plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/finalization/FinalizeInspection.java

/*
 * Copyright 2003-2009 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.finalization;

import com.intellij.codeInspection.ui.SingleCheckboxOptionsPanel;
import com.intellij.openapi.project.Project;
import com.intellij.psi.*;
import com.siyeh.HardcodedMethodConstants;
import com.siyeh.InspectionGadgetsBundle;
import com.siyeh.ig.BaseInspection;
import com.siyeh.ig.BaseInspectionVisitor;
import org.jetbrains.annotations.NotNull;

import javax.swing.*;

public class FinalizeInspection extends BaseInspection {

  @SuppressWarnings("PublicField")
  public boolean ignoreTrivialFinalizers = true;

  @Override
  @NotNull
  public String getID() {
    return "FinalizeDeclaration";
  }

  @Override
  @NotNull
  public String getDisplayName() {
    return InspectionGadgetsBundle.message(
      "finalize.declaration.display.name");
  }

  @Override
  @NotNull
  public String buildErrorString(Object... infos) {
    return InspectionGadgetsBundle.message(
      "finalize.declaration.problem.descriptor");
  }

  @Override
  public JComponent createOptionsPanel() {
    return new SingleCheckboxOptionsPanel(
      InspectionGadgetsBundle.message("ignore.trivial.finalizers.option"), this,
      "ignoreTrivialFinalizers");
  }

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

  private class FinalizeDeclaredVisitor extends BaseInspectionVisitor {

    @Override
    public void visitMethod(@NotNull PsiMethod method) {
      //note: no call to super;
      final String methodName = method.getName();
      if (!HardcodedMethodConstants.FINALIZE.equals(methodName)) {
        return;
      }
      final PsiParameterList parameterList = method.getParameterList();
      if (parameterList.getParametersCount() != 0) {
        return;
      }
      if (ignoreTrivialFinalizers && isTrivial(method)) {
        return;
      }
      registerMethodError(method);
    }

    private boolean isTrivial(PsiMethod method) {
      final PsiCodeBlock body = method.getBody();
      if (body == null) {
        return true;
      }
      final PsiStatement[] statements = body.getStatements();
      if (statements.length == 0) {
        return true;
      }
      final Project project = method.getProject();
      final JavaPsiFacade psiFacade =
        JavaPsiFacade.getInstance(project);
      final PsiConstantEvaluationHelper evaluationHelper =
        psiFacade.getConstantEvaluationHelper();
      for (PsiStatement statement : statements) {
        if (!(statement instanceof PsiIfStatement)) {
          return false;
        }
        final PsiIfStatement ifStatement =
          (PsiIfStatement)statement;
        final PsiExpression condition = ifStatement.getCondition();
        final Object result =
          evaluationHelper.computeConstantExpression(condition);
        if (result == null || !result.equals(Boolean.FALSE)) {
          return false;
        }
      }
      return true;
    }
  }
}