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

java.lang.Object
  org.apache.derby.impl.sql.compile.ExpressionClassBuilder
      org.apache.derby.impl.sql.compile.ActivationClassBuilder

All Implemented Interfaces:

org.apache.derby.iapi.sql.compile.ExpressionClassBuilderInterface

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public 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
private  org.apache.derby.iapi.services.compiler.MethodBuilder	closeActivationMethod
private  org.apache.derby.iapi.services.compiler.LocalField	cursorResultSetField
private  org.apache.derby.iapi.services.compiler.LocalField	targetResultSetField

 

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

cb, cdtField, constructor, currentDatetimeFieldName, executeMethod, gc, myCompCtx, nextExprNum, nextFieldNum, nextNonFastExpr, resultSetClosedMethod

 

Constructor Summary

ActivationClassBuilder(java.lang.String superClass, org.apache.derby.iapi.sql.compile.CompilerContext cc)           By the time this is done, it has constructed the following class:

 

Method Summary
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.
org.apache.derby.iapi.services.compiler.MethodBuilder	beginExecuteMethod()           By the time this is done, it has generated the following code
void	finishExecuteMethod(boolean genMarkAsTopNode)           An execute method always ends in a return statement, returning the result set that has been constructed.
java.lang.String	getBaseClassName()           The base class for activations is BaseActivation
org.apache.derby.iapi.services.compiler.MethodBuilder	getCloseActivationMethod()
protected  org.apache.derby.iapi.services.compiler.LocalField	getCurrentSetup()
java.lang.String	getPackageName()           Get the package name that this generated class lives in
void	getParameterReference(java.lang.String name, int position, org.apache.derby.iapi.types.DataTypeDescriptor dataType, org.apache.derby.iapi.services.compiler.MethodBuilder mb)           Generates a parameter reference.
int	getRowCount()           Get the number of ExecRows to allocate
void	rememberCursor(org.apache.derby.iapi.services.compiler.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.
void	rememberCursorTarget(org.apache.derby.iapi.services.compiler.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
org.apache.derby.iapi.services.compiler.MethodBuilder	startResetMethod()

 

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, pushResultSetClosedMethodFieldAccess, pushThisAsActivation

 

Methods inherited from class java.lang.Object

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

 

Field Detail

targetResultSetField

private org.apache.derby.iapi.services.compiler.LocalField targetResultSetField

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cursorResultSetField

private org.apache.derby.iapi.services.compiler.LocalField cursorResultSetField

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closeActivationMethod

private org.apache.derby.iapi.services.compiler.MethodBuilder closeActivationMethod

Constructor Detail

ActivationClassBuilder

public ActivationClassBuilder(java.lang.String superClass,
                              org.apache.derby.iapi.sql.compile.CompilerContext cc)
                       throws org.apache.derby.iapi.error.StandardException

By the time this is done, it has constructed the following class:

    public class #className extends #superClass {
		// public void reset() { return; }
		public ResultSet execute() throws StandardException {
			throwIfClosed("execute");
			// statements must be added here
		}
		public #className() { super(); }
    }
 

Method Detail

getPackageName

public java.lang.String getPackageName()

Get the package name that this generated class lives in

Specified by:

getPackageName in class ExpressionClassBuilder

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getBaseClassName

public java.lang.String getBaseClassName()

The base class for activations is BaseActivation

Specified by:

getBaseClassName in class ExpressionClassBuilder

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getRowCount

public int getRowCount()
                throws org.apache.derby.iapi.error.StandardException

Get the number of ExecRows to allocate

Specified by:

getRowCount in class ExpressionClassBuilder

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setNumSubqueries

public void setNumSubqueries()

Generate the assignment for numSubqueries = x

Specified by:

setNumSubqueries in class ExpressionClassBuilder

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beginExecuteMethod

public org.apache.derby.iapi.services.compiler.MethodBuilder beginExecuteMethod()
                                                                         throws org.apache.derby.iapi.error.StandardException

By the time this is done, it has generated the following code

		public ResultSet execute() throws StandardException {
			throwIfClosed("execute");
			// statements must be added here
		}
    }
 

Specified by:

beginExecuteMethod in class ExpressionClassBuilder

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startResetMethod

public org.apache.derby.iapi.services.compiler.MethodBuilder startResetMethod()

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finishExecuteMethod

public void finishExecuteMethod(boolean genMarkAsTopNode)

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

Specified by:

finishExecuteMethod in class ExpressionClassBuilder

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addCursorPositionCode

public 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

public void rememberCursorTarget(org.apache.derby.iapi.services.compiler.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:

  private CursorResultSet targetResultSet;

 

The expression that is generated is:

  (ResultSet) (targetResultSet = (CursorResultSet) #expression#)
 

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rememberCursor

public void rememberCursor(org.apache.derby.iapi.services.compiler.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:

  private CursorResultSet cursorResultSet;

 

The expression that is generated is:

  (ResultSet) (cursorResultSet = (CursorResultSet) #expression#)
 

The expression must be the top stack word when this method is called.

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getCurrentSetup

protected org.apache.derby.iapi.services.compiler.LocalField getCurrentSetup()

Overrides:

getCurrentSetup in class ExpressionClassBuilder

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getParameterReference

public void getParameterReference(java.lang.String name,
                                  int position,
                                  org.apache.derby.iapi.types.DataTypeDescriptor dataType,
                                  org.apache.derby.iapi.services.compiler.MethodBuilder mb)
                           throws org.apache.derby.iapi.error.StandardException

Generates a parameter reference. Only implemented for Filters right now.

Specified by:

getParameterReference in class ExpressionClassBuilder

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getCloseActivationMethod

public org.apache.derby.iapi.services.compiler.MethodBuilder getCloseActivationMethod()

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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

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