org.objectweb.jonathan.libs.kernel
Class JComponent

java.lang.Object
  org.objectweb.jonathan.libs.kernel.JComponent

All Implemented Interfaces:

Component, Forkable

Direct Known Subclasses:

JContextFactory.JContext, JImplicitFactory, LazyComponent

public class JComponent

extends java.lang.Object

implements Forkable

Basic implementation of a runtime component. Its behaviour is a property component's. Must be subtyped to behave differently.

Field Summary

protected int	int_value the integer value
protected Element	reference The element referencing this component
protected java.lang.Class	type the type
protected java.lang.Object	value the object reference value

Constructor Summary

JComponent()
Constructs a JComponent.

JComponent(java.lang.Class _type, int _int_value)

JComponent(java.lang.Class _type, java.lang.Object _value)

JComponent(java.lang.Class _type, java.lang.Object _value, int _int_value)

JComponent(java.lang.Class _type, java.lang.Object _value, int _int_value, Element _reference)

Method Summary

protected Component	duplicate()
Component	fork() "Forks" a copy of the target component.
Component	getComponent(Name _name) Returns the component contained in the element registered in the target component under the name name.
Element	getElement(Name name) Returns the element in the target component identified by name, null if no element exists under name name.
java.lang.Object	getFactoryValue()
int	getIntValue() Returns the value of the target component, if its class is an integer class.
Element	getReference() Returns a distinguished element referencing the target component, if any, null otherwise.
java.lang.Class	getType() Returns the type of the target component, as a Class.
java.lang.Object	getValue() Returns the value of the target component, if its type is an object reference type.
java.lang.Object	getValue(Name _name) Returns the value of the element registered in the target context under the name name.
Component	internalFork()
protected void	reset()
Element	setReference(Element _reference) Sets an element containing the target component.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

type

protected java.lang.Class type

the type

value

protected java.lang.Object value

the object reference value

int_value

protected int int_value

the integer value

reference

protected Element reference

The element referencing this component

Constructor Detail

JComponent

public JComponent()

Constructs a JComponent.

JComponent

public JComponent(java.lang.Class _type,
                  int _int_value)

JComponent

public JComponent(java.lang.Class _type,
                  java.lang.Object _value)

JComponent

public JComponent(java.lang.Class _type,
                  java.lang.Object _value,
                  int _int_value)

JComponent

public JComponent(java.lang.Class _type,
                  java.lang.Object _value,
                  int _int_value,
                  Element _reference)

Method Detail

getType

public java.lang.Class getType()

Description copied from interface: Component

Returns the type of the target component, as a Class.

Specified by:

getType in interface Component

Returns:

the type of the target component, as a Class.

getValue

public java.lang.Object getValue()

Description copied from interface: Component

Returns the value of the target component, if its type is an object reference type.

If the target component is of an integral type, NO_VALUE} is returned.

Specified by:

getValue in interface Component

Returns:

the value of the target component.

getIntValue

public int getIntValue()

Description copied from interface: Component

Returns the value of the target component, if its class is an integer class.

If the target component has an object reference type, Integer.MAX_VALUE is returned.

Specified by:

getIntValue in interface Component

Returns:

the value of the target component.

getFactoryValue

public java.lang.Object getFactoryValue()
                                 throws JonathanException

Specified by:

getFactoryValue in interface Component

Throws:

JonathanException

getReference

public Element getReference()

Description copied from interface: Component

Returns a distinguished element referencing the target component, if any, null otherwise. Implementations are not required to keep information about a given containing element. It is always legal to return null.

Specified by:

getReference in interface Component

Returns:

an element containing the target component, if any, null otherwise.

setReference

public Element setReference(Element _reference)

Description copied from interface: Component

Sets an element containing the target component. The provided element should already be initialized as a container of the component. The returned element is the former container, if any. This method MUST be called when a component is referred to by an element.

Specified by:

setReference in interface Component

Parameters:

_reference - the new element referencing the target component.

Returns:

the former element referencing the target component, if any, null otherwise.

toString

public java.lang.String toString()

duplicate

protected Component duplicate()

fork

public Component fork()

Description copied from interface: Component

"Forks" a copy of the target component. The returned component is a copy of the target component, sharing the same reference, but *NOT* referred to by this reference.

For basic components, this operation simply duplicates the component structure, but the value is still shared.

In the configuration framework, components contain a specification of their value (in the form of an assemblage, atom, alias... description). The fork() method is used to duplicate the specification, but not the value. It may thus be used to obtain several instances of a component, using getValue() on the returned component.

When the target component is a context, the returned component is a new context, roughly containing the forked versions of the target context's components.

If the target context contains an alias, and if the target T of this alias is in the scope of the context, then the target of the forked alias is a forked instance of T. But if the target is outside the scope of the context, then the target of the forked alias is T itself. The context thus defines a set of components that will be actually duplicated, all links outside the context being preserved.

The same rule applies for assemblages, and other "container" components. For instance, consider an assemblage 'A' made of factory 'F' and configuration 'C', 'C' containing an atom 'At', an alias 'In' to At, and an alias 'Out' to a component 'K' outside 'A'. Then the forked version of 'A' is a new assemblage made of a copy of 'F' and a new configuration containing a copy 'At2' of 'At', an alias 'In2' to 'At2', and an alias 'Out2' to 'K'.

Aliases are treated specifically. Calling the fork() method on an alias is like calling the same method on its target.

Specified by:

fork in interface Component

Returns:

a forked instance of the target component.

internalFork

public Component internalFork()

Specified by:

internalFork in interface Forkable

getElement

public Element getElement(Name name)

Description copied from interface: Component

Returns the element in the target component identified by name, null if no element exists under name name.

Specified by:

getElement in interface Component

Parameters:

name - the name of the element to be retrieved;

Returns:

the corresponding element, if any; null otherwise.

getComponent

public final Component getComponent(Name _name)

Description copied from interface: Component

Returns the component contained in the element registered in the target component under the name name. A call to getComponent(name) is equivalent to getElement(name).getComponent() if the provided name actually corresponds to an element. If it is not the case, null is returned.

Specified by:

getComponent in interface Component

Parameters:

_name - the name of the element whose component is seeked;

Returns:

the corresponding component, or null.

getValue

public final java.lang.Object getValue(Name _name)

Description copied from interface: Component

Returns the value of the element registered in the target context under the name name. A call to getValue(name) is equivalent to getElement(name).getValue() if the provided name actually corresponds to an element. If it is not the case, NO_VALUE is returned.

Specified by:

getValue in interface Component

Parameters:

_name - the name of the element whose value is seeked;

Returns:

the corresponding value, or NO_VALUE.

reset

protected void reset()