Avalon Framework API 4.3.1 · org.apache.avalon.framework.component.ComponentManager

A ComponentManager selects Components based on a role. The contract is that all the Components implement the differing roles and there is one Component per role. If you need to select on of many Components that implement the same role, then you need to use a ComponentSelector. Roles are usually the full interface name.

A role is better understood by the analogy of a play. There are many different roles in a script. Any actor or actress can play any given part and you get the same results (phrases said, movements made, etc.). The exact nuances of the performance is different.

Below is a list of things that might be considered the different roles:

InputAdapter and OutputAdapter
Store and Spool

The ComponentManager does not specify the methodology of getting the Component, merely the interface used to get it. Therefore the ComponentManager can be implemented with a factory pattern, an object pool, or a simple Hashtable.

Deprecated: Use org.apache.avalon.framework.service.ServiceManager instead.

Method Summary

Modifier and Type	Method and Description
public boolean	Returns: True if the component exists, False if it does not. hasComponent(String a string identifying the key to check. key) Check to see if a `Component` exists for a key.
public Component	Returns: the desired component lookup(String The key name of the `Component` to retrieve. key) Get the `Component` associated with the given key.
public void	release(Component The Component we are releasing. component) Return the `Component` when you are finished with it.

Method Detail

hasComponent back to summary

hasComponent	back to summary
public boolean hasComponent(String key) Check to see if a `Component` exists for a key. Parameters key:String a string identifying the key to check. Returns:boolean True if the component exists, False if it does not.

public boolean hasComponent(String key)

Check to see if a Component exists for a key.

Parameters

key:String: a string identifying the key to check.

Returns:boolean

True if the component exists, False if it does not.

lookup back to summary

lookup	back to summary
public Component lookup(String key) throws ComponentException Get the `Component` associated with the given key. For instance, If the `ComponentManager` had a `LoggerComponent` stored and referenced by key, I would use the following call: try { LoggerComponent log; myComponent = (LoggerComponent) m_manager.lookup(LoggerComponent.ROLE); } catch (...) { ... } Parameters key:String The key name of the `Component` to retrieve. Returns:Component the desired component Exceptions ComponentException: if an error occurs

public Component lookup(String key) throws ComponentException

Get the Component associated with the given key. For instance, If the ComponentManager had a LoggerComponent stored and referenced by key, I would use the following call:

try
{
    LoggerComponent log;
    myComponent = (LoggerComponent) m_manager.lookup(LoggerComponent.ROLE);
}
catch (...)
{
    ...
}

Parameters

key:String: The key name of the Component to retrieve.

Returns:Component

the desired component

Exceptions

ComponentException:: if an error occurs

release back to summary

release	back to summary
public void release(Component component) Return the `Component` when you are finished with it. This allows the `ComponentManager` to handle the End-Of-Life Lifecycle events associated with the Component. Please note, that no Exceptions should be thrown at this point. This is to allow easy use of the ComponentManager system without having to trap Exceptions on a release. Parameters component:Component The Component we are releasing.

public void release(Component component)

Return the Component when you are finished with it. This allows the ComponentManager to handle the End-Of-Life Lifecycle events associated with the Component. Please note, that no Exceptions should be thrown at this point. This is to allow easy use of the ComponentManager system without having to trap Exceptions on a release.

Parameters

component:Component: The Component we are releasing.

public Interface ComponentManager

Method Summary

Method Detail