Java tutorial
/* * 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.QueriableResourceProvider; import org.apache.sling.api.resource.Resource; import org.apache.sling.api.resource.ResourceProvider; import org.apache.sling.api.resource.ResourceResolver; import org.apache.sling.api.resource.ValueMap; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.mongodb.BasicDBObject; import com.mongodb.BasicDBObjectBuilder; import com.mongodb.CommandResult; import com.mongodb.DBCollection; import com.mongodb.DBCursor; import com.mongodb.DBObject; import com.mongodb.QueryBuilder; import com.mongodb.util.JSON; /** * 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, QueriableResourceProvider { /** The special path property containing the (relative) path of the resource in the tree. */ private static final String PROP_PATH = "_path"; /** The id property. */ private 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(getPROP_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); } /** * TODO - we should handle delete different and not put all child resources into the * deleted set. * Instead when getting resources, the parents of the resource should be checked * first. * This minimizes concurrency issues. * @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(getPROP_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(getPROP_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(ResourceResolver) */ public void revert(final ResourceResolver resolver) { this.changedResources.clear(); this.deletedResources.clear(); } /** * @see org.apache.sling.api.resource.ModifyingResourceProvider#commit(ResourceResolver) */ public void commit(final ResourceResolver resolver) 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) { if (col.findAndRemove(QueryBuilder.start(getPROP_PATH()).is(info[1]).get()) != null) { this.context.notifyRemoved(info); } } } for (final MongoDBResource changed : this.changedResources.values()) { final DBCollection col = this.context.getDatabase().getCollection(changed.getCollection()); if (col != null) { final String[] info = new String[] { changed.getCollection(), changed.getProperties().get(getPROP_PATH()).toString() }; // create or update? if (changed.getProperties().get(PROP_ID) != null) { col.update(QueryBuilder.start(getPROP_PATH()) .is(changed.getProperties().get(getPROP_PATH())).get(), changed.getProperties()); this.context.notifyUpdated(info); } else { // create col.save(changed.getProperties()); this.context.notifyUpdated(info); } } else { throw new PersistenceException("Unable to create collection " + changed.getCollection(), null, changed.getPath(), null); } } } finally { this.revert(resolver); } } /** * @see org.apache.sling.api.resource.ModifyingResourceProvider#hasChanges(ResourceResolver) */ public boolean hasChanges(final ResourceResolver resolver) { 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 new MongoDBResource(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); } /** * TODO - we have to check for deleted and added resources * @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(getPROP_PATH()).regex(Pattern.compile(pattern)).get(); final DBCursor cur = col.find(query).sort(BasicDBObjectBuilder.start(getPROP_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(getPROP_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 */ protected String[] extractResourceInfo(final String path) { if (path.startsWith(this.context.getRootWithSlash())) { if (path.length() == this.context.getRootWithSlash().length()) { // special resource - show all collections return new String[0]; } final String info = path.substring(this.context.getRootWithSlash().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 }; } if (path.equals(this.context.getRoot())) { // special resource - show all collections return new String[0]; } return null; } /** * Check if a collection with a given name exists */ protected boolean hasCollection(final String name) { logger.info("Mongo: Getting collection names"); 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 */ protected DBCollection getCollection(final String name) { if (this.hasCollection(name)) { return this.context.getDatabase().getCollection(name); } return null; } /** * Get a resource */ protected 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(getPROP_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; } protected Set<String> getDeletedResources() { return this.deletedResources; } protected Map<String, MongoDBResource> getChangedResources() { return this.changedResources; } protected MongoDBContext getContext() { return this.context; } protected String getPROP_PATH() { return PROP_PATH; } public Iterator<Resource> findResources(final ResourceResolver resolver, String query, String language) { if (!language.equals("mongodb") || query == null || query.length() == 0 || query.indexOf(".find(") <= 0) { return null; } Iterator<Resource> returnValue = null; final String collectionName = query.substring(0, query.indexOf(".find(")); DBCollection col = this.getCollection(collectionName); if (col != null) { String criteria = query.trim().substring(query.indexOf(".find(") + 6, query.length() - 1); DBObject dbObject = (DBObject) JSON.parse(criteria); final DBCursor cur = col.find(dbObject); final String rootPath = context.getRootWithSlash(); return new Iterator<Resource>() { public boolean hasNext() { return cur.hasNext(); } public Resource next() { final DBObject obj = cur.next(); final String objPath = obj.get(getPROP_PATH()).toString(); final int lastSlash = objPath.lastIndexOf('/'); final String name; if (lastSlash == -1) { name = objPath; } else { name = objPath.substring(lastSlash + 1); } return new MongoDBResource(resolver, rootPath + collectionName + "/" + name, collectionName, obj, MongoDBResourceProvider.this); } public void remove() { throw new UnsupportedOperationException("remove"); } }; } return returnValue; } public Iterator<ValueMap> queryResources(ResourceResolver resolver, String query, String language) { return null; } }