Use JDBC 4 API for connection validation

With this commit use the JDBC 4.0 isValid method to
validate the connection. This is favorable over a
validation query.

spring-jdbc/src/test/java/org/springframework/jdbc/support/DatabaseStartupValidatorTests.java

@@ -0,0 +1,131 @@
+/*
+ * Copyright 2003-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.springframework.jdbc.support;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+import javax.sql.DataSource;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Mock object based test for {@code DatabaseStartupValidator}.
+ *
+ * @author Marten Deinum,
+ */
+class DatabaseStartupValidatorTests {
+
+	private Connection connection;
+	private DataSource dataSource;
+
+	@BeforeEach
+	public void setUp() throws Exception {
+		connection = mock(Connection.class);
+		dataSource = mock(DataSource.class);
+		given(dataSource.getConnection()).willReturn(connection);
+	}
+
+	@Test
+	public void properSetupForDataSource() {
+		DatabaseStartupValidator validator = new DatabaseStartupValidator();
+		assertThatThrownBy(validator::afterPropertiesSet)
+				.isInstanceOf(IllegalArgumentException.class);
+	}
+
+	@Test
+	public void shouldUseJdbc4IsValidByDefault() throws Exception {
+		given(connection.isValid(1)).willReturn(true);
+		DatabaseStartupValidator validator = new DatabaseStartupValidator();
+		validator.setDataSource(dataSource);
+		validator.afterPropertiesSet();
+
+		verify(connection, times(1)).isValid(1);
+		verify(connection, times(1)).close();
+
+	}
+
+	@Test
+	public void shouldCallValidatonTwiceWhenNotValid() throws Exception {
+		given(connection.isValid(1)).willReturn(false, true);
+		DatabaseStartupValidator validator = new DatabaseStartupValidator();
+		validator.setDataSource(dataSource);
+		validator.afterPropertiesSet();
+
+		verify(connection, times(2)).isValid(1);
+		verify(connection, times(2)).close();
+
+	}
+
+	@Test
+	public void shouldCallValidatonTwiceInCaseOfException() throws Exception {
+		given(connection.isValid(1)).willThrow(new SQLException("Test")).willReturn(true);
+		DatabaseStartupValidator validator = new DatabaseStartupValidator();
+		validator.setDataSource(dataSource);
+		validator.afterPropertiesSet();
+
+		verify(connection, times(2)).isValid(1);
+		verify(connection, times(2)).close();
+
+	}
+
+	@Test
+	public void useValidationQueryInsteadOfIsValid() throws Exception {
+		String validationQuery = "SELECT NOW() FROM DUAL";
+		Statement statement = mock(Statement.class);
+		given(connection.createStatement()).willReturn(statement);
+		given(statement.execute(validationQuery)).willReturn(true);
+
+		DatabaseStartupValidator validator = new DatabaseStartupValidator();
+		validator.setDataSource(dataSource);
+		validator.setValidationQuery(validationQuery);
+		validator.afterPropertiesSet();
+
+		verify(connection, times(1)).createStatement();
+		verify(statement, times(1)).execute(validationQuery);
+		verify(connection, times(1)).close();
+		verify(statement, times(1)).close();
+	}
+
+	@Test
+	public void shouldExecuteValidatonTwiceOnError() throws Exception {
+		String validationQuery = "SELECT NOW() FROM DUAL";
+		Statement statement = mock(Statement.class);
+		given(connection.createStatement()).willReturn(statement);
+		given(statement.execute(validationQuery))
+				.willThrow(new SQLException("Test"))
+				.willReturn(true);
+
+		DatabaseStartupValidator validator = new DatabaseStartupValidator();
+		validator.setDataSource(dataSource);
+		validator.setValidationQuery(validationQuery);
+		validator.afterPropertiesSet();
+
+		verify(connection, times(2)).createStatement();
+		verify(statement, times(2)).execute(validationQuery);
+		verify(connection, times(2)).close();
+		verify(statement, times(2)).close();
+	}
+}