org.codehaus.plexus.context
Class DefaultContext

java.lang.Object
  org.codehaus.plexus.context.DefaultContext

All Implemented Interfaces:

Context

public class DefaultContext
extends Object
implements Context

Default implementation of Context. This implementation is a static hierarchial store. It has the normal get() and put methods. The hide method will hide a property. When a property has been hidden the context will not search in the parent context for the value.

Version:

$Id: DefaultContext.java 1323 2004-12-20 23:00:59Z jvanzyl $

Author:

Avalon Development Team

Constructor Summary

DefaultContext()
Create a empty Context with no parent.

DefaultContext(Context parent)
Create a Context with specified parent.

DefaultContext(Map contextData)
Create a empty Context with specified data.

DefaultContext(Map contextData, Context parent)
Create a Context with specified data and parent.

Method Summary

protected void	checkWriteable() Utility method to check if context is writeable and if not throw exception.
boolean	contains(Object key) Returns true if the map or the parent map contains the key.
Object	get(Object key) Returns the value of the key.
protected Map	getContextData() Utility method to retrieve context data.
protected Context	getParent() Get parent context if any.
void	hide(Object key) Hides the item in the context.
void	makeReadOnly() Make the context read-only.
void	put(Object key, Object value) Helper method for adding items to Context.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultContext

public DefaultContext(Map contextData,
                      Context parent)

Create a Context with specified data and parent.

Parameters:

contextData - the context data

parent - the parent Context (may be null)

DefaultContext

public DefaultContext(Map contextData)

Create a empty Context with specified data.

Parameters:

contextData - the context data

DefaultContext

public DefaultContext(Context parent)

Create a Context with specified parent.

Parameters:

parent - the parent Context (may be null)

DefaultContext

public DefaultContext()

Create a empty Context with no parent.

Method Detail

contains

public boolean contains(Object key)

Returns true if the map or the parent map contains the key.

Specified by:

contains in interface Context

Parameters:

key - The key to search for.

Returns:

Returns true if the key was found.

get

public Object get(Object key)
           throws ContextException

Returns the value of the key. If the key can't be found it will throw a exception.

Specified by:

get in interface Context

Parameters:

key - The key of the value to look up.

Returns:

Returns

Throws:

ContextException - If the key doesn't exist.

put

public void put(Object key,
                Object value)
         throws IllegalStateException

Helper method for adding items to Context.

Specified by:

put in interface Context

Parameters:

key - the items key

value - the item

Throws:

IllegalStateException - if context is read only

hide

public void hide(Object key)
          throws IllegalStateException

Hides the item in the context. After remove(key) has been called, a get(key) will always fail, even if the parent context has such a mapping.

Specified by:

hide in interface Context

Parameters:

key - the items key

Throws:

IllegalStateException - if context is read only

getContextData

protected Map getContextData()

Utility method to retrieve context data.

Returns:

the context data

getParent

protected Context getParent()

Get parent context if any.

Returns:

the parent Context (may be null)

makeReadOnly

public void makeReadOnly()

Make the context read-only. Any attempt to write to the context via put() will result in an IllegalStateException.

Specified by:

makeReadOnly in interface Context

checkWriteable

protected void checkWriteable()
                       throws IllegalStateException

Utility method to check if context is writeable and if not throw exception.

Throws:

IllegalStateException - if context is read only