Make windowsHide configurable to support Java UI dialogs (#151)

* Initial plan

* Add windowsHide configuration support with tests

Co-authored-by: nvuillam <17500430+nvuillam@users.noreply.github.com>

* Update README with windowsHide documentation and examples

Co-authored-by: nvuillam <17500430+nvuillam@users.noreply.github.com>

* Address code review feedback: improve test names and CLI flag parsing

Co-authored-by: nvuillam <17500430+nvuillam@users.noreply.github.com>

* changelog

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: nvuillam <17500430+nvuillam@users.noreply.github.com>
Co-authored-by: Nicolas Vuillamy <nicolas.vuillamy@gmail.com>

Author: Copilot

CHANGELOG.md

@@ -2,7 +2,10 @@
 
 ## Unreleased
 
+## [4.4.0] 2025-02-07
+
 - Add `timeout` and `killSignal` run options
+- Add `windowsHide` (default: true) to allow to show window if `windowHide: true` is sent
 
 ## [4.3.3] 2025-02-03
 

README.md

@@ -72,6 +72,7 @@ Example: `["-Xms256m", "--someflagwithvalue myVal", "-c"]`
 | javaArgs | List of arguments for JVM only, not the JAR or the class | `[]` | `['--add-opens=java.base/java.lang=ALL-UNNAMED']` |
 | [windowsVerbatimArguments](https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options) | No quoting or escaping of arguments is done on Windows. Ignored on Unix. This is set to true automatically when shell is specified and is CMD. | `true` | `false` |
 | [windowless](https://docs.oracle.com/en/java/javase/17/docs/specs/man/java.html#:~:text=main()%20method.-,javaw,information%20if%20a%20launch%20fails.) | If windowless is true, JavaCaller calls javaw instead of java to not create any windows, useful when using detached on Windows. Ignored on Unix. | false | true
+| [windowsHide](https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options) | On Windows, hide the subprocess console window that would normally be created. Set to `false` if you need Java UI dialogs to be visible (e.g., print dialogs). Ignored on Unix. | `true` | `false`
 | [timeout](https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options) | In milliseconds the maximum amount of time the process is allowed to run. | `undefined` | `1000`
 | [killSignal](https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options) | The signal value to be used when the spawned process will be killed by timeout or abort signal. | `SIGTERM` | `SIGINT`
 
@@ -149,6 +150,23 @@ const java = new JavaCaller({
 const { status, stdout, stderr } = await java.run(['--sleep'], { windowless: true });
 ```
 
+Call java process with visible windows (e.g., for print dialogs)
+
+```javascript
+const java = new JavaCaller({
+    classPath: 'test/java/dist',
+    mainClass: 'com.nvuillam.javacaller.JavaCallerTester'
+});
+// Set windowsHide to false to allow Java UI dialogs to be visible
+const { status, stdout, stderr } = await java.run([], { windowsHide: false });
+```
+
+When using CLI mode with `--no-windows-hide` flag:
+
+```bash
+node index.js --no-windows-hide
+```
+
 You can see **more examples in** [**test methods**](https://github.com/nvuillam/node-java-caller/blob/master/test/java-caller.test.js)
 
 ## TROUBLESHOOTING

lib/cli.js

@@ -26,7 +26,18 @@ class JavaCallerCli {
         const java = new JavaCaller(this.javaCallerOptions);
         const args = [...process.argv];
         args.splice(0, 2);
-        const { status } = await java.run(args);
+        
+        // Parse --no-windows-hide flag (remove all occurrences)
+        const runOptions = {};
+        const filteredArgs = args.filter(arg => {
+            if (arg === '--no-windows-hide') {
+                runOptions.windowsHide = false;
+                return false; // Remove from args
+            }
+            return true; // Keep in args
+        });
+        
+        const { status } = await java.run(filteredArgs, runOptions);
         process.exitCode = status;
     }
 }

lib/index.d.ts

@@ -131,6 +131,13 @@ export interface JavaCallerRunOptions {
      * @default "SIGTERM"
      */
     killSignal?: number | NodeJS.Signals;
+    
+    /**
+     * On Windows, hide the subprocess console window that would normally be created.
+     * This option is ignored on Unix.
+     * @default true
+     */
+    windowsHide?: boolean;
 }
 
 /**

lib/java-caller.js

@@ -115,7 +115,7 @@ class JavaCaller {
                 cwd: javaExeToUse === "java" || javaExeToUse === "javaw" ? runOptions.cwd : undefined,
                 env: Object.assign({}, process.env),
                 stdio: this.output === "console" ? "inherit" : runOptions.detached ? "ignore" : "pipe",
-                windowsHide: true,
+                windowsHide: runOptions.windowsHide !== undefined ? runOptions.windowsHide : true,
                 windowsVerbatimArguments: runOptions.windowsVerbatimArguments,
             };
             if (javaExeToUse.includes(" ")) {

test/java-caller.test.js

@@ -58,6 +58,36 @@ describe("Call with classes", () => {
         checkStatus(0, status, stdout, stderr);
     });
 
+    it("should call JavaCallerTester.class with windowsHide set to false", async () => {
+        const java = new JavaCaller({
+            classPath: 'test/java/dist',
+            mainClass: 'com.nvuillam.javacaller.JavaCallerTester'
+        });
+        const { status, stdout, stderr } = await java.run([], { windowsHide: false });
+        checkStatus(0, status, stdout, stderr);
+        checkStdOutIncludes(`JavaCallerTester is called !`, stdout, stderr);
+    });
+
+    it("should call JavaCallerTester.class with windowsHide explicitly set to true", async () => {
+        const java = new JavaCaller({
+            classPath: 'test/java/dist',
+            mainClass: 'com.nvuillam.javacaller.JavaCallerTester'
+        });
+        const { status, stdout, stderr } = await java.run([], { windowsHide: true });
+        checkStatus(0, status, stdout, stderr);
+        checkStdOutIncludes(`JavaCallerTester is called !`, stdout, stderr);
+    });
+
+    it("should call JavaCallerTester.class with default windowsHide (should be true)", async () => {
+        const java = new JavaCaller({
+            classPath: 'test/java/dist',
+            mainClass: 'com.nvuillam.javacaller.JavaCallerTester'
+        });
+        const { status, stdout, stderr } = await java.run([]);
+        checkStatus(0, status, stdout, stderr);
+        checkStdOutIncludes(`JavaCallerTester is called !`, stdout, stderr);
+    });
+
 
     it("should call JavaCallerTester.class with proper stdout encoding", async () => {
         const java = new JavaCaller({
@@ -188,6 +218,23 @@ describe("Call with classes", () => {
         await javaCli.process();
     });
 
+    it("should use JavaCallerCli with --no-windows-hide flag", async () => {
+        // Save original argv
+        const originalArgv = process.argv;
+        
+        // Mock process.argv to include --no-windows-hide
+        process.argv = ['node', 'script.js', '--no-windows-hide'];
+        
+        try {
+            const javaCli = new JavaCallerCli("examples/cli_app/lib");
+            await javaCli.process();
+            checkStatus(0, process.exitCode);
+        } finally {
+            // Restore original argv
+            process.argv = originalArgv;
+        }
+    });
+
     it("Should work with an absolute path", async () => {
         const absolutePath = path.join(process.cwd(), "test/java/jar/JavaCallerTesterRunnable.jar");