src/main/java/org/apache/sling/mongodb/impl/MongoDBResourceProvider.java - sling-org-apache-sling-mongodb - Git at Google

 /*
  * 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.sling.mongodb.impl;

 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
 import java.util.regex.Pattern;

 import javax.servlet.http.HttpServletRequest;

 import org.apache.sling.api.resource.ModifyingResourceProvider;
 import org.apache.sling.api.resource.PersistenceException;
 import org.apache.sling.api.resource.Resource;
 import org.apache.sling.api.resource.ResourceProvider;
 import org.apache.sling.api.resource.ResourceResolver;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 import com.mongodb.BasicDBObject;
 import com.mongodb.BasicDBObjectBuilder;
 import com.mongodb.DBCollection;
 import com.mongodb.DBCursor;
 import com.mongodb.DBObject;
 import com.mongodb.QueryBuilder;

 /**
  * The MongoDB resource provider creates resources based on MongoDB entries.
  * The resources contain all properties stored in the MongoDB except those starting with a "_".
  */
 public class MongoDBResourceProvider implements ResourceProvider, ModifyingResourceProvider {

     /** The special path property containing the (relative) path of the resource in the tree. */
     public static final String PROP_PATH = "_path";

     /** The id property. */
     public static final String PROP_ID = "_id";

     /** Logger. */
     private final Logger logger = LoggerFactory.getLogger(this.getClass());

     /** The global context .*/
     private final MongoDBContext context;

     private final Map<String, MongoDBResource> changedResources = new HashMap<String, MongoDBResource>();

     private final Set<String> deletedResources = new HashSet<String>();

     public MongoDBResourceProvider(final MongoDBContext context) {
         this.context = context;
     }

     public static String propNameToKey(final String name) {
         if ( name.startsWith("_") ) {
             return "_" + name;
         }
         return name;
     }

     public static String keyToPropName(final String key) {
         if ( key.startsWith("__") ) {
             return key.substring(1);
         } else if ( key.startsWith("_") ) {
             return null;
         }
         return key;
     }

     /**
      * @see org.apache.sling.api.resource.ModifyingResourceProvider#create(org.apache.sling.api.resource.ResourceResolver, java.lang.String, java.util.Map)
      */
     public Resource create(final ResourceResolver resolver, final String path, final Map<String, Object> properties)
     throws PersistenceException {
         final String[] info = this.extractResourceInfo(path);
         if ( info != null && info.length == 2) {
             final boolean deleted = this.deletedResources.remove(path);
             final MongoDBResource oldResource = (MongoDBResource)this.getResource(resolver, path, info);
             if ( !deleted && oldResource != null ) {
                 throw new PersistenceException("Resource already exists at " + path, null, path, null);
             }
             final DBObject dbObj = new BasicDBObject();
             dbObj.put(PROP_PATH, info[1]);
             if ( properties != null ) {
                 for(Map.Entry<String, Object> entry : properties.entrySet()) {
                     final String key = propNameToKey(entry.getKey());
                     dbObj.put(key, entry.getValue());
                 }
             }
             if ( deleted && oldResource != null ) {
                 dbObj.put(PROP_ID, oldResource.getProperties().get(PROP_ID));
             }
             final MongoDBResource rsrc = new MongoDBResource(resolver, path, info[0], dbObj, this);
             this.changedResources.put(path, rsrc);

             return rsrc;
         }
         throw new PersistenceException("Illegal path - unable to create resource at " + path, null, path, null);
     }

     /**
      * @see org.apache.sling.api.resource.ModifyingResourceProvider#delete(org.apache.sling.api.resource.ResourceResolver, java.lang.String)
      */
     public void delete(final ResourceResolver resolver, final String path)
     throws PersistenceException {
         final String[] info = this.extractResourceInfo(path);
         if ( info != null ) {
             boolean deletedResource = false;
             if ( !deletedResources.contains(path) ) {
                 final Resource rsrc = this.getResource(resolver, path, info);
                 if ( rsrc instanceof MongoDBResource ) {
                     this.deletedResources.add(path);
                     this.changedResources.remove(path);

                     final DBCollection col = this.getCollection(info[0]);
                     final String pattern = "^" + Pattern.quote(info[1]) + "/";

                     final DBObject query = QueryBuilder.start(PROP_PATH).regex(Pattern.compile(pattern)).get();
                     final DBCursor cur = col.find(query);
                     while ( cur.hasNext() ) {
                         final DBObject dbObj = cur.next();
                         final String childPath = info[0] + '/' + dbObj.get(PROP_PATH);
                         this.deletedResources.add(childPath);
                         this.changedResources.remove(childPath);
                     }
                     deletedResource = true;
                 }
             } else {
                 deletedResource = true;
             }
             if ( deletedResource ) {
                 final String prefix = path + "/";
                 final Iterator<Map.Entry<String, MongoDBResource>> i = this.changedResources.entrySet().iterator();
                 while ( i.hasNext() ) {
                     final Map.Entry<String, MongoDBResource> entry = i.next();
                     if ( entry.getKey().startsWith(prefix) ) {
                         i.remove();
                     }
                 }
                 return;
             }

         }
         throw new PersistenceException("Unable to delete resource at {}" + path, null, path, null);
     }

     /**
      * @see org.apache.sling.api.resource.ModifyingResourceProvider#revert()
      */
     public void revert() {
         this.changedResources.clear();
         this.deletedResources.clear();
     }

     /**
      * @see org.apache.sling.api.resource.ModifyingResourceProvider#commit()
      */
     public void commit() throws PersistenceException {
         try {
             for(final String deleted : this.deletedResources) {
                 final String[] info = this.extractResourceInfo(deleted);

                 // check if the collection still exists
                 final DBCollection col = this.getCollection(info[0]);
                 if ( col != null ) {
                     col.findAndRemove(QueryBuilder.start(PROP_PATH).is(info[1]).get());
                 }
             }
             for(final MongoDBResource changed : this.changedResources.values()) {

                 final DBCollection col = this.context.getDatabase().getCollection(changed.getCollection());
                 if ( col != null ) {
                     // create or update?
                     if ( changed.getProperties().get(PROP_ID) != null ) {
                         col.update(QueryBuilder.start(PROP_PATH).is(changed.getProperties().get(PROP_PATH)).get(),
                                         changed.getProperties());
                     } else {
                         // create
                         col.save(changed.getProperties());
                     }
                 } else {
                     throw new PersistenceException("Unable to create collection " + changed.getCollection(), null, changed.getPath(), null);
                 }
             }
         } finally {
             this.revert();
         }
     }

     /**
      * @see org.apache.sling.api.resource.ModifyingResourceProvider#hasChanges()
      */
     public boolean hasChanges() {
         return this.changedResources.size() > 0 || this.deletedResources.size() > 0;
     }

     /**
      * @see org.apache.sling.api.resource.ResourceProvider#getResource(org.apache.sling.api.resource.ResourceResolver, java.lang.String)
      */
     public Resource getResource(final ResourceResolver resourceResolver, final String path) {
         if ( this.deletedResources.contains(path) ) {
             return null;
         }
         if ( this.changedResources.containsKey(path) ) {
             return this.changedResources.get(path);
         }
         final String[] info = this.extractResourceInfo(path);
         if ( info != null ) {
             return this.getResource(resourceResolver, path, info);
         }
         return null;
     }

     /**
      * Inform about changes of a resource.
      */
     public void changed(final MongoDBResource resource) {
         this.deletedResources.remove(resource.getPath());
         this.changedResources.put(resource.getPath(), resource);
     }

     /**
      * @see org.apache.sling.api.resource.ResourceProvider#listChildren(org.apache.sling.api.resource.Resource)
      */
     public Iterator<Resource> listChildren(final Resource parent) {
         final String[] info = this.extractResourceInfo(parent.getPath());
         if ( info != null ) {
             if ( info.length == 0 ) {
                 // all collections
                 final Set<String> names = new HashSet<String>(context.getDatabase().getCollectionNames());
                 names.removeAll(this.context.getFilterCollectionNames());
                 final Iterator<String> i = names.iterator();
                 return new Iterator<Resource>() {

                     public boolean hasNext() {
                         return i.hasNext();
                     }

                     public Resource next() {
                         final String name = i.next();
                         return new MongoDBCollectionResource(parent.getResourceResolver(), parent.getPath() + '/' + name);
                     }

                     public void remove() {
                         throw new UnsupportedOperationException("remove");
                     }

                 };
             }
             final DBCollection col = this.getCollection(info[0]);
             if ( col != null ) {
                 final String pattern;
                 if ( info.length == 1 ) {
                     pattern = "^([^/])*$";
                 } else {
                     pattern = "^" + Pattern.quote(info[1]) + "/([^/])*$";
                 }

                 final DBObject query = QueryBuilder.start(PROP_PATH).regex(Pattern.compile(pattern)).get();
                 final DBCursor cur = col.find(query).
                                 sort(BasicDBObjectBuilder.start(PROP_PATH, 1).get());
                 return new Iterator<Resource>() {

                     public boolean hasNext() {
                         return cur.hasNext();
                     }

                     public Resource next() {
                         final DBObject obj = cur.next();
                         final String objPath = obj.get(PROP_PATH).toString();
                         final int lastSlash = objPath.lastIndexOf('/');
                         final String name;
                         if (lastSlash == -1) {
                             name = objPath;
                         } else {
                             name = objPath.substring(lastSlash + 1);
                         }
                         return new MongoDBResource(parent.getResourceResolver(),
                                         parent.getPath() + '/' + name,
                                         info[0],
                                         obj,
                                         MongoDBResourceProvider.this);
                     }

                     public void remove() {
                         throw new UnsupportedOperationException("remove");
                     }

                 };
             }
         }
         return null;
     }

     /**
      * @see org.apache.sling.api.resource.ResourceProvider#getResource(org.apache.sling.api.resource.ResourceResolver, javax.servlet.http.HttpServletRequest, java.lang.String)
      */
     @SuppressWarnings("javadoc")
     public Resource getResource(final ResourceResolver resourceResolver,
                     final HttpServletRequest request,
                     final String path) {
         return this.getResource(resourceResolver, path);
     }

     /**
      * Extract info about collection and path
      */
     private String[] extractResourceInfo(final String path) {
         for(final String root : this.context.getRootsWithSlash()) {
             if ( path.startsWith(root) ) {
                 if ( path.length() == root.length() ) {
                     // special resource - show all collections
                     return new String[0];
                 }
                 final String info = path.substring(root.length());
                 final int slashPos = info.indexOf('/');
                 if ( slashPos != -1 ) {
                     return new String[] {info.substring(0, slashPos), info.substring(slashPos + 1)};
                 }
                 // special resource - collection
                 return new String[] {info};
             }
         }
         for(final String root : this.context.getRoots()) {
             if ( path.equals(root) ) {
                 // special resource - show all collections
                 return new String[0];
             }
         }
         return null;
     }

     /**
      * Check if a collection with a given name exists
      */
     private boolean hasCollection(final String name) {
         final Set<String> names = this.context.getDatabase().getCollectionNames();
         return names.contains(name) && !this.context.isFilterCollectionName(name);
     }

     /**
      * Check if a collection with a given name exists and return it
      */
     private DBCollection getCollection(final String name) {
         if ( this.hasCollection(name) ) {
             return this.context.getDatabase().getCollection(name);
         }
         return null;
     }

     /**
      * Get a resource
      */
     private Resource getResource(final ResourceResolver resourceResolver, final String path, final String[] info) {
         if ( info.length == 0 ) {
             // special resource : all collections
             return new MongoDBCollectionResource(resourceResolver, path);
         } else if ( info.length == 1 ) {
             // special resource : collection
             if ( this.hasCollection(info[0]) ) {
                 return new MongoDBCollectionResource(resourceResolver, path);
             }
             return null;
         }
         logger.debug("Searching {} in {}", info[1], info[0]);
         final DBCollection col = this.getCollection(info[0]);
         if ( col != null ) {
             final DBObject obj = col.findOne(QueryBuilder.start(PROP_PATH).is(info[1]).get());
             logger.debug("Found {}", obj);
             if ( obj != null ) {
                 return new MongoDBResource(resourceResolver,
                                 path,
                                 info[0],
                                 obj,
                                 this);
             }
         }

         return null;
     }

     /**
      * Check if there is a newer db object for that path.
      */
     public DBObject getUpdatedDBObject(final String path, final DBObject dbObj) {
         final MongoDBResource stored = this.changedResources.get(path);
         if ( stored != null ) {
             return stored.getProperties();
         }
         return dbObj;
     }
 }
	/*
	* 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.sling.mongodb.impl;

	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.Iterator;
	import java.util.Map;
	import java.util.Set;
	import java.util.regex.Pattern;

	import javax.servlet.http.HttpServletRequest;

	import org.apache.sling.api.resource.ModifyingResourceProvider;
	import org.apache.sling.api.resource.PersistenceException;
	import org.apache.sling.api.resource.Resource;
	import org.apache.sling.api.resource.ResourceProvider;
	import org.apache.sling.api.resource.ResourceResolver;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	import com.mongodb.BasicDBObject;
	import com.mongodb.BasicDBObjectBuilder;
	import com.mongodb.DBCollection;
	import com.mongodb.DBCursor;
	import com.mongodb.DBObject;
	import com.mongodb.QueryBuilder;

	/**
	* The MongoDB resource provider creates resources based on MongoDB entries.
	* The resources contain all properties stored in the MongoDB except those starting with a "_".
	*/
	public class MongoDBResourceProvider implements ResourceProvider, ModifyingResourceProvider {

	/** The special path property containing the (relative) path of the resource in the tree. */
	public static final String PROP_PATH = "_path";

	/** The id property. */
	public static final String PROP_ID = "_id";

	/** Logger. */
	private final Logger logger = LoggerFactory.getLogger(this.getClass());

	/** The global context .*/
	private final MongoDBContext context;

	private final Map<String, MongoDBResource> changedResources = new HashMap<String, MongoDBResource>();

	private final Set<String> deletedResources = new HashSet<String>();

	public MongoDBResourceProvider(final MongoDBContext context) {
	this.context = context;
	}

	public static String propNameToKey(final String name) {
	if ( name.startsWith("_") ) {
	return "_" + name;
	}
	return name;
	}

	public static String keyToPropName(final String key) {
	if ( key.startsWith("__") ) {
	return key.substring(1);
	} else if ( key.startsWith("_") ) {
	return null;
	}
	return key;
	}

	/**
	* @see org.apache.sling.api.resource.ModifyingResourceProvider#create(org.apache.sling.api.resource.ResourceResolver, java.lang.String, java.util.Map)
	*/
	public Resource create(final ResourceResolver resolver, final String path, final Map<String, Object> properties)
	throws PersistenceException {
	final String[] info = this.extractResourceInfo(path);
	if ( info != null && info.length == 2) {
	final boolean deleted = this.deletedResources.remove(path);
	final MongoDBResource oldResource = (MongoDBResource)this.getResource(resolver, path, info);
	if ( !deleted && oldResource != null ) {
	throw new PersistenceException("Resource already exists at " + path, null, path, null);
	}
	final DBObject dbObj = new BasicDBObject();
	dbObj.put(PROP_PATH, info[1]);
	if ( properties != null ) {
	for(Map.Entry<String, Object> entry : properties.entrySet()) {
	final String key = propNameToKey(entry.getKey());
	dbObj.put(key, entry.getValue());
	}
	}
	if ( deleted && oldResource != null ) {
	dbObj.put(PROP_ID, oldResource.getProperties().get(PROP_ID));
	}
	final MongoDBResource rsrc = new MongoDBResource(resolver, path, info[0], dbObj, this);
	this.changedResources.put(path, rsrc);

	return rsrc;
	}
	throw new PersistenceException("Illegal path - unable to create resource at " + path, null, path, null);
	}

	/**
	* @see org.apache.sling.api.resource.ModifyingResourceProvider#delete(org.apache.sling.api.resource.ResourceResolver, java.lang.String)
	*/
	public void delete(final ResourceResolver resolver, final String path)
	throws PersistenceException {
	final String[] info = this.extractResourceInfo(path);
	if ( info != null ) {
	boolean deletedResource = false;
	if ( !deletedResources.contains(path) ) {
	final Resource rsrc = this.getResource(resolver, path, info);
	if ( rsrc instanceof MongoDBResource ) {
	this.deletedResources.add(path);
	this.changedResources.remove(path);

	final DBCollection col = this.getCollection(info[0]);
	final String pattern = "^" + Pattern.quote(info[1]) + "/";

	final DBObject query = QueryBuilder.start(PROP_PATH).regex(Pattern.compile(pattern)).get();
	final DBCursor cur = col.find(query);
	while ( cur.hasNext() ) {
	final DBObject dbObj = cur.next();
	final String childPath = info[0] + '/' + dbObj.get(PROP_PATH);
	this.deletedResources.add(childPath);
	this.changedResources.remove(childPath);
	}
	deletedResource = true;
	}
	} else {
	deletedResource = true;
	}
	if ( deletedResource ) {
	final String prefix = path + "/";
	final Iterator<Map.Entry<String, MongoDBResource>> i = this.changedResources.entrySet().iterator();
	while ( i.hasNext() ) {
	final Map.Entry<String, MongoDBResource> entry = i.next();
	if ( entry.getKey().startsWith(prefix) ) {
	i.remove();
	}
	}
	return;
	}

	}
	throw new PersistenceException("Unable to delete resource at {}" + path, null, path, null);
	}

	/**
	* @see org.apache.sling.api.resource.ModifyingResourceProvider#revert()
	*/
	public void revert() {
	this.changedResources.clear();
	this.deletedResources.clear();
	}

	/**
	* @see org.apache.sling.api.resource.ModifyingResourceProvider#commit()
	*/
	public void commit() throws PersistenceException {
	try {
	for(final String deleted : this.deletedResources) {
	final String[] info = this.extractResourceInfo(deleted);

	// check if the collection still exists
	final DBCollection col = this.getCollection(info[0]);
	if ( col != null ) {
	col.findAndRemove(QueryBuilder.start(PROP_PATH).is(info[1]).get());
	}
	}
	for(final MongoDBResource changed : this.changedResources.values()) {

	final DBCollection col = this.context.getDatabase().getCollection(changed.getCollection());
	if ( col != null ) {
	// create or update?
	if ( changed.getProperties().get(PROP_ID) != null ) {
	col.update(QueryBuilder.start(PROP_PATH).is(changed.getProperties().get(PROP_PATH)).get(),
	changed.getProperties());
	} else {
	// create
	col.save(changed.getProperties());
	}
	} else {
	throw new PersistenceException("Unable to create collection " + changed.getCollection(), null, changed.getPath(), null);
	}
	}
	} finally {
	this.revert();
	}
	}

	/**
	* @see org.apache.sling.api.resource.ModifyingResourceProvider#hasChanges()
	*/
	public boolean hasChanges() {
	return this.changedResources.size() > 0 \|\| this.deletedResources.size() > 0;
	}

	/**
	* @see org.apache.sling.api.resource.ResourceProvider#getResource(org.apache.sling.api.resource.ResourceResolver, java.lang.String)
	*/
	public Resource getResource(final ResourceResolver resourceResolver, final String path) {
	if ( this.deletedResources.contains(path) ) {
	return null;
	}
	if ( this.changedResources.containsKey(path) ) {
	return this.changedResources.get(path);
	}
	final String[] info = this.extractResourceInfo(path);
	if ( info != null ) {
	return this.getResource(resourceResolver, path, info);
	}
	return null;
	}

	/**
	* Inform about changes of a resource.
	*/
	public void changed(final MongoDBResource resource) {
	this.deletedResources.remove(resource.getPath());
	this.changedResources.put(resource.getPath(), resource);
	}

	/**
	* @see org.apache.sling.api.resource.ResourceProvider#listChildren(org.apache.sling.api.resource.Resource)
	*/
	public Iterator<Resource> listChildren(final Resource parent) {
	final String[] info = this.extractResourceInfo(parent.getPath());
	if ( info != null ) {
	if ( info.length == 0 ) {
	// all collections
	final Set<String> names = new HashSet<String>(context.getDatabase().getCollectionNames());
	names.removeAll(this.context.getFilterCollectionNames());
	final Iterator<String> i = names.iterator();
	return new Iterator<Resource>() {

	public boolean hasNext() {
	return i.hasNext();
	}

	public Resource next() {
	final String name = i.next();
	return new MongoDBCollectionResource(parent.getResourceResolver(), parent.getPath() + '/' + name);
	}

	public void remove() {
	throw new UnsupportedOperationException("remove");
	}

	};
	}
	final DBCollection col = this.getCollection(info[0]);
	if ( col != null ) {
	final String pattern;
	if ( info.length == 1 ) {
	pattern = "^([^/])*$";
	} else {
	pattern = "^" + Pattern.quote(info[1]) + "/([^/])*$";
	}

	final DBObject query = QueryBuilder.start(PROP_PATH).regex(Pattern.compile(pattern)).get();
	final DBCursor cur = col.find(query).
	sort(BasicDBObjectBuilder.start(PROP_PATH, 1).get());
	return new Iterator<Resource>() {

	public boolean hasNext() {
	return cur.hasNext();
	}

	public Resource next() {
	final DBObject obj = cur.next();
	final String objPath = obj.get(PROP_PATH).toString();
	final int lastSlash = objPath.lastIndexOf('/');
	final String name;
	if (lastSlash == -1) {
	name = objPath;
	} else {
	name = objPath.substring(lastSlash + 1);
	}
	return new MongoDBResource(parent.getResourceResolver(),
	parent.getPath() + '/' + name,
	info[0],
	obj,
	MongoDBResourceProvider.this);
	}

	public void remove() {
	throw new UnsupportedOperationException("remove");
	}

	};
	}
	}
	return null;
	}

	/**
	* @see org.apache.sling.api.resource.ResourceProvider#getResource(org.apache.sling.api.resource.ResourceResolver, javax.servlet.http.HttpServletRequest, java.lang.String)
	*/
	@SuppressWarnings("javadoc")
	public Resource getResource(final ResourceResolver resourceResolver,
	final HttpServletRequest request,
	final String path) {
	return this.getResource(resourceResolver, path);
	}

	/**
	* Extract info about collection and path
	*/
	private String[] extractResourceInfo(final String path) {
	for(final String root : this.context.getRootsWithSlash()) {
	if ( path.startsWith(root) ) {
	if ( path.length() == root.length() ) {
	// special resource - show all collections
	return new String[0];
	}
	final String info = path.substring(root.length());
	final int slashPos = info.indexOf('/');
	if ( slashPos != -1 ) {
	return new String[] {info.substring(0, slashPos), info.substring(slashPos + 1)};
	}
	// special resource - collection
	return new String[] {info};
	}
	}
	for(final String root : this.context.getRoots()) {
	if ( path.equals(root) ) {
	// special resource - show all collections
	return new String[0];
	}
	}
	return null;
	}

	/**
	* Check if a collection with a given name exists
	*/
	private boolean hasCollection(final String name) {
	final Set<String> names = this.context.getDatabase().getCollectionNames();
	return names.contains(name) && !this.context.isFilterCollectionName(name);
	}

	/**
	* Check if a collection with a given name exists and return it
	*/
	private DBCollection getCollection(final String name) {
	if ( this.hasCollection(name) ) {
	return this.context.getDatabase().getCollection(name);
	}
	return null;
	}

	/**
	* Get a resource
	*/
	private Resource getResource(final ResourceResolver resourceResolver, final String path, final String[] info) {
	if ( info.length == 0 ) {
	// special resource : all collections
	return new MongoDBCollectionResource(resourceResolver, path);
	} else if ( info.length == 1 ) {
	// special resource : collection
	if ( this.hasCollection(info[0]) ) {
	return new MongoDBCollectionResource(resourceResolver, path);
	}
	return null;
	}
	logger.debug("Searching {} in {}", info[1], info[0]);
	final DBCollection col = this.getCollection(info[0]);
	if ( col != null ) {
	final DBObject obj = col.findOne(QueryBuilder.start(PROP_PATH).is(info[1]).get());
	logger.debug("Found {}", obj);
	if ( obj != null ) {
	return new MongoDBResource(resourceResolver,
	path,
	info[0],
	obj,
	this);
	}
	}

	return null;
	}

	/**
	* Check if there is a newer db object for that path.
	*/
	public DBObject getUpdatedDBObject(final String path, final DBObject dbObj) {
	final MongoDBResource stored = this.changedResources.get(path);
	if ( stored != null ) {
	return stored.getProperties();
	}
	return dbObj;
	}
	}