Check if java exists instead of javac. Allow JRE path to be specified in xml.java home, java.home, or detect automatically.

Signed-off-by: David Kwon <dakwon@redhat.com>

Author: angelozerr

README.md

@@ -36,13 +36,14 @@ See the [changelog](CHANGELOG.md) for the latest release. You might also find us
 
 ## Requirements
 
-  * Java JDK 8 or more recent
+  * Java JDK (or JRE) 8 or more recent
   * Ensure Java path is set in either: 
     * `xml.java.home` in VSCode preferences
     * `java.home` in VSCode preferences
     * Environment variable `JAVA_HOME` or `JDK_HOME`  
     * **Note**: The path should end at the parent folder that contains the `bin` folder.  
-      **Example Path**: `/usr/lib/jvm/java-1.8.0` if `bin` exists at `/usr/lib/jvm/java-1.8.0/bin`.
+      **Example Path**: `/usr/lib/jvm/java-1.8.0` if `bin` exists at `/usr/lib/jvm/java-1.8.0/bin`.  
+    * **Note**: If the path is not set, the extension will attempt to find the path to the JDK or JRE.
 
 ## Supported VS Code settings
 

src/requirements.ts

@@ -8,7 +8,7 @@ const pathExists = require('path-exists');
 const expandHomeDir = require('expand-home-dir');
 const findJavaHome = require('find-java-home');
 const isWindows = process.platform.indexOf('win') === 0;
-const JAVAC_FILENAME = 'javac' + (isWindows?'.exe':'');
+const JAVA_FILENAME = 'java' + (isWindows?'.exe':'');
 
 export interface RequirementsData {
     java_home: string;
@@ -36,14 +36,37 @@ export async function resolveRequirements(): Promise<RequirementsData> {
 
 function checkJavaRuntime(): Promise<string> {
     return new Promise((resolve, reject) => {
+        let source : string;
+        let javaHome: string = readXMLJavaHomeConfig();
+
+        if (javaHome) {
+            source = 'The xml.java.home variable defined in VS Code settings';
+        } else {
+            javaHome = readJavaHomeConfig();
+            if (javaHome) {
+                source = 'The java.home variable defined in VS Code settings';
+            } else {
+                javaHome = process.env['JDK_HOME'];
+                if (javaHome) {
+                    source = 'The JDK_HOME environment variable';
+                } else {
+                    javaHome = process.env['JAVA_HOME'];
+                    source = 'The JAVA_HOME environment variable';
+                }
+            }
+        }
 
-        checkXMLJavaHome(resolve, reject);
-        checkJavaHome(resolve, reject);
-        checkEnvVariable('JDK_HOME', resolve, reject);
-        checkEnvVariable('JAVA_HOME', resolve, reject);
-
+        if (javaHome) {
+            javaHome = expandHomeDir(javaHome);
+            if (!pathExists.sync(javaHome)) {
+                openJDKDownload(reject, source+' points to a missing folder');
+            } else if (!pathExists.sync(path.resolve(javaHome, 'bin', JAVA_FILENAME))){
+                openJDKDownload(reject, source+ ' does not point to a Java runtime.');
+            }
+            return resolve(javaHome);
+        }
         //No settings, let's try to detect as last resort.
-        findJavaHome(function (err, home) {
+        findJavaHome({ allowJre: true }, function (err, home) {
             if (err){
                 openJDKDownload(reject, 'Java runtime could not be located.');
             }
@@ -54,31 +77,6 @@ function checkJavaRuntime(): Promise<string> {
     });
 }
 
-function checkXMLJavaHome(resolve, reject) {
-    const javaHome = readXMLJavaHomeConfig();
-    if (!javaHome) {
-        return;
-    }
-    const source = 'The xml.java.home variable defined in VS Code settings';
-    handleJavaPath(javaHome, source, resolve, reject);
-}
-
-function checkJavaHome(resolve, reject) {
-    const javaHome = readJavaHomeConfig();
-    if (!javaHome) {
-        return;
-    }
-    const source = 'The java.home variable defined in VS Code settings';
-    handleJavaPath(javaHome, source, resolve, reject);
-}
-
-function checkEnvVariable(name : string, resolve, reject) {
-    if (!process.env[name]) {
-        return;
-    } 
-    const source = `The ${name} environment variable`;
-    handleJavaPath(process.env[name], source, resolve, reject);
-}
 
 function readXMLJavaHomeConfig() : string {
     return workspace.getConfiguration('xml').java.home;
@@ -88,18 +86,6 @@ function readJavaHomeConfig() : string {
     const config = workspace.getConfiguration();
     return config.get<string>('java.home',null);
 }
-
-function handleJavaPath(javaHome : string, source : string, resolve, reject) {
-    const javaHomeExpanded = expandHomeDir(javaHome);
-
-    if (!pathExists.sync(javaHomeExpanded)) {
-        openJDKDownload(reject, source + ' points to a missing folder.');
-    }
-    if (!pathExists.sync(path.resolve(javaHomeExpanded, 'bin', JAVAC_FILENAME))) {
-        openJDKDownload(reject, source + ' does not point to a JDK.');
-    }
-    return resolve(javaHomeExpanded);
-}
 
 function checkJavaVersion(java_home: string): Promise<number> {
     return new Promise((resolve, reject) => {