Draft

max_opened_projects/build.gradle

@@ -6,7 +6,7 @@ plugins {
 }
 
 group 'org.intellij.sdk'
-version '2.0.0'
+version '2.1.0'
 
 sourceCompatibility = 1.8
 
@@ -17,7 +17,7 @@ repositories {
 // See https://github.com/JetBrains/gradle-intellij-plugin/
 intellij {
     version '2019.3.3'
-    updateSinceUntilBuild = false
+    sameSinceUntilBuild = true
 }
 patchPluginXml {
     version = project.version

max_opened_projects/src/main/java/org/intellij/sdk/maxOpenPrj/MaxProject.java

@@ -1,55 +0,0 @@
-// Copyright 2000-2020 JetBrains s.r.o. and other contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
-
-package org.intellij.sdk.maxOpenPrj;
-
-import com.intellij.openapi.components.*;
-import com.intellij.openapi.project.*;
-import com.intellij.openapi.ui.Messages;
-import org.jetbrains.annotations.NotNull;
-
-/**
- * Created by IntelliJ IDEA.
- * User: Alexey.Chursin
- * Date: Aug 13, 2010
- * Time: 3:50:25 PM
- * To change this template use File | Settings | File Templates.
- */
-public class MaxProject implements ProjectComponent {
-  public MaxProject(Project project) {
-  }
-
-  public void initComponent() {
-    // TODO: insert component initialization logic here
-  }
-
-  public void disposeComponent() {
-    // TODO: insert component disposal logic here
-  }
-
-  @NotNull
-  public String getComponentName() {
-    return "MaxProject";
-  }
-
-  public void projectOpened() {
-    // called when project is opened
-    MyCounter CommandCounter = ServiceManager.getService(MyCounter.class);
-
-    if (CommandCounter.IncreaseCounter() == -1) {
-      Messages.showMessageDialog(
-          "The maximum number of opened projects exceeds " + String.valueOf(CommandCounter.MaxCount) +
-          " projects!", "Error", Messages.getErrorIcon());
-      ProjectManager PM = ProjectManager.getInstance();
-      Project[] AllProjects = PM.getOpenProjects();
-      Project project = AllProjects[AllProjects.length - 1];
-      PM.closeProject(project);
-    }
-  }
-
-
-  public void projectClosed() {
-    // called when project is being closed
-    MyCounter CommandCounter = ServiceManager.getService(MyCounter.class);
-    CommandCounter.DecreaseCounter();
-  }
-}

max_opened_projects/src/main/java/org/intellij/sdk/maxOpenPrj/MyCounter.java

@@ -1,32 +0,0 @@
-// Copyright 2000-2020 JetBrains s.r.o. and other contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
-
-package org.intellij.sdk.maxOpenPrj;
-
-/**
- * Created by IntelliJ IDEA.
- * User: Alexey.Chursin
- * Date: Aug 13, 2010
- * Time: 3:49:33 PM
- * To change this template use File | Settings | File Templates.
- */
-public class MyCounter {
-  private int Count = 0;
-  // Sets the maximum allowed number of opened projects.
-  public final int MaxCount = 3;
-
-  public MyCounter() {
-
-
-  }
-
-  public int IncreaseCounter() {
-    Count++;
-    return (Count > MaxCount) ? -1 : Count;
-  }
-
-  public int DecreaseCounter() {
-    Count--;
-    return (Count > MaxCount) ? -1 : Count;
-  }
-
-}

max_opened_projects/src/main/java/org/intellij/sdk/maxOpenPrj/ProjectCountingService.java

@@ -0,0 +1,21 @@
+// Copyright 2000-2020 JetBrains s.r.o. and other contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+
+package org.intellij.sdk.maxOpenPrj;
+
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.project.ProjectManager;
+
+/**
+ * Application service implementation to keep a running count of
+ * how many projects are open at a given time.
+ */
+public class ProjectCountingService {
+  // Sets the maximum allowed number of opened projects.
+  private final int MAX_OPEN_PRJ_LIMIT = 3;
+
+  public boolean projLimitExceeded() {
+    ProjectManager prjMgr = ProjectManager.getInstance();
+    return prjMgr.getOpenProjects().length > MAX_OPEN_PRJ_LIMIT;
+  }
+
+}

max_opened_projects/src/main/java/org/intellij/sdk/maxOpenPrj/ProjectOpenListener.java

@@ -0,0 +1,38 @@
+// Copyright 2000-2020 JetBrains s.r.o. and other contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+
+package org.intellij.sdk.maxOpenPrj;
+
+import com.intellij.openapi.components.ServiceManager;
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.project.ProjectManager;
+import com.intellij.openapi.project.ProjectManagerListener;
+import com.intellij.openapi.ui.Messages;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Listener to detect opening of projects.
+ */
+public class ProjectOpenListener implements ProjectManagerListener {
+
+  /**
+   * Invoked on project open.
+   *
+   * @param project opening project
+   */
+  @Override
+  public void projectOpened(@NotNull Project project) {
+    // Get the counting service
+    ProjectCountingService prjCountingSrvc = ServiceManager.getService(ProjectCountingService.class);
+    // See if the total # of projects violates the limit.
+    if (prjCountingSrvc.projLimitExceeded()) {
+      Messages.showMessageDialog(
+              "The number of open projects exceeds the SDK plugin max_opened_projects limit. Close at least one open project and try again.",
+              "Cannot open project \"" + project.getName() + "\"",
+              Messages.getErrorIcon());
+      ProjectManager prjMgr = ProjectManager.getInstance();
+      boolean closedSuccessfully = prjMgr.closeProject(project);
+      System.out.println(String.format("Project closing was %s", closedSuccessfully));
+    }
+  }
+
+}

max_opened_projects/src/main/resources/META-INF/plugin.xml

@@ -8,11 +8,10 @@
   <!-- Text to display as name on Preferences/Settings | Plugin page  -->
   <name>SDK: Maximum Open Projects Sample</name>
 
-  <!-- The version of this plugin -->
-  <version>2.0.0</version>
+  <!-- The version of this plugin is set by build.gradle -->
 
-  <!-- Compatible with the following versions of IntelliJ Platform -->
-  <idea-version since-build="191"/>
+  <!-- The idea-version of this plugin is set by build.gradle -->
+  <idea-version since-build="193"/>
 
   <!-- Product and plugin compatibility requirements -->
   <depends>com.intellij.modules.platform</depends>
@@ -20,12 +19,13 @@
   <!-- Text to display as description on Preferences/Settings | Plugin page  -->
   <description>
     <![CDATA[
-      Demonstrates adding project and application components. Shows warning dialog when more than 3 open projects is exceeded.
+      Demonstrates adding application services and listeners. Shows warning dialog when more than 3 open projects is exceeded.
     ]]>
   </description>
   <change-notes>
     <![CDATA[
       <ul>
+        <li><b>2.1.0</b> Remove project component and use listener instead.</li>
         <li><b>2.0.0</b> Convert to Gradle-based plugin.</li>
         <li><b>1.0.0</b> Release 2018.3 and earlier.</li>
       </ul>
@@ -35,14 +35,11 @@
   <!-- Text to display as company information on Preferences/Settings | Plugin page -->
   <vendor url="https://plugins.jetbrains.com">IntelliJ Platform SDK</vendor>
 
-  <project-components>
-    <component>
-      <implementation-class>org.intellij.sdk.maxOpenPrj.MaxProject</implementation-class>
-    </component>
-  </project-components>
+  <applicationListeners>
+    <listener class="org.intellij.sdk.maxOpenPrj.ProjectOpenListener" topic="com.intellij.openapi.project.ProjectManagerListener"/>
+  </applicationListeners>
 
   <extensions defaultExtensionNs="com.intellij">
-    <applicationService serviceInterface="org.intellij.sdk.maxOpenPrj.MyCounter"
-                        serviceImplementation="org.intellij.sdk.maxOpenPrj.MyCounter"/>
+    <applicationService serviceImplementation="org.intellij.sdk.maxOpenPrj.ProjectCountingService"/>
   </extensions>
 </idea-plugin>