Convenience constructors for CompositeDatabasePopulator

Issue: SPR-14313

spring-jdbc/src/main/java/org/springframework/jdbc/datasource/init/CompositeDatabasePopulator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -20,24 +20,53 @@ import java.sql.Connection;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 
 /**
- * {@link DatabasePopulator} implementation that delegates to a list of other
+ * Composite {@link DatabasePopulator} that delegates to a list of given
  * {@code DatabasePopulator} implementations, executing all scripts.
  *
  * @author Dave Syer
  * @author Juergen Hoeller
  * @author Sam Brannen
+ * @author Kazuki Shimizu
  * @since 3.1
  */
 public class CompositeDatabasePopulator implements DatabasePopulator {
 
-	private List<DatabasePopulator> populators = new ArrayList<DatabasePopulator>();
+	private final List<DatabasePopulator> populators = new ArrayList<DatabasePopulator>(4);
 
 
 	/**
-	 * Specify a list of populators to delegate to.
+	 * Create an empty {@code CompositeDatabasePopulator}.
+	 * @see #setPopulators
+	 * @see #addPopulators
+	 */
+	public CompositeDatabasePopulator() {
+	}
+
+	/**
+	 * Create a {@code CompositeDatabasePopulator} with the given populators.
+	 * @param populators one or more populators to delegate to
+	 * @since 4.3
+	 */
+	public CompositeDatabasePopulator(Collection<DatabasePopulator> populators) {
+		this.populators.addAll(populators);
+	}
+
+	/**
+	 * Create a {@code CompositeDatabasePopulator} with the given populators.
+	 * @param populators one or more populators to delegate to
+	 * @since 4.3
+	 */
+	public CompositeDatabasePopulator(DatabasePopulator... populators) {
+		this.populators.addAll(Arrays.asList(populators));
+	}
+
+
+	/**
+	 * Specify one or more populators to delegate to.
 	 */
 	public void setPopulators(DatabasePopulator... populators) {
 		this.populators.clear();
@@ -51,9 +80,7 @@ public class CompositeDatabasePopulator implements DatabasePopulator {
 		this.populators.addAll(Arrays.asList(populators));
 	}
 
-	/**
-	 * {@inheritDoc}
-	 */
+
 	@Override
 	public void populate(Connection connection) throws SQLException, ScriptException {
 		for (DatabasePopulator populator : this.populators) {

spring-jdbc/src/test/java/org/springframework/jdbc/datasource/init/CompositeDatabasePopulatorTests.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright 2002-2016 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
+ *
+ *      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.springframework.jdbc.datasource.init;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.util.LinkedHashSet;
+import java.util.Set;
+
+import org.junit.Test;
+
+import static org.mockito.Mockito.*;
+
+/**
+ * Unit tests for {@link CompositeDatabasePopulator}.
+ *
+ * @author Kazuki Shimizu
+ * @author Juergen Hoeller
+ * @since 4.3
+ */
+public class CompositeDatabasePopulatorTests {
+
+	private final Connection mockedConnection = mock(Connection.class);
+
+	private final DatabasePopulator mockedDatabasePopulator1 = mock(DatabasePopulator.class);
+
+	private final DatabasePopulator mockedDatabasePopulator2 = mock(DatabasePopulator.class);
+
+
+	@Test
+	public void addPopulators() throws SQLException {
+		CompositeDatabasePopulator populator = new CompositeDatabasePopulator();
+		populator.addPopulators(mockedDatabasePopulator1, mockedDatabasePopulator2);
+		populator.populate(mockedConnection);
+		verify(mockedDatabasePopulator1,times(1)).populate(mockedConnection);
+		verify(mockedDatabasePopulator2, times(1)).populate(mockedConnection);
+	}
+
+	@Test
+	public void setPopulatorsWithMultiple() throws SQLException {
+		CompositeDatabasePopulator populator = new CompositeDatabasePopulator();
+		populator.setPopulators(mockedDatabasePopulator1, mockedDatabasePopulator2);  // multiple
+		populator.populate(mockedConnection);
+		verify(mockedDatabasePopulator1, times(1)).populate(mockedConnection);
+		verify(mockedDatabasePopulator2, times(1)).populate(mockedConnection);
+	}
+
+	@Test
+	public void setPopulatorsForOverride() throws SQLException {
+		CompositeDatabasePopulator populator = new CompositeDatabasePopulator();
+		populator.setPopulators(mockedDatabasePopulator1);
+		populator.setPopulators(mockedDatabasePopulator2);  // override
+		populator.populate(mockedConnection);
+		verify(mockedDatabasePopulator1, times(0)).populate(mockedConnection);
+		verify(mockedDatabasePopulator2, times(1)).populate(mockedConnection);
+	}
+
+	@Test
+	public void constructWithVarargs() throws SQLException {
+		CompositeDatabasePopulator populator =
+				new CompositeDatabasePopulator(mockedDatabasePopulator1, mockedDatabasePopulator2);
+		populator.populate(mockedConnection);
+		verify(mockedDatabasePopulator1, times(1)).populate(mockedConnection);
+		verify(mockedDatabasePopulator2, times(1)).populate(mockedConnection);
+	}
+
+	@Test
+	public void constructWithCollection() throws SQLException {
+		Set<DatabasePopulator> populators = new LinkedHashSet<>();
+		populators.add(mockedDatabasePopulator1);
+		populators.add(mockedDatabasePopulator2);
+		CompositeDatabasePopulator populator = new CompositeDatabasePopulator(populators);
+		populator.populate(mockedConnection);
+		verify(mockedDatabasePopulator1, times(1)).populate(mockedConnection);
+		verify(mockedDatabasePopulator2, times(1)).populate(mockedConnection);
+	}
+
+}