ReplaceWhileLoopWithDoWhileLoopIntention.java

/*
 * Copyright 2006-2013 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.siyeh.ig.PsiReplacementUtil;
import com.siyeh.ig.psiutils.BoolUtils;
import com.siyeh.ipp.base.Intention;
import com.siyeh.ipp.base.PsiElementPredicate;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;

public class ReplaceWhileLoopWithDoWhileLoopIntention extends Intention {

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

  protected void processIntention(@NotNull PsiElement element) {
    final PsiWhileStatement whileStatement = (PsiWhileStatement)element.getParent();
    if (whileStatement == null) {
      return;
    }
    final PsiStatement body = whileStatement.getBody();
    final PsiExpression condition = whileStatement.getCondition();
    final boolean infiniteLoop = BoolUtils.isTrue(condition);
    @NonNls final StringBuilder doWhileStatementText = new StringBuilder();
    if (!infiniteLoop) {
      doWhileStatementText.append("if(");
      if (condition != null) {
        doWhileStatementText.append(condition.getText());
      }
      doWhileStatementText.append(") {\n");
    }
    if (body instanceof PsiBlockStatement) {
      doWhileStatementText.append("do {");
      final PsiBlockStatement blockStatement = (PsiBlockStatement)body;
      final PsiCodeBlock codeBlock = blockStatement.getCodeBlock();
      final PsiElement[] children = codeBlock.getChildren();
      if (children.length > 2) {
        for (int i = 1; i < children.length - 1; i++) {
          final PsiElement child = children[i];
          doWhileStatementText.append(child.getText());
        }
      }
      doWhileStatementText.append('}');
    }
    else if (body != null) {
      doWhileStatementText.append("do ").append(body.getText()).append('\n');
    }
    doWhileStatementText.append("while(");
    if (condition != null) {
      doWhileStatementText.append(condition.getText());
    }
    doWhileStatementText.append(");");
    if (!infiniteLoop) {
      doWhileStatementText.append("\n}");
    }
    PsiReplacementUtil.replaceStatement(whileStatement, doWhileStatementText.toString());
  }
}