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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.net.events.internal;
import com.tangosol.internal.tracing.Scope;
import com.tangosol.internal.tracing.Span;
import com.tangosol.internal.tracing.TracingHelper;
import com.tangosol.net.CacheFactory;
import com.tangosol.net.events.Event;
import com.tangosol.net.events.EventDispatcher;
import com.tangosol.net.events.EventInterceptor;
import com.tangosol.net.events.internal.AbstractEventDispatcher.EventStats;
import com.tangosol.util.Base;
import java.util.Collection;
import java.util.Iterator;
/**
* Abstract base implementation of {@link Event}.
*
* @author mwj, nsa, rhl 2011.03.29
* @since Coherence 12.1.2
*
* @param the type of event
*/
public abstract class AbstractEvent>
implements Event
{
// ----- constructor ----------------------------------------------------
/**
* Construct a new {@link Event} using the specified type.
*
* @param eventType the type of {@link Event} raised
*/
public AbstractEvent(T eventType)
{
this(null, eventType);
}
/**
* Construct a new {@link Event} using the specified type.
*
* @param dispatcher the event dispatcher that raised this event
* @param eventType the type of {@link Event} raised
*/
public AbstractEvent(EventDispatcher dispatcher, T eventType)
{
m_dispatcher = dispatcher;
m_eventType = eventType;
}
// ----- accessors ------------------------------------------------------
/**
* Return the iterator of remaining interceptors to dispatch to.
*
* @return the iterator of interceptors
*/
protected Iterator> getIterator()
{
return m_iterInterceptor;
}
/**
* Set the iterator of interceptors to dispatch to.
*
* @param iter the iterator of interceptors
*/
protected void setIterator(Iterator> iter)
{
m_iterInterceptor = iter;
}
// ----- Event interface ------------------------------------------------
/**
* {@inheritDoc}
*/
public T getType()
{
return m_eventType;
}
/**
* {@inheritDoc}
*/
public EventDispatcher getDispatcher()
{
return m_dispatcher;
}
/**
* {@inheritDoc}
*/
@SuppressWarnings("unchecked")
public void nextInterceptor()
{
EventDispatcher dispatcher = m_dispatcher;
EventStats stats = null;
if (dispatcher instanceof AbstractEventDispatcher)
{
stats = ((AbstractEventDispatcher) dispatcher).getStats();
}
// EventInterceptors receiving this event can optionally call
// nextInterceptor (recursively) to explicitly control dispatch to the
// following interceptor(s), and subsequently observe any side-effects.
// If the interceptor does not recurse, we continue the dispatch chain
// iteratively.
for (Iterator> iter = getIterator(); iter.hasNext(); )
{
EventInterceptor interceptor = iter.next();
Span span = TracingHelper.newSpan("process", this)
.withMetadata("interceptor", interceptor.getClass().getName())
.startSpan();
try (Scope ignored = TracingHelper.getTracer().withSpan(span))
{
// dispatch the event
interceptor.onEvent(this);
}
catch (Exception e)
{
TracingHelper.augmentSpanWithErrorDetails(span, true, e);
if (stats != null)
{
stats.registerEventException(e, this, interceptor);
}
if (isVetoable())
{
String sMsg = "Exception vetoed by \"" + interceptor + "\".";
span.log(sMsg);
// Drain the iterator so no one else can re-start processing
while (iter.hasNext())
{
iter.next();
}
throw Base.ensureRuntimeException(e, sMsg);
}
else
{
CacheFactory.log("Exception caught while dispatching to \""
+ interceptor + "\": "
+ Base.printStackTrace(e), Base.LOG_ERR);
}
}
finally
{
span.end();
}
}
}
// ----- AbstractEvent methods ------------------------------------------
/**
* Dispatch this event over the specified interceptors.
*
* @param colIter the interceptors to trigger for this event
*/
protected void dispatch(Collection> colIter)
{
setIterator(colIter.iterator());
nextInterceptor();
}
/**
* Return true if this represents a mutable operation.
*
* @return true if this event represents a mutable operation
*/
protected boolean isMutableEvent()
{
return false;
}
/**
* Return true iff an exception raised by an {@link EventInterceptor} during
* the processing of this event should interrupt the {@link
* EventInterceptor} chaining of the {@link Event} and terminate the
* operation.
*
* @return true iff an exception raised during processing of this event
* should terminate the operation
*/
protected boolean isVetoable()
{
// by default, all mutable events are terminal
return isMutableEvent();
}
/**
* Returns this Event's description.
*
* @return this Event's description
*/
protected String getDescription()
{
return "Type=" + getType();
}
// ----- Object methods -------------------------------------------------
/**
* {@inheritDoc}
*/
public String toString()
{
String sEvt = getClass().getName();
return sEvt.substring(sEvt.lastIndexOf('.') + 1) + '{' + getDescription() + '}';
}
// ----- data members ---------------------------------------------------
/**
* The event type being raised.
*/
protected final T m_eventType;
/**
* The iterator used by nextInterceptor to iterate through a chain of interceptors.
*/
protected Iterator> m_iterInterceptor;
/**
* Event dispatcher that raised this event.
*/
protected final EventDispatcher m_dispatcher;
}