plugins/IntentionPowerPak/src/com/siyeh/ipp/whileloop/ExtractWhileLoopConditionToIfStatementIntention.java

/*
 * Copyright 2007 Bas Leijdekkers
 *
 * 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.siyeh.ipp.whileloop;

import com.intellij.psi.*;
import com.intellij.psi.codeStyle.CodeStyleManager;
import com.intellij.util.IncorrectOperationException;
import com.siyeh.ipp.base.Intention;
import com.siyeh.ipp.base.PsiElementPredicate;
import org.jetbrains.annotations.NotNull;

public class ExtractWhileLoopConditionToIfStatementIntention extends Intention {

  @NotNull
  protected PsiElementPredicate getElementPredicate() {
    return new WhileLoopPredicate();
  }

  protected void processIntention(@NotNull PsiElement element)
    throws IncorrectOperationException {
    final PsiWhileStatement whileStatement =
      (PsiWhileStatement)element.getParent();
    if (whileStatement == null) {
      return;
    }
    final PsiExpression condition = whileStatement.getCondition();
    if (condition == null) {
      return;
    }
    final String conditionText = condition.getText();
    final PsiManager manager = whileStatement.getManager();
    final PsiElementFactory factory = JavaPsiFacade.getInstance(manager.getProject()).getElementFactory();
    final PsiExpression newCondition =
      factory.createExpressionFromText("true", whileStatement);
    condition.replace(newCondition);
    final PsiStatement body = whileStatement.getBody();
    final String ifStatementText = "if (!(" + conditionText + ")) break;";
    final PsiStatement ifStatement =
      factory.createStatementFromText(ifStatementText,
                                      whileStatement);
    final PsiElement newElement;
    if (body instanceof PsiBlockStatement) {
      final PsiBlockStatement blockStatement = (PsiBlockStatement)body;
      final PsiCodeBlock codeBlock = blockStatement.getCodeBlock();
      final PsiElement bodyElement = codeBlock.getFirstBodyElement();
      newElement = codeBlock.addBefore(ifStatement, bodyElement);
    }
    else if (body != null) {
      final PsiBlockStatement blockStatement =
        (PsiBlockStatement)factory.createStatementFromText("{}",
                                                           whileStatement);
      final PsiCodeBlock codeBlock = blockStatement.getCodeBlock();
      codeBlock.add(ifStatement);
      if (!(body instanceof PsiEmptyStatement)) {
        codeBlock.add(body);
      }
      newElement = body.replace(blockStatement);
    }
    else {
      return;
    }
    final CodeStyleManager codeStyleManager = CodeStyleManager.getInstance(manager.getProject());
    codeStyleManager.reformat(newElement);
  }
}