EnumSwitchStatementWhichMissesCasesInspection.java

/*
 * Copyright 2003-2011 Dave Griffith, 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.ig.controlflow;

import com.intellij.psi.*;
import com.intellij.codeInspection.ui.SingleCheckboxOptionsPanel;
import com.siyeh.InspectionGadgetsBundle;
import com.siyeh.ig.BaseInspection;
import com.siyeh.ig.BaseInspectionVisitor;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import javax.swing.*;

public class EnumSwitchStatementWhichMissesCasesInspection
  extends BaseInspection {

  @Override
  @NotNull
  public String getDisplayName() {
    return InspectionGadgetsBundle.message(
      "enum.switch.statement.which.misses.cases.display.name");
  }

  /**
   * @noinspection PublicField
   */
  public boolean ignoreSwitchStatementsWithDefault = false;

  @Override
  @NotNull
  public String buildErrorString(Object... infos) {
    final PsiSwitchStatement switchStatement =
      (PsiSwitchStatement)infos[0];
    assert switchStatement != null;
    final PsiExpression switchStatementExpression =
      switchStatement.getExpression();
    assert switchStatementExpression != null;
    final PsiType switchStatementType =
      switchStatementExpression.getType();
    assert switchStatementType != null;
    final String switchStatementTypeText =
      switchStatementType.getPresentableText();
    return InspectionGadgetsBundle.message(
      "enum.switch.statement.which.misses.cases.problem.descriptor",
      switchStatementTypeText);
  }

  @Override
  @Nullable
  public JComponent createOptionsPanel() {
    return new SingleCheckboxOptionsPanel(
      InspectionGadgetsBundle.message(
        "enum.switch.statement.which.misses.cases.option"),
      this, "ignoreSwitchStatementsWithDefault");
  }

  @Override
  public BaseInspectionVisitor buildVisitor() {
    return new EnumSwitchStatementWhichMissesCasesVisitor();
  }

  private class EnumSwitchStatementWhichMissesCasesVisitor
    extends BaseInspectionVisitor {

    @Override
    public void visitSwitchStatement(
      @NotNull PsiSwitchStatement statement) {
      super.visitSwitchStatement(statement);
      if (!switchStatementMissingCases(statement)) {
        return;
      }
      registerStatementError(statement, statement);
    }

    private boolean switchStatementMissingCases(
      PsiSwitchStatement statement) {
      final PsiExpression expression = statement.getExpression();
      if (expression == null) {
        return false;
      }
      final PsiType type = expression.getType();
      if (!(type instanceof PsiClassType)) {
        return false;
      }
      final PsiClassType classType = (PsiClassType)type;
      final PsiClass aClass = classType.resolve();
      if (aClass == null || !aClass.isEnum()) {
        return false;
      }
      final PsiCodeBlock body = statement.getBody();
      if (body == null) {
        return false;
      }
      final PsiStatement[] statements = body.getStatements();
      int numCases = 0;
      for (final PsiStatement child : statements) {
        if (child instanceof PsiSwitchLabelStatement) {
          final PsiSwitchLabelStatement switchLabelStatement =
            (PsiSwitchLabelStatement)child;
          if (!switchLabelStatement.isDefaultCase()) {
            numCases++;
          }
          else if (ignoreSwitchStatementsWithDefault) {
            return false;
          }
        }
      }
      final PsiField[] fields = aClass.getFields();
      int numEnums = 0;
      for (final PsiField field : fields) {
        if (!(field instanceof PsiEnumConstant)) {
          continue;
        }
        numEnums++;
      }
      return numEnums != numCases;
    }
  }
}