Backported "Work around JDK7 String#substring performance regression"

Issue: SPR-9781
Issue: SPR-9784

org.springframework.jdbc/src/main/java/org/springframework/jdbc/datasource/init/ResourceDatabasePopulator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -43,13 +43,14 @@ import org.springframework.util.StringUtils;
  * @author Dave Syer
  * @author Juergen Hoeller
  * @author Chris Beams
+ * @author Oliver Gierke
  * @since 3.0
  */
 public class ResourceDatabasePopulator implements DatabasePopulator {
 
-	private static String DEFAULT_COMMENT_PREFIX = "--";
+	private static final String DEFAULT_COMMENT_PREFIX = "--";
 
-	private static String DEFAULT_STATEMENT_SEPARATOR = ";";
+	private static final String DEFAULT_STATEMENT_SEPARATOR = ";";
 
 	private static final Log logger = LogFactory.getLog(ResourceDatabasePopulator.class);
 
@@ -265,7 +266,7 @@ public class ResourceDatabasePopulator implements DatabasePopulator {
 			if (content[i] == '\'') {
 				inLiteral = !inLiteral;
 			}
-			if (!inLiteral && script.substring(i).startsWith(delim)) {
+			if (!inLiteral && startsWithDelimiter(script, i, delim)) {
 				return true;
 			}
 		}
@@ -273,8 +274,24 @@ public class ResourceDatabasePopulator implements DatabasePopulator {
 	}
 
 	/**
-	 * Split an SQL script into separate statements delimited with the provided delimiter character.
-	 * Each individual statement will be added to the provided <code>List</code>.
+	 * Return whether the substring of a given source {@link String} starting at the
+	 * given index starts with the given delimiter.
+	 * @param source the source {@link String} to inspect
+	 * @param startIndex the index to look for the delimiter
+	 * @param delim the delimiter to look for
+	 */
+	private boolean startsWithDelimiter(String source, int startIndex, String delim) {
+		int endIndex = startIndex + delim.length();
+		if (source.length() < endIndex) {
+			// String is too short to contain the delimiter
+			return false;
+		}
+		return source.substring(startIndex, endIndex).equals(delim);
+	}
+
+	/**
+	 * Split an SQL script into separate statements delimited with the provided delimiter
+	 * character. Each individual statement will be added to the provided {@code List}.
 	 * @param script the SQL script
 	 * @param delim character delimiting each statement (typically a ';' character)
 	 * @param statements the List that will contain the individual statements
@@ -301,7 +318,7 @@ public class ResourceDatabasePopulator implements DatabasePopulator {
 				inLiteral = !inLiteral;
 			}
 			if (!inLiteral) {
-				if (script.substring(i).startsWith(delim)) {
+				if (startsWithDelimiter(script, i, delim)) {
 					if (sb.length() > 0) {
 						statements.add(sb.toString());
 						sb = new StringBuilder();

org.springframework.jdbc/src/test/java/org/springframework/jdbc/datasource/init/DatabasePopulatorTests.java

@@ -41,11 +41,16 @@ import org.springframework.transaction.support.TransactionSynchronizationManager
 public class DatabasePopulatorTests {
 
 	private final EmbeddedDatabaseBuilder builder = new EmbeddedDatabaseBuilder();
+
 	private final EmbeddedDatabase db = builder.build();
+
 	private final ResourceDatabasePopulator databasePopulator = new ResourceDatabasePopulator();
+
 	private final ClassRelativeResourceLoader resourceLoader = new ClassRelativeResourceLoader(getClass());
+
 	private final JdbcTemplate jdbcTemplate = new JdbcTemplate(db);
 
+
 	private void assertTestDatabaseCreated() {
 		assertTestDatabaseCreated("Keith");
 	}
@@ -61,15 +66,14 @@ public class DatabasePopulatorTests {
 
 	@After
 	public void shutDown() {
-
 		if (TransactionSynchronizationManager.isSynchronizationActive()) {
 			TransactionSynchronizationManager.clear();
 			TransactionSynchronizationManager.unbindResource(db);
 		}
-
 		db.shutdown();
 	}
 
+
 	@Test
 	public void testBuildWithCommentsAndFailedDrop() throws Exception {
 		databasePopulator.addScript(resourceLoader.getResource("db-schema-failed-drop-comments.sql"));
@@ -78,7 +82,8 @@ public class DatabasePopulatorTests {
 		Connection connection = db.getConnection();
 		try {
 			databasePopulator.populate(connection);
-		} finally {
+		}
+		finally {
 			connection.close();
 		}
 
@@ -92,7 +97,8 @@ public class DatabasePopulatorTests {
 		Connection connection = db.getConnection();
 		try {
 			databasePopulator.populate(connection);
-		} finally {
+		}
+		finally {
 			connection.close();
 		}
 
@@ -106,7 +112,8 @@ public class DatabasePopulatorTests {
 		Connection connection = db.getConnection();
 		try {
 			databasePopulator.populate(connection);
-		} finally {
+		}
+		finally {
 			connection.close();
 		}
 
@@ -120,7 +127,8 @@ public class DatabasePopulatorTests {
 		Connection connection = db.getConnection();
 		try {
 			databasePopulator.populate(connection);
-		} finally {
+		}
+		finally {
 			connection.close();
 		}
 
@@ -136,7 +144,8 @@ public class DatabasePopulatorTests {
 		Connection connection = db.getConnection();
 		try {
 			databasePopulator.populate(connection);
-		} finally {
+		}
+		finally {
 			connection.close();
 		}
 
@@ -152,7 +161,8 @@ public class DatabasePopulatorTests {
 		Connection connection = db.getConnection();
 		try {
 			databasePopulator.populate(connection);
-		} finally {
+		}
+		finally {
 			connection.close();
 		}
 
@@ -167,7 +177,8 @@ public class DatabasePopulatorTests {
 		Connection connection = db.getConnection();
 		try {
 			databasePopulator.populate(connection);
-		} finally {
+		}
+		finally {
 			connection.close();
 		}
 
@@ -183,7 +194,8 @@ public class DatabasePopulatorTests {
 		Connection connection = db.getConnection();
 		try {
 			databasePopulator.populate(connection);
-		} finally {
+		}
+		finally {
 			connection.close();
 		}
 
@@ -198,7 +210,8 @@ public class DatabasePopulatorTests {
 		Connection connection = db.getConnection();
 		try {
 			databasePopulator.populate(connection);
-		} finally {
+		}
+		finally {
 			connection.close();
 		}
 
@@ -212,7 +225,8 @@ public class DatabasePopulatorTests {
 		Connection connection = db.getConnection();
 		try {
 			databasePopulator.populate(connection);
-		} finally {
+		}
+		finally {
 			connection.close();
 		}
 
@@ -225,7 +239,6 @@ public class DatabasePopulatorTests {
 	 */
 	@Test
 	public void usesBoundConnectionIfAvailable() throws SQLException {
-
 		TransactionSynchronizationManager.initSynchronization();
 		Connection connection = DataSourceUtils.getConnection(db);
 
@@ -238,4 +251,22 @@ public class DatabasePopulatorTests {
 
 		EasyMock.verify(populator);
 	}
+
+	/**
+	 * @see SPR-9781
+	 */
+	@Test(timeout = 1000)
+	public void executesHugeScriptInReasonableTime() throws SQLException {
+		databasePopulator.addScript(resourceLoader.getResource("db-schema.sql"));
+		databasePopulator.addScript(resourceLoader.getResource("db-test-data-huge.sql"));
+
+		Connection connection = db.getConnection();
+		try {
+			databasePopulator.populate(connection);
+		}
+		finally {
+			connection.close();
+		}
+	}
+
 }