Support Tomcat's high-performance connection pool

In the process, refactored code towards allowing user-contributable
pool implementation.

spring-service-connector/pom.xml

@@ -84,6 +84,12 @@
 			<version>${tomcat.version}</version>
 			<scope>provided</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.apache.tomcat</groupId>
+			<artifactId>tomcat-dbcp</artifactId>
+			<version>${tomcat.version}</version>
+			<scope>provided</scope>
+		</dependency>
 
 	    <dependency>
 	        <groupId>commons-dbcp</groupId>

spring-service-connector/src/main/java/org/springframework/cloud/service/relational/BasicDbcpPooledDataSourceCreator.java

@@ -0,0 +1,31 @@
+package org.springframework.cloud.service.relational;
+
+import static org.springframework.cloud.service.Util.hasClass;
+
+import javax.sql.DataSource;
+
+import org.springframework.cloud.service.ServiceConnectorConfig;
+import org.springframework.cloud.service.common.RelationalServiceInfo;
+
+/**
+ * 
+ * @author Ramnivas Laddad
+ *
+ * @param <SI>
+ */
+public class BasicDbcpPooledDataSourceCreator<SI extends RelationalServiceInfo> extends DbcpLikePooledDataSourceCreator<SI> {
+
+	@Override
+	public DataSource create(RelationalServiceInfo serviceInfo, ServiceConnectorConfig serviceConnectorConfig,
+			                 String driverClassName, String validationQuery) {
+		if (hasClass("org.apache.commons.dbcp.BasicDataSource")) {
+			logger.info("Found DBCP on the classpath. Using it for DataSource connection pooling.");
+			org.apache.commons.dbcp.BasicDataSource ds = new org.apache.commons.dbcp.BasicDataSource();
+			setBasicDataSourceProperties(ds, serviceInfo, serviceConnectorConfig, driverClassName, validationQuery);
+			return ds;
+		} else {
+			return null;
+		}
+	}
+
+}

spring-service-connector/src/main/java/org/springframework/cloud/service/relational/DataSourceCreator.java

@@ -1,15 +1,12 @@
 package org.springframework.cloud.service.relational;
 
-import static org.springframework.cloud.service.Util.hasClass;
-
 import java.sql.DriverManager;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.logging.Logger;
 
 import javax.sql.DataSource;
 
-import org.springframework.beans.BeanWrapper;
-import org.springframework.beans.BeanWrapperImpl;
-import org.springframework.cloud.Cloud;
 import org.springframework.cloud.service.AbstractServiceConnectorCreator;
 import org.springframework.cloud.service.ServiceConnectorConfig;
 import org.springframework.cloud.service.ServiceConnectorCreationException;
@@ -24,52 +21,41 @@ import org.springframework.jdbc.datasource.SimpleDriverDataSource;
  */
 public abstract class DataSourceCreator<SI extends RelationalServiceInfo> extends AbstractServiceConnectorCreator<DataSource, SI> {
 
-	private static Logger logger = Logger.getLogger(DataSourceCreator.class.getName());
-	
-	private DataSourceConfigurer configurer = new DataSourceConfigurer();
+	protected static Logger logger = Logger.getLogger(DataSourceCreator.class.getName());
 	
 	public abstract String getDriverClassName();
 
 	public abstract String getValidationQuery();
 
+	private List<PooledDataSourceCreator<SI>> pooledDataSourceCreators = new ArrayList<PooledDataSourceCreator<SI>>();
+	
+	public DataSourceCreator() {
+		if (pooledDataSourceCreators.size() == 0) {
+			pooledDataSourceCreators.add(new BasicDbcpPooledDataSourceCreator<SI>());
+			pooledDataSourceCreators.add(new TomcatDbcpPooledDataSourceCreator<SI>());
+			pooledDataSourceCreators.add(new TomcatHighPerformancePooledDataSourceCreator<SI>());
+		}
+	}
+	
 	@Override
 	public DataSource create(SI serviceInfo, ServiceConnectorConfig serviceConnectorConfig) {
 		try {
 			Class.forName(getDriverClassName());
-			// Give first preference to user's DBCP datasource
-			if (hasClass("org.apache.commons.dbcp.BasicDataSource")) {
-				logger.info("Found DBCP on the classpath. Using it for DataSource connection pooling.");
-				org.apache.commons.dbcp.BasicDataSource ds = new org.apache.commons.dbcp.BasicDataSource();
-				setBasicDataSourceProperties(ds, serviceInfo, serviceConnectorConfig);
-				return ds;
-				// else, we have one from Tomcat
-			} else if (hasClass("org.apache.tomcat.jdbc.pool.DataSource")) {
-				logger.info("Found Tomcat connection pool on the classpath. Using it for DataSource connection pooling.");
-				org.apache.tomcat.jdbc.pool.DataSource ds = new org.apache.tomcat.jdbc.pool.DataSource();
-				setBasicDataSourceProperties(ds, serviceInfo, serviceConnectorConfig);
-				return ds;
-			} else {
-				// Only for testing outside Tomcat/CloudFoundry
-				logger.warning("Found neither DBCP nor Tomcat connection pool on the classpath (no pooling in effect)");
-				return new SimpleDriverDataSource(DriverManager.getDriver(serviceInfo.getJdbcUrl()),
-						serviceInfo.getJdbcUrl());
+			
+			for (PooledDataSourceCreator<SI> delegate: pooledDataSourceCreators) {
+				DataSource ds = delegate.create(serviceInfo, serviceConnectorConfig, getDriverClassName(), getValidationQuery());
+				
+				if (ds != null) {
+					return ds;
+				}
 			}
+			// Only for testing outside Tomcat/CloudFoundry
+			logger.warning("Found neither DBCP nor Tomcat connection pool on the classpath (no pooling is in effect).");
+			return new SimpleDriverDataSource(DriverManager.getDriver(serviceInfo.getJdbcUrl()), serviceInfo.getJdbcUrl());
 		} catch (Exception e) {
 			throw new ServiceConnectorCreationException(
 					"Failed to created cloud datasource for "
 							+ serviceInfo.getId() + " service", e);
 		}
 	}
-
-	private void setBasicDataSourceProperties(DataSource basicDataSource, RelationalServiceInfo serviceInfo,
-											  ServiceConnectorConfig serviceConnectorConfig) {
-		BeanWrapper target = new BeanWrapperImpl(basicDataSource);
-		target.setPropertyValue("driverClassName", getDriverClassName());
-		target.setPropertyValue("url", serviceInfo.getJdbcUrl());
-		if (getValidationQuery() != null) {
-			target.setPropertyValue("validationQuery", getValidationQuery());
-			target.setPropertyValue("testOnBorrow", true);
-		}
-		configurer.configure(basicDataSource, (DataSourceConfig)serviceConnectorConfig);
-	}
 }

spring-service-connector/src/main/java/org/springframework/cloud/service/relational/DbcpLikePooledDataSourceCreator.java

@@ -0,0 +1,38 @@
+package org.springframework.cloud.service.relational;
+
+import java.util.logging.Logger;
+
+import javax.sql.DataSource;
+
+import org.springframework.beans.BeanWrapper;
+import org.springframework.beans.BeanWrapperImpl;
+import org.springframework.cloud.service.ServiceConnectorConfig;
+import org.springframework.cloud.service.common.RelationalServiceInfo;
+
+/**
+ * Common implementation that assumes DBCP connection pool properties.
+ * 
+ * @author Ramnivas Laddad
+ *
+ * @param <SI>
+ */
+public abstract class DbcpLikePooledDataSourceCreator<SI extends RelationalServiceInfo> implements PooledDataSourceCreator<SI> {
+	
+	protected static Logger logger = Logger.getLogger(PooledDataSourceCreator.class.getName());
+
+	private DataSourceConfigurer configurer = new DataSourceConfigurer();
+
+	protected void setBasicDataSourceProperties(DataSource basicDataSource, RelationalServiceInfo serviceInfo,
+											   ServiceConnectorConfig serviceConnectorConfig,
+  											   String driverClassName, String validationQuery) {
+		BeanWrapper target = new BeanWrapperImpl(basicDataSource);
+		target.setPropertyValue("driverClassName", driverClassName);
+		target.setPropertyValue("url", serviceInfo.getJdbcUrl());
+		if (validationQuery != null) {
+			target.setPropertyValue("validationQuery", validationQuery);
+			target.setPropertyValue("testOnBorrow", true);
+		}
+		configurer.configure(basicDataSource, (DataSourceConfig)serviceConnectorConfig);
+	}
+
+}

spring-service-connector/src/main/java/org/springframework/cloud/service/relational/PooledDataSourceCreator.java

@@ -0,0 +1,19 @@
+package org.springframework.cloud.service.relational;
+
+import javax.sql.DataSource;
+
+import org.springframework.cloud.service.ServiceConnectorConfig;
+import org.springframework.cloud.service.common.RelationalServiceInfo;
+
+/**
+ * DataSource creator that produces a pooled connection
+ * 
+ * @author Ramnivas Laddad
+ *
+ * @param <SI>
+ */
+public interface PooledDataSourceCreator<SI extends RelationalServiceInfo> {
+	public abstract DataSource create(RelationalServiceInfo serviceInfo, ServiceConnectorConfig serviceConnectorConfig,
+			                          String driverClassName, String validationQuery);
+}
+

spring-service-connector/src/main/java/org/springframework/cloud/service/relational/TomcatDbcpPooledDataSourceCreator.java

@@ -0,0 +1,31 @@
+package org.springframework.cloud.service.relational;
+
+import static org.springframework.cloud.service.Util.hasClass;
+
+import javax.sql.DataSource;
+
+import org.springframework.cloud.service.ServiceConnectorConfig;
+import org.springframework.cloud.service.common.RelationalServiceInfo;
+
+/**
+ * 
+ * @author Ramnivas Laddad
+ *
+ * @param <SI>
+ */
+public class TomcatDbcpPooledDataSourceCreator<SI extends RelationalServiceInfo> extends DbcpLikePooledDataSourceCreator<SI> {
+
+	@Override
+	public DataSource create(RelationalServiceInfo serviceInfo, ServiceConnectorConfig serviceConnectorConfig,
+                             String driverClassName, String validationQuery) {
+		if (hasClass("org.apache.tomcat.dbcp.dbcp.BasicDataSource")) {
+			logger.info("Found Tomcat dbcp connection pool on the classpath. Using it for DataSource connection pooling.");
+			org.apache.tomcat.dbcp.dbcp.BasicDataSource ds = new org.apache.tomcat.dbcp.dbcp.BasicDataSource();
+			setBasicDataSourceProperties(ds, serviceInfo, serviceConnectorConfig, driverClassName, validationQuery);
+			return ds;
+		} else {
+			return null;
+		}
+	}
+
+}

spring-service-connector/src/main/java/org/springframework/cloud/service/relational/TomcatHighPerformancePooledDataSourceCreator.java

@@ -0,0 +1,32 @@
+package org.springframework.cloud.service.relational;
+
+import static org.springframework.cloud.service.Util.hasClass;
+
+import javax.sql.DataSource;
+
+import org.springframework.cloud.service.ServiceConnectorConfig;
+import org.springframework.cloud.service.common.RelationalServiceInfo;
+
+/**
+ * 
+ * @author Ramnivas Laddad
+ *
+ * @param <SI>
+ */
+public class TomcatHighPerformancePooledDataSourceCreator<SI extends RelationalServiceInfo> 
+	extends DbcpLikePooledDataSourceCreator<SI> {
+
+	@Override
+	public DataSource create(RelationalServiceInfo serviceInfo, ServiceConnectorConfig serviceConnectorConfig,
+                             String driverClassName, String validationQuery) {
+		if (hasClass("org.apache.tomcat.jdbc.pool.DataSource")) {
+			logger.info("Found Tomcat connection pool on the classpath. Using it for DataSource connection pooling.");
+			org.apache.tomcat.jdbc.pool.DataSource ds = new org.apache.tomcat.jdbc.pool.DataSource();
+			setBasicDataSourceProperties(ds, serviceInfo, serviceConnectorConfig, driverClassName, validationQuery);
+			return ds;
+		} else {
+			return null;
+		}
+	}
+
+}

spring-service-connector/src/test/java/org/springframework/cloud/service/relational/PooledDataSourceCreatorsTest.java

@@ -0,0 +1,42 @@
+package org.springframework.cloud.service.relational;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.sql.DataSource;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.springframework.cloud.service.common.MysqlServiceInfo;
+
+public class PooledDataSourceCreatorsTest {
+	@Mock private MysqlServiceInfo mockMysqlServiceInfo;
+
+	// Just to grab driver class name and validation query string 
+	private MysqlDataSourceCreator mysqlDataSourceCreator = new MysqlDataSourceCreator();
+	
+	@Before
+	public void setup() {
+		MockitoAnnotations.initMocks(this);
+	}
+
+	@Test
+	public void pooledDataSourceCreation() {
+		List<PooledDataSourceCreator<MysqlServiceInfo>> pooledDataSourceCreators = new ArrayList<PooledDataSourceCreator<MysqlServiceInfo>>();
+
+		pooledDataSourceCreators.add(new BasicDbcpPooledDataSourceCreator<MysqlServiceInfo>());
+		pooledDataSourceCreators.add(new TomcatDbcpPooledDataSourceCreator<MysqlServiceInfo>());
+		pooledDataSourceCreators.add(new TomcatHighPerformancePooledDataSourceCreator<MysqlServiceInfo>());
+
+		for (PooledDataSourceCreator<MysqlServiceInfo> testCreator : pooledDataSourceCreators) {
+			DataSource ds = testCreator.create(mockMysqlServiceInfo, null, 
+					                           mysqlDataSourceCreator.getDriverClassName(), 
+					                           mysqlDataSourceCreator.getValidationQuery());
+			
+			Assert.assertNotNull(ds);
+		}
+	}
+}