HHH-11817 Allow schema-export commands written to file to truncate in addition to current appending

documentation/src/main/asciidoc/userguide/appendices/Configurations.adoc

@@ -887,6 +887,10 @@ For cases where the `javax.persistence.schema-generation.scripts.action` value i
 `*javax.persistence.schema-generation.scripts.drop-target*`::
 For cases where the `javax.persistence.schema-generation.scripts.action` value indicates that schema dropping commands should be written to DDL script file, `javax.persistence.schema-generation.scripts.drop-target` specifies either a `java.io.Writer` configured for output of the DDL script or a string specifying the file URL for the DDL script.
 
+`*hibernate.hbm2ddl.schema-generation.script.append*` (e.g. `true` (default value) or `false`)::
+For cases where the `javax.persistence.schema-generation.scripts.action` value indicates that schema commands should be written to DDL script file, `hibernate.hbm2ddl.schema-generation.script.append` specifies if schema commands should be appended to the end of the file rather than written at the beginning of the file.
+Values are `true` for appending schema commands to the end of the file, `false` for writing achema commands at the beginning of the file.
+
 `*javax.persistence.hibernate.hbm2ddl.import_files*` (e.g. `import.sql` (default value))::
 Comma-separated names of the optional files containing SQL DML statements executed during the `SessionFactory` creation.
 File order matters, the statements of a given file are executed before the statements of the following one.

hibernate-core/src/main/java/org/hibernate/cfg/AvailableSettings.java

@@ -1588,6 +1588,16 @@ public interface AvailableSettings extends org.hibernate.jpa.AvailableSettings {
 	@SuppressWarnings("JavaDoc")
 	String HBM2DDL_SCRIPTS_CREATE_TARGET = "javax.persistence.schema-generation.scripts.create-target";
 
+	/**
+	 * For cases where the {@value #HBM2DDL_SCRIPTS_ACTION} value indicates that schema commands should
+	 * be written to DDL script file, specifies if schema commands should be appended to the end of the file rather than written at the beginning of the file.
+	 *
+	 * Values are: {@code true} for appending schema commands to the end of the file, {@code false} for writing schema commands at the beginning.
+	 *
+	 * The default value is {@code true}
+	 */
+	String HBM2DDL_SCRIPTS_CREATE_APPEND = "hibernate.hbm2ddl.schema-generation.script.append";
+
 	/**
 	 * For cases where the {@value #HBM2DDL_SCRIPTS_ACTION} value indicates that schema drop commands should
 	 * be written to DDL script file, {@value #HBM2DDL_SCRIPTS_DROP_TARGET} specifies either a

hibernate-core/src/main/java/org/hibernate/tool/hbm2ddl/SchemaExport.java

@@ -135,6 +135,7 @@ else if ( actionText.equalsIgnoreCase( "drop-and-create" ) ) {
 		}
 	}
 
+	boolean append = true;
 	boolean haltOnError = false;
 	boolean format = false;
 	boolean manageNamespaces = false;
@@ -159,6 +160,18 @@ public SchemaExport setOutputFile(String filename) {
 		return this;
 	}
 
+	/**
+	 * For generating a export script file, by default the content will be appended at the begin or end of the file.
+	 *
+	 * The sql will be written at the beginning of the file rather append to the end.
+	 *
+	 * @return this
+	 */
+	public SchemaExport setOverrideOutputFileContent() {
+		append = false;
+		return this;
+	}
+
 	/**
 	 * Comma-separated list of resource names to use for database init commands on create.
 	 *
@@ -244,7 +257,12 @@ public void execute(EnumSet<TargetType> targetTypes, Action action, Metadata met
 
 		LOG.runningHbm2ddlSchemaExport();
 
-		final TargetDescriptor targetDescriptor = buildTargetDescriptor( targetTypes, outputFile, serviceRegistry );
+		final TargetDescriptor targetDescriptor = buildTargetDescriptor(
+				targetTypes,
+				outputFile,
+				append,
+				serviceRegistry
+		);
 
 		doExecution( action, needsJdbcConnection( targetTypes ), metadata, serviceRegistry, targetDescriptor );
 	}
@@ -316,6 +334,14 @@ public static TargetDescriptor buildTargetDescriptor(
 			EnumSet<TargetType> targetTypes,
 			String outputFile,
 			ServiceRegistry serviceRegistry) {
+		return buildTargetDescriptor( targetTypes, outputFile, true, serviceRegistry );
+	}
+
+	public static TargetDescriptor buildTargetDescriptor(
+			EnumSet<TargetType> targetTypes,
+			String outputFile,
+			boolean append,
+			ServiceRegistry serviceRegistry) {
 		final ScriptTargetOutput scriptTarget;
 		if ( targetTypes.contains( TargetType.SCRIPT ) ) {
 			if ( outputFile == null ) {
@@ -324,7 +350,8 @@ public static TargetDescriptor buildTargetDescriptor(
 			scriptTarget = Helper.interpretScriptTargetSetting(
 					outputFile,
 					serviceRegistry.getService( ClassLoaderService.class ),
-					(String) serviceRegistry.getService( ConfigurationService.class ).getSettings().get( AvailableSettings.HBM2DDL_CHARSET_NAME )
+					(String) serviceRegistry.getService( ConfigurationService.class ).getSettings().get( AvailableSettings.HBM2DDL_CHARSET_NAME ),
+					append
 			);
 		}
 		else {

hibernate-core/src/main/java/org/hibernate/tool/hbm2ddl/SchemaUpdate.java

@@ -55,6 +55,7 @@ public class SchemaUpdate {
 	boolean haltOnError = false;
 
 	private String outputFile;
+	private boolean append = true;
 	private String delimiter;
 	private boolean format;
 
@@ -87,7 +88,7 @@ public void execute(EnumSet<TargetType> targetTypes, Metadata metadata, ServiceR
 				exceptionHandler
 		);
 
-		final TargetDescriptor targetDescriptor = SchemaExport.buildTargetDescriptor( targetTypes, outputFile, serviceRegistry );
+		final TargetDescriptor targetDescriptor = SchemaExport.buildTargetDescriptor( targetTypes, outputFile, append, serviceRegistry );
 
 		try {
 			tool.getSchemaMigrator( config ).doMigration( metadata, executionOptions, targetDescriptor );
@@ -123,6 +124,18 @@ public SchemaUpdate setOutputFile(String outputFile) {
 		return this;
 	}
 
+	/**
+	 * For generating a export script file, by default the content will be appended at the begin or end of the file.
+	 *
+	 * The sql will be written at the beginning of the file rather append to the end.
+	 *
+	 * @return this
+	 */
+	public SchemaUpdate setOverrideOutputFileContent() {
+		append = false;
+		return this;
+	}
+
 	/**
 	 * Set the end of statement delimiter
 	 *

hibernate-core/src/main/java/org/hibernate/tool/schema/internal/Helper.java

@@ -93,7 +93,8 @@ private static ScriptSourceInput interpretScriptSourceSetting(
 	public static ScriptTargetOutput interpretScriptTargetSetting(
 			Object scriptTargetSetting,
 			ClassLoaderService classLoaderService,
-			String charsetName ) {
+			String charsetName,
+			boolean append) {
 		if ( scriptTargetSetting == null ) {
 			return null;
 		}
@@ -118,7 +119,7 @@ else if ( Writer.class.isInstance( scriptTargetSetting ) ) {
 
 			// assume it is a File path
 			final File file = new File( scriptTargetSettingString );
-			return new ScriptTargetOutputToFile( file, charsetName );
+			return new ScriptTargetOutputToFile( file, charsetName, append );
 		}
 	}
 

hibernate-core/src/main/java/org/hibernate/tool/schema/internal/exec/ScriptTargetOutputToFile.java

@@ -28,6 +28,7 @@ public class ScriptTargetOutputToFile extends AbstractScriptTargetOutput impleme
 
 	private final File file;
 	private final String charsetName;
+	private final boolean append;
 
 	private Writer writer;
 
@@ -36,10 +37,24 @@ public class ScriptTargetOutputToFile extends AbstractScriptTargetOutput impleme
 	 *
 	 * @param file The file to read from
 	 * @param charsetName The charset name
+	 * @param append If true, then bytes will be written to the end of the file rather than the beginning
 	 */
-	public ScriptTargetOutputToFile(File file, String charsetName) {
+	public ScriptTargetOutputToFile(File file, String charsetName, boolean append) {
 		this.file = file;
 		this.charsetName = charsetName;
+		this.append = append;
+	}
+
+	/**
+	 * Constructs a ScriptTargetOutputToFile instance,
+	 * the bytes will be written to the end of the file rather than the beginning
+	 *
+	 * @param file The file to read from
+	 * @param charsetName The charset name
+	 *
+	 */
+	public ScriptTargetOutputToFile(File file, String charsetName ) {
+		this(file, charsetName, true);
 	}
 
 	@Override
@@ -53,7 +68,7 @@ protected Writer writer() {
 	@Override
 	public void prepare() {
 		super.prepare();
-		this.writer = toFileWriter( this.file, this.charsetName );
+		this.writer = toFileWriter( this.file, this.charsetName, append );
 	}
 
 	@Override
@@ -63,7 +78,7 @@ public void release() {
 				writer.close();
 			}
 			catch (IOException e) {
-				throw new SchemaManagementException( "Unable to close file writer : " + e.toString() );
+				throw new SchemaManagementException( "Unable to close file writer : " + e );
 			}
 			finally {
 				writer = null;
@@ -72,7 +87,7 @@ public void release() {
 	}
 
 	@SuppressWarnings("ResultOfMethodCallIgnored")
-	static Writer toFileWriter( File file, String charsetName ) {
+	static Writer toFileWriter(File file, String charsetName, boolean append) {
 		try {
 			if ( ! file.exists() ) {
 				// best effort, since this is very likely not allowed in EE environments
@@ -84,17 +99,17 @@ static Writer toFileWriter( File file, String charsetName ) {
 			}
 		}
 		catch (Exception e) {
-			log.debug( "Exception calling File#createNewFile : " + e.toString() );
+			log.debug( "Exception calling File#createNewFile : " + e );
 		}
 		try {
 			return charsetName != null ?
 					new OutputStreamWriter(
-							new FileOutputStream( file, true ),
+							new FileOutputStream( file, append ),
 							charsetName
 					) :
 					new OutputStreamWriter( new FileOutputStream(
 							file,
-							true
+							append
 					) );
 		}
 		catch (IOException e) {

hibernate-core/src/main/java/org/hibernate/tool/schema/internal/exec/ScriptTargetOutputToUrl.java

@@ -28,6 +28,7 @@ public class ScriptTargetOutputToUrl extends AbstractScriptTargetOutput implemen
 
 	private final URL url;
 	private final String charsetName;
+	private final boolean append;
 
 	private Writer writer;
 
@@ -36,10 +37,23 @@ public class ScriptTargetOutputToUrl extends AbstractScriptTargetOutput implemen
 	 *
 	 * @param url The url to read from
 	 * @param charsetName The charset name
+	 * @param append If true, then bytes will be written to the end of the file rather than the beginning
 	 */
-	public ScriptTargetOutputToUrl(URL url, String charsetName) {
+	public ScriptTargetOutputToUrl(URL url, String charsetName, boolean append) {
 		this.url = url;
 		this.charsetName = charsetName;
+		this.append = append;
+	}
+
+	/**
+	 * Constructs a ScriptTargetOutputToUrl instance
+	 * the bytes will be written to the end of the file rather than the beginning
+	 *
+	 * @param url The url to read from
+	 * @param charsetName The charset name
+	 */
+	public ScriptTargetOutputToUrl(URL url, String charsetName) {
+		this( url, charsetName, true );
 	}
 
 	@Override
@@ -53,7 +67,7 @@ protected Writer writer() {
 	@Override
 	public void prepare() {
 		super.prepare();
-		this.writer = toWriter( url, charsetName );
+		this.writer = toWriter( url, charsetName, append );
 	}
 
 	@Override
@@ -62,17 +76,17 @@ public void release() {
 			writer().close();
 		}
 		catch (IOException e) {
-			throw new SchemaManagementException( "Unable to close file writer : " + e.toString() );
+			throw new SchemaManagementException( "Unable to close file writer : " + e );
 		}
 	}
 
 
-	private static Writer toWriter( URL url, String charsetName ) {
+	private static Writer toWriter( URL url, String charsetName, boolean append ) {
 		log.debug( "Attempting to resolve writer for URL : " + url );
 		// technically only "strings corresponding to file URLs" are supported, which I take to mean URLs whose
 		// protocol is "file"
 		try {
-			return ScriptTargetOutputToFile.toFileWriter( new File( url.toURI() ), charsetName );
+			return ScriptTargetOutputToFile.toFileWriter( new File( url.toURI() ), charsetName, append );
 		}
 		catch (URISyntaxException e) {
 			throw new SchemaManagementException(

hibernate-core/src/main/java/org/hibernate/tool/schema/spi/SchemaManagementToolCoordinator.java

@@ -77,7 +77,7 @@ public static void process(
 						ExceptionHandlerLoggedImpl.INSTANCE
 		);
 
-		performScriptAction( actions.getScriptAction(), metadata, tool, serviceRegistry, executionOptions );
+		performScriptAction( actions.getScriptAction(), metadata, tool, serviceRegistry, executionOptions, configService );
 		performDatabaseAction( actions.getDatabaseAction(), metadata, tool, serviceRegistry, executionOptions );
 
 		if ( actions.getDatabaseAction() == Action.CREATE_DROP ) {
@@ -260,13 +260,15 @@ private static void performScriptAction(
 			Metadata metadata,
 			SchemaManagementTool tool,
 			ServiceRegistry serviceRegistry,
-			ExecutionOptions executionOptions) {
+			ExecutionOptions executionOptions,
+			ConfigurationService configurationService) {
 		switch ( scriptAction ) {
 			case CREATE_ONLY: {
 				final JpaTargetAndSourceDescriptor createDescriptor = buildScriptTargetDescriptor(
 						executionOptions.getConfigurationValues(),
 						CreateSettingSelector.INSTANCE,
-						serviceRegistry
+						serviceRegistry,
+						configurationService
 				);
 				tool.getSchemaCreator( executionOptions.getConfigurationValues() ).doCreation(
 						metadata,
@@ -281,7 +283,8 @@ private static void performScriptAction(
 				final JpaTargetAndSourceDescriptor dropDescriptor = buildScriptTargetDescriptor(
 						executionOptions.getConfigurationValues(),
 						DropSettingSelector.INSTANCE,
-						serviceRegistry
+						serviceRegistry,
+						configurationService
 				);
 				tool.getSchemaDropper( executionOptions.getConfigurationValues() ).doDrop(
 						metadata,
@@ -292,7 +295,8 @@ private static void performScriptAction(
 				final JpaTargetAndSourceDescriptor createDescriptor = buildScriptTargetDescriptor(
 						executionOptions.getConfigurationValues(),
 						CreateSettingSelector.INSTANCE,
-						serviceRegistry
+						serviceRegistry,
+						configurationService
 				);
 				tool.getSchemaCreator( executionOptions.getConfigurationValues() ).doCreation(
 						metadata,
@@ -306,7 +310,8 @@ private static void performScriptAction(
 				final JpaTargetAndSourceDescriptor dropDescriptor = buildScriptTargetDescriptor(
 						executionOptions.getConfigurationValues(),
 						DropSettingSelector.INSTANCE,
-						serviceRegistry
+						serviceRegistry,
+						configurationService
 				);
 				tool.getSchemaDropper( executionOptions.getConfigurationValues() ).doDrop(
 						metadata,
@@ -320,7 +325,8 @@ private static void performScriptAction(
 				final JpaTargetAndSourceDescriptor migrateDescriptor = buildScriptTargetDescriptor(
 						executionOptions.getConfigurationValues(),
 						MigrateSettingSelector.INSTANCE,
-						serviceRegistry
+						serviceRegistry,
+						configurationService
 				);
 				tool.getSchemaMigrator( executionOptions.getConfigurationValues() ).doMigration(
 						metadata,
@@ -338,7 +344,8 @@ private static void performScriptAction(
 	private static JpaTargetAndSourceDescriptor buildScriptTargetDescriptor(
 			Map configurationValues,
 			SettingSelector settingSelector,
-			ServiceRegistry serviceRegistry) {
+			ServiceRegistry serviceRegistry,
+			ConfigurationService configurationService) {
 		final Object scriptSourceSetting = settingSelector.getScriptSourceSetting( configurationValues );
 		final SourceType sourceType = SourceType.interpret(
 				settingSelector.getSourceTypeSetting( configurationValues ),
@@ -358,10 +365,13 @@ private static JpaTargetAndSourceDescriptor buildScriptTargetDescriptor(
 				? Helper.interpretScriptSourceSetting( scriptSourceSetting, serviceRegistry.getService( ClassLoaderService.class ), charsetName )
 				: null;
 
+
+		boolean append = configurationService.getSetting( AvailableSettings.HBM2DDL_SCRIPTS_CREATE_APPEND, StandardConverters.BOOLEAN, true );
 		final ScriptTargetOutput scriptTargetOutput = Helper.interpretScriptTargetSetting(
 				settingSelector.getScriptTargetSetting( configurationValues ),
 				serviceRegistry.getService( ClassLoaderService.class ),
-				charsetName
+				charsetName,
+				append
 		);
 
 		return new JpaTargetAndSourceDescriptor() {