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package com.sun.enterprise.resource.pool;
import com.sun.appserv.connectors.internal.api.PoolingException;
import com.sun.enterprise.resource.AssocWithThreadResourceHandle;
import com.sun.enterprise.resource.ResourceHandle;
import com.sun.enterprise.resource.ResourceSpec;
import com.sun.enterprise.resource.allocator.ResourceAllocator;
import com.sun.enterprise.resource.pool.datastructure.DataStructureFactory;
import com.sun.enterprise.resource.pool.resizer.AssocWithThreadPoolResizer;
import com.sun.enterprise.resource.pool.resizer.Resizer;
import org.glassfish.resourcebase.resources.api.PoolInfo;
import javax.transaction.Transaction;
import java.util.Hashtable;
/**
* Associates a resource with the thread. When the same thread is used again,
* it checks whether the resource associated with the thread can serve the request.
*
* @author Aditya Gore, Jagadish Ramu
*/
public class AssocWithThreadResourcePool extends ConnectionPool {
private ThreadLocal<AssocWithThreadResourceHandle> localResource =
new ThreadLocal<AssocWithThreadResourceHandle>();
public AssocWithThreadResourcePool(PoolInfo poolInfo, Hashtable env)
throws PoolingException {
super(poolInfo, env);
}
@Override
protected void initializePoolDataStructure() throws PoolingException {
ds = DataStructureFactory.getDataStructure(
"com.sun.enterprise.resource.pool.datastructure.ListDataStructure",
dataStructureParameters,
maxPoolSize, this, resourceSelectionStrategyClass);
}
/**
* Prefetch is called to check whether there there is a free resource is already associated with the thread
* Only when prefetch is unable to find a resource, normal routine (getUnenlistedResource) will happen.
* @param spec ResourceSpec
* @param alloc ResourceAllocator
* @param tran Transaction
* @return ResourceHandle resource associated with the thread, if any
*/
protected ResourceHandle prefetch(ResourceSpec spec,
ResourceAllocator alloc, Transaction tran) {
AssocWithThreadResourceHandle ar = localResource.get();
if (ar != null) {
//synch on ar and do a quick-n-dirty check to see if the local
//resource is usable at all
synchronized (ar.lock) {
if ((ar.getThreadId() != Thread.currentThread().getId()) ||
ar.hasConnectionErrorOccurred() ||
ar.isDirty() || !ar.isAssociated()) {
//we were associated with someone else or resource error
//occurred or resource was disassociated and used by some one else. So evict
//NOTE: We do not setAssociated to false here since someone
//else has associated this resource to themself. Also, if
//the eviction is because of a resourceError, the resource is
//not going to be used anyway.
localResource.remove();
return null;
}
if (ar.getResourceState().isFree() &&
ar.getResourceState().isUnenlisted()) {
if (matchConnections) {
if (!alloc.matchConnection(ar)) {
//again, since the credentials of the caller don't match
//evict from ThreadLocal
//also, mark the resource as unassociated and make this resource
//potentially usable
localResource.remove();
ar.setAssociated(false);
if(poolLifeCycleListener != null){
poolLifeCycleListener.connectionNotMatched();
}
return null;
}
if(poolLifeCycleListener != null){
poolLifeCycleListener.connectionMatched();
}
}
if (!isConnectionValid(ar, alloc)) {
localResource.remove();
ar.setAssociated(false);
// disassociating the connection from the thread.
// validation failure will mark the connectionErrorOccurred flag
// and the connection will be removed whenever it is retrieved again
// from the pool.
return null;
}
setResourceStateToBusy(ar);
if (maxConnectionUsage_ > 0) {
ar.incrementUsageCount();
}
if(poolLifeCycleListener != null) {
poolLifeCycleListener.connectionUsed(ar.getId());
//Decrement numConnFree
poolLifeCycleListener.decrementNumConnFree();
}
return ar;
}
}
}
return null;
}
@Override
protected Resizer initializeResizer() {
return new AssocWithThreadPoolResizer(poolInfo, ds, this, this,
preferValidateOverRecreate);
}
/**
* to associate a resource with the thread
* @param h ResourceHandle
*/
private void setInThreadLocal(AssocWithThreadResourceHandle h) {
if (h != null) {
synchronized (h.lock) {
h.setThreadId(Thread.currentThread().getId());
h.setAssociated(true);
localResource.set(h);
}
}
}
/**
* check whether the resource is unused
* @param h ResourceHandle
* @return boolean representing resource usefullness
*/
protected boolean isResourceUnused(ResourceHandle h) {
if(h instanceof AssocWithThreadResourceHandle){
return h.getResourceState().isFree() && !((AssocWithThreadResourceHandle) h).isAssociated();
}else{
return h.getResourceState().isFree();
}
}
// this is the RI getResource() with some modifications
/**
* return resource in free list. If none is found, returns null
*/
protected ResourceHandle getUnenlistedResource(ResourceSpec spec,
ResourceAllocator alloc, Transaction tran) throws PoolingException {
ResourceHandle result;
result = super.getUnenlistedResource(spec, alloc, tran);
//It is possible that Resizer might have marked the resource for recycle
//and hence we should not use this resource.
if(result != null) {
synchronized(result.lock) {
if(ds.getAllResources().contains(result) &&
((AssocWithThreadResourceHandle)result).isDirty()) {
//Remove the resource and set to null
ds.removeResource(result);
result = null;
}
}
}
//If we came here, that's because free doesn't have anything
//to offer us. This could be because:
//1. All free resources are associated
//2. There are no free resources
//3. We cannot create anymore free resources
//Handle case 1 here
//DISASSOCIATE
if (result == null) {
synchronized (this) {
for (ResourceHandle resource : ds.getAllResources()) {
synchronized (resource.lock) {
//though we are checking resources from within the free list,
//we could have a situation where the resource was free upto
//this point, put just before we entered the synchronized block,
//the resource "h" got used by the thread that was associating it
//so we need to check for isFree also
if (resource.getResourceState().isUnenlisted() &&
resource.getResourceState().isFree() &&
!(((AssocWithThreadResourceHandle) resource).isDirty())) {
if (!matchConnection(resource, alloc)) {
continue;
}
if (resource.hasConnectionErrorOccurred()) {
continue;
}
result = resource;
setResourceStateToBusy(result);
((AssocWithThreadResourceHandle) result).setAssociated(false);
break;
}
}
}
}
}
if (localResource.get() == null) {
setInThreadLocal((AssocWithThreadResourceHandle) result);
}
return result;
}
/**
* return the resource back to pool only if it is not associated with the thread.
* @param h ResourceHandle
*/
protected synchronized void freeUnenlistedResource(ResourceHandle h) {
if (this.cleanupResource(h)) {
if (h instanceof AssocWithThreadResourceHandle) {
//Only when resource handle usage count is more than maxConnUsage
if (maxConnectionUsage_ > 0 &&
h.getUsageCount() >= maxConnectionUsage_) {
performMaxConnectionUsageOperation(h);
} else {
if (!((AssocWithThreadResourceHandle) h).isAssociated()) {
ds.returnResource(h);
}
//update monitoring data
if (poolLifeCycleListener != null) {
poolLifeCycleListener.decrementConnectionUsed(h.getId());
poolLifeCycleListener.incrementNumConnFree(false, steadyPoolSize);
}
}
//for both the cases of free.add and maxConUsageOperation, a free resource is added.
// Hence notify waiting threads
notifyWaitingThreads();
}
}
}
/**
* destroys the resource
* @param resourceHandle resource to be destroyed
*/
public void deleteResource(ResourceHandle resourceHandle) {
try {
super.deleteResource(resourceHandle);
} finally {
//Note: here we are using the connectionErrorOccurred flag to indicate
//that this resource is no longer usable. This flag would be checked while
//getting from ThreadLocal
//The main intention of marking this is to handle the case where
//failAllConnections happens
//Note that setDirty only happens here - i.e during destroying of a
//resource
if(resourceHandle instanceof AssocWithThreadResourceHandle){
synchronized (resourceHandle.lock) {
((AssocWithThreadResourceHandle) resourceHandle).setDirty();
}
}
}
}
}