Improved macOS support: Small fixes

.github/workflows/build.yaml

@@ -12,10 +12,17 @@ jobs:
   test:
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        os:
+          - image: ubuntu-latest
+          - image: macos-latest
+            mac-backend: jdk
+          - image: macos-latest
+            mac-backend: jna
+          - image: windows-latest
         jdk: [11, 17, 21]
+
       fail-fast: false
-    runs-on: ${{ matrix.os }}
+    runs-on: ${{ matrix.os.image }}
     steps:
       - uses: actions/checkout@v4
       - run: echo " " >> pom.xml # make sure the cache is slightly different for these runners
@@ -27,7 +34,7 @@ jobs:
           cache: 'maven'
 
       - name: test
-        run: mvn -B clean test
+        run: mvn -B clean test -DargLine="-Dengineering.swat.java-watch.mac=${{ matrix.os.mac-backend }}"
         env:
           DELAY_FACTOR: 3
 

README.md

@@ -57,13 +57,13 @@ try(var active = watcherSetup.start()) {
 // no new events will be scheduled on the threadpool
 ```
 
-## Internals
+## Backends
 
 On all platforms except macOS, the library internally uses the JDK default implementation of the Java NIO [`WatchService`](https://docs.oracle.com/javase/8/docs/api/java/nio/file/WatchService.html) API.
 
 On macOS, the library internally uses our custom `WatchService` implementation based on macOS's native [file system event streams](https://developer.apple.com/documentation/coreservices/file_system_events?language=objc) (using JNA).
 Generally, it offers better performance than the JDK default implementation (because the latter uses a polling loop to detect changes only once every two seconds).
-To force the library to use the JDK default implementation on macOS, set system property `engineering.swat.watch.impl` to `default`.
+To force the library to use the JDK default implementation on macOS, set system property `engineering.swat.java-watch.mac` to `jdk`.
 
 ## Related work
 

pom.xml

@@ -74,6 +74,7 @@
     <checkerframework.version>3.49.2</checkerframework.version>
     <junit.version>5.12.2</junit.version>
     <log4j.version>2.24.3</log4j.version>
+    <jna.version>5.16.0</jna.version>
     <maven.compiler.source>11</maven.compiler.source>
     <maven.compiler.target>11</maven.compiler.target>
   </properties>
@@ -226,12 +227,12 @@
     <dependency>
       <groupId>net.java.dev.jna</groupId>
       <artifactId>jna</artifactId>
-      <version>5.16.0</version>
+      <version>${jna.version}</version>
     </dependency>
     <dependency>
       <groupId>net.java.dev.jna</groupId>
       <artifactId>jna-platform</artifactId>
-      <version>5.16.0</version>
+      <version>${jna.version}</version>
     </dependency>
   </dependencies>
 

src/main/java/engineering/swat/watch/impl/jdk/JDKPoller.java

@@ -190,20 +190,22 @@ public Watchable newWatchable(Path path) {
         static final Platform CURRENT = current(); // Assumption: the platform doesn't change
 
         private static Platform current() {
-            var key = "engineering.swat.watch.impl";
-            var val = System.getProperty(key);
-            if (val != null) {
-                if (val.equals("mac")) {
-                    return MAC;
-                } else if (val.equals("default")) {
-                    return DEFAULT;
-                } else {
-                    logger.warn("Unexpected value \"{}\" for system property \"{}\". Using value \"default\" instead.", val, key);
-                    return DEFAULT;
+            if (com.sun.jna.Platform.isMac()) {
+                var key = "engineering.swat.java-watch.mac";
+                var val = System.getProperty(key);
+                if (val != null) {
+                    if (val.equals("jna")) {
+                        return MAC;
+                    } else if (val.equals("jdk")) {
+                        return DEFAULT;
+                    } else {
+                        logger.warn("Unexpected value \"{}\" for system property \"{}\". Using value \"jdk\" instead.", val, key);
+                        return DEFAULT;
+                    }
                 }
             }
 
-            return com.sun.jna.Platform.isMac() ? MAC : DEFAULT;
+            return DEFAULT;
         }
 
         static Platform get() {