de.tmasoft.acaf.jdbc

Class JdbcStatementUpdateVisitor

java.lang.Object

de.tmasoft.acaf.visitors.VisitorBase

de.tmasoft.acaf.jdbc.JdbcStatementUpdateVisitor

All Implemented Interfaces:

Visitor

public class JdbcStatementUpdateVisitor
extends VisitorBase

This visitor class is used to set the parameters of a JDBC prepared statement with the attribute values of simple attributes (string, enumeration, integer, reference, date, ...) of a component. It cannot be used to update a statement with the content of a container. Therefore container attributes are not considered by this visitor. This visitor must be sent to a component first, calling the method ComponentInterface.acceptVisitor(Visitor) of a component or visitComponent(ComponentInterface) of this visitor.

This visitor cannot be reused! It must be instantiated each time before it is sent to a component.

The visitor is initialized with a prepared JDBC statement, an attribute mediator list and an optional index of the first field to be updated in the prepared statement (default is 1). The parameters of the prepared statement are set by the method JdbcAttributeMediatorInterface.fillStatement(List,PreparedStatement,ComponentInterface,AttributeInterface) of the attribute mediators. The method JdbcAttributeMediatorInterface.getAttributeKeyword() of these attribute mediators is called to determine the attributes of the component this visitor is sent to. The order of the attribute mediators in the list determines the visiting order of the attributes. The order of the parameters in the prepared statement must match the order of the attribute mediators in the list. The method JdbcAttributeMediatorInterface.getColumnNames() of the attribute mediator is called to determine how many parameters are processed by the mediator. This array is used to create the index list for the method fillStatement() of the mediators. The order of the column names in this array must match the order of the parameters in the prepared statement.

For each visited attribute the method fillStatement() of the related attribute mediator is called, passing the prepared statement, the index list of the parameters in the statement to be updated, the parent component of the attribute and the attribute itself.

Constructor Summary

Constructors

Constructor and Description
JdbcStatementUpdateVisitor(java.sql.PreparedStatement statement, java.util.Collection<? extends JdbcAttributeMediatorInterface> attributeMediators, int firstParameterIndex) The constructor initializes the private members with the passed parameters.

Method Summary

Modifier and Type	Method and Description
void	visitAttribute(AttributeInterface<?> attribute) This method overrides the method of the base class and sets the value of the passed attribute into the prepared statement using the current attribute mediator.
void	visitComponent(ComponentInterface<?> component) This method overrides the method of the base class and forwards the visitor to all attributes of the component specified by the attribute mediator collection passed to the constructor.
<C extends ComponentInterface<?>> void	visitComponentReference(ComponentReferenceInterface<?,C> componentReference) This method overrides the method of the base class and calls the method visitAttribute(AttributeInterface).

Methods inherited from class de.tmasoft.acaf.visitors.VisitorBase

visitComponentContainer, visitContainerReference, visitSequenceContainer

Methods inherited from class java.lang.Object

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

Constructor Detail

JdbcStatementUpdateVisitor

public JdbcStatementUpdateVisitor(java.sql.PreparedStatement statement,
                                  java.util.Collection<? extends JdbcAttributeMediatorInterface> attributeMediators,
                                  int firstParameterIndex)

The constructor initializes the private members with the passed parameters.

Parameters:

statement - The prepared statement, of which the the parameters should be set by the visitor.

attributeMediators - The attribute mediators used to set the statement parameters.

firstParameterIndex - The index of the first parameter in the statement to be updated.

Method Detail

visitAttribute

public void visitAttribute(AttributeInterface<?> attribute)
                    throws AcafException

This method overrides the method of the base class and sets the value of the passed attribute into the prepared statement using the current attribute mediator. The current attribute mediator is set by the method visitComponent(ComponentInterface).

This method cannot be used as entry point for this visitor.

Specified by:

visitAttribute in interface Visitor

Overrides:

visitAttribute in class VisitorBase

Parameters:

attribute - The attribute, used to retrieve the value for the parameter of the prepared statement.

Throws:

AcafException - Thrown, when retrieving the attribute values or setting the statement parameter fails.

visitComponent

public void visitComponent(ComponentInterface<?> component)
                    throws AcafException

This method overrides the method of the base class and forwards the visitor to all attributes of the component specified by the attribute mediator collection passed to the constructor. The current component and attribute mediator is set, which are used by the method visitAttribute(AttributeInterface).

Specified by:

visitComponent in interface Visitor

Overrides:

visitComponent in class VisitorBase

Parameters:

component - The component, of which the attribute values are inserted into the statement parameters.

Throws:

AcafException - Thrown, when retrieving the attribute values or setting the statement parameter fails.

visitComponentReference

public <C extends ComponentInterface<?>> void visitComponentReference(ComponentReferenceInterface<?,C> componentReference)
                                                               throws AcafException

This method overrides the method of the base class and calls the method visitAttribute(AttributeInterface).

Specified by:

visitComponentReference in interface Visitor

Overrides:

visitComponentReference in class VisitorBase

Type Parameters:

C - The type of the component referenced by the attribute.

Parameters:

componentReference - The reference attribute, which accepted the visitor.

Throws:

AcafException - Thrown, when retrieving the attribute values or setting the statement parameter fails.