Faster response to file changes.

src/main/java/com/airhacks/wad/boundary/WADFlow.java

@@ -1,12 +1,9 @@
 
 package com.airhacks.wad.boundary;
 
-import com.airhacks.wad.control.Builder;
-import com.airhacks.wad.control.Copier;
-import com.airhacks.wad.control.FolderWatchService;
-import com.airhacks.wad.control.TerminalColors;
+import com.airhacks.wad.control.*;
+
 import java.io.IOException;
-import java.io.InputStream;
 import java.nio.file.Path;
 import java.time.LocalTime;
 import java.time.format.DateTimeFormatter;
@@ -16,7 +13,6 @@
 import static java.time.temporal.ChronoField.SECOND_OF_MINUTE;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.List;
 import java.util.LongSummaryStatistics;
 import java.util.concurrent.atomic.AtomicLong;
 import org.apache.maven.shared.invoker.InvocationResult;
@@ -41,22 +37,8 @@ public WADFlow(Path dir, Path war, Collection<Path> deploymentTargets) throws IO
         this.copier = new Copier(war, deploymentTargets);
         Runnable changeListener = this::buildAndDeploy;
         changeListener.run();
-        registerEnterListener(changeListener);
-        FolderWatchService.listenForChanges(dir, changeListener);
-    }
-
-    void registerEnterListener(Runnable listener) {
-        InputStream in = System.in;
-        Runnable task = () -> {
-            int c;
-        try {
-            while ((c = in.read()) != -1) {
-                listener.run();
-            }
-            } catch (IOException ex) {
-            }
-        };
-        new Thread(task).start();
+        Watcher watcher = new Watcher(dir,changeListener);
+        watcher.runBlocking();
     }
 
     void buildAndDeploy() {

src/main/java/com/airhacks/wad/control/Copier.java

@@ -1,6 +1,7 @@
 
 package com.airhacks.wad.control;
 
+import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -54,7 +55,7 @@ Optional<Path> findWarInPath(Path fromDirectory) {
             e.printStackTrace();
         }
 
-        return null;
+        return Optional.empty();
     }
 
     List<Path> addWarName(Collection<Path> deploymentDirectories, String warName) {
@@ -64,16 +65,21 @@ List<Path> addWarName(Collection<Path> deploymentDirectories, String warName) {
             collect(Collectors.toList());
     }
 
-    Path copySingle(Path from, Path to) {
+    void copySingle(Path from, Path to) {
         long kb;
         try {
             kb = Files.size(from) / 1024;
             warSizes.add(kb);
             System.out.printf("Copying %dkB ThinWAR %s to %s %s %s \n", kb,  from.toString(), TerminalColors.FILE.value(), shortenForDisplay(to, 40), TerminalColors.RESET.value());
-            return Files.copy(from, to, StandardCopyOption.REPLACE_EXISTING);
-
+            Files.copy(from, to, StandardCopyOption.REPLACE_EXISTING);
         } catch (IOException ex) {
-            throw new IllegalStateException(ex.getMessage(), ex);
+            File targetFile = to.toFile();
+            boolean targetFileIsLocked = !targetFile.renameTo(targetFile);
+            if(targetFileIsLocked) {
+                System.err.println("Cannot copy because server has locked file \""+to+"\"");
+            }else{
+                throw new IllegalStateException(ex.getMessage(), ex);
+            }
         }
     }
 

src/main/java/com/airhacks/wad/control/Watcher.java

@@ -0,0 +1,52 @@
+package com.airhacks.wad.control;
+
+import com.sun.nio.file.SensitivityWatchEventModifier;
+
+import java.io.IOException;
+import java.nio.file.*;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.time.Duration;
+import java.time.LocalDateTime;
+import java.time.temporal.TemporalAmount;
+
+public class Watcher {
+    private static final TemporalAmount MIN_RUN_DELAY = Duration.ofSeconds(2);
+
+    private final WatchService watchService;
+    private final Runnable runnable;
+    private LocalDateTime lastChange = LocalDateTime.MIN;
+
+    public Watcher(Path dir, Runnable runnable) throws IOException {
+        watchService = FileSystems.getDefault().newWatchService();
+        registerAll(dir, watchService);
+        this.runnable = runnable;
+    }
+
+    private void registerAll(final Path start, WatchService watchService) throws IOException {
+        Files.walkFileTree(start, new SimpleFileVisitor<Path>() {
+            @Override
+            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
+                dir.register(watchService, new WatchEvent.Kind[] {StandardWatchEventKinds.ENTRY_MODIFY, StandardWatchEventKinds.ENTRY_CREATE, StandardWatchEventKinds.ENTRY_DELETE}, SensitivityWatchEventModifier.HIGH);
+                return FileVisitResult.CONTINUE;
+            }
+        });
+    }
+
+    public void runBlocking() {
+        try{
+            WatchKey key;
+            while ((key = watchService.take()) != null) {
+                if(LocalDateTime.now().isAfter(lastChange.plus(MIN_RUN_DELAY))){
+                    runnable.run();
+                }else{
+                    //Not running deploy because last deploy was less than "MIN_RUN_DELAY" seconds ago.
+                }
+                key.pollEvents().clear(); //remove all pending events to prevent second deploy
+                lastChange = LocalDateTime.now();
+                key.reset();
+            }
+        }catch (InterruptedException e){
+            throw new RuntimeException(e);
+        }
+    }
+}