultValue - The default value for this parameter
    
    cm - The context manager
- Method Detail
  - getParameterNumber
```
int getParameterNumber()
```
    Get the parameter number
    
    Returns:
    
    The parameter number
  - setDescriptors
```
void setDescriptors(DataTypeDescriptor[] descriptors)
```
    Set the descriptor array
    
    Parameters:
    
    descriptors - The array of DataTypeServices to fill in when the parameters are bound.
  - setType
```
void setType(DataTypeDescriptor descriptor)
      throws StandardException
```
    Set the DataTypeServices for this parameter
    
    Overrides:
    
    setType in class ValueNode
    
    Parameters:
    
    descriptor - The DataTypeServices to set for this parameter
    
    Throws:
    
    StandardException
  - setReturnOutputParam
```
void setReturnOutputParam(ValueNode valueNode)
```
    Mark this as a return output parameter (e.g. ? = CALL myMethod())
  - isReturnOutputParam
```
boolean isReturnOutputParam()
```
    Is this as a return output parameter (e.g. ? = CALL myMethod())
    
    Returns:
    
    true if it is a return param
  - bindExpression
```
ValueNode bindExpression(FromList fromList,
                         SubqueryList subqueryList,
                         java.util.List<AggregateNode> aggregates)
                  throws StandardException
```
    Bind this expression. A parameter can't figure out what its type is without knowing where it appears, so this method does nothing. It is up to the node that points to this parameter node to figure out the type of the parameter and set it, using the setType() method above.
    
    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
  - 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:
    
    ValueNode.constantExpression(org.apache.derby.impl.sql.compile.PredicateList)
  - 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.
  - setOrderableVariantType
```
void setOrderableVariantType(int type)
```
    In a special circumstance, we want to consider parameters as constants. For that situation, we allow a caller to temporarily set us to CONSTANT and then restore us.
  - setJSQLType
```
public void setJSQLType(JSQLType type)
```
    Set the JSQLType of this parameter. This supports the unnamed parameters that we use for replicated work units.
    
    Parameters:
    
    type - the JSQLType associated with this parameter
  - getJSQLType
```
public JSQLType getJSQLType()
```
    Get the JSQLType associated with this parameter. Again, part of method resolution for replicated work units.
    
    Returns:
    
    the JSQLType that the remote system assigned
  - generateExpression
```
void generateExpression(ExpressionClassBuilder acb,
                        MethodBuilder mb)
                 throws StandardException
```
    For a ParameterNode, we generate for the return value: () ( (BaseActivation) this.getParameter(parameterNumber) )
    
    Overrides:
    
    generateExpression in class ValueNode
    
    Parameters:
    
    acb - The ExpressionClassBuilder for the class being built
    
    mb - The method the expression will go into
    
    Throws:
    
    StandardException - Thrown on error
  - getTypeId
```
TypeId getTypeId()
          throws StandardException
```
    Description copied from class: ValueNode
    
    Get the TypeId from this ValueNode.
    
    Overrides:
    
    getTypeId in class ValueNode
    
    Returns:
    
    The TypeId from this ValueNode. This may be null if the node isn't bound yet.
    
    Throws:
    
    StandardException
  - generateParameterValueSet
```
static void generateParameterValueSet(ExpressionClassBuilder acb,
                                      int numberOfParameters,
                                      java.util.List<ParameterNode> parameterList)
                               throws StandardException
```
    Generate the code to create the ParameterValueSet, if necessary, when constructing the activation. Also generate the code to call a method that will throw an exception if we try to execute without all the parameters being set. This generated code goes into the Activation's constructor early on.
    
    Parameters:
    
    acb - The ExpressionClassBuilder for the class we're building
    
    numberOfParameters - number of parameters for this statement
    
    parameterList - The parameter list for the statement.
    
    Throws:
    
    StandardException - on error
  - getDefaultValue
```
DataValueDescriptor getDefaultValue()
```
    Get the default value for the parameter. Parameters may get default values for optimization purposes.
    
    Returns:
    
    the value, may be null
  - requiresTypeFromContext
```
boolean requiresTypeFromContext()
```
    Description copied from class: ValueNode
    
    Returns TRUE if the type of this node will be determined from the context in which it is getting used. If true is returned then after bindExpression() is called on the node, its type must be set (from the relevant context) using setType().
    
    Overrides:
    
    requiresTypeFromContext in class ValueNode
    
    Returns:
    
    Whether this node's type will be determined from the context
    
    See Also:
    
    ValueNode.requiresTypeFromContext()
  - isParameterNode
```
boolean isParameterNode()
```
    Description copied from class: ValueNode
    
    Returns TRUE if this is a parameter node. We do lots of special things with Parameter Nodes.
    
    Overrides:
    
    isParameterNode in class ValueNode
    
    See Also:
    
    ValueNode.isParameterNode()
  - isEquivalent
```
boolean isEquivalent(ValueNode o)
```
    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.
  - setValueToGenerate
```
protected void setValueToGenerate(ValueNode vn)
```
    Save the received ValueNode locally so that we can generate it (in place of "this") at generation time. See the preprocess() method of InListOperatorNode for more on how this is used.
    
    Parameters:
    
    vn - The ValueNode to generate in place of this ParameterNode.

Class ParameterNode

Field Summary

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

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

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

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

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

Field Detail

parameterNumber

userParameterTypes

defaultValue

jsqlType

orderableVariantType

returnOutputParameter

valToGenerate

Constructor Detail

ParameterNode

Method Detail

getParameterNumber

setDescriptors

setType

setReturnOutputParam

isReturnOutputParam

bindExpression

isConstantExpression

constantExpression

getOrderableVariantType

setOrderableVariantType

setJSQLType

getJSQLType

generateExpression

getTypeId

generateParameterValueSet

getDefaultValue

requiresTypeFromContext

isParameterNode

isEquivalent

setValueToGenerate