Issue #6020 Fix redeploy error jetty-maven-plugin (#6023)

* Issue #6020 Fix redeploy error jetty-maven-plugin

Signed-off-by: Jan Bartel <janb@webtide.com>

documentation/jetty-documentation/src/main/asciidoc/programming-guide/.asciidoctorconfig

@@ -1,3 +1,4 @@
 // Asciidoctor IDE configuration file.
 // See https://github.com/asciidoctor/asciidoctor-intellij-plugin/wiki/Support-project-specific-configurations
+:experimental:
 :doc_code: ../../java

documentation/jetty-documentation/src/main/asciidoc/programming-guide/maven/jetty-maven-plugin.adoc

@@ -55,7 +55,7 @@ We recommend either the traditional link:{DISTGUIDE}[distribution] deployment ap
 ====
 
 [[get-up-and-running]]
-==== Quick Start: Get Up and Running
+==== Get Up and Running
 
 First, add `jetty-maven-plugin` to your `pom.xml` definition:
 
@@ -77,10 +77,10 @@ mvn jetty:run
 This starts Jetty and serves up your project on http://localhost:8080/.
 
 Jetty will continue to run until you stop it.
-By default, it will not automatically restart your webapp: you can force a redeploy by hitting the `Enter` key.
-Set a non-zero <scan> value to have jetty scan your webapp for changes and automatically redeploy.
+By default, it will not automatically restart your webapp.
+Set a non-zero `<scan>` value to have jetty scan your webapp for changes and automatically redeploy, or set `<scan>` to `0` to cause manual redeployment by hitting the kbd:[Enter] key.
 
-You can terminate the plugin with a `ctrl-c` in the terminal window where it is running.
+You can terminate the plugin with a kbd:[Ctrl+c] in the terminal window where it is running.
 
 [NOTE]
 ====
@@ -300,7 +300,7 @@ For example, by default it looks for:
 * `web.xml` in `${project.basedir}/src/main/webapp/WEB-INF/`
 
 The plugin first runs a maven parallel build to ensure that the classes are built and up-to-date before deployment.
-If you change the source of a class and your IDE automatically compiles it in the background, the plugin picks up the changed class (note you need to configure a non-zero `scan` interval for automatic redeployment, otherwise redeployment only occurs if you hit the `Enter` key).
+If you change the source of a class and your IDE automatically compiles it in the background, the plugin picks up the changed class (note you need to configure a non-zero `scan` interval for automatic redeployment).
 
 If the plugin is invoked in a multi-module build, any dependencies that are also in the maven reactor are used from their compiled classes.
 Prior to jetty-9.4.7 any dependencies needed to be built first.
@@ -389,8 +389,9 @@ If true, the classes from `testClassesDirectory` and dependencies of scope "test
 By default this is false.
 scan::
 The pause in seconds between sweeps of the webapp to check for changes and automatically hot redeploy if any are detected.
-*By default this is 0, which disables hot deployment scanning. Redeployment is by hitting `Enter` key.*
-A number greater than 0 enables it.
+*By default this is `-1`, which disables hot redeployment scanning.*
+A value of `0` means no hot redeployment is done, and that you must use the kbd:[Enter] key to manually force a redeploy.
+Any positive integer will enable hot redeployment, using the number as the sweep interval in seconds.
 scanTargetPatterns::
 Optional.
 List of extra directories with glob-style include/excludes patterns (see http://docs.oracle.com/javase/8/docs/api/java/nio/file/FileSystem.html#getPathMatcher-java.lang.String-[javadoc] for http://docs.oracle.com/javase/8/docs/api/java/nio/file/FileSystem.html#getPathMatcher-java.lang.String-[FileSystem.getPathMatcher]) to specify other files to periodically scan for changes.
@@ -462,7 +463,6 @@ When invoked at the command line this goal first executes a maven build of your
 By default it then deploys the resultant war to jetty, but you can use this goal instead to deploy _any_ war file by simply setting the `&lt;webApp&gt;&lt;war&gt;` configuration parameter to its location.
 
 If you set a non-zero `scan`, Jetty watches your `pom.xml` and the WAR file; if either changes, it redeploys the war.
-With a zero `scan` interval, redeployment is manual via hitting the `Enter` key.
 
 The maven build is held up until jetty exits, which is achieved by typing `cntrl-c` at the command line.
 
@@ -501,8 +501,9 @@ contextXml:::
 The path to a context xml file that is applied to your webapp AFTER the `webApp` element.
 scan::
 The pause in seconds between sweeps of the webapp to check for changes and automatically hot redeploy if any are detected.
-*By default this is 0, which disables hot deployment scanning. Redeployment is by hitting `Enter` key.*
-A number greater than 0 enables it.
+*By default this is `-1`, which disables hot redeployment scanning.*
+A value of `0` means no hot redeployment is done, and that you must use the kbd:[Enter] key to manually force a redeploy.
+Any positive integer will enable hot redeployment, using the number as the sweep interval in seconds.
 scanTargetPatterns::
 Optional.
 List of directories with ant-style include/excludes patterns to specify other files to periodically scan for changes.
@@ -531,7 +532,6 @@ Here's an example of using the `pre-integration-test` and `post-integration-test
   <artifactId>jetty-maven-plugin</artifactId>
   <version>{VERSION}</version>
   <configuration>
-    <scan>10</scan>
     <stopKey>foo</stopKey>
     <stopPort>9999</stopPort>
   </configuration>
@@ -542,9 +542,6 @@ Here's an example of using the `pre-integration-test` and `post-integration-test
       <goals>
         <goal>start</goal>
       </goals>
-      <configuration>
-        <scan>0</scan>
-      </configuration>
     </execution>
     <execution>
       <id>stop-jetty</id>

jetty-maven-plugin/src/main/java/org/eclipse/jetty/maven/plugin/JettyRunMojo.java

@@ -29,7 +29,9 @@
 import org.apache.maven.plugins.annotations.ResolutionScope;
 import org.eclipse.jetty.util.IncludeExcludeSet;
 import org.eclipse.jetty.util.Scanner;
+import org.eclipse.jetty.util.component.LifeCycle;
 import org.eclipse.jetty.util.resource.Resource;
+import org.eclipse.jetty.util.thread.Scheduler;
 import org.eclipse.jetty.webapp.WebAppContext;
 
 /**
@@ -52,14 +54,16 @@
 @Execute (phase = LifecyclePhase.TEST_COMPILE)
 public class JettyRunMojo extends AbstractUnassembledWebAppMojo
 {
-    //Start of parameters only valid for runType=inprocess  
+    //Start of parameters only valid for deploymentType=EMBED  
     /**
-     * The interval in seconds to pause before checking if changes
-     * have occurred and re-deploying as necessary. A value 
-     * of 0 indicates no re-deployment will be done. In that case, you
-     * can force redeployment by typing a linefeed character at the command line.
+     * Controls redeployment of the webapp.
+     * <ol>
+     * <li> -1 : means no redeployment will be done </li>
+     * <li>  0 : means redeployment only occurs if you hit the ENTER key </li>
+     * <li>  otherwise, the interval in seconds to pause before checking and redeploying if necessary </li>
+     * </ol>
      */
-    @Parameter(defaultValue = "0", property = "jetty.scan", required = true)
+    @Parameter(defaultValue = "-1", property = "jetty.scan", required = true)
     protected int scan;
 
     /**
@@ -138,15 +142,40 @@ public void startJettyHome() throws MojoExecutionException
     private void startScanner()
         throws Exception
     {
+        if (scan < 0)
+        {
+            getLog().info("Redeployment not enabled");
+            return; //no automatic or manual redeployment
+        }
+
         // start scanning for changes, or wait for linefeed on stdin
         if (scan > 0)
         {
             scanner = new Scanner();
             scanner.setScanInterval(scan);
             scanner.setScanDepth(Scanner.MAX_SCAN_DEPTH); //always fully walk directory hierarchies
             scanner.setReportExistingFilesOnStartup(false);
+            scanner.addListener(new Scanner.BulkListener()
+            {   
+                public void filesChanged(Set<String> changes)
+                {
+                    try
+                    {
+                        restartWebApp(changes.contains(project.getFile().getCanonicalPath()));
+                    }
+                    catch (Exception e)
+                    {
+                        getLog().error("Error reconfiguring/restarting webapp after change in watched files", e);
+                    }
+                }
+            });
             configureScanner();
-            getLog().info("Scan interval ms = " + scan);
+            getLog().info("Scan interval sec = " + scan);
+
+            //unmanage scheduler so it is not stopped with the scanner
+            Scheduler scheduler = scanner.getBean(Scheduler.class);
+            scanner.unmanage(scheduler);
+            LifeCycle.start(scheduler);
             scanner.start();
         }
         else
@@ -184,21 +213,6 @@ protected void configureScanner()
         {
             throw new MojoExecutionException("Error forming scan list", e);
         }
-        scanner.addListener(new Scanner.BulkListener()
-        {
-            public void filesChanged(Set<String> changes)
-            {
-                try
-                {
-                    boolean reconfigure = changes.contains(project.getFile().getCanonicalPath());
-                    restartWebApp(reconfigure);
-                }
-                catch (Exception e)
-                {
-                    getLog().error("Error reconfiguring/restarting webapp after change in watched files", e);
-                }
-            }
-        });
     }
 
     public void gatherScannables() throws Exception

jetty-util/src/main/java/org/eclipse/jetty/util/Scanner.java

@@ -36,7 +36,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Predicate;
 
-import org.eclipse.jetty.util.component.AbstractLifeCycle;
+import org.eclipse.jetty.util.component.ContainerLifeCycle;
 import org.eclipse.jetty.util.thread.ScheduledExecutorScheduler;
 import org.eclipse.jetty.util.thread.Scheduler;
 import org.slf4j.Logger;
@@ -48,7 +48,7 @@
  * Utility for scanning a directory for added, removed and changed
  * files and reporting these events via registered Listeners.
  */
-public class Scanner extends AbstractLifeCycle
+public class Scanner extends ContainerLifeCycle
 {
     /**
      * When walking a directory, a depth of 1 ensures that
@@ -69,7 +69,7 @@ public class Scanner extends AbstractLifeCycle
     private boolean _reportExisting = true;
     private boolean _reportDirs = true;
     private Scheduler.Task _task;
-    private Scheduler _scheduler;
+    private final Scheduler _scheduler;
     private int _scanDepth = DEFAULT_SCAN_DEPTH;
 
     private enum Status
@@ -279,9 +279,17 @@ default void scanEnded(int cycle) throws Exception
         {
         }
     }
-
+    
     public Scanner()
     {
+        this(new ScheduledExecutorScheduler("Scanner-" + SCANNER_IDS.getAndIncrement(), true, 1));
+    }
+
+    public Scanner(Scheduler scheduler)
+    {
+        //Create the scheduler and start it
+        _scheduler = scheduler;
+        addBean(_scheduler);
     }
 
     /**
@@ -514,10 +522,7 @@ public void doStart() throws Exception
             _prevScan = scanFiles();
         }
 
-
-        //Create the scheduler and start it
-        _scheduler = new ScheduledExecutorScheduler("Scanner-" + SCANNER_IDS.getAndIncrement(), true, 1);
-        _scheduler.start();
+        super.doStart();
 
         //schedule the scan
         schedule();
@@ -539,10 +544,6 @@ public void doStop() throws Exception
         _task = null;
         if (task != null)
             task.cancel();
-        Scheduler scheduler = _scheduler;
-        _scheduler = null;
-        if (scheduler != null)
-            scheduler.stop();
     }
 
     /**