Class ActivationClassBuilder
- java.lang.Object
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- org.apache.derby.impl.sql.compile.ExpressionClassBuilder
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- org.apache.derby.impl.sql.compile.ActivationClassBuilder
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- All Implemented Interfaces:
ExpressionClassBuilderInterface
class ActivationClassBuilder extends ExpressionClassBuilder
ActivationClassBuilder provides an interface to satisfy generation's common tasks in building an activation class, as well as a repository for the JavaFactory used to generate the basic language constructs for the methods in the class. Common tasks include the setting of a static field for each expression function that gets added, the creation of the execute method that gets expanded as the query tree is walked, setting the superclass.An activation class is defined for each statement. It has the following basic layout: TBD See the document \\Jeeves\Unversioned Repository 1\Internal Technical Documents\Other\GenAndExec.doc for details.
We could also verify methods as they are added, to have 0 parameters, ...
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Field Summary
Fields Modifier and Type Field Description private MethodBuilder
closeActivationMethod
private LocalField
cursorResultSetField
private LocalField
targetResultSetField
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Fields inherited from class org.apache.derby.impl.sql.compile.ExpressionClassBuilder
cb, cdtField, constructor, currentDatetimeFieldName, executeMethod, gc, myCompCtx, nextExprNum, nextFieldNum, nextNonFastExpr
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Constructor Summary
Constructors Constructor Description ActivationClassBuilder(java.lang.String superClass, CompilerContext cc)
By the time this is done, it has constructed the following class:
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description (package private) void
addCursorPositionCode()
Updatable cursors need to add a getter method for use in BaseActivation to access the result set that identifies target rows for a positioned update or delete.(package private) void
finishExecuteMethod()
An execute method always ends in a return statement, returning the result set that has been constructed.(package private) java.lang.String
getBaseClassName()
The base class for activations is BaseActivation(package private) MethodBuilder
getCloseActivationMethod()
protected LocalField
getCurrentSetup()
java.lang.String
getPackageName()
Get the package name that this generated class lives inint
getRowCount()
Get the number of ExecRows to allocate(package private) void
rememberCursor(MethodBuilder mb)
Updatable cursors need to add a field and its initialization for use in BaseActivation to access the result set that identifies cursor result rows for a positioned update or delete.(package private) void
rememberCursorTarget(MethodBuilder mb)
Updatable cursors need to add a field and its initialization for use in BaseActivation to access the result set that identifies target rows for a positioned update or delete.void
setNumSubqueries()
Generate the assignment for numSubqueries = x(package private) MethodBuilder
startResetMethod()
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Methods inherited from class org.apache.derby.impl.sql.compile.ExpressionClassBuilder
addColumnToOrdering, addItem, finishConstructor, generateDataValue, generateNull, generateNullWithExpress, getClassBuilder, getColumnOrdering, getColumnOrdering, getConstructor, getCurrentDateExpression, getCurrentTimeExpression, getCurrentTimestampExpression, getExecuteMethod, getGeneratedClass, getRowLocationScanResultSetName, getTypeCompiler, newExprFun, newFieldDeclaration, newFieldDeclaration, newGeneratedFun, newGeneratedFun, newRowLocationScanResultSetName, newUserExprFun, pushColumnReference, pushDataValueFactory, pushGetExecutionFactoryExpression, pushGetResultSetFactoryExpression, pushMethodReference, pushPVSReference, pushThisAsActivation
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Field Detail
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targetResultSetField
private LocalField targetResultSetField
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cursorResultSetField
private LocalField cursorResultSetField
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closeActivationMethod
private MethodBuilder closeActivationMethod
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Constructor Detail
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ActivationClassBuilder
ActivationClassBuilder(java.lang.String superClass, CompilerContext cc) throws StandardException
By the time this is done, it has constructed the following class:final public class #className extends #superClass { // public void reset() { return; } protected ResultSet doExecute() throws StandardException { // statements must be added here } public #className() { super(); } }
- Throws:
StandardException
- thrown on failure
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Method Detail
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getPackageName
public java.lang.String getPackageName()
Get the package name that this generated class lives in- Specified by:
getPackageName
in classExpressionClassBuilder
- Returns:
- package name
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getBaseClassName
java.lang.String getBaseClassName()
The base class for activations is BaseActivation- Specified by:
getBaseClassName
in classExpressionClassBuilder
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getRowCount
public int getRowCount() throws StandardException
Get the number of ExecRows to allocate- Specified by:
getRowCount
in classExpressionClassBuilder
- Returns:
- package name
- Throws:
StandardException
- thrown on failure
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setNumSubqueries
public void setNumSubqueries()
Generate the assignment for numSubqueries = x- Specified by:
setNumSubqueries
in classExpressionClassBuilder
- Throws:
StandardException
- thrown on failure
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startResetMethod
MethodBuilder startResetMethod()
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finishExecuteMethod
void finishExecuteMethod()
An execute method always ends in a return statement, returning the result set that has been constructed. We want to do some bookkeeping on that statement, so we generate the return given the result set. Upon entry the only word on the stack is the result set expression
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addCursorPositionCode
void addCursorPositionCode()
Updatable cursors need to add a getter method for use in BaseActivation to access the result set that identifies target rows for a positioned update or delete.The code that is generated is:
public CursorResultSet getTargetResultSet() { return targetResultSet; } public CursorResultSet getCursorResultSet() { return cursorResultSet; }
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rememberCursorTarget
void rememberCursorTarget(MethodBuilder mb)
Updatable cursors need to add a field and its initialization for use in BaseActivation to access the result set that identifies target rows for a positioned update or delete.The code that is generated is:
The expression that is generated is:private CursorResultSet targetResultSet; (ResultSet) (targetResultSet = (CursorResultSet) #expression#)
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rememberCursor
void rememberCursor(MethodBuilder mb)
Updatable cursors need to add a field and its initialization for use in BaseActivation to access the result set that identifies cursor result rows for a positioned update or delete.The code that is generated is:
The expression that is generated is:private CursorResultSet cursorResultSet;
The expression must be the top stack word when this method is called.(ResultSet) (cursorResultSet = (CursorResultSet) #expression#)
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getCurrentSetup
protected LocalField getCurrentSetup()
- Overrides:
getCurrentSetup
in classExpressionClassBuilder
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getCloseActivationMethod
MethodBuilder getCloseActivationMethod()
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