PolicyContextHandler (Java EE 5)

This interface defines the methods that must be implemented by handlers that are to be registered and activated by the PolicyContext class. The PolicyContext class provides methods for containers to register and activate container-specific PolicyContext handlers. Policy providers use the PolicyContext class to activate handlers to obtain (from the container) additional policy relevant context to apply in their access decisions. All handlers registered and activated via the PolicyContext class must implement the PolicyContextHandler interface.

Author:

Ron Monzillo, Gary Ellison

See Also:

PolicyContext, PolicyContextException

public boolean supports(String key) throws PolicyContextException
此公共方法返回 boolean 结果，指示处理程序是否支持密钥值（区分大小写）标识的上下文对象。

key	标识可能由处理程序支持的上下文对象的 String 值。此参数的值不得为 null。
return	指示处理程序是否处理与参数密钥对应的上下文对象的 boolean 值。
Throws	PolicyContextException: 如果实现抛出方法签名未知的经过检查的异常。实现类抛出的异常将封装（构造期间）在抛出的 PolicyContextException 中。

英文文档：

supports

boolean supports(String key)
                 throws PolicyContextException

This public method returns a boolean result indicating whether or not the handler supports the context object identified by the (case-sensitive) key value.

Parameters:

key - a String value identifying a context object that could be supported by the handler. The value of this parameter must not be null.

Returns:

a boolean indicating whether or not the context object corresponding to the argument key is handled by the handler.

Throws:

PolicyContextException - if the implementation throws a checked exception that has not been accounted for by the method signature. The exception thrown by the implementation class will be encapsulated (during construction) in the thrown PolicyContextException

public String[] getKeys() throws PolicyContextException
此公共方法返回标识处理程序支持的上下文对象的键。处理程序支持的每个键的值必须为非 null String 值。

return	包含标识处理程序支持的上下文对象的 String 值的数组。数组不得包含重复的键值。如果处理程序不支持任何键（这种情况不太可能发生），则处理程序必须返回长度为 0 的数组。此方法一定不会返回 null 值。
Throws	PolicyContextException: 如果实现抛出方法签名未知的经过检查的异常。实现类抛出的异常将封装（构造期间）在抛出的 PolicyContextException 中。

英文文档：

getKeys

String[] getKeys()
                 throws PolicyContextException

This public method returns the keys identifying the context objects supported by the handler. The value of each key supported by a handler must be a non-null String value.

Returns:

an array containing String values identifing the context objects supported by the handler. The array must not contain duplicate key values. In the unlikely case that the Handler supports no keys, the handler must return a zero length array. The value null must never be returned by this method.

Throws:

PolicyContextException - if the implementation throws a checked exception that has not been accounted for by the method signature. The exception thrown by the implementation class will be encapsulated (during construction) in the thrown PolicyContextException

public Object getContext(String key, Object data) throws PolicyContextException
PolicyContext 类使用此公共方法激活处理程序，并从中获取由键（区分大小写）标识的上下文对象。除键外，还可以使用 PolicyContext 类中与线程（在其中调用此方法）关联的处理程序数据值激活处理程序。

注意，通过调用 PolicyContext.getContextID()，可以使用与线程关联的策略上下文标识符。

key	标识处理程序返回的上下文对象的字符串。此参数的值不得为 null。
data	与调用此方法的线程关联的处理程序数据 Object。注意，此参数传递的值可以为 null。
return	包含所需上下文的特定于容器和处理程序的 Object。如果相应上下文的值为 null，则返回 null 值。
Throws	PolicyContextException: 如果实现抛出方法签名未知的经过检查的异常。实现类抛出的异常将封装（构造期间）在抛出的 PolicyContextException 中。

英文文档：

getContext

Object getContext(String key,
                  Object data)
                  throws PolicyContextException

This public method is used by the PolicyContext class to activate the handler and obtain from it the context object identified by the (case-sensitive) key. In addition to the key, the handler will be activated with the handler data value associated within the PolicyContext class with the thread on which the call to this method is made.

Note that the policy context identifier associated with a thread is available to the handler by calling PolicyContext.getContextID().

Parameters:

key - a String that identifies the context object to be returned by the handler. The value of this paramter must not be null.

data - the handler data Object associated with the thread on which the call to this method has been made. Note that the value passed through this parameter may be null.

Returns:

The container and handler specific Object containing the desired context. A null value may be returned if the value of the corresponding context is null.

Throws:

PolicyContextException - if the implementation throws a checked exception that has not been accounted for by the method signature. The exception thrown by the implementation class will be encapsulated (during construction) in the thrown PolicyContextException

Copyright 2007 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.