Add SpEL expression parsing for database names (#103)

Author: mpv1989

ChangeLog.md

@@ -18,6 +18,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) a
 - added convenience method `ArangoOperations#query(String, Map<String, Object>, Class)`
 - added support for non-String `@Id`s (issue #79)
 - added convenience method `AbstractArangoConfiguration#customConverters()` to add custom converters
+- added SpEL expression parsing for database names
+
+  SpEL expressions can now be used within `AbstractArangoConfiguration#database()`. This allows Multi-tenancy on database level.
 
 ### Changed
 

src/main/java/com/arangodb/springframework/core/template/ArangoTemplate.java

@@ -33,10 +33,19 @@
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
+import org.springframework.beans.BeansException;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
+import org.springframework.context.expression.BeanFactoryAccessor;
+import org.springframework.context.expression.BeanFactoryResolver;
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.data.domain.Persistable;
 import org.springframework.data.mapping.PersistentPropertyAccessor;
+import org.springframework.expression.Expression;
+import org.springframework.expression.ParserContext;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
+import org.springframework.expression.spel.support.StandardEvaluationContext;
 
 import com.arangodb.ArangoCollection;
 import com.arangodb.ArangoCursor;
@@ -81,15 +90,20 @@
  * @author Christian Lechner
  * @author Reşat SABIQ
  */
-public class ArangoTemplate implements ArangoOperations, CollectionCallback {
+public class ArangoTemplate implements ArangoOperations, CollectionCallback, ApplicationContextAware {
+
+	private static final SpelExpressionParser PARSER = new SpelExpressionParser();
 
 	private volatile ArangoDBVersion version;
 	private final PersistenceExceptionTranslator exceptionTranslator;
 	private final ArangoConverter converter;
 	private final ArangoDB arango;
-	private volatile ArangoDatabase database;
 	private final String databaseName;
-	private final Map<String, ArangoCollection> collectionCache;
+	private final Expression databaseExpression;
+	private final Map<String, ArangoDatabase> databaseCache;
+	private final Map<CollectionCacheKey, CollectionCacheValue> collectionCache;
+
+	private final StandardEvaluationContext context;
 
 	public ArangoTemplate(final ArangoDB arango, final String database) {
 		this(arango, database, null);
@@ -105,32 +119,26 @@ public ArangoTemplate(final ArangoDB arango, final String database, final Arango
 		this.arango = arango._setCursorInitializer(
 			new com.arangodb.springframework.core.template.ArangoCursorInitializer(converter));
 		this.databaseName = database;
+		this.databaseExpression = PARSER.parseExpression(databaseName, ParserContext.TEMPLATE_EXPRESSION);
 		this.converter = converter;
 		this.exceptionTranslator = exceptionTranslator;
+		this.context = new StandardEvaluationContext();
 		// set concurrency level to 1 as writes are very rare compared to reads
 		collectionCache = new ConcurrentHashMap<>(8, 0.9f, 1);
+		databaseCache = new ConcurrentHashMap<>(8, 0.9f, 1);
 		version = null;
 	}
 
 	private ArangoDatabase db() {
-		// guard against NPE because database can be set to null by dropDatabase() by another thread
-		ArangoDatabase db = database;
-		if (db != null) {
-			return db;
-		}
-		// make sure the database is only created once
-		synchronized (this) {
-			db = database;
-			if (db != null) {
-				return db;
-			}
-			db = arango.db(databaseName);
+		final String key = databaseExpression != null ? databaseExpression.getValue(context, String.class)
+				: databaseName;
+		return databaseCache.computeIfAbsent(key, name -> {
+			final ArangoDatabase db = arango.db(name);
 			if (!db.exists()) {
 				db.create();
 			}
-			database = db;
 			return db;
-		}
+		});
 	}
 
 	private DataAccessException translateExceptionIfPossible(final RuntimeException exception) {
@@ -157,16 +165,23 @@ private ArangoCollection _collection(
 		final ArangoPersistentEntity<?> persistentEntity,
 		final CollectionCreateOptions options) {
 
-		return collectionCache.computeIfAbsent(name, collName -> {
-			final ArangoCollection collection = db().collection(collName);
-			if (!collection.exists()) {
-				collection.create(options);
-			}
-			if (persistentEntity != null) {
-				ensureCollectionIndexes(collection(collection), persistentEntity);
-			}
-			return collection;
-		});
+		final ArangoDatabase db = db();
+		final Class<?> entityClass = persistentEntity != null ? persistentEntity.getType() : null;
+		final CollectionCacheValue value = collectionCache.computeIfAbsent(new CollectionCacheKey(db.name(), name),
+			key -> {
+				final ArangoCollection collection = db.collection(name);
+				if (!collection.exists()) {
+					collection.create(options);
+				}
+				return new CollectionCacheValue(collection);
+			});
+		final Collection<Class<?>> entities = value.getEntities();
+		final ArangoCollection collection = value.getCollection();
+		if (persistentEntity != null && !entities.contains(entityClass)) {
+			value.addEntityClass(entityClass);
+			ensureCollectionIndexes(collection(collection), persistentEntity);
+		}
+		return collection;
 	}
 
 	private static void ensureCollectionIndexes(
@@ -656,18 +671,15 @@ public boolean exists(final Object id, final Class<?> entityClass) throws DataAc
 
 	@Override
 	public void dropDatabase() throws DataAccessException {
-		// guard against NPE because another thread could also call dropDatabase()
-		ArangoDatabase db = database;
-		if (db == null) {
-			db = arango.db(databaseName);
-		}
+		final ArangoDatabase db = db();
 		try {
 			db.drop();
 		} catch (final ArangoDBException e) {
 			throw translateExceptionIfPossible(e);
 		}
-		database = null;
-		collectionCache.clear();
+		databaseCache.remove(db.name());
+		collectionCache.keySet().stream().filter(key -> key.getDb().equals(db.name()))
+				.forEach(key -> collectionCache.remove(key));
 	}
 
 	@Override
@@ -709,4 +721,11 @@ public ArangoConverter getConverter() {
 		return this.converter;
 	}
 
+	@Override
+	public void setApplicationContext(final ApplicationContext applicationContext) throws BeansException {
+		context.setRootObject(applicationContext);
+		context.setBeanResolver(new BeanFactoryResolver(applicationContext));
+		context.addPropertyAccessor(new BeanFactoryAccessor());
+	}
+
 }

src/main/java/com/arangodb/springframework/core/template/CollectionCacheKey.java

@@ -0,0 +1,60 @@
+package com.arangodb.springframework.core.template;
+
+class CollectionCacheKey {
+
+	private final String db;
+	private final String collection;
+
+	public CollectionCacheKey(final String db, final String collection) {
+		super();
+		this.db = db;
+		this.collection = collection;
+	}
+
+	public String getDb() {
+		return db;
+	}
+
+	public String getCollection() {
+		return collection;
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + ((collection == null) ? 0 : collection.hashCode());
+		result = prime * result + ((db == null) ? 0 : db.hashCode());
+		return result;
+	}
+
+	@Override
+	public boolean equals(final Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj == null) {
+			return false;
+		}
+		if (getClass() != obj.getClass()) {
+			return false;
+		}
+		final CollectionCacheKey other = (CollectionCacheKey) obj;
+		if (collection == null) {
+			if (other.collection != null) {
+				return false;
+			}
+		} else if (!collection.equals(other.collection)) {
+			return false;
+		}
+		if (db == null) {
+			if (other.db != null) {
+				return false;
+			}
+		} else if (!db.equals(other.db)) {
+			return false;
+		}
+		return true;
+	}
+
+}

src/main/java/com/arangodb/springframework/core/template/CollectionCacheValue.java

@@ -0,0 +1,31 @@
+package com.arangodb.springframework.core.template;
+
+import java.util.ArrayList;
+import java.util.Collection;
+
+import com.arangodb.ArangoCollection;
+
+class CollectionCacheValue {
+
+	private final ArangoCollection collection;
+	private final Collection<Class<?>> entities;
+
+	public CollectionCacheValue(final ArangoCollection collection) {
+		super();
+		this.collection = collection;
+		this.entities = new ArrayList<>();
+	}
+
+	public ArangoCollection getCollection() {
+		return collection;
+	}
+
+	public Collection<Class<?>> getEntities() {
+		return entities;
+	}
+
+	public void addEntityClass(final Class<?> entityClass) {
+		entities.add(entityClass);
+	}
+
+}

src/main/java/com/arangodb/springframework/core/template/DefaultCollectionOperations.java

@@ -45,11 +45,12 @@
 public class DefaultCollectionOperations implements CollectionOperations {
 
 	private final ArangoCollection collection;
-	private final Map<String, ArangoCollection> collectionCache;
+	private final Map<CollectionCacheKey, CollectionCacheValue> collectionCache;
 	private final PersistenceExceptionTranslator exceptionTranslator;
 
 	protected DefaultCollectionOperations(final ArangoCollection collection,
-		final Map<String, ArangoCollection> collectionCache, final PersistenceExceptionTranslator exceptionTranslator) {
+		final Map<CollectionCacheKey, CollectionCacheValue> collectionCache,
+		final PersistenceExceptionTranslator exceptionTranslator) {
 		this.collection = collection;
 		this.collectionCache = collectionCache;
 		this.exceptionTranslator = exceptionTranslator;
@@ -66,7 +67,7 @@ public String name() {
 
 	@Override
 	public void drop() throws DataAccessException {
-		collectionCache.remove(collection.name());
+		collectionCache.remove(new CollectionCacheKey(collection.db().name(), collection.name()));
 		try {
 			collection.drop();
 		} catch (final ArangoDBException e) {

src/test/java/com/arangodb/springframework/ArangoMultiTenancyTestConfiguration.java

@@ -0,0 +1,65 @@
+/*
+ * DISCLAIMER
+ *
+ * Copyright 2017 ArangoDB GmbH, Cologne, Germany
+ *
+ * Licensed 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.
+ *
+ * Copyright holder is ArangoDB GmbH, Cologne, Germany
+ */
+
+package com.arangodb.springframework;
+
+import java.util.ArrayList;
+import java.util.Collection;
+
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.convert.converter.Converter;
+
+import com.arangodb.ArangoDB;
+import com.arangodb.springframework.config.AbstractArangoConfiguration;
+import com.arangodb.springframework.core.mapping.CustomMappingTest;
+
+/**
+ * 
+ * @author Mark Vollmary
+ * @author Christian Lechner
+ */
+@Configuration
+@ComponentScan("com.arangodb.springframework.component")
+public class ArangoMultiTenancyTestConfiguration extends AbstractArangoConfiguration {
+
+	public static final String DB = "spring-test-db";
+
+	@Override
+	public ArangoDB.Builder arango() {
+		return new ArangoDB.Builder();
+	}
+
+	@Override
+	public String database() {
+		return DB + "#{tenantProvider.getId()}";
+	}
+
+	@Override
+	protected Collection<Converter<?, ?>> customConverters() {
+		final Collection<Converter<?, ?>> converters = new ArrayList<>();
+		converters.add(new CustomMappingTest.CustomVPackReadTestConverter());
+		converters.add(new CustomMappingTest.CustomVPackWriteTestConverter());
+		converters.add(new CustomMappingTest.CustomDBEntityReadTestConverter());
+		converters.add(new CustomMappingTest.CustomDBEntityWriteTestConverter());
+		return converters;
+	}
+
+}

src/test/java/com/arangodb/springframework/core/mapping/MultiTenancyMappingTest.java renamed to src/test/java/com/arangodb/springframework/core/mapping/MultiTenancyCollectionLevelMappingTest.java

@@ -35,7 +35,7 @@
  * @author Mark Vollmary
  *
  */
-public class MultiTenancyMappingTest extends AbstractArangoTest {
+public class MultiTenancyCollectionLevelMappingTest extends AbstractArangoTest {
 
 	@Document("#{tenantProvider.getId()}_collection")
 	static class MultiTenancyTestEntity {