Stop teaching people to use components (#233)

- Replace documentation on writing components with documentation on migrating away from components
- Split documentation on extensions and extension points (extensions are always needed and EPs are quite uncommon)
- Add documentation on listeners
- Remove application and project components in sample plugins whenever possible

plugin_sample/resources/META-INF/plugin.xml

@@ -28,31 +28,6 @@
   <!-- Resource bundle from which the text of plugin descriptions, action names and etc. will be loaded -->
   <resource-bundle>org.jetbrains.tutorials.sample.PluginSampleBundle</resource-bundle>
 
-  <!-- Plugin's application components -->
-  <application-components>
-    <component>
-      <!-- Component's interface class -->
-      <interface-class>org.jetbrains.tutorials.sample.DummyApplicationComponent</interface-class>
-      <!-- Component's implementation class -->
-      <implementation-class>org.jetbrains.tutorials.sample.DummyApplicationComponentImpl</implementation-class>
-    </component>
-  </application-components>
-
-  <!-- Plugin's project components -->
-  <project-components>
-    <component>
-      <!-- Interface and implementation classes are the same -->
-      <interface-class>org.jetbrains.tutorials.sample.DummyProjectComponent</interface-class>
-      <implementation-class>org.jetbrains.tutorials.sample.DummyProjectComponentImpl</implementation-class>
-      <!-- If the "workspace" option is set "true", the component saves its state to the .iws file
-        instead of the .ipr file.  Note that the <option> element is used only if the component implements the JDOMExternalizable interface. Otherwise, the use of the <option> element takes no effect.-->
-
-      <option name="workspace" value="true"/>
-      <!-- If the "loadForDefaultProject" tag is present, the project component is instantiated also for the default project. -->
-      <loadForDefaultProject/>
-    </component>
-  </project-components>
-
   <!-- Actions -->
   <actions>
     <!-- The <action> element defines an action to register.

plugin_sample/src/org/jetbrains/tutorials/sample/DummyApplicationComponent.java

@@ -1,9 +0,0 @@
-package org.jetbrains.tutorials.sample;
-
-import com.intellij.openapi.components.BaseComponent;
-
-/**
- * @author Anna Bulenkova
- */
-interface DummyApplicationComponent extends BaseComponent {
-}

plugin_sample/src/org/jetbrains/tutorials/sample/DummyApplicationComponentImpl.java

@@ -1,24 +0,0 @@
-package org.jetbrains.tutorials.sample;
-
-import org.jetbrains.annotations.NotNull;
-
-/**
- * @author Anna Bulenkova
- */
-public class DummyApplicationComponentImpl implements DummyApplicationComponent {
-  @Override
-  public void initComponent() {
-
-  }
-
-  @Override
-  public void disposeComponent() {
-
-  }
-
-  @NotNull
-  @Override
-  public String getComponentName() {
-    return "DummyApplicationComponent";
-  }
-}

plugin_sample/src/org/jetbrains/tutorials/sample/DummyProjectComponent.java

@@ -1,9 +0,0 @@
-package org.jetbrains.tutorials.sample;
-
-import com.intellij.openapi.components.ProjectComponent;
-
-/**
- * @author Anna Bulenkova
- */
-public interface DummyProjectComponent extends ProjectComponent {
-}

plugin_sample/src/org/jetbrains/tutorials/sample/DummyProjectComponentImpl.java

@@ -1,34 +0,0 @@
-package org.jetbrains.tutorials.sample;
-
-import org.jetbrains.annotations.NotNull;
-
-/**
- * @author Anna Bulenkova
- */
-public class DummyProjectComponentImpl implements DummyProjectComponent {
-  @Override
-  public void projectOpened() {
-
-  }
-
-  @Override
-  public void projectClosed() {
-
-  }
-
-  @Override
-  public void initComponent() {
-
-  }
-
-  @Override
-  public void disposeComponent() {
-
-  }
-
-  @NotNull
-  @Override
-  public String getComponentName() {
-    return "DummyProjectComponent";
-  }
-}