org.apache.jackrabbit.webdav.jcr.observation.SubscriptionImpl Maven / Gradle / Ivy
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WebDAV server implementations for JCR
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jackrabbit.webdav.jcr.observation;
import org.apache.jackrabbit.commons.webdav.EventUtil;
import org.apache.jackrabbit.commons.webdav.JcrRemotingConstants;
import org.apache.jackrabbit.spi.Name;
import org.apache.jackrabbit.spi.commons.AdditionalEventInfo;
import org.apache.jackrabbit.spi.commons.SessionExtensions;
import org.apache.jackrabbit.webdav.DavException;
import org.apache.jackrabbit.webdav.DavResourceLocator;
import org.apache.jackrabbit.webdav.DavServletResponse;
import org.apache.jackrabbit.webdav.transaction.TransactionResource;
import org.apache.jackrabbit.webdav.jcr.transaction.TransactionListener;
import org.apache.jackrabbit.webdav.jcr.JcrDavException;
import org.apache.jackrabbit.webdav.jcr.JcrDavSession;
import org.apache.jackrabbit.webdav.observation.EventBundle;
import org.apache.jackrabbit.webdav.observation.EventDiscovery;
import org.apache.jackrabbit.webdav.observation.EventType;
import org.apache.jackrabbit.webdav.observation.Filter;
import org.apache.jackrabbit.webdav.observation.ObservationConstants;
import org.apache.jackrabbit.webdav.observation.ObservationResource;
import org.apache.jackrabbit.webdav.observation.Subscription;
import org.apache.jackrabbit.webdav.observation.SubscriptionInfo;
import org.apache.jackrabbit.webdav.observation.DefaultEventType;
import org.apache.jackrabbit.webdav.xml.DomUtil;
import org.apache.jackrabbit.webdav.xml.Namespace;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import javax.jcr.RepositoryException;
import javax.jcr.Session;
import javax.jcr.UnsupportedRepositoryOperationException;
import javax.jcr.observation.Event;
import javax.jcr.observation.EventIterator;
import javax.jcr.observation.EventListener;
import javax.jcr.observation.ObservationManager;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.UUID;
/**
* The Subscription class encapsulates a single subscription with
* the following responsibilities:
* - Providing access to the subscription info,
* - Recording events this subscription is interested in,
* - Providing access to the events.
*
*/
public class SubscriptionImpl implements Subscription, ObservationConstants, EventListener {
private static Logger log = LoggerFactory.getLogger(SubscriptionImpl.class);
private static final long DEFAULT_TIMEOUT = 300000; // 5 minutes
private SubscriptionInfo info;
private long expirationTime;
private final DavResourceLocator locator;
private final String subscriptionId = UUID.randomUUID().toString();
private final List eventBundles = new ArrayList();
private final ObservationManager obsMgr;
private final Session session;
/**
* Create a new Subscription with the given {@link SubscriptionInfo}
* and {@link org.apache.jackrabbit.webdav.observation.ObservationResource resource}.
*
* @param info
* @param resource
* @throws DavException if resource is not based on a JCR repository or
* the repository does not support observation.
*/
public SubscriptionImpl(SubscriptionInfo info, ObservationResource resource)
throws DavException {
setInfo(info);
locator = resource.getLocator();
session = JcrDavSession.getRepositorySession(resource.getSession());
try {
obsMgr = session.getWorkspace().getObservationManager();
} catch (RepositoryException e) {
throw new DavException(DavServletResponse.SC_INTERNAL_SERVER_ERROR, e);
}
}
//-------------------------------------------------------< Subscription >---
/**
* Returns the id of this subscription.
*
* @return subscriptionId
*/
public String getSubscriptionId() {
return subscriptionId;
}
public boolean eventsProvideNodeTypeInformation() {
String t = session.getRepository().getDescriptor("org.apache.jackrabbit.spi.commons.AdditionalEventInfo");
return t == null ? false : Boolean.parseBoolean(t);
}
public boolean eventsProvideNoLocalFlag() {
return session instanceof SessionExtensions;
}
//----------------------------------------------------< XmlSerializable >---
/**
* Return the Xml representation of this Subscription as required
* for the {@link org.apache.jackrabbit.webdav.observation.SubscriptionDiscovery}
* webdav property that in included in the response body of a successful SUBSCRIBE
* request or as part of a PROPFIND response.
*
* @return Xml representation
* @see org.apache.jackrabbit.webdav.xml.XmlSerializable#toXml(Document)
* @param document
*/
public Element toXml(Document document) {
Element subscr = DomUtil.createElement(document, XML_SUBSCRIPTION, NAMESPACE);
subscr.appendChild(info.toXml(document));
subscr.appendChild(DomUtil.depthToXml(info.isDeep(), document));
subscr.appendChild(DomUtil.timeoutToXml(info.getTimeOut(), document));
if (getSubscriptionId() != null) {
Element id = DomUtil.addChildElement(subscr, XML_SUBSCRIPTIONID, NAMESPACE);
id.appendChild(DomUtil.hrefToXml(getSubscriptionId(), document));
}
DomUtil.addChildElement(subscr, XML_EVENTSWITHTYPES, NAMESPACE,
Boolean.toString(eventsProvideNodeTypeInformation()));
DomUtil.addChildElement(subscr, XML_EVENTSWITHLOCALFLAG, NAMESPACE,
Boolean.toString(eventsProvideNoLocalFlag()));
return subscr;
}
//--------------------------------------------< implementation specific >---
/**
* Modify the {@link SubscriptionInfo} for this subscription.
*
* @param info
*/
void setInfo(SubscriptionInfo info) {
this.info = info;
// validate the timeout and adjust value, if it is invalid or missing
long timeout = info.getTimeOut();
if (timeout <= 0) {
timeout = DEFAULT_TIMEOUT;
}
expirationTime = System.currentTimeMillis() + timeout;
}
/**
* @return JCR compliant integer representation of the event types defined
* for this {@link SubscriptionInfo}.
*/
int getJcrEventTypes() throws DavException {
EventType[] eventTypes = info.getEventTypes();
int events = 0;
for (EventType eventType : eventTypes) {
events |= getJcrEventType(eventType);
}
return events;
}
/**
* @return a String array with size > 0 or null
*/
String[] getUuidFilters() {
return getFilterValues(XML_UUID);
}
/**
* @return a String array with size > 0 or null
*/
String[] getNodetypeNameFilters() {
return getFilterValues(XML_NODETYPE_NAME);
}
private String[] getFilterValues(String filterLocalName) {
List values = new ArrayList();
for (Filter filter : info.getFilters(filterLocalName, NAMESPACE)) {
String val = filter.getValue();
if (val != null) {
values.add(val);
}
}
return (values.size() > 0) ? values.toArray(new String[values.size()]) : null;
}
/**
*
* @return true if a {@link ObservationConstants#XML_NOLOCAL} element
* is present in the {@link SubscriptionInfo}.
*/
boolean isNoLocal() {
return info.isNoLocal();
}
/**
* @return true if this subscription is intended to be deep.
*/
boolean isDeep() {
return info.isDeep();
}
/**
* @return the locator of the {@link ObservationResource resource} this
* Subscription was requested for.
*/
DavResourceLocator getLocator() {
return locator;
}
/**
* Returns true if this Subscription matches the given
* resource.
*
* @param resource
* @return true if this Subscription matches the given
* resource.
*/
boolean isSubscribedToResource(ObservationResource resource) {
return locator.getResourcePath().equals(resource.getResourcePath());
}
/**
* Returns true if this Subscription is expired and therefore
* stopped recording events.
*
* @return true if this Subscription is expired
*/
boolean isExpired() {
return System.currentTimeMillis() > expirationTime;
}
/**
* Returns a {@link org.apache.jackrabbit.webdav.observation.EventDiscovery} object listing all events that were
* recorded since the last call to this method and clears the list of event
* bundles.
*
* @param timeout time in milliseconds to wait at most for events if none
* are present currently.
* @return object listing all events that were recorded.
* @see #onEvent(EventIterator)
*/
synchronized EventDiscovery discoverEvents(long timeout) {
EventDiscovery ed = new EventDiscovery();
if (eventBundles.isEmpty() && timeout > 0) {
try {
wait(timeout);
} catch (InterruptedException e) {
// continue and possibly return empty event discovery
}
}
for (EventBundle eb : eventBundles) {
ed.addEventBundle(eb);
}
// clear list
eventBundles.clear();
return ed;
}
/**
* Creates a new transaction listener for the scope of a transaction
* commit (save call).
* @return a transaction listener for this subscription.
*/
TransactionListener createTransactionListener() {
if (info.isNoLocal()) {
// a subscription which is not interested in local changes does
// not need the transaction id
return new TransactionEvent() {
@Override
public void onEvent(EventIterator events) {
// ignore
}
@Override
public void beforeCommit(TransactionResource resource, String lockToken) {
// ignore
}
@Override
public void afterCommit(TransactionResource resource,
String lockToken,
boolean success) {
// ignore
}
};
} else {
return new TransactionEvent();
}
}
/**
* Suspend this subscription. This call will remove this subscription as
* event listener from the observation manager.
*/
void suspend() throws DavException {
try {
obsMgr.removeEventListener(this);
} catch (RepositoryException e) {
throw new JcrDavException(e);
}
}
/**
* Resumes this subscription. This call will register this subscription
* again as event listener to the observation manager.
*/
void resume() throws DavException {
try {
obsMgr.addEventListener(this, getJcrEventTypes(),
getLocator().getRepositoryPath(), isDeep(), getUuidFilters(),
getNodetypeNameFilters(), isNoLocal());
} catch (RepositoryException e) {
throw new JcrDavException(e);
}
}
//--------------------------------------------< EventListener interface >---
/**
* Records the events passed as a new event bundle in order to make them
* available with the next {@link #discoverEvents(long)} request. If this
* subscription is expired it will remove itself as listener from the
* observation manager.
*
* @param events to be recorded.
* @see EventListener#onEvent(EventIterator)
* @see #discoverEvents(long)
*/
public synchronized void onEvent(EventIterator events) {
if (!isExpired()) {
eventBundles.add(new EventBundleImpl(events));
} else {
// expired -> unsubscribe
try {
obsMgr.removeEventListener(this);
} catch (RepositoryException e) {
log.warn("Exception while unsubscribing: " + e);
}
}
notifyAll();
}
//--------------------------------------------------------------------------
/**
* Static utility method to convert the type defined by a
* {@link javax.jcr.observation.Event JCR event} into an EventType
* object.
*
* @param jcrEventType
* @return EventType representation of the given JCR event type.
* @throws IllegalArgumentException if the given int does not represent a
* valid type constants as defined by {@link Event}.
* Valid values are
*
* - {@link Event#NODE_ADDED}
* - {@link Event#NODE_REMOVED}
* - {@link Event#PROPERTY_ADDED}
* - {@link Event#PROPERTY_REMOVED}
* - {@link Event#PROPERTY_CHANGED}
* - {@link Event#NODE_MOVED}
* - {@link Event#PERSIST}
*
*/
public static EventType getEventType(int jcrEventType) {
String localName = EventUtil.getEventName(jcrEventType);
return DefaultEventType.create(localName, NAMESPACE);
}
/**
* @return The DAV event type representation for all known JCR event types.
*/
public static EventType[] getAllEventTypes() {
EventType[] types = DefaultEventType.create(EventUtil.EVENT_ALL, NAMESPACE);
return types;
}
/**
* Static utility method to convert an EventType as present in
* the Xml body into the corresponding JCR event constant defined by
* {@link javax.jcr.observation.Event}.
*
* @param eventType
* @return Any of the event types defined by {@link Event}.
* Possible values are
*
* - {@link Event#NODE_ADDED}
* - {@link Event#NODE_REMOVED}
* - {@link Event#PROPERTY_ADDED}
* - {@link Event#PROPERTY_REMOVED}
* - {@link Event#PROPERTY_CHANGED}
* - {@link Event#NODE_MOVED}
* - {@link Event#PERSIST}
*
* @throws DavException if the given event type does not define a valid
* JCR event type, such as returned by {@link #getEventType(int)}.
*/
public static int getJcrEventType(EventType eventType) throws DavException {
if (eventType == null || !NAMESPACE.equals(eventType.getNamespace())) {
throw new DavException(DavServletResponse.SC_UNPROCESSABLE_ENTITY, "Invalid JCR event type: "+ eventType + ": Namespace mismatch.");
}
String eventName = eventType.getName();
if (!EventUtil.isValidEventName(eventName)) {
throw new DavException(DavServletResponse.SC_UNPROCESSABLE_ENTITY, "Invalid event type: "+eventName);
}
return EventUtil.getJcrEventType(eventName);
}
/**
* Inner class EventBundle encapsulates an event bundle as
* recorded {@link SubscriptionImpl#onEvent(EventIterator) on event} and
* provides the possibility to retrieve the Xml representation of the
* bundle and the events included in order to respond to a POLL request.
*
* @see SubscriptionImpl#discoverEvents(long)
*/
private class EventBundleImpl implements EventBundle {
private final EventIterator events;
private final String transactionId;
private EventBundleImpl(EventIterator events) {
this(events, null);
}
private EventBundleImpl(EventIterator events, String transactionId) {
this.events = events;
this.transactionId = transactionId;
}
public Element toXml(Document document) {
Element bundle = DomUtil.createElement(document, XML_EVENTBUNDLE, NAMESPACE);
// TODO: this appears to be unused now
if (transactionId != null) {
DomUtil.setAttribute(bundle, XML_EVENT_TRANSACTION_ID, NAMESPACE, transactionId);
}
boolean localFlagSet = false;
while (events.hasNext()) {
Event event = events.nextEvent();
if (!localFlagSet) {
// obtain remote session identifier
localFlagSet = true;
String name = JcrRemotingConstants.RELATION_REMOTE_SESSION_ID;
Object forSessionId = session.getAttribute(name);
// calculate "local" flags
if (forSessionId != null
&& event instanceof AdditionalEventInfo) {
AdditionalEventInfo aei = (AdditionalEventInfo) event;
try {
boolean isLocal = forSessionId.equals(
aei.getSessionAttribute(name));
DomUtil.setAttribute(
bundle, XML_EVENT_LOCAL, null,
Boolean.toString(isLocal));
} catch (UnsupportedRepositoryOperationException ex) {
// optional feature
}
}
}
Element eventElem = DomUtil.addChildElement(bundle, XML_EVENT, NAMESPACE);
// href
String eHref = "";
try {
boolean isCollection = (event.getType() == Event.NODE_ADDED || event.getType() == Event.NODE_REMOVED);
eHref = locator.getFactory().createResourceLocator(locator.getPrefix(), locator.getWorkspacePath(), event.getPath(), false).getHref(isCollection);
} catch (RepositoryException e) {
// should not occur....
log.error(e.getMessage());
}
eventElem.appendChild(DomUtil.hrefToXml(eHref, document));
// event type
Element eType = DomUtil.addChildElement(eventElem, XML_EVENTTYPE, NAMESPACE);
eType.appendChild(getEventType(event.getType()).toXml(document));
// user id
DomUtil.addChildElement(eventElem, XML_EVENTUSERID, NAMESPACE, event.getUserID());
// try to compute nodetype information
if (event instanceof AdditionalEventInfo) {
try {
DomUtil.addChildElement(eventElem,
XML_EVENTPRIMARNODETYPE, NAMESPACE,
((AdditionalEventInfo) event)
.getPrimaryNodeTypeName().toString());
for (Name mixin : ((AdditionalEventInfo) event)
.getMixinTypeNames()) {
DomUtil.addChildElement(eventElem,
XML_EVENTMIXINNODETYPE, NAMESPACE,
mixin.toString());
}
} catch (UnsupportedRepositoryOperationException ex) {
// optional
}
}
// Additional JCR 2.0 event information
// user data
try {
DomUtil.addChildElement(eventElem, XML_EVENTUSERDATA, NAMESPACE, event.getUserData());
} catch (RepositoryException e) {
log.error("Internal error while retrieving event user data.", e.getMessage());
}
// time stamp
try {
DomUtil.addChildElement(eventElem, XML_EVENTDATE, NAMESPACE, String.valueOf(event.getDate()));
} catch (RepositoryException e) {
log.error("Internal error while retrieving event date.", e.getMessage());
}
// identifier
try {
DomUtil.addChildElement(eventElem, XML_EVENTIDENTIFIER, NAMESPACE, event.getIdentifier());
} catch (RepositoryException e) {
log.error("Internal error while retrieving event identifier.", e.getMessage());
}
// info
Element info = DomUtil.addChildElement(eventElem, XML_EVENTINFO, NAMESPACE);
try {
Map m = event.getInfo();
for (Map.Entry entry : m.entrySet()) {
String key = entry.getKey().toString();
Object value = entry.getValue();
if (value != null) {
DomUtil.addChildElement(info, key, Namespace.EMPTY_NAMESPACE, value.toString());
} else {
DomUtil.addChildElement(info, key, Namespace.EMPTY_NAMESPACE);
}
}
} catch (RepositoryException e) {
log.error("Internal error while retrieving event info.", e.getMessage());
}
}
return bundle;
}
}
//----------------------------< TransactionEvent >------------------------
/**
* Implements a transaction event which listeners for events during a save
* call on the repository.
*/
private class TransactionEvent implements EventListener, TransactionListener {
private String transactionId;
/**
* {@inheritDoc}
*/
public void onEvent(EventIterator events) {
String tId = transactionId;
if (tId == null) {
tId = UUID.randomUUID().toString();
}
synchronized (SubscriptionImpl.this) {
eventBundles.add(new EventBundleImpl(events, tId));
SubscriptionImpl.this.notifyAll();
}
}
//-----------------------------< TransactionListener >------------------
/**
* {@inheritDoc}
*/
public void beforeCommit(TransactionResource resource, String lockToken) {
try {
transactionId = lockToken;
obsMgr.addEventListener(this, getJcrEventTypes(),
getLocator().getRepositoryPath(), isDeep(), getUuidFilters(),
getNodetypeNameFilters(), isNoLocal());
// suspend the subscription
suspend();
} catch (RepositoryException e) {
log.warn("Unable to register TransactionListener: " + e);
} catch (DavException e) {
log.warn("Unable to register TransactionListener: " + e);
}
}
/**
* {@inheritDoc}
*/
public void afterCommit(TransactionResource resource,
String lockToken,
boolean success) {
try {
// resume the subscription
resume();
// remove this transaction event
obsMgr.removeEventListener(this);
} catch (RepositoryException e) {
log.warn("Unable to remove listener: " + e);
} catch (DavException e) {
log.warn("Unable to resume Subscription: " + e);
}
}
}
}