/*
* Mojito Distributed Hash Table (Mojito DHT)
* Copyright (C) 2006-2007 LimeWire LLC
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.limewire.mojito.manager;
import java.io.IOException;
import java.net.SocketAddress;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map.Entry;
import java.util.concurrent.ExecutionException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.limewire.mojito.Context;
import org.limewire.mojito.EntityKey;
import org.limewire.mojito.KUID;
import org.limewire.mojito.concurrent.DHTFuture;
import org.limewire.mojito.concurrent.DHTTask;
import org.limewire.mojito.concurrent.DHTValueFuture;
import org.limewire.mojito.db.DHTValueEntity;
import org.limewire.mojito.db.DHTValueType;
import org.limewire.mojito.exceptions.DHTBackendException;
import org.limewire.mojito.exceptions.DHTException;
import org.limewire.mojito.handler.response.AbstractResponseHandler;
import org.limewire.mojito.handler.response.FindNodeResponseHandler;
import org.limewire.mojito.handler.response.FindValueResponseHandler;
import org.limewire.mojito.handler.response.LookupResponseHandler;
import org.limewire.mojito.handler.response.StoreResponseHandler;
import org.limewire.mojito.messages.FindNodeResponse;
import org.limewire.mojito.messages.RequestMessage;
import org.limewire.mojito.messages.ResponseMessage;
import org.limewire.mojito.messages.SecurityTokenProvider;
import org.limewire.mojito.result.LookupResult;
import org.limewire.mojito.result.Result;
import org.limewire.mojito.result.StoreResult;
import org.limewire.mojito.routing.Contact;
import org.limewire.mojito.settings.LookupSettings;
import org.limewire.mojito.settings.StoreSettings;
import org.limewire.mojito.util.ContactUtils;
import org.limewire.mojito.util.ContactsScrubber;
import org.limewire.mojito.util.EntityUtils;
import org.limewire.mojito.util.EntryImpl;
import org.limewire.security.SecurityToken;
/**
* Controls the whole process of storing
* values along a path. There are 3 different options:
* <pre>
* 1) No Contact is specified.
* The StoreProcess will do a full lookup for the k-closest
* Nodes and will store the value(s) along the path.
*
* 2) A single Contact is specified but a SecurityToken is missing.
* The StoreProcess will try to obtain the SecurityToken
* and will store the value(s) at the given Node.
*
* 3) A single Contact is specified and a SecurityToken is not required.
* This is a special case and will never occur in reality.
* It's meant for DHT implementations (say you want to create a
* DHT is a closed environment where SecurityTokens make little
* sense).
* </pre>
* Regarding values and the first case, it's possible to store multiple
* values in a batch but all values must have the same primary key.
*/
class StoreProcess implements DHTTask<StoreResult> {
//private static final Log LOG = LogFactory.getLog(StoreProcess.class);
private final Context context;
private final List<DHTTask<?>> tasks = new ArrayList<DHTTask<?>>();
private boolean cancelled = false;
private DHTFuture<StoreResult> future;
private final KUID primaryKey;
private final Entry<? extends Contact, ? extends SecurityToken> node;
private final Collection<? extends DHTValueEntity> entities;
private final long waitOnLock;
public StoreProcess(Context context, Collection<? extends DHTValueEntity> entities) {
this(context, null, entities);
}
public StoreProcess(Context context, Entry<? extends Contact, ? extends SecurityToken> node,
Collection<? extends DHTValueEntity> entities) {
this.context = context;
this.entities = entities;
this.node = node;
if (node != null && node.getKey() == null) {
throw new IllegalArgumentException("Contact is null");
}
if (entities.isEmpty()) {
throw new IllegalArgumentException("No Values to store");
}
// If Node is null it means we've to search for the
// k-closest Nodes first which only works if all
// DHTValueEntities have the same primary key!
if (node == null) {
this.primaryKey = EntityUtils.getPrimaryKey(entities);
if (primaryKey == null) {
throw new IllegalArgumentException("All DHTValues must have the same primary key");
}
} else {
this.primaryKey = null;
}
this.waitOnLock = StoreSettings.getWaitOnLock(node != null);
}
public long getWaitOnLockTimeout() {
return waitOnLock;
}
public void start(DHTFuture<StoreResult> future) {
this.future = future;
// Regular store operation
if (node == null) {
findNearestNodes();
// Get the SecurityToken and store the value(s)
// at the given Node
} else if (node.getValue() == null
&& StoreSettings.STORE_REQUIRES_SECURITY_TOKEN.getValue()) {
doGetSecurityToken();
} else {
doStoreOnPath(Collections.singleton(node));
}
}
private void findNearestNodes() {
DHTFuture<LookupResult> c = new DHTValueFuture<LookupResult>() {
@Override
public synchronized boolean setValue(LookupResult value) {
if (super.setValue(value)) {
handleNearestNodes(value);
return true;
}
return false;
}
@Override
public synchronized boolean setException(Throwable exception) {
if (super.setException(exception)) {
future.setException(exception);
return true;
}
return false;
}
};
// Do a lookup for the k-closest Nodes where we're
// going to store the value
LookupResponseHandler<LookupResult> handler = createLookupResponseHandler();
// Use only alive Contacts from the RouteTable
handler.setSelectAliveNodesOnly(true);
start(handler, c);
}
private void handleNearestNodes(LookupResult value) {
doStoreOnPath(value.getEntryPath());
}
private void doGetSecurityToken() {
DHTFuture<GetSecurityTokenResult> c = new DHTValueFuture<GetSecurityTokenResult>() {
@Override
public synchronized boolean setValue(GetSecurityTokenResult value) {
if (super.setValue(value)) {
handleSecurityToken(value);
return true;
}
return false;
}
@Override
public synchronized boolean setException(Throwable exception) {
if (super.setException(exception)) {
future.setException(exception);
return true;
}
return false;
}
};
GetSecurityTokenHandler handler
= new GetSecurityTokenHandler(context, node.getKey());
start(handler, c);
}
private void handleSecurityToken(GetSecurityTokenResult result) {
SecurityToken securityToken = result.getSecurityToken();
if (securityToken == null) {
future.setException(new ExecutionException(
new DHTException("Could not get SecurityToken from " + node)));
} else {
Entry<Contact, SecurityToken> entry
= new EntryImpl<Contact, SecurityToken>(node.getKey(), securityToken);
doStoreOnPath(Collections.singleton(entry));
}
}
private void doStoreOnPath(Collection<? extends Entry<? extends Contact, ? extends SecurityToken>> path) {
// And store the values along the path
StoreResponseHandler handler
= new StoreResponseHandler(context, path, entities);
start(handler, future);
}
private <T> void start(DHTTask<T> task, DHTFuture<T> c) {
boolean doStart = false;
synchronized (tasks) {
if (!cancelled) {
tasks.add(task);
doStart = true;
}
}
if (doStart) {
task.start(c);
}
}
public void cancel() {
List<DHTTask<?>> copy = null;
synchronized (tasks) {
if (!cancelled) {
copy = new ArrayList<DHTTask<?>>(tasks);
tasks.clear();
cancelled = true;
}
}
if (copy != null) {
for (DHTTask<?> task : copy) {
task.cancel();
}
}
}
@SuppressWarnings("unchecked")
private LookupResponseHandler<LookupResult> createLookupResponseHandler() {
LookupResponseHandler<? extends LookupResult> handler = null;
if (LookupSettings.FIND_NODE_FOR_SECURITY_TOKEN.getValue()) {
handler = new FindNodeResponseHandler(context, primaryKey);
} else {
EntityKey lookupKey = EntityKey.createEntityKey(primaryKey, DHTValueType.ANY);
handler = new FindValueResponseHandler(context, lookupKey);
}
return (LookupResponseHandler<LookupResult>)handler;
}
/**
* GetSecurityTokenHandler tries to get the SecurityToken of a Node
*/
private static class GetSecurityTokenHandler extends AbstractResponseHandler<GetSecurityTokenResult> {
private static final Log LOG = LogFactory.getLog(GetSecurityTokenHandler.class);
private final Contact node;
private GetSecurityTokenHandler(Context context, Contact node) {
super(context);
this.node = node;
}
@Override
protected void start() throws DHTException {
RequestMessage request = createLookupRequest();
try {
context.getMessageDispatcher().send(node, request, this);
} catch (IOException err) {
throw new DHTException(err);
}
}
private RequestMessage createLookupRequest() {
if (LookupSettings.FIND_NODE_FOR_SECURITY_TOKEN.getValue()) {
return context.getMessageHelper()
.createFindNodeRequest(node.getContactAddress(), node.getNodeID());
} else {
Collection<KUID> noKeys = Collections.emptySet();
return context.getMessageHelper()
.createFindValueRequest(node.getContactAddress(), node.getNodeID(), noKeys, DHTValueType.ANY);
}
}
@Override
protected void response(ResponseMessage message, long time) throws IOException {
if (message instanceof FindNodeResponse) {
FindNodeResponse response = (FindNodeResponse)message;
Contact sender = response.getContact();
Collection<? extends Contact> nodes = response.getNodes();
if (!nodes.isEmpty()) {
ContactsScrubber scrubber = ContactsScrubber.scrub(
context, sender, nodes,
LookupSettings.CONTACTS_SCRUBBER_REQUIRED_RATIO.getValue());
if (scrubber.isValidResponse()) {
// We did a FIND_NODE lookup use the info
// to fill/update our routing table
for(Contact node : scrubber.getScrubbed()) {
assert (node.isAlive() == false);
context.getRouteTable().add(node);
}
}
}
}
SecurityToken securityToken = null;
if (message instanceof SecurityTokenProvider) {
securityToken = ((SecurityTokenProvider)message).getSecurityToken();
}
setReturnValue(new GetSecurityTokenResult(securityToken));
}
@Override
protected void timeout(KUID nodeId, SocketAddress dst, RequestMessage message, long time) throws IOException {
fireTimeoutException(nodeId, dst, message, time);
}
@Override
protected void error(KUID nodeId, SocketAddress dst, RequestMessage message, IOException e) {
if (LOG.isErrorEnabled()) {
LOG.error("Getting the SecurityToken from " + ContactUtils.toString(nodeId, dst) + " failed", e);
}
setException(new DHTBackendException(nodeId, dst, message, e));
}
}
/**
* Returned by GetSecurityTokenHandler. Used only internally!
*/
private static class GetSecurityTokenResult implements Result {
private final SecurityToken securityToken;
public GetSecurityTokenResult(SecurityToken securityToken) {
this.securityToken = securityToken;
}
public SecurityToken getSecurityToken() {
return securityToken;
}
}
}