getDetachedInitializer() to avoid excessive stub-to-AST switches in PsiUtil.isConstantExpression()

java/java-psi-api/src/com/intellij/psi/JavaPsiFacade.java

@@ -144,4 +144,6 @@ public abstract class JavaPsiFacade {
 
   @NotNull
   public abstract Project getProject();
+
+  public abstract boolean isConstantExpression(@NotNull PsiExpression expression);
 }

java/java-psi-api/src/com/intellij/psi/util/IsConstantExpressionVisitor.java

@@ -1,151 +0,0 @@
-/*
- * Copyright 2000-2014 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.intellij.psi.util;
-
-import com.intellij.psi.*;
-import com.intellij.psi.tree.IElementType;
-import gnu.trove.THashMap;
-
-import java.util.Map;
-
-class IsConstantExpressionVisitor extends JavaElementVisitor {
-  private boolean myIsConstant;
-  private final Map<PsiVariable, Boolean> varIsConst = new THashMap<PsiVariable, Boolean>();
-
-  public boolean isConstant() {
-    return myIsConstant;
-  }
-
-  @Override
-  public void visitExpression(PsiExpression expression) {
-    myIsConstant = false;
-  }
-
-  @Override
-  public void visitLiteralExpression(PsiLiteralExpression expression) {
-    myIsConstant = !"null".equals(expression.getText());
-  }
-
-  @Override
-  public void visitClassObjectAccessExpression(PsiClassObjectAccessExpression expression) {
-    myIsConstant = true;
-  }
-
-  @Override
-  public void visitParenthesizedExpression(PsiParenthesizedExpression expression) {
-    PsiExpression expr = expression.getExpression();
-    if (expr != null) {
-      expr.accept(this);
-    }
-  }
-
-  @Override
-  public void visitTypeCastExpression(PsiTypeCastExpression expression) {
-    PsiExpression operand = expression.getOperand();
-    if (operand == null) {
-      myIsConstant = false;
-      return;
-    }
-    operand.accept(this);
-    if (!myIsConstant) return;
-    PsiTypeElement element = expression.getCastType();
-    if (element == null) {
-      myIsConstant = false;
-      return;
-    }
-    PsiType type = element.getType();
-    if (type instanceof PsiPrimitiveType) return;
-    if (type.equalsToText(CommonClassNames.JAVA_LANG_STRING)) return;
-    myIsConstant = false;
-  }
-
-  @Override
-  public void visitPrefixExpression(PsiPrefixExpression expression) {
-    PsiExpression operand = expression.getOperand();
-    if (operand == null) {
-      myIsConstant = false;
-      return;
-    }
-    operand.accept(this);
-    if (!myIsConstant) return;
-    IElementType opType = expression.getOperationTokenType();
-    if (opType == JavaTokenType.PLUS || opType == JavaTokenType.MINUS || opType == JavaTokenType.TILDE || opType == JavaTokenType.EXCL) {
-      return;
-    }
-    myIsConstant = false;
-  }
-
-  @Override
-  public void visitPolyadicExpression(PsiPolyadicExpression expression) {
-    for (PsiExpression operand : expression.getOperands()) {
-      operand.accept(this);
-      if (!myIsConstant) return;
-      final PsiType type = operand.getType();
-      if (type != null && !(type instanceof PsiPrimitiveType) && !type.equalsToText(CommonClassNames.JAVA_LANG_STRING)) {
-        myIsConstant = false;
-        return;
-      }
-    }
-  }
-
-  @Override
-  public void visitConditionalExpression(PsiConditionalExpression expression) {
-    PsiExpression thenExpr = expression.getThenExpression();
-    PsiExpression elseExpr = expression.getElseExpression();
-    if (thenExpr == null || elseExpr == null) {
-      myIsConstant = false;
-      return;
-    }
-
-    expression.getCondition().accept(this);
-    if (!myIsConstant) return;
-    thenExpr.accept(this);
-    if (!myIsConstant) return;
-    elseExpr.accept(this);
-  }
-
-  @Override
-  public void visitReferenceExpression(PsiReferenceExpression expression) {
-    PsiElement refElement = expression.resolve();
-    if (!(refElement instanceof PsiVariable)) {
-      myIsConstant = false;
-      return;
-    }
-    PsiVariable variable = (PsiVariable)refElement;
-    Boolean isConst = varIsConst.get(variable);
-    if (isConst != null) {
-      myIsConstant &= isConst.booleanValue();
-      return;
-    }
-    if (variable instanceof PsiEnumConstant) {
-      myIsConstant = true;
-      varIsConst.put(variable, Boolean.TRUE);
-      return;
-    }
-    varIsConst.put(variable, Boolean.FALSE);
-    if (!variable.hasModifierProperty(PsiModifier.FINAL)){
-      myIsConstant = false;
-      return;
-    }
-    PsiExpression initializer = variable.getInitializer();
-    if (initializer == null){
-      myIsConstant = false;
-      return;
-    }
-    initializer.accept(this);
-    varIsConst.put(variable, myIsConstant);
-  }
-}

java/java-psi-api/src/com/intellij/psi/util/PsiUtil.java

@@ -153,10 +153,7 @@ public final class PsiUtil extends PsiUtilCore {
   }
 
   public static boolean isConstantExpression(@Nullable PsiExpression expression) {
-    if (expression == null) return false;
-    IsConstantExpressionVisitor visitor = new IsConstantExpressionVisitor();
-    expression.accept(visitor);
-    return visitor.isConstant();
+    return expression != null && JavaPsiFacade.getInstance(expression.getProject()).isConstantExpression(expression);
   }
 
   // todo: move to PsiThrowsList?