com.viaoa.hub

Class HubLink

java.lang.Object

com.viaoa.hub.HubLink

public class HubLink
extends Object

Used to connect Hubs together based on a reference property. A Hub can be linked to a reference property of the active object in another Hub.

Types of linking:
1: link the active object in a Hub to a property in another Hub, where the property type is the same Class as the objects in this Hub.
2: link the position of the active object in a Hub to a property (numeric) in another Hub.
3: link a property in a Hub to a property in another Hub.
4: a link that will automatically create a new object in another Hub and set the link property, whenever the active object in a Hub is changed.

Examples:

 // Link department Hub to the department property in a Employee Hub
 Hub hubDept = new Hub(Department.class);   // create new Hub for Department objects
 hubDept.select();      // select all departments from datasource
 Hub hubEmp = new Hub(Employee.class);
 hubEmp.select();   // select all employees from datasource
 new HubLink(hubDept, hubEmp, "Department");

 // Link the position of a value to a property in another Hub
 Hub hub = new Hub(String.class);
 hub.add("Yes");
 hub.add("No");
 hub.add("Maybe");
 new HubLink(hub, true, hubEmployee, "retiredStatus");  // values will be set to 0,1, or 2

 // Link a the property value of active object to a property in the link Hub
 Hub hub = new Hub(State.class);  // Class that stores information about all 50 states
 hub.select();   // select all
 new HubLink(hub, "stateName", hubEmp, "state");  // set the state property to name of state

 // automatically create an object and set link property when active object is changed
 Hub hubItem = new Hub(Item.class);
 Hub hubOrder = new Hub(Order.class);
 Hub hubOrderItem = new HubDetail(hubOrder, "OrderItems");  // create detail Hub for
                                                            // order items
 new HubLink(hubItem, hubOrderItem, "item", true);  // whenever hubItem's active object is
                                       // changed, a new OrderItem object will
                                       // be created with a reference to the
                                       // selected Item object.
    

Example:

The Hub on the left is a collection of Employee objects. The Hub on the right has Department objects.
if the (A) active object is changed to "Emp 2", the (B) active object is changed to "Dept B", since that is the Dept for "Emp 2".
If the (C) active object is changed to "Dept C", the (D) Dept for the active object will be set to "Dept C".

This is a common setup when using ComboBoxes. In the above example, a form that displays an Employee would have a ComboBox that is a dropdown list of Departments to choose from. When the active object in the Employee Hub is changed, the Employees Department is retrieved and used to set the active object in the Department Hub - this will then display the correct Department in the ComboBox. When the user selects a different Department using the CombBox, the active object in the Department Hub is changed, which automatically changes the Department for the Employee.

    Hub hubDepartment = new Hub(Department.class);
    hubDepartment.select();
    Hub hubEmployee = new Hub(Employee.class);
    hubEmployee.select();
    HubLink hl = new HubLink(hubDepartment, hubEmployee, "Department");
    

Note: HubLink finalize (called during garbage collection) will remove a HubLink.

Since:

2004/03/19 using methods built into Hub. see Hub.setLink(com.viaoa.hub.Hub)

Constructor Summary

Constructors

Constructor and Description
HubLink(Hub fromHub, boolean bUseHubPosition, Hub toHub, String toProperty) Link the position of the active object in a Hub to a numeric property of the active object in another Hub.
HubLink(Hub fromHub, Hub toHub) Link the active object in a Hub to a property of the active object in another Hub.
HubLink(Hub fromHub, Hub toHub, String toProperty) Link a Hub to the active object of a property of the same Class in another Hub.
HubLink(Hub fromHub, Hub toHub, String toProperty, boolean bAutoCreate) Used to automatically create a new Object in "to" Hub whenever the active object in "from" Hub is changed.
HubLink(Hub fromHub, String fromProperty, Hub toHub, String toProperty) Link the value of a property of the active object in a Hub to a property of the active object in another Hub.

Method Summary

Modifier and Type	Method and Description
protected void	finalize() Removes HubLink from toHub.
boolean	getAutoCreate() Returns true if a new object is created and added to the toHub when the active object in the fromHub is changed.
Hub	getFromHub() Returns Hub that is linked to another Hub.
String	getFromProperty() Returns the property name in fromHub that is linked to the active object of a property in the toHub.
Hub	getToHub() Returns Hub that is updated by toHub.
String	getToProperty() Returns property in toHub that is automatically update by linkHub.
boolean	getUseHubPosition() Returns true if the position of the active object in the fromHub is used to update the property in the toHub.

Methods inherited from class java.lang.Object

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

Constructor Detail

HubLink

public HubLink(Hub fromHub,
               Hub toHub,
               String toProperty)

Link a Hub to the active object of a property of the same Class in another Hub.

HubLink

public HubLink(Hub fromHub,
               boolean bUseHubPosition,
               Hub toHub,
               String toProperty)

Link the position of the active object in a Hub to a numeric property of the active object in another Hub.

Parameters:

bUseHubPosition - if true, then use the position of the object in the fromHub.

HubLink

public HubLink(Hub fromHub,
               String fromProperty,
               Hub toHub,
               String toProperty)

Link the value of a property of the active object in a Hub to a property of the active object in another Hub.

Parameters:

fromProperty - property in fromHub to use.

toProperty - property in toHub to use.

HubLink

public HubLink(Hub fromHub,
               Hub toHub)

Link the active object in a Hub to a property of the active object in another Hub.

HubLink

public HubLink(Hub fromHub,
               Hub toHub,
               String toProperty,
               boolean bAutoCreate)

Used to automatically create a new Object in "to" Hub whenever the active object in "from" Hub is changed.

Parameters:

bAutoCreate - if true then a new object will be created and added to linkHub.

toProperty - is name of property in "to" Hub that will be set.

Method Detail

finalize

protected void finalize()
                 throws Throwable

Removes HubLink from toHub.

Overrides:

finalize in class Object

Throws:

Throwable

getFromHub

public Hub getFromHub()

Returns Hub that is linked to another Hub.

getToHub

public Hub getToHub()

Returns Hub that is updated by toHub.

getFromProperty

public String getFromProperty()

Returns the property name in fromHub that is linked to the active object of a property in the toHub. If null, then the actual object in the fromHub is used.

getToProperty

public String getToProperty()

Returns property in toHub that is automatically update by linkHub.

getUseHubPosition

public boolean getUseHubPosition()

Returns true if the position of the active object in the fromHub is used to update the property in the toHub.

getAutoCreate

public boolean getAutoCreate()

Returns true if a new object is created and added to the toHub when the active object in the fromHub is changed.