/*
* Bitronix Transaction Manager
*
* Copyright (c) 2010, Bitronix Software.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package bitronix.tm;
import bitronix.tm.utils.Uid;
import javax.transaction.xa.Xid;
/**
* Implementation of {@link javax.transaction.xa.Xid}.
* <p>A XID is divided in two parts: globalTransactionId (GTRID) and branchQualifier (BQUAL). The first one uniquely
* identifies the global transaction while the latter uniquely identifies the transaction branch, or the local part of
* the global transaction inside a resource.</p>
* <p>Technically in the Bitronix implementation, GTRID and BQUAL have the same format as described by Mike Spille.
* Each {@link bitronix.tm.BitronixTransaction} get assigned a GTRID at creation time and full XIDs are created and
* assigned to every {@link bitronix.tm.internal.XAResourceHolderState} when enlisted in the transaction's
* {@link bitronix.tm.internal.XAResourceManager}. Both GTRID and XIDs are generated
* by the {@link bitronix.tm.utils.UidGenerator}.</p>
*
* @author lorban
* @see bitronix.tm.utils.UidGenerator
* @see bitronix.tm.BitronixTransaction
* @see bitronix.tm.internal.XAResourceManager
* @see <a href="http://jroller.com/page/pyrasun?entry=xa_exposed_part_iii_the">XA Exposed, Part III: The Implementor's Notebook</a>
*/
public class BitronixXid implements Xid {
/**
* int-encoded "Btnx" string. This is used as the globally unique ID to discriminate BTM XIDs.
*/
public static final int FORMAT_ID = 0x42746e78;
private Uid globalTransactionId;
private Uid branchQualifier;
/**
* Create a new XID using the specified GTRID and BQUAL.
* @param globalTransactionId the GTRID.
* @param branchQualifier the BQUAL.
*/
public BitronixXid(Uid globalTransactionId, Uid branchQualifier) {
this.globalTransactionId = globalTransactionId;
this.branchQualifier = branchQualifier;
}
public BitronixXid(Xid xid) {
this.globalTransactionId = new Uid(xid.getGlobalTransactionId());
this.branchQualifier = new Uid(xid.getBranchQualifier());
}
/**
* Get Bitronix XID format ID. Defined by {@link BitronixXid#FORMAT_ID}.
* @return the Bitronix XID format ID.
*/
public int getFormatId() {
return FORMAT_ID;
}
/**
* Get the BQUAL of the XID.
* @return the XID branch qualifier.
*/
public byte[] getBranchQualifier() {
return branchQualifier.getArray();
}
public Uid getBranchQualifierUid() {
return branchQualifier;
}
/**
* Get the GTRID of the XID.
* @return the XID global transaction ID.
*/
public byte[] getGlobalTransactionId() {
return globalTransactionId.getArray();
}
public Uid getGlobalTransactionIdUid() {
return globalTransactionId;
}
/**
* Get a human-readable string representation of the XID.
* @return a human-readable string representation.
*/
public String toString() {
StringBuffer sb = new StringBuffer(288);
sb.append("a Bitronix XID [");
sb.append(globalTransactionId.toString());
sb.append(" : ");
sb.append(branchQualifier.toString());
sb.append("]");
return sb.toString();
}
/**
* Compare two XIDs for equality.
* @param obj the XID to compare to.
* @return true if both XIDs have the same format ID and contain exactly the same GTRID and BQUAL.
*/
public boolean equals(Object obj) {
if (!(obj instanceof BitronixXid))
return false;
BitronixXid otherXid = (BitronixXid) obj;
return FORMAT_ID == otherXid.getFormatId() &&
globalTransactionId.equals(otherXid.getGlobalTransactionIdUid()) &&
branchQualifier.equals(otherXid.getBranchQualifierUid());
}
/**
* Get an integer hash for the XID.
* @return a constant hash value.
*/
public int hashCode() {
int hashCode = FORMAT_ID;
if (globalTransactionId != null)
hashCode += globalTransactionId.hashCode();
if (branchQualifier != null)
hashCode += branchQualifier.hashCode();
return hashCode;
}
}