com.atomikos.datasource.xa.SiblingMapper Maven / Gradle / Ivy
/**
* Copyright (C) 2000-2020 Atomikos
*
* LICENSE CONDITIONS
*
* See http://www.atomikos.com/Main/WhichLicenseApplies for details.
*/
package com.atomikos.datasource.xa;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import com.atomikos.datasource.ResourceException;
import com.atomikos.datasource.ResourceTransaction;
import com.atomikos.icatch.CompositeTransaction;
/**
* A SiblingMapper encapsulates the policies for creating or reusing XA branches.
*
* Assumption: there is one instance per root transaction, per resource.
*/
class SiblingMapper
{
private Map> siblingsOfSameRoot;
private XATransactionalResource res;
private String root ;
SiblingMapper ( XATransactionalResource res , String root )
{
this.siblingsOfSameRoot = new HashMap>();
this.res = res;
this.root = root;
}
private XAResourceTransaction findSiblingBranchToJoin(CompositeTransaction ct) {
XAResourceTransaction ret = null;
if (ct.isSerial()) {
Iterator > allSiblingLists = this.siblingsOfSameRoot.values().iterator();
while (ret == null && allSiblingLists.hasNext()) {
List siblings = allSiblingLists.next();
ret = findJoinableBranchInList(siblings);
}
}
return ret;
}
private XAResourceTransaction findJoinableBranchInList(List siblings) {
XAResourceTransaction ret = null;
Iterator it = siblings.iterator();
while (ret == null && it.hasNext()) {
XAResourceTransaction candidate = it.next();
if (candidate.supportsTmJoin()) ret = candidate;
}
return ret;
}
protected synchronized ResourceTransaction findOrCreateBranchForTransaction(CompositeTransaction ct)
throws ResourceException, IllegalStateException
{
XAResourceTransaction ret = findOrCreateBranchWithResourceException(ct);
ct.addParticipant(ret);
return ret;
}
private XAResourceTransaction findOrCreateBranchWithResourceException(CompositeTransaction ct) {
XAResourceTransaction ret = null;
try {
ret = findOrCreateBranch(ct);
} catch (Exception e) {
throw new ResourceException ( "Failed to get branch", e );
}
return ret;
}
private XAResourceTransaction findOrCreateBranch(CompositeTransaction ct) {
XAResourceTransaction ret;
ret = findPreviousBranchToJoin(ct);
if (ret == null) {
ret = findSiblingBranchToJoin(ct);
if (ret == null) {
ret = createNewBranch(ct);
}
}
ct.addSubTxAwareParticipant(new ResourceTransactionSuspender(ret)); //cf case 175941
return ret;
}
private XAResourceTransaction createNewBranch(CompositeTransaction ct) {
XAResourceTransaction ret;
ret = new XAResourceTransaction(this.res, ct, this.root);
rememberBranch(ct, ret);
return ret;
}
private XAResourceTransaction findPreviousBranchToJoin(CompositeTransaction ct) {
List candidates = findSiblingsForTransaction(ct);
return findJoinableBranchInList(candidates);
}
private List findSiblingsForTransaction(CompositeTransaction ct) {
List ret = this.siblingsOfSameRoot.get(ct);
if (ret == null) {
ret = new ArrayList();
}
return Collections.unmodifiableList(ret);
}
private void rememberBranch(CompositeTransaction ct, XAResourceTransaction branch) {
List list = this.siblingsOfSameRoot.get(ct);
if (list == null) {
list = new ArrayList();
this.siblingsOfSameRoot.put(ct,list);
}
list.add(branch);
}
}