applied patch from bug https://bugs.eclipse.org/bugs/show_bug.cgi?id=248463

plugins/org.eclipse.xtext/META-INF/MANIFEST.MF

@@ -34,5 +34,4 @@ Require-Bundle: org.eclipse.xtext.log4j;bundle-version="1.2.15",
  org.eclipse.xtext.service;visibility:=reexport,
  org.eclipse.xtext.util,
  org.junit;resolution:=optional,
- org.eclipse.xtend.util.stdlib,
  org.antlr.runtime;bundle-version="3.0.0";visibility:=reexport

plugins/org.eclipse.xtext/src/log4j.properties

@@ -2,6 +2,6 @@ log4j.rootLogger=debug, default
 
 log4j.appender.default=org.apache.log4j.ConsoleAppender
 log4j.appender.default.layout=org.apache.log4j.PatternLayout
-log4j.appender.default.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n
+log4j.appender.default.layout.ConversionPattern=%-4r [%t] %-5p %35.35c %x - %m%n
 
 log4j.logger.org.eclipse.xtext=DEBUG

plugins/org.eclipse.xtext/src/org/eclipse/xtext/parsetree/reconstr/IParseTreeConstructor.java

@@ -8,13 +8,21 @@
  *******************************************************************************/
 package org.eclipse.xtext.parsetree.reconstr;
 
+import java.io.OutputStream;
+import java.util.Map;
+
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.xtext.service.ILanguageService;
 
 /**
  * @author Sven Efftinge - Initial contribution and API
- *
+ * 
  */
+
+// TODO: rename to ISerializer
 public interface IParseTreeConstructor extends ILanguageService {
-	public void update(EObject object, IParseTreeConstructorCallback callback);
+	
+	public static final String OPTION_SERIALIZER_STRATEGY = "OPTION_SERIALIZER_STRATEGY";
+	
+	public void serialize(OutputStream outputStream, EObject object, Map<?, ?> options);
 }

plugins/org.eclipse.xtext/src/org/eclipse/xtext/parsetree/reconstr/IParseTreeConstructorCallback.java

@@ -8,12 +8,15 @@
  *******************************************************************************/
 package org.eclipse.xtext.parsetree.reconstr;
 
+import java.io.OutputStream;
+
 import org.eclipse.xtext.Action;
 import org.eclipse.xtext.CrossReference;
 import org.eclipse.xtext.Keyword;
 import org.eclipse.xtext.RuleCall;
 import org.eclipse.xtext.service.ILanguageService;
 
+// TODO: rename to ISerializerStrategy
 public interface IParseTreeConstructorCallback extends ILanguageService {
 
 	void parserRuleCallStart(IInstanceDescription current, RuleCall call);
@@ -34,7 +37,7 @@ public interface IParseTreeConstructorCallback extends ILanguageService {
 
 	void crossRefCall(IInstanceDescription current, CrossReference call);
 
-	void beginSerialize();
+	void beginSerialize(OutputStream output);
 
 	void endSerialize();
 }

plugins/org.eclipse.xtext/src/org/eclipse/xtext/parsetree/reconstr/callbacks/DefaultParsetreeReconstructorCallback.java

@@ -8,6 +8,8 @@
  *******************************************************************************/
 package org.eclipse.xtext.parsetree.reconstr.callbacks;
 
+import java.io.OutputStream;
+
 import org.eclipse.xtext.Action;
 import org.eclipse.xtext.CrossReference;
 import org.eclipse.xtext.Keyword;
@@ -41,10 +43,9 @@ public class DefaultParsetreeReconstructorCallback implements IParseTreeConstruc
 	public void lexerRuleCall(IInstanceDescription current, RuleCall call) {
 	}
 
-	public void beginSerialize() {
+	public void beginSerialize(OutputStream output) {
 	}
 
 	public void endSerialize() {
 	}
-
 }

plugins/org.eclipse.xtext/src/org/eclipse/xtext/parsetree/reconstr/callbacks/SimpleSerializingCallback.java

@@ -12,19 +12,17 @@ import org.eclipse.xtext.Keyword;
 import org.eclipse.xtext.RuleCall;
 import org.eclipse.xtext.conversion.IValueConverterService;
 import org.eclipse.xtext.parsetree.reconstr.IInstanceDescription;
+import org.eclipse.xtext.service.Inject;
 
 public class SimpleSerializingCallback extends
 		DefaultParsetreeReconstructorCallback {
 
-	protected final OutputStream out;
-	protected final IValueConverterService converterService;
-	protected boolean outputHasStarted;
+	@Inject
+	protected IValueConverterService converterService;
 
-	public SimpleSerializingCallback(OutputStream output,
-			IValueConverterService converterService) {
-		this.converterService = converterService;
-		this.out = output;
-	}
+	protected OutputStream out;
+
+	protected boolean outputHasStarted;
 
 	protected void append(String str) {
 		try {
@@ -43,9 +41,10 @@ public class SimpleSerializingCallback extends
 			append(" ");
 	}
 
-	public void beginSerialize() {
-		super.beginSerialize();
+	public void beginSerialize(OutputStream output) {
+		super.beginSerialize(output);
 		outputHasStarted = false;
+		out = output;
 	}
 
 	public void crossRefCall(IInstanceDescription current, CrossReference call) {
@@ -65,6 +64,10 @@ public class SimpleSerializingCallback extends
 				+ object);
 	}
 
+	public IValueConverterService getConverterService() {
+		return converterService;
+	}
+
 	public void keywordCall(IInstanceDescription current, Keyword call) {
 		before(current, call);
 		append(call.getValue());
@@ -75,4 +78,8 @@ public class SimpleSerializingCallback extends
 		before(current, call);
 		append(converterService.toString(value, call.getName()));
 	}
+
+	public void setConverterService(IValueConverterService converterService) {
+		this.converterService = converterService;
+	}
 }

plugins/org.eclipse.xtext/src/org/eclipse/xtext/parsetree/reconstr/callbacks/WhitespacePreservingCallback.java

@@ -6,7 +6,6 @@ import java.util.List;
 import org.eclipse.emf.ecore.util.EcoreUtil;
 import org.eclipse.xtext.AbstractElement;
 import org.eclipse.xtext.Assignment;
-import org.eclipse.xtext.conversion.IValueConverterService;
 import org.eclipse.xtext.parsetree.CompositeNode;
 import org.eclipse.xtext.parsetree.LeafNode;
 import org.eclipse.xtext.parsetree.NodeAdapter;
@@ -19,10 +18,6 @@ public class WhitespacePreservingCallback extends SimpleSerializingCallback {
 
 	private int lastLeaf = -1;
 
-	public WhitespacePreservingCallback(OutputStream output,
-			IValueConverterService converterService) {
-		super(output, converterService);
-	}
 
 	protected void before(IInstanceDescription curr, AbstractElement ele) {
 		int i = lastLeaf, last = findLeafNodeFor(curr, ele);
@@ -36,7 +31,8 @@ public class WhitespacePreservingCallback extends SimpleSerializingCallback {
 			}
 	}
 
-	public void beginSerialize() {
+	public void beginSerialize(OutputStream output) {
+		super.beginSerialize(output);
 		lastLeaf = -1;
 		allLeafs = null;
 	}

plugins/org.eclipse.xtext/src/org/eclipse/xtext/parsetree/reconstr/impl/AbstractParseTreeConstructor.java

@@ -1,23 +1,20 @@
 package org.eclipse.xtext.parsetree.reconstr.impl;
 
-
-import java.io.ByteArrayOutputStream;
+import java.io.OutputStream;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
+import java.util.Map;
 
+import org.apache.log4j.Logger;
 import org.eclipse.emf.common.util.URI;
 import org.eclipse.emf.ecore.EObject;
-import org.eclipse.emf.ecore.util.EcoreUtil;
 import org.eclipse.xtext.Grammar;
-import org.eclipse.xtext.GrammarUtil;
 import org.eclipse.xtext.IGrammarAccess;
-import org.eclipse.xtext.ParserRule;
 import org.eclipse.xtext.conversion.IValueConverterService;
 import org.eclipse.xtext.parser.IAstFactory;
 import org.eclipse.xtext.parsetree.reconstr.IInstanceDescription;
 import org.eclipse.xtext.parsetree.reconstr.IParseTreeConstructor;
 import org.eclipse.xtext.parsetree.reconstr.IParseTreeConstructorCallback;
-import org.eclipse.xtext.parsetree.reconstr.callbacks.SimpleSerializingCallback;
 import org.eclipse.xtext.service.Inject;
 
 public abstract class AbstractParseTreeConstructor implements
@@ -104,11 +101,12 @@ public abstract class AbstractParseTreeConstructor implements
 		}
 
 		private String dsl(AbstractToken ele) {
-			ByteArrayOutputStream out = new ByteArrayOutputStream();
-			SimpleSerializingCallback cb = new SimpleSerializingCallback(out,
-					converterService);
-			executeAllCallbacks(cb);
-			return out.toString();
+			// ByteArrayOutputStream out = new ByteArrayOutputStream();
+			// SimpleSerializingCallback cb = new SimpleSerializingCallback(out,
+			// converterService);
+			// executeAllCallbacks(cb);
+			// return out.toString();
+			return "";
 		}
 
 		public void executeAllCallbacks(IParseTreeConstructorCallback callback) {
@@ -123,16 +121,17 @@ public abstract class AbstractParseTreeConstructor implements
 		}
 
 		public Solution firstSolution() {
-			System.out.println("->" + depth(this) + getClass().getSimpleName()
-					+ "\t " + current + " -> " + dsl(this));
+			if (log.isDebugEnabled())
+				log.debug("->" + depth(this) + getClass().getSimpleName()
+						+ "\t " + current + " -> " + dsl(this));
 			Solution t1 = createSolution();
-			System.out
-					.println("< "
-							+ depth(this)
-							+ getClass().getSimpleName()
-							+ " -> "
-							+ ((t1 == null) ? "failed" : "success" + "\t "
-									+ t1.current));
+			if (log.isDebugEnabled())
+				log.debug("< "
+						+ depth(this)
+						+ getClass().getSimpleName()
+						+ " -> "
+						+ ((t1 == null) ? "failed" : "success" + "\t "
+								+ t1.current));
 			if (t1 == null)
 				return required ? null : new Solution(current, predecessor);
 			if (many) {
@@ -235,8 +234,13 @@ public abstract class AbstractParseTreeConstructor implements
 
 	}
 
+	protected Logger log = Logger.getLogger(AbstractParseTreeConstructor.class);
+
 	@Inject
-	protected IValueConverterService converterService;
+	private IParseTreeConstructorCallback serializerStrategy;
+
+	@Inject
+	private IValueConverterService converterService;
 
 	@Inject
 	private IAstFactory factory;
@@ -265,18 +269,33 @@ public abstract class AbstractParseTreeConstructor implements
 				URI.createURI(string), true);
 	}
 
-	protected IValueConverterService getValueConverterService() {
+	public IValueConverterService getValueConverterService() {
 		return converterService;
 	}
 
-	protected abstract void internalDoUpdate(EObject obj, String ruleToCall,
-			IParseTreeConstructorCallback callback);
+	public static final String OPTION_SERIALIZER_STRATEGY = "OPTION_SERIALIZER_STRATEGY";
 
-	public void update(EObject object, IParseTreeConstructorCallback callback) {
-		EObject root = EcoreUtil.getRootContainer(object);
-		ParserRule parserRule = GrammarUtil.getDefaultEntryRule(getGrammar());
-		String ruleToCall = parserRule.getName();
-		internalDoUpdate(root, ruleToCall, callback);
+	private IParseTreeConstructorCallback getSerializerStrategy(
+			Map<?, ?> options) {
+		Object serObj = options.get(OPTION_SERIALIZER_STRATEGY);
+		if (serObj == null)
+			return serializerStrategy;
+		if (serObj instanceof IParseTreeConstructorCallback)
+			return (IParseTreeConstructorCallback) serObj;
+		throw new IllegalStateException("The Object supplied with "
+				+ OPTION_SERIALIZER_STRATEGY + " needs to be of type "
+				+ IParseTreeConstructorCallback.class.getName());
 	}
 
+	public void serialize(OutputStream outputStream, EObject object,
+			Map<?, ?> options) {
+		IParseTreeConstructorCallback ser = getSerializerStrategy(options);
+		ser.beginSerialize(outputStream);
+		internalSerialize(object, ser);
+		ser.endSerialize();
+	}
+
+	protected abstract void internalSerialize(EObject object,
+			IParseTreeConstructorCallback strategy);
+
 }

plugins/org.eclipse.xtext/src/org/eclipse/xtext/resource/XtextResource.java

@@ -21,7 +21,6 @@ import org.eclipse.emf.common.util.URI;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.resource.impl.ResourceImpl;
 import org.eclipse.emf.ecore.util.EcoreUtil;
-import org.eclipse.xtext.conversion.IValueConverterService;
 import org.eclipse.xtext.crossref.BrokenLink;
 import org.eclipse.xtext.crossref.IFragmentProvider;
 import org.eclipse.xtext.crossref.ILinker;
@@ -31,7 +30,6 @@ import org.eclipse.xtext.parser.IParser;
 import org.eclipse.xtext.parsetree.CompositeNode;
 import org.eclipse.xtext.parsetree.NodeContentAdapter;
 import org.eclipse.xtext.parsetree.reconstr.IParseTreeConstructor;
-import org.eclipse.xtext.parsetree.reconstr.callbacks.WhitespacePreservingCallback;
 import org.eclipse.xtext.service.Inject;
 
 /**
@@ -55,9 +53,6 @@ public class XtextResource extends ResourceImpl {
 	@Inject
 	private IParseTreeConstructor parseTreeConstructor;
 	
-	@Inject
-	private IValueConverterService valueConverterService;
-
 	private IParseResult parseResult;
 
 	public XtextResource(URI uri) {
@@ -136,25 +131,11 @@ public class XtextResource extends ResourceImpl {
 		}
 		setIntrinsicIDToEObjectMap(map);
 	}
-
+	
 	@Override
 	public void doSave(OutputStream outputStream, Map<?, ?> options) throws IOException {
-		if (contents.size() > 1) {
-			throw new IllegalStateException("Xtext resource cannot contain multiple root elements");
-		}
-		if (!contents.isEmpty()) {
-			EObject rootElement = contents.get(0);
-			WhitespacePreservingCallback cb = new WhitespacePreservingCallback(
-					outputStream, valueConverterService);
-			parseTreeConstructor.update(rootElement, cb);
-			// outputStream.write(cb.toString().getBytes());
-		}
+		if (contents.size() != 1)
+			throw new IllegalStateException("The Xtext resource must contain exactly one root element");
+		parseTreeConstructor.serialize(outputStream, contents.get(0), options);
 	}
-	
-//	public String serialize(EObject o) {
-//		WhitespacePreservingCallback cb = new WhitespacePreservingCallback(valueConverterService);
-//		parseTreeConstructor.update(o, cb);
-//		return o.toString();
-//	}
-
 }

tests/org.eclipse.xtext.generator.tests/.classpath

@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
+	<classpathentry kind="src" path="src"/>
 	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/J2SE-1.5"/>
 	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
 	<classpathentry kind="src" path="src-gen"/>
-	<classpathentry kind="src" path="src"/>
 	<classpathentry kind="output" path="bin"/>
 </classpath>

tests/org.eclipse.xtext.generator.tests/src/log4j.properties

@@ -0,0 +1,7 @@
+log4j.rootLogger=debug, default
+
+log4j.appender.default=org.apache.log4j.ConsoleAppender
+log4j.appender.default.layout=org.apache.log4j.PatternLayout
+log4j.appender.default.layout.ConversionPattern=%-4r [%t] %-5p %35.35c %x - %m%n
+
+log4j.logger.org.eclipse=INFO

tests/org.eclipse.xtext.generator.tests/src/org/eclipse/xtext/parsetree/reconstr/ComplexReconstrTest.java

@@ -9,12 +9,12 @@
 package org.eclipse.xtext.parsetree.reconstr;
 
 import java.io.ByteArrayOutputStream;
+import java.util.Collections;
 
 import org.eclipse.emf.common.util.URI;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.resource.ResourceSet;
 import org.eclipse.xtext.ParserRule;
-import org.eclipse.xtext.parsetree.reconstr.callbacks.WhitespacePreservingCallback;
 import org.eclipse.xtext.resource.XtextResourceSet;
 import org.eclipse.xtext.tests.AbstractGeneratorTest;
 import org.eclipse.xtext.tests.EcoreModelComparator;
@@ -40,7 +40,6 @@ public class ComplexReconstrTest extends AbstractGeneratorTest {
 					System.out.println(EmfFormater.objToStr(pr, ""));
 				}
 			}
-
 	}
 
 	public void testSimple() throws Exception {
@@ -58,9 +57,7 @@ public class ComplexReconstrTest extends AbstractGeneratorTest {
 		System.out.println(EmfFormater.objToStr(result, ""));
 		IParseTreeConstructor con = getParseTreeConstructor();
 		ByteArrayOutputStream out = new ByteArrayOutputStream();
-		WhitespacePreservingCallback callback = new WhitespacePreservingCallback(out,
-				getValueConverterService());
-		con.update(result, callback);
+		con.serialize(out, result, Collections.emptyMap());
 		return out.toString();
 	}
 

tests/org.eclipse.xtext.generator.tests/src/org/eclipse/xtext/parsetree/reconstr/ComplexReconstrTest.xtext

@@ -28,20 +28,20 @@ StrangeStuff :
 */
 
 
-TrickyA returns TypeA1: TrickyA1 (name += ID)* ({TypeB.x=current} 'x' | {TypeC.x=current} 'y')? name+=STRING;
+TrickyA returns TypeA1: 'TA' TrickyA1 (name += ID)* ({TypeB.x=current} 'x' | {TypeC.x=current} 'y')? name+=STRING;
 TrickyA1 returns TypeD: name+=ID;
 
-TrickyB : (name = ID type += INT)? (type += ID)*;
+TrickyB : 'TB' (name = ID type += INT)? (type += ID)*;
 
-TrickyC : name = ID ({C1.x=current} 'x')? ({C2.y=current} 'y')? ({C3.z=current} 'z')?;
+TrickyC : 'TC' name = ID ({C1.x=current} 'x')? ({C2.y=current} 'y')? ({C3.z=current} 'z')?;
 
-TrickyD: (name += INT foo = STRING type += ID)? (name += INT type += ID)? (type += ID)*;  
+TrickyD: 'TD' (name += INT foo = STRING type += ID)? (name += INT type += ID)? (type += ID)*;  
 
 // 34 "abc" XX 123 "de" YY x 34 DD 45 CC
-TrickyE: (name+=INT foo+=STRING type+=ID)* 'x' (name+=INT type+=ID)*;
+TrickyE: 'TE' (name+=INT foo+=STRING type+=ID)* 'x' (name+=INT type+=ID)*;
 
 // 
-TrickyF: (name+=ID type+=INT)* (name+=ID | type+=INT);
+TrickyF: 'TF' (name+=ID type+=INT)* (name+=ID | type+=INT);
 
 
 // TrickyG: TrickyG1 | TrickyG2;

tests/org.eclipse.xtext.generator.tests/src/org/eclipse/xtext/parsetree/reconstr/SimpleReconstrTest.java

@@ -9,10 +9,10 @@
 package org.eclipse.xtext.parsetree.reconstr;
 
 import java.io.ByteArrayOutputStream;
+import java.util.Collections;
 
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.xtext.parsetree.NodeUtil;
-import org.eclipse.xtext.parsetree.reconstr.callbacks.WhitespacePreservingCallback;
 import org.eclipse.xtext.testlanguages.SimpleExpressionsStandaloneSetup;
 import org.eclipse.xtext.tests.AbstractGeneratorTest;
 import org.eclipse.xtext.util.EmfFormater;
@@ -49,9 +49,7 @@ public class SimpleReconstrTest extends AbstractGeneratorTest {
 
 		IParseTreeConstructor con = getParseTreeConstructor();
 		ByteArrayOutputStream out = new ByteArrayOutputStream();
-		WhitespacePreservingCallback callback = new WhitespacePreservingCallback(out,
-				getValueConverterService());
-		con.update(result, callback);
+		con.serialize(out, result, Collections.emptyMap());
 		return out.toString();
 	}
 

tests/org.eclipse.xtext.generator.tests/src/org/eclipse/xtext/parsetree/reconstr/WhitespacePreservingCallbackTest.java

@@ -1,10 +1,9 @@
 package org.eclipse.xtext.parsetree.reconstr;
 
 import java.io.ByteArrayOutputStream;
+import java.util.Collections;
 
 import org.eclipse.emf.ecore.EObject;
-import org.eclipse.xtext.parser.IAstFactory;
-import org.eclipse.xtext.parsetree.reconstr.callbacks.WhitespacePreservingCallback;
 import org.eclipse.xtext.tests.AbstractGeneratorTest;
 
 public class WhitespacePreservingCallbackTest extends AbstractGeneratorTest {
@@ -65,10 +64,14 @@ public class WhitespacePreservingCallbackTest extends AbstractGeneratorTest {
 	}
 
 	private String serialize(EObject result) {
+//		IParseTreeConstructor con = getParseTreeConstructor();
+//		ByteArrayOutputStream out = new ByteArrayOutputStream();
+//		WhitespacePreservingCallback cb = new WhitespacePreservingCallback(out,getValueConverterService());
+//		con.update(result, cb);
+//		return out.toString();
 		IParseTreeConstructor con = getParseTreeConstructor();
 		ByteArrayOutputStream out = new ByteArrayOutputStream();
-		WhitespacePreservingCallback cb = new WhitespacePreservingCallback(out,getValueConverterService());
-		con.update(result, cb);
+		con.serialize(out, result, Collections.emptyMap());
 		return out.toString();
 	}
 
@@ -76,8 +79,7 @@ public class WhitespacePreservingCallbackTest extends AbstractGeneratorTest {
 		try {
 			IParseTreeConstructor con = getParseTreeConstructor();
 			ByteArrayOutputStream out = new ByteArrayOutputStream();
-			WhitespacePreservingCallback cb = new WhitespacePreservingCallback(out,getValueConverterService());
-			con.update(o, cb);
+			con.serialize(out, o, Collections.emptyMap());
 			fail("Should fail with "+clazz.getSimpleName());
 		} catch (RuntimeException e) {
 			if (!clazz.isInstance(e)) {