Java 类org.eclipse.xtext.xbase.XIfExpression 实例源码

protected void _computeTypes(XIfExpression object, ITypeComputationState state) {
    ITypeComputationState conditionExpectation = state.withExpectation(getRawTypeForName(Boolean.TYPE, state));
    XExpression condition = object.getIf();
    conditionExpectation.computeTypes(condition);

    // TODO then expression may influence the expected type of else and vice versa
    XExpression thenExpression = getThen(object);
    ITypeComputationState thenState = reassignCheckedType(condition, thenExpression, state);
    ITypeComputationResult thenResult = thenState.computeTypes(thenExpression);
    XExpression elseExpression = getElse(object);
    if (elseExpression != null) {
        state.computeTypes(elseExpression);
    } else {
        BranchExpressionProcessor processor = new BranchExpressionProcessor(state, object) {
            @Override
            protected String getMessage() {
                return "Missing else branch for conditional expression with primitive type";
            }
        };
        processor.process(thenResult);
        processor.commit();
    }
}

/**
 * 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);
}

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;
}

@Test public void testSerialize_02() throws Exception {
    Resource resource = newResource("'foo' as String");
    XCastedExpression casted = (XCastedExpression) resource.getContents().get(0);

    XbaseFactory factory = XbaseFactory.eINSTANCE;
    XIfExpression ifExpression = factory.createXIfExpression();
    ifExpression.setIf(factory.createXBooleanLiteral());
    XStringLiteral stringLiteral = factory.createXStringLiteral();
    stringLiteral.setValue("value");
    ifExpression.setThen(stringLiteral);
    XInstanceOfExpression instanceOfExpression = factory.createXInstanceOfExpression();
    instanceOfExpression.setExpression(ifExpression);
    instanceOfExpression.setType(EcoreUtil.copy(casted.getType()));
    resource.getContents().clear();
    resource.getContents().add(instanceOfExpression);
    ISerializer serializer = get(ISerializer.class);
    String string = serializer.serialize(instanceOfExpression);
    // see https://bugs.eclipse.org/bugs/show_bug.cgi?id=464846
    assertEquals("( if(false) \"value\" ) instanceof String", string);

    XInstanceOfExpression parsedExpression = parseHelper.parse(string);
    assertTrue(EcoreUtil.equals(instanceOfExpression, parsedExpression));
}

@Test
public void testReassignedType_01() {
  try {
    StringConcatenation _builder = new StringConcatenation();
    _builder.append("{ var it = new Object() if (it instanceof String) {} }");
    XExpression _expression = this.expression(_builder, false);
    XExpression _last = IterableExtensions.<XExpression>last(((XBlockExpression) _expression).getExpressions());
    final XIfExpression ifExpr = ((XIfExpression) _last);
    XExpression _then = ifExpr.getThen();
    final XBlockExpression block = ((XBlockExpression) _then);
    final IExpressionScope expressionScope = this._iBatchTypeResolver.resolveTypes(block).getExpressionScope(block, IExpressionScope.Anchor.BEFORE);
    this.contains(expressionScope, "charAt");
    this.contains(expressionScope, "it");
    this.contains(expressionScope, "operator_lessThan");
  } catch (Throwable _e) {
    throw Exceptions.sneakyThrow(_e);
  }
}

@Test
public void testReassignedType_02() {
  try {
    StringConcatenation _builder = new StringConcatenation();
    _builder.append("{ var it = new Object() if (it instanceof String) { it = new Object() } }");
    XExpression _expression = this.expression(_builder, false);
    XExpression _last = IterableExtensions.<XExpression>last(((XBlockExpression) _expression).getExpressions());
    final XIfExpression ifExpr = ((XIfExpression) _last);
    XExpression _then = ifExpr.getThen();
    final XBlockExpression block = ((XBlockExpression) _then);
    final IExpressionScope expressionScope = this._iBatchTypeResolver.resolveTypes(block).getExpressionScope(block, IExpressionScope.Anchor.BEFORE);
    this.contains(expressionScope, "charAt");
    this.contains(expressionScope, "it");
    this.contains(expressionScope, "operator_lessThan");
  } catch (Throwable _e) {
    throw Exceptions.sneakyThrow(_e);
  }
}

@Test
public void testReassignedType_03() {
  try {
    StringConcatenation _builder = new StringConcatenation();
    _builder.append("{ var it = new Object() if (it instanceof String) { it = new Object() } }");
    XExpression _expression = this.expression(_builder, false);
    XExpression _last = IterableExtensions.<XExpression>last(((XBlockExpression) _expression).getExpressions());
    final XIfExpression ifExpr = ((XIfExpression) _last);
    XExpression _then = ifExpr.getThen();
    final XBlockExpression block = ((XBlockExpression) _then);
    final XExpression assignment = IterableExtensions.<XExpression>head(block.getExpressions());
    final IExpressionScope expressionScope = this._iBatchTypeResolver.resolveTypes(assignment).getExpressionScope(assignment, IExpressionScope.Anchor.AFTER);
    this.containsNot(expressionScope, "charAt");
    this.contains(expressionScope, "it");
    this.containsNot(expressionScope, "operator_lessThan");
  } catch (Throwable _e) {
    throw Exceptions.sneakyThrow(_e);
  }
}

private List<XExpression> collectIfParts(XIfExpression expression, List<XExpression> result) {
    result.add(expression.getIf());
    if (expression.getElse() instanceof XIfExpression) {
        collectIfParts((XIfExpression) expression.getElse(), result);
    }
    return result;
}

@Check
public void checkDeadCode(XIfExpression condition) {
    if (!earlyExitComputer.isEarlyExit(condition.getIf())) {
        validateCondition(condition.getIf(), false);
    } else {
        if (!markAsDeadCode(condition.getThen())) {
            markAsDeadCode(condition.getElse());
        }
    }
}

@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);
    }
}

protected void _toJavaStatement(XIfExpression expr, ITreeAppendable b, boolean isReferenced) {
    if (isReferenced)
        declareSyntheticVariable(expr, b);
    internalToJavaStatement(expr.getIf(), b, true);
    b.newLine().append("if (");
    internalToJavaExpression(expr.getIf(), b);
    b.append(") {").increaseIndentation();
    final boolean canBeReferenced = isReferenced && !isPrimitiveVoid(expr.getThen());
    internalToJavaStatement(expr.getThen(), b, canBeReferenced);
    if (canBeReferenced) {
        b.newLine();
        b.append(getVarName(expr, b));
        b.append(" = ");
        internalToConvertedExpression(expr.getThen(), b, getLightweightType(expr));
        b.append(";");
    }
    b.decreaseIndentation().newLine().append("}");
    if (expr.getElse() != null) {
        b.append(" else {").increaseIndentation();
        final boolean canElseBeReferenced = isReferenced && !isPrimitiveVoid(expr.getElse());
        internalToJavaStatement(expr.getElse(), b, canElseBeReferenced);
        if (canElseBeReferenced) {
            b.newLine();
            b.append(getVarName(expr, b));
            b.append(" = ");
            internalToConvertedExpression(expr.getElse(), b, getLightweightType(expr));
            b.append(";");
        }
        b.decreaseIndentation().newLine().append("}");
    }
}

protected Object _doEvaluate(XIfExpression ifExpression, IEvaluationContext context, CancelIndicator indicator) {
    Object conditionResult = internalEvaluate(ifExpression.getIf(), context, indicator);
    if (Boolean.TRUE.equals(conditionResult)) {
        return internalEvaluate(ifExpression.getThen(), context, indicator);
    } else {
        if (ifExpression.getElse() == null)
            return getDefaultObjectValue(typeResolver.resolveTypes(ifExpression).getActualType(ifExpression));
        return internalEvaluate(ifExpression.getElse(), context, indicator);
    }
}

protected Collection<IEarlyExitComputer.ExitPoint> _exitPoints(final XIfExpression expression) {
  Collection<IEarlyExitComputer.ExitPoint> ifExitPoints = this.getExitPoints(expression.getIf());
  boolean _isNotEmpty = this.isNotEmpty(ifExitPoints);
  if (_isNotEmpty) {
    return ifExitPoints;
  }
  Collection<IEarlyExitComputer.ExitPoint> thenExitPoints = this.getExitPoints(expression.getThen());
  Collection<IEarlyExitComputer.ExitPoint> elseExitPoints = this.getExitPoints(expression.getElse());
  if ((this.isNotEmpty(thenExitPoints) && this.isNotEmpty(elseExitPoints))) {
    Collection<IEarlyExitComputer.ExitPoint> result = Lists.<IEarlyExitComputer.ExitPoint>newArrayList(thenExitPoints);
    result.addAll(elseExitPoints);
    return result;
  }
  return Collections.<IEarlyExitComputer.ExitPoint>emptyList();
}

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());
  }
}

@Test public void testIf_3() throws Exception {
    XIfExpression ie = (XIfExpression) expression("if (foo) bar else if (baz) if (apa) bpa else cpa");
    XIfExpression nestedIf = (XIfExpression) ie.getElse();
    XIfExpression secondNested = (XIfExpression) nestedIf.getThen();
    XFeatureCall cpa = (XFeatureCall) secondNested.getElse();
    assertEquals("cpa",cpa.getConcreteSyntaxFeatureName());
}

@Test public void testIfExpression() throws Exception {
    XIfExpression target = (XIfExpression) expressionWithExpectedType("if (null) null else null", "String");

    assertExpected("boolean", target.getIf()); // if (null) is invalid thus we expect the primitive boolean
    assertExpected("java.lang.String", target.getThen());
    assertExpected("java.lang.String", target.getElse());
}

@Test
public void testIf01() {
  try {
    StringConcatenation _builder = new StringConcatenation();
    _builder.append("if (true) 1 else 2");
    XExpression _expression = this.expression(_builder);
    final XIfExpression expr = ((XIfExpression) _expression);
    this.hasImplicitReturns(expr, expr.getThen(), expr.getElse());
  } catch (Throwable _e) {
    throw Exceptions.sneakyThrow(_e);
  }
}

@Deprecated
protected void sequence_XIfExpression(EObject context, XIfExpression semanticObject) {
    sequence_XIfExpression(createContext(context, semanticObject), semanticObject);
}

@Check
public void checkInstanceOfOrder(XIfExpression expression) {
    if (isIgnored(IssueCodes.UNREACHABLE_IF_BLOCK)) {
        return;
    }
    if (expression.eContainer() instanceof XIfExpression) {
        XIfExpression container = (XIfExpression) expression.eContainer();
        if (container.getElse() == expression) {
            return;
        }
    }
    List<XExpression> ifParts = collectIfParts(expression, new ArrayList<XExpression>());
    ITypeReferenceOwner owner = new StandardTypeReferenceOwner(getServices(), expression);
    Multimap<JvmIdentifiableElement, LightweightTypeReference> previousTypeReferences = HashMultimap.create();
    for (XExpression ifPart : ifParts) {
        if (!(ifPart instanceof XInstanceOfExpression)) {
            continue;
        }
        XInstanceOfExpression instanceOfExpression = (XInstanceOfExpression) ifPart;
        if (!(instanceOfExpression.getExpression() instanceof XAbstractFeatureCall)) {
            continue;
        }
        XAbstractFeatureCall featureCall = (XAbstractFeatureCall) instanceOfExpression.getExpression();
        JvmIdentifiableElement feature = featureCall.getFeature();
        if (!(feature instanceof XVariableDeclaration)
                && !(feature instanceof JvmField)
                && !(feature instanceof JvmFormalParameter)) {
            continue;
        }
        JvmTypeReference type = instanceOfExpression.getType();
        LightweightTypeReference actualType = owner.toLightweightTypeReference(type);
        if (actualType == null) {
            continue;
        }
        if (isHandled(actualType, previousTypeReferences.get(feature))) {
            addIssue("Unreachable code: The if condition can never match. It is already handled by a previous condition.", type, IssueCodes.UNREACHABLE_IF_BLOCK);
            continue;
        }
        previousTypeReferences.put(feature, actualType);
    }
}

@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);
    }
}

/**
 * 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);
    }
}

protected void _toJavaExpression(XIfExpression expr, ITreeAppendable b) {
    b.trace(expr, false).append(getVarName(expr, b));
}

@Override
protected boolean isVariableDeclarationRequired(XExpression expr, ITreeAppendable b, boolean recursive) {
    if (expr instanceof XAnnotation) {
        return false;
    }
    if (expr instanceof XListLiteral) {
        return false;
    }
    if (expr instanceof XSetLiteral) {
        return false;
    }
    if (expr instanceof XCastedExpression) {
        return false;
    }
    if (expr instanceof XInstanceOfExpression) {
        return false;
    }
    if (expr instanceof XMemberFeatureCall && isVariableDeclarationRequired((XMemberFeatureCall) expr, b))
        return true;
    EObject container = expr.eContainer();
    if ((container instanceof XVariableDeclaration)
        || (container instanceof XReturnExpression) 
        || (container instanceof XThrowExpression)) {
        return false;
    }
    if (container instanceof XIfExpression) {
        XIfExpression ifExpression = (XIfExpression) container;
        if (ifExpression.getThen() == expr || ifExpression.getElse() == expr) {
            return false;
        }
    }
    if (container instanceof XCasePart) {
        XCasePart casePart = (XCasePart) container;
        if (casePart.getThen() == expr) {
            return false;
        }
    }
    if (container instanceof XSwitchExpression) {
        XSwitchExpression switchExpression = (XSwitchExpression) container;
        if (switchExpression.getDefault() == expr) {
            return false;
        }
    }
    if (container instanceof XBlockExpression) {
        List<XExpression> siblings = ((XBlockExpression) container).getExpressions();
        if (siblings.get(siblings.size() - 1) == expr) {
            return isVariableDeclarationRequired(getFeatureCall(expr), expr, b);
        }
    }
    if (container instanceof XClosure) {
        if (((XClosure) container).getExpression() == expr) {
            return false;
        }
    }
    if (expr instanceof XAssignment) {
        XAssignment a = (XAssignment) expr;
        for (XExpression arg : getActualArguments(a)) {
            if (isVariableDeclarationRequired(arg, b, recursive)) {
                return true;
            }
        }
    }
    return super.isVariableDeclarationRequired(expr, b, recursive);
}

/**
 * don't call this directly. Always call evaluate() internalEvaluate()
 */
protected Object doEvaluate(XExpression expression, IEvaluationContext context, CancelIndicator indicator) {
    if (expression instanceof XAssignment) {
      return _doEvaluate((XAssignment)expression, context, indicator);
    } else if (expression instanceof XDoWhileExpression) {
      return _doEvaluate((XDoWhileExpression)expression, context, indicator);
    } else if (expression instanceof XMemberFeatureCall) {
      return _doEvaluate((XMemberFeatureCall)expression, context, indicator);
    } else if (expression instanceof XWhileExpression) {
      return _doEvaluate((XWhileExpression)expression, context, indicator);
    } else if (expression instanceof XFeatureCall) {
        return _doEvaluate((XFeatureCall)expression, context, indicator);
    } else if (expression instanceof XAbstractFeatureCall) {
        return _doEvaluate((XAbstractFeatureCall)expression, context, indicator);
    } else if (expression instanceof XBlockExpression) {
      return _doEvaluate((XBlockExpression)expression, context, indicator);
    } else if (expression instanceof XSynchronizedExpression) {
      return _doEvaluate((XSynchronizedExpression)expression, context, indicator);
    } else if (expression instanceof XBooleanLiteral) {
      return _doEvaluate((XBooleanLiteral)expression, context, indicator);
    } else if (expression instanceof XCastedExpression) {
      return _doEvaluate((XCastedExpression)expression, context, indicator);
    } else if (expression instanceof XClosure) {
      return _doEvaluate((XClosure)expression, context, indicator);
    } else if (expression instanceof XConstructorCall) {
      return _doEvaluate((XConstructorCall)expression, context, indicator);
    } else if (expression instanceof XForLoopExpression) {
      return _doEvaluate((XForLoopExpression)expression, context, indicator);
    } else if (expression instanceof XBasicForLoopExpression) {
      return _doEvaluate((XBasicForLoopExpression)expression, context, indicator);
    } else if (expression instanceof XIfExpression) {
      return _doEvaluate((XIfExpression)expression, context, indicator);
    } else if (expression instanceof XInstanceOfExpression) {
      return _doEvaluate((XInstanceOfExpression)expression, context, indicator);
    } else if (expression instanceof XNullLiteral) {
      return _doEvaluate((XNullLiteral)expression, context, indicator);
    } else if (expression instanceof XNumberLiteral) {
      return _doEvaluate((XNumberLiteral)expression, context, indicator);
    } else if (expression instanceof XReturnExpression) {
      return _doEvaluate((XReturnExpression)expression, context, indicator);
    } else if (expression instanceof XStringLiteral) {
      return _doEvaluate((XStringLiteral)expression, context, indicator);
    } else if (expression instanceof XSwitchExpression) {
      return _doEvaluate((XSwitchExpression)expression, context, indicator);
    } else if (expression instanceof XThrowExpression) {
      return _doEvaluate((XThrowExpression)expression, context, indicator);
    } else if (expression instanceof XTryCatchFinallyExpression) {
      return _doEvaluate((XTryCatchFinallyExpression)expression, context, indicator);
    } else if (expression instanceof XTypeLiteral) {
      return _doEvaluate((XTypeLiteral)expression, context, indicator);
    } else if (expression instanceof XVariableDeclaration) {
          return _doEvaluate((XVariableDeclaration)expression, context, indicator);
    } else if (expression instanceof XListLiteral) {
          return _doEvaluate((XListLiteral)expression, context, indicator);
    } else if (expression instanceof XSetLiteral) {
          return _doEvaluate((XSetLiteral)expression, context, indicator);
    } else {
      throw new IllegalArgumentException("Unhandled parameter types: " +
        Arrays.<Object>asList(expression, context, indicator).toString());
    }
}

protected void _findImplicitReturns(final XIfExpression expression, final ImplicitReturnFinder.Acceptor acceptor) {
  this.findImplicitReturns(expression.getThen(), acceptor);
  this.findImplicitReturns(expression.getElse(), acceptor);
}

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());
  }
}

@Override
protected XExpression getThen(XIfExpression ifExpression) {
    if (ifExpression.getElse() != null)
        return ifExpression.getElse();
    return super.getThen(ifExpression);
}

@Override
protected XExpression getElse(XIfExpression ifExpression) {
    if (ifExpression.getElse() != null)
        return ifExpression.getThen();
    return super.getElse(ifExpression);
}

@Test public void testIf_0() throws Exception {
    XIfExpression ie = (XIfExpression) expression("if (true) false");
    assertTrue(((XBooleanLiteral) ie.getIf()).isIsTrue());
    assertFalse(((XBooleanLiteral) ie.getThen()).isIsTrue());
    assertNull(ie.getElse());
}

@Test public void testIf_1() throws Exception {
    XIfExpression ie = (XIfExpression) expression("if (true) false else bar");
    assertTrue(((XBooleanLiteral) ie.getIf()).isIsTrue());
    assertFalse(((XBooleanLiteral) ie.getThen()).isIsTrue());
    assertTrue(ie.getElse() instanceof XFeatureCall);
}

@Test public void testIf_2() throws Exception {
    XIfExpression ie = (XIfExpression) expression("if (foo) bar else if (baz) apa else bpa");
    XIfExpression nestedIf = (XIfExpression) ie.getElse();
    XFeatureCall bpa = (XFeatureCall) nestedIf.getElse();
    assertEquals("bpa",bpa.getConcreteSyntaxFeatureName());
}

@Test public void testIfWithClosure() throws Exception {
    XIfExpression ie = (XIfExpression) expression("if (foo) [| if (bar) zonk else bar]");
    assertNull(ie.getElse());
}

@Test public void testIfWithAdd() throws Exception {
    XBinaryOperation bo = (XBinaryOperation) expression("1 + if (foo) bar + 2");
    assertTrue(bo.getExplicitArguments().get(1) instanceof XIfExpression);
}

/**
 * Contexts:
 *     XExpression returns XIfExpression
 *     XAssignment returns XIfExpression
 *     XAssignment.XBinaryOperation_1_1_0_0_0 returns XIfExpression
 *     XOrExpression returns XIfExpression
 *     XOrExpression.XBinaryOperation_1_0_0_0 returns XIfExpression
 *     XAndExpression returns XIfExpression
 *     XAndExpression.XBinaryOperation_1_0_0_0 returns XIfExpression
 *     XEqualityExpression returns XIfExpression
 *     XEqualityExpression.XBinaryOperation_1_0_0_0 returns XIfExpression
 *     XRelationalExpression returns XIfExpression
 *     XRelationalExpression.XInstanceOfExpression_1_0_0_0_0 returns XIfExpression
 *     XRelationalExpression.XBinaryOperation_1_1_0_0_0 returns XIfExpression
 *     XOtherOperatorExpression returns XIfExpression
 *     XOtherOperatorExpression.XBinaryOperation_1_0_0_0 returns XIfExpression
 *     XAdditiveExpression returns XIfExpression
 *     XAdditiveExpression.XBinaryOperation_1_0_0_0 returns XIfExpression
 *     XMultiplicativeExpression returns XIfExpression
 *     XMultiplicativeExpression.XBinaryOperation_1_0_0_0 returns XIfExpression
 *     XUnaryOperation returns XIfExpression
 *     XCastedExpression returns XIfExpression
 *     XCastedExpression.XCastedExpression_1_0_0_0 returns XIfExpression
 *     XPostfixOperation returns XIfExpression
 *     XPostfixOperation.XPostfixOperation_1_0_0 returns XIfExpression
 *     XMemberFeatureCall returns XIfExpression
 *     XMemberFeatureCall.XAssignment_1_0_0_0_0 returns XIfExpression
 *     XMemberFeatureCall.XMemberFeatureCall_1_1_0_0_0 returns XIfExpression
 *     XPrimaryExpression returns XIfExpression
 *     XParenthesizedExpression returns XIfExpression
 *     XIfExpression returns XIfExpression
 *     XExpressionOrVarDeclaration returns XIfExpression
 *
 * Constraint:
 *     (if=XExpression then=XExpression else=XExpression?)
 */
protected void sequence_XIfExpression(ISerializationContext context, XIfExpression semanticObject) {
    genericSequencer.createSequence(context, semanticObject);
}

/**
 * Only for testing purpose.
 * @nooverride This method is not intended to be re-implemented or extended by clients.
 * @noreference This method is not intended to be referenced by clients.
 */
/* @Nullable */
protected XExpression getElse(XIfExpression ifExpression) {
    return ifExpression.getElse();
}

/**
 * Only for testing purpose.
 * @nooverride This method is not intended to be re-implemented or extended by clients.
 * @noreference This method is not intended to be referenced by clients.
 */
/* @Nullable */
protected XExpression getThen(XIfExpression ifExpression) {
    return ifExpression.getThen();
}

/**
 * Constraint:
 *     (if=XExpression then=XExpression else=XExpression?)
 */
protected void sequence_XIfExpression(EObject context, XIfExpression semanticObject) {
    genericSequencer.createSequence(context, semanticObject);
}

/**
 * Constraint:
 *     (if=XExpression then=XExpression else=XExpression?)
 */
protected void sequence_XIfExpression(EObject context, XIfExpression semanticObject) {
    genericSequencer.createSequence(context, semanticObject);
}