## javax.xml.rpc.handler
Interface Handler

All Known Implementing Classes:
  GenericHandler

public interface Handler

The `javax.xml.rpc.handler.Handler` interface is required to be implemented by a SOAP message handler. The `handleRequest`, `handleResponse` and `handleFault` methods for a SOAP message handler get access to the `SOAPMessage` from the `SOAPMessageContext`. The implementation of these methods can modify the `SOAPMessage` including the headers and body elements.

Version:
  1.0

Method Summary
`void` `destroy()` The `destroy` method indicates the end of lifecycle for a Handler instance.
`QName[]` `getHeaders()` Gets the header blocks processed by this Handler instance.
`boolean` `handleFault(MessageContext context)` The `handleFault` method processes the SOAP faults based on the SOAP message processing model.
`boolean` `handleRequest(MessageContext context)` The `handleRequest` method processes the request message.
`boolean` `handleResponse(MessageContext context)` The `handleResponse` method processes the response SOAP message.
`void` `init(HandlerInfo config)` The `init` method enables the Handler instance to initialize itself.

Method Detail

### handleRequest

    public boolean handleRequest(MessageContext context)

  The `handleRequest` method processes the request message.

  Parameters:
    `context` - MessageContext parameter provides access to the request message.
  Returns:
    boolean boolean Indicates the processing mode
    - Return `true` to indicate continued processing of the request handler chain. The `HandlerChain` takes the responsibility of invoking the next entity. The next entity may be the next handler in the `HandlerChain` or if this handler is the last handler in the chain, the next entity is the service endpoint object.
    - Return `false` to indicate blocking of the request handler chain. In this case, further processing of the request handler chain is blocked and the target service endpoint is not dispatched. The JAX-RPC runtime system takes the responsibility of invoking the response handler chain next with the SOAPMessageContext. The Handler implementation class has the the responsibility of setting the appropriate response SOAP message in either handleRequest and/or handleResponse method. In the default processing model, the response handler chain starts processing from the same Handler instance (that returned false) and goes backward in the execution sequence.
  Throws:
    `JAXRPCException` - indicates a handler-specific runtime error. If `JAXRPCException` is thrown by a handleRequest method, the HandlerChain terminates the further processing of this handler chain. On the server side, the HandlerChain generates a SOAP fault that indicates that the message could not be processed for reasons not directly attributable to the contents of the message itself but rather to a runtime error during the processing of the message. On the client side, the exception is propagated to the client code
    `SOAPFaultException` - indicates a SOAP fault. The Handler implementation class has the the responsibility of setting the SOAP fault in the SOAP message in either handleRequest and/or handleFault method. If SOAPFaultException is thrown by a server-side request handler's handleRequest method, the HandlerChain terminates the further processing of the request handlers in this handler chain and invokes the handleFault method on the HandlerChain with the SOAP message context. Next, the HandlerChain invokes the handleFault method on handlers registered in the handler chain, beginning with the Handler instance that threw the exception and going backward in execution. The client-side request handler's handleRequest method should not throw the SOAPFaultException.

### handleResponse

    public boolean handleResponse(MessageContext context)

  The `handleResponse` method processes the response SOAP message.

  Parameters:
    `context` - MessageContext parameter provides access to the response SOAP message
  Returns:
    boolean Indicates the processing mode
    - Return `true` to indicate continued processing ofthe response handler chain. The HandlerChain invokes the `handleResponse` method on the next `Handler` in the handler chain.
    - Return `false` to indicate blocking of the response handler chain. In this case, no other response handlers in the handler chain are invoked.
  Throws:
    `JAXRPCException` - indicates a handler specific runtime error. If JAXRPCException is thrown by a handleResponse method, the HandlerChain terminates the further processing of this handler chain. On the server side, the HandlerChain generates a SOAP fault that indicates that the message could not be processed for reasons not directly attributable to the contents of the message itself but rather to a runtime error during the processing of the message. On the client side, the runtime exception is propagated to the client code.

### handleFault

    public boolean handleFault(MessageContext context)

  The `handleFault` method processes the SOAP faults based on the SOAP message processing model.

  Parameters:
    `context` - MessageContext parameter provides access to the SOAP message
  Returns:
    boolean Indicates the processing mode
    - Return `true` to indicate continued processing of SOAP Fault. The HandlerChain invokes the `handleFault` method on the next `Handler` in the handler chain.
    - Return `false` to indicate end of the SOAP fault processing. In this case, no other handlers in the handler chain are invoked.
  Throws:
    `JAXRPCException` - indicates handler specific runtime error. If JAXRPCException is thrown by a handleFault method, the HandlerChain terminates the further processing of this handler chain. On the server side, the HandlerChain generates a SOAP fault that indicates that the message could not be processed for reasons not directly attributable to the contents of the message itself but rather to a runtime error during the processing of the message. On the client side, the JAXRPCException is propagated to the client code.

### init

    public void init(HandlerInfo config)

  The `init` method enables the Handler instance to initialize itself. The `init` method passes the handler configuration as a `HandlerInfo` instance. The HandlerInfo is used to configure the Handler (for example: setup access to an external resource or service) during the initialization.

  In the init method, the Handler class may get access to any resources (for example; access to a logging service or database) and maintain these as part of its instance variables. Note that these instance variables must not have any state specific to the SOAP message processing performed in the various handle method.

  Parameters:
    `config` - HandlerInfo configuration for the initialization of this handler
  Throws:
    `JAXRPCException` - if initialization of the handler fails

### destroy

    public void destroy()

  The `destroy` method indicates the end of lifecycle for a Handler instance. The Handler implementation class should release its resources and perform cleanup in the implementation of the `destroy` method.

  Throws:
    `JAXRPCException` - if there was any error during destroy

### getHeaders

    public QName[] getHeaders()

  Gets the header blocks processed by this Handler instance.

  Returns:
    Array of QNames of header blocks processed by this handler instance. `QName` is the qualified name of the outermost element of the Header block.

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