org.eclipse.xtext.xbase.XTryCatchFinallyExpression Java Examples

/** Generate the given object.
 *
 * @param tryStatement the try-catch-finally statement.
 * @param it the target for the generated content.
 * @param context the context.
 * @return the statement.
 */
protected XExpression _generate(XTryCatchFinallyExpression tryStatement, IAppendable it, IExtraLanguageGeneratorContext context) {
	it.append("try:"); //$NON-NLS-1$
	it.increaseIndentation().newLine();
	generate(tryStatement.getExpression(), context.getExpectedExpressionType(), it, context);
	it.decreaseIndentation().newLine();
	for (final XCatchClause clause : tryStatement.getCatchClauses()) {
		it.append("except "); //$NON-NLS-1$
		it.append(clause.getDeclaredParam().getParameterType().getType());
		it.append(", "); //$NON-NLS-1$
		it.append(it.declareUniqueNameVariable(clause.getDeclaredParam(), clause.getDeclaredParam().getSimpleName()));
		it.append(":"); //$NON-NLS-1$
		it.increaseIndentation().newLine();
		generate(clause.getExpression(), context.getExpectedExpressionType(), it, context);
		it.decreaseIndentation().newLine();
	}
	if (tryStatement.getFinallyExpression() != null) {
		it.append("finally:"); //$NON-NLS-1$
		it.increaseIndentation().newLine();
		generate(tryStatement.getFinallyExpression(), it, context);
		it.decreaseIndentation();
	}
	return tryStatement;
}
 

protected Collection<IEarlyExitComputer.ExitPoint> _exitPoints(final XTryCatchFinallyExpression expression) {
  Collection<IEarlyExitComputer.ExitPoint> tryExitPoints = this.getExitPoints(expression.getExpression());
  boolean _isNotEmpty = this.isNotEmpty(tryExitPoints);
  if (_isNotEmpty) {
    Collection<IEarlyExitComputer.ExitPoint> result = Lists.<IEarlyExitComputer.ExitPoint>newArrayList(tryExitPoints);
    EList<XCatchClause> _catchClauses = expression.getCatchClauses();
    for (final XCatchClause catchClause : _catchClauses) {
      {
        Collection<IEarlyExitComputer.ExitPoint> catchExitPoints = this.getExitPoints(catchClause.getExpression());
        boolean _isNotEmpty_1 = this.isNotEmpty(catchExitPoints);
        if (_isNotEmpty_1) {
          result.addAll(catchExitPoints);
        } else {
          return this.getExitPoints(expression.getFinallyExpression());
        }
      }
    }
    return result;
  }
  return this.getExitPoints(expression.getFinallyExpression());
}
 

protected boolean bracesAreAddedByOuterStructure(XExpression expression) {
	EObject container = expression.eContainer();
	if (container instanceof XTryCatchFinallyExpression 
			|| container instanceof XIfExpression
			|| container instanceof XClosure
			|| container instanceof XSynchronizedExpression) {
		return true;
	}
	if (container instanceof XBlockExpression) {
		XBlockExpression blockExpression = (XBlockExpression) container;
		EList<XExpression> expressions = blockExpression.getExpressions();
		if (expressions.size() == 1 && expressions.get(0) == expression) {
			return bracesAreAddedByOuterStructure(blockExpression);
		}
	}
	if (!(container instanceof XExpression)) {
		return true;
	}
	return false;
}
 

/**
 * Syntax: '('*
 */
@Override
protected void emit_XParenthesizedExpression_LeftParenthesisKeyword_0_a(EObject semanticObject,
		ISynNavigable transition, List<INode> nodes) {

	Keyword kw = grammarAccess.getXParenthesizedExpressionAccess().getLeftParenthesisKeyword_0();

	if (nodes == null) {
		if (semanticObject instanceof XIfExpression || semanticObject instanceof XTryCatchFinallyExpression) {
			EObject cnt = semanticObject.eContainer();
			if (cnt instanceof XExpression && !(cnt instanceof XBlockExpression)
					&& !(cnt instanceof XForLoopExpression))
				acceptUnassignedKeyword(kw, kw.getValue(), null);
		}
		if (semanticObject instanceof XConstructorCall) {
			XConstructorCall call = (XConstructorCall) semanticObject;
			if (!call.isExplicitConstructorCall() && call.getArguments().isEmpty()) {
				acceptUnassignedKeyword(kw, kw.getValue(), null);
			}
		}
	}
	acceptNodes(transition, nodes);
}
 

/**
 * Syntax: '('*
 */
@Override
protected void emit_XParenthesizedExpression_LeftParenthesisKeyword_0_a(EObject semanticObject,
		ISynNavigable transition, List<INode> nodes) {

	Keyword kw = grammarAccess.getXParenthesizedExpressionAccess().getLeftParenthesisKeyword_0();

	if (nodes == null) {
		if (semanticObject instanceof XIfExpression || semanticObject instanceof XTryCatchFinallyExpression) {
			EObject cnt = semanticObject.eContainer();
			if (cnt instanceof XExpression && !(cnt instanceof XBlockExpression)
					&& !(cnt instanceof XForLoopExpression))
				acceptUnassignedKeyword(kw, kw.getValue(), null);
		}
		if (semanticObject instanceof XConstructorCall) {
			XConstructorCall call = (XConstructorCall) semanticObject;
			if (!call.isExplicitConstructorCall() && call.getArguments().isEmpty()) {
				acceptUnassignedKeyword(kw, kw.getValue(), null);
			}
		}
	}
	acceptNodes(transition, nodes);
}
 

@Check
public void checkCatchClausesOrder(XTryCatchFinallyExpression expression) {
	ITypeReferenceOwner owner = new StandardTypeReferenceOwner(getServices(), expression);
	List<LightweightTypeReference> previousTypeReferences = new ArrayList<LightweightTypeReference>();
	for (XCatchClause catchClause : expression.getCatchClauses()) {
		LightweightTypeReference actualTypeReference = owner.toLightweightTypeReference(catchClause.getDeclaredParam().getParameterType());
		if (actualTypeReference == null) {
			continue;
		}
		if (isHandled(actualTypeReference, previousTypeReferences)) {
			error("Unreachable code: The catch block can never match. It is already handled by a previous condition.", catchClause.getDeclaredParam().getParameterType(), null, IssueCodes.UNREACHABLE_CATCH_BLOCK);
			continue;
		}
		previousTypeReferences.add(actualTypeReference);
	}
}
 

/** Test if the given expression has side effects.
 *
 * @param expression the expression.
 * @param context the list of context expressions.
 * @return {@code true} if the expression has side effects.
 */
protected Boolean _hasSideEffects(XTryCatchFinallyExpression expression, ISideEffectContext context) {
	final List<Map<String, List<XExpression>>> buffers = new ArrayList<>();
	Map<String, List<XExpression>> buffer = context.createVariableAssignmentBufferForBranch();
	if (hasSideEffects(expression.getExpression(), context.branch(buffer))) {
		return true;
	}
	buffers.add(buffer);
	for (final XCatchClause clause : expression.getCatchClauses()) {
		context.open();
		try {
			buffer = context.createVariableAssignmentBufferForBranch();
			if (hasSideEffects(clause.getExpression(), context.branch(buffer))) {
				return true;
			}
			buffers.add(buffer);
		} finally {
			context.close();
		}
	}
	context.mergeBranchVariableAssignments(buffers);
	if (hasSideEffects(expression.getFinallyExpression(), context)) {
		return true;
	}
	return false;
}
 

@Test public void testResourceNotVisibleInFinally() throws Exception {
	XtendFunction function = function("def tryCatch() {\n" + 
			"	    try(val a = []) {} finally a" + 
			"	}");
	XTryCatchFinallyExpression tryCatch = (XTryCatchFinallyExpression) ((XBlockExpression) function.getExpression()).getExpressions().get(0);
	XFeatureCall call = (XFeatureCall) tryCatch.getFinallyExpression();
	JvmIdentifiableElement feature = call.getFeature();
	assertTrue(feature.eIsProxy());
}
 

@Test public void testResourceNotVisibleInCatch() throws Exception {
	XtendFunction function = function("def tryCatch() {\n" + 
			"	    try(val a = []) {} catch(Exception e) a" + 
			"	}");
	XTryCatchFinallyExpression tryCatch = (XTryCatchFinallyExpression) ((XBlockExpression) function.getExpression()).getExpressions().get(0);
	XFeatureCall call = (XFeatureCall) tryCatch.getCatchClauses().get(0).getExpression();
	JvmIdentifiableElement feature = call.getFeature();
	assertTrue(feature.eIsProxy());
}
 

@Test public void testResourceVisibleInTry() throws Exception {
	XtendFunction function = function("def tryCatch() {\n" + 
			"	    try(val a = []) a" + 
			"	}");
	XTryCatchFinallyExpression tryCatch = (XTryCatchFinallyExpression) ((XBlockExpression) function.getExpression()).getExpressions().get(0);
	XFeatureCall call = (XFeatureCall) tryCatch.getExpression();
	JvmIdentifiableElement feature = call.getFeature();
	assertFalse(feature.eIsProxy());
}
 

@Test
public void testMultiCatch_02() throws Exception {
	XtendClass clazz = clazz("class Foo { def void m() { try {} catch(extension NullPointerException | IllegalArgumentException | IllegalStateException e) {} } }");
	assertEquals(1, clazz.getMembers().size());
	XtendFunction m = (XtendFunction) clazz.getMembers().get(0);
	XBlockExpression body = (XBlockExpression) m.getExpression();
	assertEquals(1, body.getExpressions().size());
	XTryCatchFinallyExpression tryCatch = (XTryCatchFinallyExpression) body.getExpressions().get(0);
	XCatchClause singleCatchClause = tryCatch.getCatchClauses().get(0);
	XtendFormalParameter parameter = (XtendFormalParameter) singleCatchClause.getDeclaredParam();
	assertTrue(parameter.isExtension());
	JvmSynonymTypeReference parameterType = (JvmSynonymTypeReference) parameter.getParameterType();
	assertEquals(3, parameterType.getReferences().size());
}
 

@Test
public void testMultiCatch_01() throws Exception {
	XtendClass clazz = clazz("class Foo { def void m() { try {} catch(NullPointerException | IllegalArgumentException e) {} } }");
	assertEquals(1, clazz.getMembers().size());
	XtendFunction m = (XtendFunction) clazz.getMembers().get(0);
	XBlockExpression body = (XBlockExpression) m.getExpression();
	assertEquals(1, body.getExpressions().size());
	XTryCatchFinallyExpression tryCatch = (XTryCatchFinallyExpression) body.getExpressions().get(0);
	XCatchClause singleCatchClause = tryCatch.getCatchClauses().get(0);
	XtendFormalParameter parameter = (XtendFormalParameter) singleCatchClause.getDeclaredParam();
	assertFalse(parameter.isExtension());
	JvmSynonymTypeReference parameterType = (JvmSynonymTypeReference) parameter.getParameterType();
	assertEquals(2, parameterType.getReferences().size());
}
 

@Test
public void testExtensionOnCatchClause_01() throws Exception {
	XtendClass clazz = clazz("class Foo { def void m() { try {} catch(extension NullPointerException e) {} } }");
	assertEquals(1, clazz.getMembers().size());
	XtendFunction m = (XtendFunction) clazz.getMembers().get(0);
	XBlockExpression body = (XBlockExpression) m.getExpression();
	assertEquals(1, body.getExpressions().size());
	XTryCatchFinallyExpression tryCatch = (XTryCatchFinallyExpression) body.getExpressions().get(0);
	XCatchClause singleCatchClause = tryCatch.getCatchClauses().get(0);
	XtendFormalParameter parameter = (XtendFormalParameter) singleCatchClause.getDeclaredParam();
	assertTrue(parameter.isExtension());
}
 

@Test public void testTryCatchExpression() throws Exception {
	XTryCatchFinallyExpression exp = (XTryCatchFinallyExpression)  
			expressionWithExpectedType("try null catch (java.lang.Throwable t) null finally null", "String");

	assertExpected("java.lang.String", exp.getExpression());
	for (XCatchClause cc : exp.getCatchClauses()) {
		assertExpected("java.lang.String", cc.getExpression());
	}
	assertExpected(null, exp.getFinallyExpression());
}
 

/**
 * see bug https://bugs.eclipse.org/bugs/show_bug.cgi?id=356722
 */
@Test public void testTryCatchExpression_3() throws Exception {
	XTryCatchFinallyExpression tryEx = (XTryCatchFinallyExpression) expression(
			"try foo catch (java.lang.Exception) {}");
	Iterator<INode> iterator = ((XtextResource)tryEx.eResource()).getParseResult().getSyntaxErrors().iterator();
	final INode errorNode = iterator.next();
	assertEquals(")",errorNode.getText());
	assertEquals("missing RULE_ID at ')'",errorNode.getSyntaxErrorMessage().getMessage());
}
 

protected void doTestTryCatchExpression_2(XTryCatchFinallyExpression tryEx) {
	assertFeatureCall("foo", tryEx.getExpression());
	assertNull(tryEx.getFinallyExpression());
	
	assertEquals(1,tryEx.getCatchClauses().size());
	XCatchClause clause = tryEx.getCatchClauses().get(0);
	assertFeatureCall("bar", clause.getExpression());
	assertEquals("java.lang.Exception", clause.getDeclaredParam().getParameterType().getIdentifier());
	assertEquals("e", clause.getDeclaredParam().getName());
}
 

protected void doTestTryCatchExpression(XTryCatchFinallyExpression tryEx) {
	assertFeatureCall("foo", ((XThrowExpression)tryEx.getExpression()).getExpression());
	assertFeatureCall("baz", tryEx.getFinallyExpression());
	
	assertEquals(1,tryEx.getCatchClauses().size());
	XCatchClause clause = tryEx.getCatchClauses().get(0);
	assertFeatureCall("bar", clause.getExpression());
	assertEquals("java.lang.Exception", clause.getDeclaredParam().getParameterType().getIdentifier());
	assertEquals("e", clause.getDeclaredParam().getName());
}
 

protected Collection<IEarlyExitComputer.ExitPoint> exitPoints(final XExpression expression) {
  if (expression instanceof XDoWhileExpression) {
    return _exitPoints((XDoWhileExpression)expression);
  } else if (expression instanceof XWhileExpression) {
    return _exitPoints((XWhileExpression)expression);
  } else if (expression instanceof XAbstractFeatureCall) {
    return _exitPoints((XAbstractFeatureCall)expression);
  } else if (expression instanceof XBasicForLoopExpression) {
    return _exitPoints((XBasicForLoopExpression)expression);
  } else if (expression instanceof XBlockExpression) {
    return _exitPoints((XBlockExpression)expression);
  } else if (expression instanceof XConstructorCall) {
    return _exitPoints((XConstructorCall)expression);
  } else if (expression instanceof XForLoopExpression) {
    return _exitPoints((XForLoopExpression)expression);
  } else if (expression instanceof XIfExpression) {
    return _exitPoints((XIfExpression)expression);
  } else if (expression instanceof XReturnExpression) {
    return _exitPoints((XReturnExpression)expression);
  } else if (expression instanceof XSwitchExpression) {
    return _exitPoints((XSwitchExpression)expression);
  } else if (expression instanceof XSynchronizedExpression) {
    return _exitPoints((XSynchronizedExpression)expression);
  } else if (expression instanceof XThrowExpression) {
    return _exitPoints((XThrowExpression)expression);
  } else if (expression instanceof XTryCatchFinallyExpression) {
    return _exitPoints((XTryCatchFinallyExpression)expression);
  } else if (expression instanceof XVariableDeclaration) {
    return _exitPoints((XVariableDeclaration)expression);
  } else if (expression != null) {
    return _exitPoints(expression);
  } else {
    throw new IllegalArgumentException("Unhandled parameter types: " +
      Arrays.<Object>asList(expression).toString());
  }
}
 

protected void _findImplicitReturns(final XTryCatchFinallyExpression expression, final ImplicitReturnFinder.Acceptor acceptor) {
  this.findImplicitReturns(expression.getExpression(), acceptor);
  final Consumer<XCatchClause> _function = (XCatchClause it) -> {
    this.findImplicitReturns(it.getExpression(), acceptor);
  };
  expression.getCatchClauses().forEach(_function);
}
 

@Override
protected void internalToConvertedExpression(XExpression obj, ITreeAppendable appendable) {
	if (obj instanceof XBlockExpression) {
		_toJavaExpression((XBlockExpression) obj, appendable);
	} else if (obj instanceof XCastedExpression) {
		_toJavaExpression((XCastedExpression) obj, appendable);
	} else if (obj instanceof XClosure) {
		_toJavaExpression((XClosure) obj, appendable);
	} else if (obj instanceof XAnnotation) {
		_toJavaExpression((XAnnotation) obj, appendable);
	} else if (obj instanceof XConstructorCall) {
		_toJavaExpression((XConstructorCall) obj, appendable);
	} else if (obj instanceof XIfExpression) {
		_toJavaExpression((XIfExpression) obj, appendable);
	} else if (obj instanceof XInstanceOfExpression) {
		_toJavaExpression((XInstanceOfExpression) obj, appendable);
	} else if (obj instanceof XSwitchExpression) {
		_toJavaExpression((XSwitchExpression) obj, appendable);
	} else if (obj instanceof XTryCatchFinallyExpression) {
		_toJavaExpression((XTryCatchFinallyExpression) obj, appendable);
	} else if (obj instanceof XListLiteral) {
		_toJavaExpression((XListLiteral) obj, appendable);
	} else if (obj instanceof XSetLiteral) {
		_toJavaExpression((XSetLiteral) obj, appendable);
	} else if (obj instanceof XSynchronizedExpression) {
		_toJavaExpression((XSynchronizedExpression) obj, appendable);
	} else if (obj instanceof XReturnExpression) {
		_toJavaExpression((XReturnExpression) obj, appendable);
	} else if (obj instanceof XThrowExpression) {
		_toJavaExpression((XThrowExpression) obj, appendable);
	} else {
		super.internalToConvertedExpression(obj, appendable);
	}
}
 

/**
 * @since 2.18
 */
protected void appendFinallyWithResources(XTryCatchFinallyExpression expr, ITreeAppendable b) {
	final String throwablesStore = b.getName(Tuples.pair(expr, "_caughtThrowables"));
	List<XVariableDeclaration> resources = expr.getResources();
	if (!resources.isEmpty()) {
		for (int i = resources.size() - 1; i >= 0; i--) {
			b.openPseudoScope();
			XVariableDeclaration res = resources.get(i);
			String resName = getVarName(res, b);
			b.newLine().append("if (" + resName + " != null) {");
			b.increaseIndentation();
			b.newLine().append("try {");
			b.increaseIndentation();
			b.newLine().append(resName + ".close();");
			// close inner try
			closeBlock(b);
			String throwable = b.declareSyntheticVariable(Tuples.pair(res, "_caughtThrowable"), "_t");
			b.append(" catch (").append(Throwable.class).append(" " + throwable + ") {");
			b.increaseIndentation();
			b.newLine().append(throwablesStore);
			b.append(".add(" + throwable + ");");
			// close inner catch
			closeBlock(b);
			// close if != null check
			closeBlock(b);
			b.closeScope();
		}
		b.newLine().append("if(!");
		b.append(throwablesStore);
		b.append(".isEmpty()) ");
		appendSneakyThrow(expr, b, throwablesStore + ".get(0)");
	}
}
 

protected void appendSneakyThrow(XTryCatchFinallyExpression expr, ITreeAppendable b, String variable) {
	final JvmType sneakyThrowType = findKnownTopLevelType(Exceptions.class, expr);
	if (sneakyThrowType == null) {
		b.append("COMPILE ERROR : '" + Exceptions.class.getCanonicalName()
				+ "' could not be found on the classpath!");
	} else {
		b.append("throw ");
		b.append(sneakyThrowType);
		b.append(".sneakyThrow(");
		b.append(variable);
		b.append(");");
	}
}
 

public void findImplicitReturns(final XExpression expression, final ImplicitReturnFinder.Acceptor acceptor) {
  if (expression instanceof XAbstractFeatureCall) {
    _findImplicitReturns((XAbstractFeatureCall)expression, acceptor);
    return;
  } else if (expression instanceof XBlockExpression) {
    _findImplicitReturns((XBlockExpression)expression, acceptor);
    return;
  } else if (expression instanceof XBooleanLiteral) {
    _findImplicitReturns((XBooleanLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XCastedExpression) {
    _findImplicitReturns((XCastedExpression)expression, acceptor);
    return;
  } else if (expression instanceof XClosure) {
    _findImplicitReturns((XClosure)expression, acceptor);
    return;
  } else if (expression instanceof XCollectionLiteral) {
    _findImplicitReturns((XCollectionLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XConstructorCall) {
    _findImplicitReturns((XConstructorCall)expression, acceptor);
    return;
  } else if (expression instanceof XIfExpression) {
    _findImplicitReturns((XIfExpression)expression, acceptor);
    return;
  } else if (expression instanceof XInstanceOfExpression) {
    _findImplicitReturns((XInstanceOfExpression)expression, acceptor);
    return;
  } else if (expression instanceof XNullLiteral) {
    _findImplicitReturns((XNullLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XNumberLiteral) {
    _findImplicitReturns((XNumberLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XStringLiteral) {
    _findImplicitReturns((XStringLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XSwitchExpression) {
    _findImplicitReturns((XSwitchExpression)expression, acceptor);
    return;
  } else if (expression instanceof XSynchronizedExpression) {
    _findImplicitReturns((XSynchronizedExpression)expression, acceptor);
    return;
  } else if (expression instanceof XTryCatchFinallyExpression) {
    _findImplicitReturns((XTryCatchFinallyExpression)expression, acceptor);
    return;
  } else if (expression instanceof XTypeLiteral) {
    _findImplicitReturns((XTypeLiteral)expression, acceptor);
    return;
  } else if (expression != null) {
    _findImplicitReturns(expression, acceptor);
    return;
  } else if (expression == null) {
    _findImplicitReturns((Void)null, acceptor);
    return;
  } else {
    throw new IllegalArgumentException("Unhandled parameter types: " +
      Arrays.<Object>asList(expression, acceptor).toString());
  }
}
 

@Deprecated
protected void sequence_XTryCatchFinallyExpression(EObject context, XTryCatchFinallyExpression semanticObject) {
	sequence_XTryCatchFinallyExpression(createContext(context, semanticObject), semanticObject);
}
 

public void findImplicitReturns(final XExpression expression, final ImplicitReturnFinder.Acceptor acceptor) {
  if (expression instanceof AnonymousClass) {
    _findImplicitReturns((AnonymousClass)expression, acceptor);
    return;
  } else if (expression instanceof RichString) {
    _findImplicitReturns((RichString)expression, acceptor);
    return;
  } else if (expression instanceof XAbstractFeatureCall) {
    _findImplicitReturns((XAbstractFeatureCall)expression, acceptor);
    return;
  } else if (expression instanceof XBlockExpression) {
    _findImplicitReturns((XBlockExpression)expression, acceptor);
    return;
  } else if (expression instanceof XBooleanLiteral) {
    _findImplicitReturns((XBooleanLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XCastedExpression) {
    _findImplicitReturns((XCastedExpression)expression, acceptor);
    return;
  } else if (expression instanceof XClosure) {
    _findImplicitReturns((XClosure)expression, acceptor);
    return;
  } else if (expression instanceof XCollectionLiteral) {
    _findImplicitReturns((XCollectionLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XConstructorCall) {
    _findImplicitReturns((XConstructorCall)expression, acceptor);
    return;
  } else if (expression instanceof XIfExpression) {
    _findImplicitReturns((XIfExpression)expression, acceptor);
    return;
  } else if (expression instanceof XInstanceOfExpression) {
    _findImplicitReturns((XInstanceOfExpression)expression, acceptor);
    return;
  } else if (expression instanceof XNullLiteral) {
    _findImplicitReturns((XNullLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XNumberLiteral) {
    _findImplicitReturns((XNumberLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XStringLiteral) {
    _findImplicitReturns((XStringLiteral)expression, acceptor);
    return;
  } else if (expression instanceof XSwitchExpression) {
    _findImplicitReturns((XSwitchExpression)expression, acceptor);
    return;
  } else if (expression instanceof XSynchronizedExpression) {
    _findImplicitReturns((XSynchronizedExpression)expression, acceptor);
    return;
  } else if (expression instanceof XTryCatchFinallyExpression) {
    _findImplicitReturns((XTryCatchFinallyExpression)expression, acceptor);
    return;
  } else if (expression instanceof XTypeLiteral) {
    _findImplicitReturns((XTypeLiteral)expression, acceptor);
    return;
  } else if (expression != null) {
    _findImplicitReturns(expression, acceptor);
    return;
  } else if (expression == null) {
    _findImplicitReturns((Void)null, acceptor);
    return;
  } else {
    throw new IllegalArgumentException("Unhandled parameter types: " +
      Arrays.<Object>asList(expression, acceptor).toString());
  }
}
 

@Override
public void computeTypes(XExpression expression, ITypeComputationState state) {
	if (expression instanceof XAssignment) {
		_computeTypes((XAssignment)expression, state);
	} else if (expression instanceof XAbstractFeatureCall) {
		_computeTypes((XAbstractFeatureCall)expression, state);
	} else if (expression instanceof XDoWhileExpression) {
		_computeTypes((XDoWhileExpression)expression, state);
	} else if (expression instanceof XWhileExpression) {
		_computeTypes((XWhileExpression)expression, state);
	} else if (expression instanceof XBlockExpression) {
		_computeTypes((XBlockExpression)expression, state);
	} else if (expression instanceof XBooleanLiteral) {
		_computeTypes((XBooleanLiteral)expression, state);
	} else if (expression instanceof XCastedExpression) {
		_computeTypes((XCastedExpression)expression, state);
	} else if (expression instanceof XClosure) {
		_computeTypes((XClosure)expression, state);
	} else if (expression instanceof XConstructorCall) {
		_computeTypes((XConstructorCall)expression, state);
	} else if (expression instanceof XForLoopExpression) {
		_computeTypes((XForLoopExpression)expression, state);
	} else if (expression instanceof XBasicForLoopExpression) {
		_computeTypes((XBasicForLoopExpression)expression, state);
	} else if (expression instanceof XIfExpression) {
		_computeTypes((XIfExpression)expression, state);
	} else if (expression instanceof XInstanceOfExpression) {
		_computeTypes((XInstanceOfExpression)expression, state);
	} else if (expression instanceof XNumberLiteral) {
		_computeTypes((XNumberLiteral)expression, state);
	} else if (expression instanceof XNullLiteral) {
		_computeTypes((XNullLiteral)expression, state);
	} else if (expression instanceof XReturnExpression) {
		_computeTypes((XReturnExpression)expression, state);
	} else if (expression instanceof XStringLiteral) {
		_computeTypes((XStringLiteral)expression, state);
	} else if (expression instanceof XSwitchExpression) {
		_computeTypes((XSwitchExpression)expression, state);
	} else if (expression instanceof XThrowExpression) {
		_computeTypes((XThrowExpression)expression, state);
	} else if (expression instanceof XTryCatchFinallyExpression) {
		_computeTypes((XTryCatchFinallyExpression)expression, state);
	} else if (expression instanceof XTypeLiteral) {
		_computeTypes((XTypeLiteral)expression, state);
	} else if (expression instanceof XVariableDeclaration) {
		_computeTypes((XVariableDeclaration)expression, state);
	} else if (expression instanceof XListLiteral) {
		_computeTypes((XListLiteral)expression, state);
	} else if (expression instanceof XSetLiteral) {
		_computeTypes((XSetLiteral)expression, state);
	} else if (expression instanceof XSynchronizedExpression) {
		_computeTypes((XSynchronizedExpression)expression, state);
	} else {
		throw new UnsupportedOperationException("Missing type computation for expression type: " + expression.eClass().getName() + " / " + state);
	}
}
 

@Override
public Boolean caseXTryCatchFinallyExpression(XTryCatchFinallyExpression object) {
	List<XVariableDeclaration> resources = object.getResources();
	List<XCatchClause> clauses = object.getCatchClauses();

	if (clauses.isEmpty()) {
		// collect exceptions thrown by automatic close method
		// of given resources
		processExceptionsFromAutoclosable(resources, delegate);
		// let procedure traverse child elements, to check if they throw
		// exceptions
		return Boolean.TRUE;
	}

	// traverse child elements explicitly, to filter for caught exceptions
	final List<LightweightTypeReference> caughtExceptions = Lists.newArrayList();
	boolean wasThrowable = false;
	for (XCatchClause clause : clauses) {
		JvmTypeReference caught = clause.getDeclaredParam().getParameterType();
		if (caught != null) {
			LightweightTypeReference caughtException = delegate.toLightweightReference(caught)
					.getRawTypeReference();
			if (caughtException.isType(Throwable.class)) {
				wasThrowable = true;
			}
			if (caughtException.isSynonym()) {
				caughtExceptions.addAll(caughtException.getMultiTypeComponents());
			} else {
				caughtExceptions.add(caughtException);
			}
		}
		delegate.collectThrownExceptions(clause.getExpression());
	}
	delegate.collectThrownExceptions(object.getFinallyExpression());
	if (wasThrowable) {
		// Stop child traversing of procedure
		return Boolean.FALSE;
	}

	// Filter caught exceptions from all thrown excpetions
	// (thrown by resource constructor/automatic close, try expressions)
	IThrownExceptionDelegate filteredDelegate = delegate.catchExceptions(caughtExceptions);
	processExceptionsFromAutoclosable(resources, filteredDelegate);
	filteredDelegate.collectThrownExceptions(object.getExpression());
	// Stop child traversing of procedure
	return Boolean.FALSE;
}
 

/**
 * Returns <code>true</code> for expressions that seem to be early exit expressions, e.g.
 * <pre>
 *   while(condition) {
 *     if (anotherCondition)
 *       return value
 *     changeResultOfFirstCondition
 *   }
 * </pre>
 */
public boolean isIntentionalEarlyExit(/* @Nullable */ XExpression expression) {
	if (expression == null) {
		return true;
	}
	if (expression instanceof XBlockExpression) {
		XBlockExpression block = (XBlockExpression) expression;
		List<XExpression> children = block.getExpressions();
		for(XExpression child: children) {
			if (isIntentionalEarlyExit(child)) {
				return true;
			}
		}
	} else if (expression instanceof XIfExpression) {
		return isIntentionalEarlyExit(((XIfExpression) expression).getThen()) 
				|| isIntentionalEarlyExit(((XIfExpression) expression).getElse());
	} else if (expression instanceof XSwitchExpression) {
		XSwitchExpression switchExpression = (XSwitchExpression) expression;
		for(XCasePart caseExpression: switchExpression.getCases()) {
			if (isIntentionalEarlyExit(caseExpression.getThen())) {
				return true;
			}
		}
		if (isIntentionalEarlyExit(switchExpression.getDefault())) {
			return true;
		}
	} else if (expression instanceof XTryCatchFinallyExpression) {
		XTryCatchFinallyExpression tryCatchFinally = (XTryCatchFinallyExpression) expression;
		if (isIntentionalEarlyExit(tryCatchFinally.getExpression())) {
			for(XCatchClause catchClause: tryCatchFinally.getCatchClauses()) {
				if (!isIntentionalEarlyExit(catchClause.getExpression()))
					return false;
			}
			return true;
		}
		return false;
	} else if (expression instanceof XAbstractWhileExpression) {
		return isIntentionalEarlyExit(((XAbstractWhileExpression) expression).getBody());
	} else if (expression instanceof XForLoopExpression) {
		return isIntentionalEarlyExit(((XForLoopExpression) expression).getEachExpression());
	} else if (expression instanceof XBasicForLoopExpression) {
		return isIntentionalEarlyExit(((XBasicForLoopExpression) expression).getEachExpression());
	} else if (expression instanceof XSynchronizedExpression) {
		return isIntentionalEarlyExit(((XSynchronizedExpression) expression).getExpression());
	}
	return expression instanceof XReturnExpression || expression instanceof XThrowExpression;
}
 

public boolean isDefiniteEarlyExit(XExpression expression) {
	// TODO further improvements
	if (expression instanceof XIfExpression) {
		XIfExpression ifExpression = (XIfExpression) expression;
		return isDefiniteEarlyExit(ifExpression.getThen()) && isDefiniteEarlyExit(ifExpression.getElse());
	} else if (expression instanceof XSwitchExpression) {
		XSwitchExpression switchExpression = (XSwitchExpression) expression;
		if (isDefiniteEarlyExit(switchExpression.getDefault())) {
			for(XCasePart caseExpression: switchExpression.getCases()) {
				if (!isDefiniteEarlyExit(caseExpression.getThen())) {
					return false;
				}
			}
			return true;
		}
		return false;
	} else if (expression instanceof XTryCatchFinallyExpression) {
		XTryCatchFinallyExpression tryExpression = (XTryCatchFinallyExpression) expression;
		if (isDefiniteEarlyExit(tryExpression.getFinallyExpression())) {
			return true;
		}
		if (isDefiniteEarlyExit(tryExpression.getExpression())) {
			for(XCatchClause catchClause: tryExpression.getCatchClauses()) {
				if (!isDefiniteEarlyExit(catchClause.getExpression())) {
					return false;
				}
			}
			return true;
		}
		return false;
	} else if (expression instanceof XBlockExpression) {
		List<XExpression> expressions = ((XBlockExpression) expression).getExpressions();
		for(int i = expressions.size() - 1; i >= 0; i--) {
			if (isDefiniteEarlyExit(expressions.get(i))) {
				return true;
			}
		}
	} else if (expression instanceof XSynchronizedExpression) {
		return isDefiniteEarlyExit(((XSynchronizedExpression) expression).getExpression());
	}
	return expression instanceof XReturnExpression || expression instanceof XThrowExpression;
}
 

@Override
protected void doInternalToJavaStatement(XExpression obj, ITreeAppendable appendable, boolean isReferenced) {
	if (obj instanceof XBlockExpression) {
		_toJavaStatement((XBlockExpression) obj, appendable, isReferenced);
	} else if (obj instanceof XCastedExpression) {
		_toJavaStatement((XCastedExpression) obj, appendable, isReferenced);
	} else if (obj instanceof XClosure) {
		_toJavaStatement((XClosure) obj, appendable, isReferenced);
	} else if (obj instanceof XConstructorCall) {
		_toJavaStatement((XConstructorCall) obj, appendable, isReferenced);
	} else if (obj instanceof XDoWhileExpression) {
		_toJavaStatement((XDoWhileExpression) obj, appendable, isReferenced);
	} else if (obj instanceof XForLoopExpression) {
		_toJavaStatement((XForLoopExpression) obj, appendable, isReferenced);
	} else if (obj instanceof XBasicForLoopExpression) {
		_toJavaStatement((XBasicForLoopExpression) obj, appendable, isReferenced);
	} else if (obj instanceof XIfExpression) {
		_toJavaStatement((XIfExpression) obj, appendable, isReferenced);
	} else if (obj instanceof XInstanceOfExpression) {
		_toJavaStatement((XInstanceOfExpression) obj, appendable, isReferenced);
	} else if (obj instanceof XReturnExpression) {
		_toJavaStatement((XReturnExpression) obj, appendable, isReferenced);
	} else if (obj instanceof XSwitchExpression) {
		_toJavaStatement((XSwitchExpression) obj, appendable, isReferenced);
	} else if (obj instanceof XThrowExpression) {
		_toJavaStatement((XThrowExpression) obj, appendable, isReferenced);
	} else if (obj instanceof XTryCatchFinallyExpression) {
		_toJavaStatement((XTryCatchFinallyExpression) obj, appendable, isReferenced);
	} else if (obj instanceof XVariableDeclaration) {
		_toJavaStatement((XVariableDeclaration) obj, appendable, isReferenced);
	} else if (obj instanceof XWhileExpression) {
		_toJavaStatement((XWhileExpression) obj, appendable, isReferenced);
	} else if (obj instanceof XListLiteral) {
		_toJavaStatement((XListLiteral) obj, appendable, isReferenced);
	} else if (obj instanceof XSetLiteral) {
		_toJavaStatement((XSetLiteral) obj, appendable, isReferenced);
	} else if (obj instanceof XSynchronizedExpression) {
		_toJavaStatement((XSynchronizedExpression) obj, appendable, isReferenced);
	} else {
		super.doInternalToJavaStatement(obj, appendable, isReferenced);
	}
}