io.apiman.gateway.engine.policy

Class Chain<H>

java.lang.Object

io.apiman.gateway.engine.io.AbstractStream<H>

io.apiman.gateway.engine.policy.Chain<H>

Type Parameters:

H - Head type

All Implemented Interfaces:

IAbortable, IReadStream<H>, IReadWriteStream<H>, IStream, IWriteStream, IPolicyChain<H>, Iterable<PolicyWithConfiguration>

Direct Known Subclasses:

RequestChain, ResponseChain

public abstract class Chain<H>
extends AbstractStream<H>
implements IAbortable, IPolicyChain<H>, Iterable<PolicyWithConfiguration>

Traverses and executes a series of policies according to implementor's settings and iterator. This can be used to chain together and execute policies in arbitrary order. The head handler is the first executed, arriving chunks are passed into write(IApimanBuffer), followed by the end() signal. Intermediate policy handlers are chained together, according to the ordering provided by #policyIterator(). The tail handler is executed last: the result object (getHead() is sent to handleHead(Object); chunks are streamed to out AbstractStream.handleBody(IApimanBuffer); end of transmission indicated via AbstractStream.handleEnd().

Author:

Marc Savy

Field Summary

Fields inherited from class io.apiman.gateway.engine.io.AbstractStream

bodyHandler, endHandler, finished, headHandler

Constructor Summary

Constructors

Constructor and Description
Chain(List<PolicyWithConfiguration> policies, IPolicyContext context) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
void	abort() Send abort signal to all policies.
protected abstract void	applyPolicy(PolicyWithConfiguration policy, IPolicyContext context) Called to apply the given policy to the service object (request or response).
protected void	chainPolicyHandlers() Chain together the body handlers.
void	doApply(H serviceObject) Called by a policy when it has successfully completed applying itself.
void	doFailure(io.apiman.gateway.engine.beans.PolicyFailure failure) Handle a policy failure.
void	end() Signal transmission has ended.
protected IPolicyContext	getContext()
H	getHead() Return the head object's handler (e.g.
List<PolicyWithConfiguration>	getPolicies()
protected abstract IReadWriteStream<H>	getServiceHandler(IPolicy policy) Gets the service handler for the policy.
protected void	handleHead(H service) Called to handle the head.
void	policyErrorHandler(IAsyncHandler<Throwable> policyErrorHandler) Sets the policy error handler.
void	policyFailureHandler(IAsyncHandler<io.apiman.gateway.engine.beans.PolicyFailure> failureHandler) Sets the policy failure handler.
void	throwError(Throwable error) Called when an unexpected and unrecoverable error is encountered.
void	write(IApimanBuffer chunk) Write a chunk to the stream.

Methods inherited from class io.apiman.gateway.engine.io.AbstractStream

bodyHandler, endHandler, handleBody, handleEnd, headHandler, isFinished

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

iterator

Constructor Detail

Chain

public Chain(List<PolicyWithConfiguration> policies,
     IPolicyContext context)

Constructor.

Parameters:

policies -

context -

Method Detail

chainPolicyHandlers

protected void chainPolicyHandlers()

Chain together the body handlers.

doApply

public void doApply(H serviceObject)

Description copied from interface: IPolicyChain

Called by a policy when it has successfully completed applying itself. This triggers the next policy in the chain.

Specified by:

doApply in interface IPolicyChain<H>

See Also:

IPolicyChain.doApply(java.lang.Object)

write

public void write(IApimanBuffer chunk)

Description copied from interface: IWriteStream

Write a chunk to the stream. No writes should be made after IWriteStream.end() has been signalled.

Specified by:

write in interface IWriteStream

Overrides:

write in class AbstractStream<H>

See Also:

AbstractStream.write(io.apiman.gateway.engine.io.IApimanBuffer)

end

public void end()

Description copied from interface: IWriteStream

Signal transmission has ended. This should only be called once, after which no further calls to IWriteStream.write(IApimanBuffer) should be made.

Specified by:

end in interface IWriteStream

Overrides:

end in class AbstractStream<H>

See Also:

AbstractStream.end()

getHead

public H getHead()

Description copied from interface: IReadStream

Return the head object's handler (e.g. ServiceRequest).

Specified by:

getHead in interface IReadStream<H>

Returns:

the head object

See Also:

IReadStream.getHead()

handleHead

protected void handleHead(H service)

Description copied from class: AbstractStream

Called to handle the head.

Specified by:

handleHead in class AbstractStream<H>

See Also:

AbstractStream.handleHead(java.lang.Object)

policyFailureHandler

public void policyFailureHandler(IAsyncHandler<io.apiman.gateway.engine.beans.PolicyFailure> failureHandler)

Sets the policy failure handler.

Parameters:

failureHandler -

doFailure

public void doFailure(io.apiman.gateway.engine.beans.PolicyFailure failure)

Handle a policy failure.

Specified by:

doFailure in interface IPolicyChain<H>

Parameters:

failure - the policy failure

policyErrorHandler

public void policyErrorHandler(IAsyncHandler<Throwable> policyErrorHandler)

Sets the policy error handler.

Parameters:

policyErrorHandler -

throwError

public void throwError(Throwable error)

Called when an unexpected and unrecoverable error is encountered.

Specified by:

throwError in interface IPolicyChain<H>

Parameters:

error -

abort

public void abort()

Send abort signal to all policies.

Specified by:

abort in interface IAbortable

getServiceHandler

protected abstract IReadWriteStream<H> getServiceHandler(IPolicy policy)

Gets the service handler for the policy.

Parameters:

policy -

applyPolicy

protected abstract void applyPolicy(PolicyWithConfiguration policy,
               IPolicyContext context)

Called to apply the given policy to the service object (request or response).

Parameters:

policy -

context -

getPolicies

public List<PolicyWithConfiguration> getPolicies()

Returns:

the policies

getContext

protected IPolicyContext getContext()

Returns:

the context