package com.cdai.plugin.rapidg;
import com.intellij.openapi.components.ApplicationComponent;
import com.intellij.openapi.ui.Messages;
import org.jetbrains.annotations.NotNull;
/**
 * My Component
 * User: cdai
 * Date: 13-11-4
 * Time: 上午10:08
 */
public class MyComponent implements ApplicationComponent {
  public MyComponent() {
  }

  public void initComponent() {
    // TODO: insert component initialization logic here
  }

  public void disposeComponent() {
    // TODO: insert component disposal logic here
  }

  @NotNull
  public String getComponentName() {
    return "MyComponent";
  }

  public void sayHello() {
    // Show dialog with message
    Messages.showMessageDialog(
        "Hello World!",
        "Sample",
        Messages.getInformationIcon()
    );
  }
}

package com.cdai.plugin.rapidg;
import com.intellij.openapi.actionSystem.AnAction;
import com.intellij.openapi.actionSystem.AnActionEvent;
import com.intellij.openapi.application.Application;
import com.intellij.openapi.application.ApplicationManager;

/**
 * Say Hello Action
 * User: cdai
 * Date: 13-11-4
 * Time: 上午10:16
 */
public class SayHelloAction extends AnAction {
  @Override
  public void actionPerformed(AnActionEvent e) {
    Application application = ApplicationManager.getApplication();
    MyComponent myComponent = application.getComponent(MyComponent.class);
    myComponent.sayHello();

  }
}

<idea-plugin version="2">
 <id>com.cdai.plugin.rapidg</id>
 <name>CDai's Rapid Generator Plugin</name>
 <version>1.0</version>
 <vendor email="dc_726@163.com" url="http://www.yourcompany.com">CDai</vendor> 

 <description><![CDATA[
   Enter short description for your plugin here.<br>
   <small>most HTML tags may be used</small>
   ]]></description> 

 <change-notes><![CDATA[
   Add change notes here.<br>
   <small>most HTML tags may be used</small>
   ]]>

 </change-notes>

 <!-- please see http://confluence.jetbrains.net/display/IDEADEV/Build+Number+Ranges for description -->
 <idea-version since-build="107.105"/>

 <!-- please see http://confluence.jetbrains.net/display/IDEADEV/Plugin+Compatibility+with+IntelliJ+Platform+Products

    on how to target different products -->
 <!-- uncomment to enable plugin in all products
 <depends>com.intellij.modules.lang</depends>
 -->

 <application-components>
  <!-- Add your application components here -->
   <component>
     <implementation-class>com.cdai.plugin.rapidg.MyComponent</implementation-class>
   </component>
 </application-components>

 <project-components>
  <!-- Add your project components here -->
 </project-components>

 <actions>
  <!-- Add your actions here -->
   <action id="SayHello" class="com.cdai.plugin.rapidg.SayHelloAction" text="Say Hello!">
     <add-to-group group-id="WindowMenu" anchor="first"/>
   </action>
 </actions>

 <extensions defaultExtensionNs="com.intellij">
  <!-- Add your extensions here -->
 </extensions>
</idea-plugin>