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package com.sun.enterprise.admin.common.domains.registry;
import java.util.Iterator;
import java.util.HashMap;
import java.io.Serializable;
import java.io.File;
import java.lang.UnsupportedOperationException;
import java.util.NoSuchElementException;
import java.io.IOException;
import java.io.EOFException;
/**
This class provides a registry for domains, abstracting the
persistent storage and coordination activities required to permit
uniqueness invariants to be maintained between domains no matter
which JVM they are being referred from.
<p>
The directory in which the persistent store is kept is denoted by
the <code>System</code> property
<code>com.sun.aas.admin.configRoot</code>. The name of the
file is <code>domains.ser</code>
<p>
The principal invariants this registry maintains is that no two
domains shall have the same name, and no two domains shall have the
same location.
<p>
The registry can be considered to be a table whose keys are domain
name and domain location, and whose values are the remote contact
information by which the adminstration server within that domain
can be contacted remotely.
<p>
A row in this table is abstracted into the {@link DomainEntry} class.
*
* @author <a href="mailto:toby.h.ferguson@sun.com">Toby H Ferguson</a>
* @version $Revision: 1.5 $
*/
public class DomainRegistry implements DomainRegistryI
{
/**
* Return an instance of the DomainRegistry
* @return a <code>DomainRegistry</code> value
@throws DomainRegistryException if there was a problem
instantiating the class
*/
synchronized static public DomainRegistry newInstance() throws DomainRegistryException {
if (instance == null){
instance = new DomainRegistry();
instance.init();
}
return instance;
}
public synchronized void registerDomain(DomainEntry de) throws DomainRegistryException {
prepareForUpdate();
try {
registry.registerDomain(de);
}
catch (DomainRegistryException e){
store.unlock();
throw e;
}
saveRegistry();
}
public void unregisterDomain(String domain_name) throws DomainRegistryException {
prepareForUpdate();
try{
registry.unregisterDomain(domain_name);
}
catch (DomainRegistryException e){
store.unlock();
throw e;
}
saveRegistry();
}
public void unregisterDomain(DomainEntry de) throws DomainRegistryException {
this.unregisterDomain(de.getName());
}
public void reregisterDomain(DomainEntry de) throws DomainRegistryException {
prepareForUpdate();
try {
registry.reregisterDomain(de);
}
catch (DomainRegistryException e){
store.unlock();
throw e;
}
saveRegistry();
}
public boolean containsDomain(DomainEntry de) throws DomainRegistryException {
refreshRegistry();
return registry.containsDomain(de);
}
public DomainEntry getDomain(String name) throws DomainRegistryException {
refreshRegistry();
return registry.getDomain(name);
}
public Iterator iterator() throws DomainRegistryException {
refreshRegistry();
return registry.iterator();
}
public int size() throws DomainRegistryException {
refreshRegistry();
return registry.size();
}
synchronized void reset() throws IOException {
store.unlock();
registry = null;
store = null;
instance = null;
}
private void refreshRegistry() throws DomainRegistryException {
if (lastModified < store.lastModified()){
try {
registry = getRegistryFromStore();
}
catch (Exception te){
throw new DomainRegistryException("problem reading from store", te);
}
}
}
private Registry getRegistryFromStore() throws IOException, TimeoutException, ClassNotFoundException {
Registry br;
br = (Registry) store.readObject();
return (br != null ? br : new Registry());
}
private void prepareForUpdate() throws DomainRegistryException {
try {
store.lock();
}
catch (Exception e){
throw new DomainRegistryException("problem locking store ", e);
}
refreshRegistry();
}
private void saveRegistry() throws DomainRegistryException {
try {
store.writeObject(registry);
store.unlock();
lastModified = store.lastModified();
}
catch (Exception e){
e.printStackTrace();
throw new DomainRegistryException("couldn't save registry", e);
}
}
private void init() throws DomainRegistryException {
try {
store = LockingStoreFactory.getInstance();
registry = getRegistryFromStore();
}
catch (Exception e){
throw new DomainRegistryException("couldn't initialize registry. Error message: "+ e.getMessage());
}
}
/*
PersistentStore getPS(){
return (PersistentStore) store;
}
*/
private Registry registry;
private LockingStore store;
private static DomainRegistry instance = null;
private long lastModified = 0;
private DomainRegistry(){}
}
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