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Oracle Coherence Community Edition
/*
* Copyright (c) 2000, 2020, Oracle and/or its affiliates.
*
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
package com.tangosol.coherence.config.builder;
import com.tangosol.coherence.config.ParameterList;
import com.tangosol.config.annotation.Injectable;
import com.tangosol.config.expression.Parameter;
import com.tangosol.config.expression.ParameterResolver;
import com.tangosol.net.events.EventInterceptor;
import com.tangosol.net.events.annotation.Interceptor;
import com.tangosol.net.events.annotation.Interceptor.Order;
import com.tangosol.net.events.internal.NamedEventInterceptor;
import com.tangosol.util.RegistrationBehavior;
/**
* An NamedEventInterceptorBuilder facilitates the construction of a
* {@link NamedEventInterceptor}, which wraps an {@link EventInterceptor}. The
* wrapped EventInterceptor will be constructed based on its instance /
* class-scheme XML declaration, honoring any init-params
* defined.
*
* The construction of a NamedEventInterceptor allows metadata associated
* with the EventInterceptor to be held. This metadata is used to determine
* eligibility against {@link com.tangosol.net.events.EventDispatcher}s and
* for registration purposes.
*
* In addition to XML being used as input in defining an EventInterceptor and
* its metadata the presence of an annotation ({@link Interceptor}) can also
* contribute. This annotation can define the identifier for this interceptor,
* the event types to subscribe to and whether to be placed first in the chain
* of EventInterceptors ({@link Order#HIGH}.
*
* NamedEventInterceptor objects also use class level generic type
* definitions as input for configuration. The generic type definition allows
* EventInterceptor implementations to restrict on event types by narrowing
* the type definition within the reference to the EventInterceptor interface.
* For example, the following interceptor restricts to only accept transfer
* events:
*
* class MyInterceptor
* implements EventInterceptor<TransferEvent>
* {
* public void onEvent(TransferEvent event);
* }
*
* The precedence, in highest order first reading left to right, for
* configuration is as follows:
*
* XML -> Annotation -> Generic Type Bounds
*
*
* @author hr 2011.10.05
* @since Coherence 12.1.2
*/
public class NamedEventInterceptorBuilder
implements ParameterizedBuilder, BuilderCustomization
{
// ----- ParameterizedBuilder interface ---------------------------------
/**
* {@inheritDoc}
*/
@SuppressWarnings("rawtypes")
public NamedEventInterceptor realize(ParameterResolver resolver, ClassLoader loader, ParameterList listParameters)
{
// ensure we have a classloader
loader = loader == null ? getClass().getClassLoader() : loader;
ParameterizedBuilder bldr = getCustomBuilder();
EventInterceptor interceptor = null;
try
{
interceptor = bldr.realize(resolver, loader, listParameters);
}
catch (Exception e)
{
throw new IllegalArgumentException("Unable to build an EventInterceptor based on the specified class: "
+ String.valueOf(bldr), e);
}
// determine the service and cache name for the event interceptor
Parameter paramServiceName = resolver.resolve("service-name");
String sServiceName = paramServiceName == null ? null : paramServiceName.evaluate(resolver).as(String.class);
Parameter paramCacheName = resolver.resolve("cache-name");
String sCacheName = paramCacheName == null ? null : paramCacheName.evaluate(resolver).as(String.class);
// instantiate the NamedEventInterceptor which provides a store for the
// metadata used in determining the interceptor's applicability to an
// event dispatcher
// if a RegistrationBehavior is prescribed in the XML we will honor it
// otherwise we make an appropriate decision on the correct behavior in
// NamedEventInterceptor.ensureInitialized()
NamedEventInterceptor incptrNamed = new NamedEventInterceptor(getName(), interceptor, sCacheName, sServiceName,
getOrder(), getRegistrationBehavior());
return incptrNamed;
}
// ----- BuilderCustomization interface ---------------------------------
/**
* {@inheritDoc}
*/
public ParameterizedBuilder getCustomBuilder()
{
return m_bldrEventInterceptor;
}
/**
* {@inheritDoc}
*/
@Override
public void setCustomBuilder(ParameterizedBuilder bldr)
{
m_bldrEventInterceptor = bldr;
}
// ----- accessors ------------------------------------------------------
/**
* Get the logical name / identifier for this {@link EventInterceptor}.
*
* @return the logical name / identifier for this {@link EventInterceptor}
*/
public String getName()
{
return m_sName;
}
/**
* Set the logical name / identifier for this {@link EventInterceptor}.
*
* @param sName logical name / identifier for this {@link EventInterceptor}.
*
* @return a reference to {@code this} builder
*/
@Injectable
public NamedEventInterceptorBuilder setName(String sName)
{
m_sName = sName;
return this;
}
/**
* Whether this {@link EventInterceptor} should be head of the stack.
*
* @return whether this {@link EventInterceptor} should be head of the stack
*/
public boolean isFirst()
{
return m_order != null && Interceptor.Order.HIGH.equals(m_order);
}
/**
* Return the {@link Order} of this interceptor.
*
* @return the {@link Order} of this interceptor
*/
public Order getOrder()
{
return m_order;
}
/**
* Set the {@link EventInterceptor}'s order (HIGH || LOW), hence
* whether it should be at the start of the chain of interceptors.
*
* @param order whether this {@link EventInterceptor} should be
* head of the stack based on the values {@link Order#HIGH}
* or {@link Order#LOW}
*
* @return a reference to {@code this} builder
*/
@Injectable
public NamedEventInterceptorBuilder setOrder(Order order)
{
m_order = order;
return this;
}
/**
* Returns the behavior upon duplicate registration.
*
* @return the behavior upon duplicate registration.
*/
public RegistrationBehavior getRegistrationBehavior()
{
return m_behavior;
}
/**
* Specifies the behavior upon duplicate registration.
*
* @param behavior the behavior upon duplicate registration
*
* @return a reference to {@code this} builder
*/
@Injectable
public NamedEventInterceptorBuilder setRegistrationBehavior(RegistrationBehavior behavior)
{
m_behavior = behavior;
return this;
}
// ----- Object methods -------------------------------------------------
/**
* {@inheritDoc}
*/
@Override
public String toString()
{
return "NamedEventInterceptorBuilder{" + "Builder = " + m_bldrEventInterceptor + ", name = '" + m_sName + '\''
+ ", priority = '" + isFirst() + '}';
}
// ---- data members ----------------------------------------------------
/**
* The logical name / identifier to be used for the realized {@link EventInterceptor}.
*/
private String m_sName;
/**
* The {@link ParameterizedBuilder} responsible for realizing an instance
* of an {@link EventInterceptor} class.
*/
private ParameterizedBuilder m_bldrEventInterceptor;
/**
* Whether this {@link EventInterceptor} should be head of the stack, with
* default behaviour being the tail/end.
*/
private Order m_order;
/**
* Specifies the behavior upon duplicate registration.
*/
private RegistrationBehavior m_behavior;
}