Support variables in Maven Installations

Currently maven installations only support a fixed path but for certain
setups it would be desirable to use a variable.

This adds support for specify a variable in the path for an external
installation.

Fix #1372

RELEASE_NOTES.md

@@ -22,6 +22,10 @@ If you want to switch back to an older runtime you currently need to modify you
 
 ![grafik](https://github.com/eclipse-m2e/m2e-core/assets/1331477/ef04e7f4-e36b-4bbc-a4d3-ff92e6a5f9f4)
 
+### Support for variables in maven installations
+
+In the preferences for maven installations one can now specify variables for maven location.
+
 ## 2.3.0
 
 * 📅 Release Date: 23th May 2023

org.eclipse.m2e.core.ui/META-INF/MANIFEST.MF

@@ -1,7 +1,7 @@
 Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-SymbolicName: org.eclipse.m2e.core.ui;singleton:=true
-Bundle-Version: 2.0.6.qualifier
+Bundle-Version: 2.4.0.qualifier
 Bundle-RequiredExecutionEnvironment: JavaSE-17
 Bundle-Name: %Bundle-Name
 Bundle-Vendor: %Bundle-Vendor
@@ -42,7 +42,8 @@ Require-Bundle: org.eclipse.m2e.core;bundle-version="[2.0.0,3.0.0)",
  org.eclipse.jface.text,
  org.eclipse.core.filebuffers,
  org.eclipse.ui,
- org.eclipse.ui.navigator
+ org.eclipse.ui.navigator,
+ org.eclipse.debug.ui
 Import-Package: org.eclipse.compare.rangedifferencer,
  org.eclipse.ltk.core.refactoring,
  org.slf4j;version="[1.7.0,3.0.0)"

org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/Messages.java

@@ -985,6 +985,8 @@ public class Messages extends NLS {
 
   public static String ExternalInstallPage_btnDirectory_text;
 
+  public static String ExternalInstallPage_btnVariables_text;
+
   public static String ExternalInstallPage_lblInstallationLibraries_text;
 
   public static String ExternalInstallPage_btnRestoreDefault_text;

org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/messages.properties

@@ -48,6 +48,7 @@ EnableNatureAction_job_enable=Enabling Maven Dependency Management
 EnableNatureAction_wizard_shell=Create new POM
 ExternalInstallPage_btnAddProject_text=Project...
 ExternalInstallPage_btnDirectory_text=Directory...
+ExternalInstallPage_btnVariables_text=&Variables...
 ExternalInstallPage_btnDown_text=Down
 ExternalInstallPage_btnRemove_text=Remove
 ExternalInstallPage_btnRestoreDefault_text=Restore Default

org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/preferences/launch/MavenInstallationWizardPage.java

@@ -22,6 +22,7 @@
 import java.util.Set;
 
 import org.eclipse.core.resources.IProject;
+import org.eclipse.debug.ui.StringVariableSelectionDialog;
 import org.eclipse.jface.viewers.ILabelProvider;
 import org.eclipse.jface.viewers.ILabelProviderListener;
 import org.eclipse.jface.viewers.IStructuredSelection;
@@ -189,11 +190,24 @@ public void createControl(Composite parent) {
     location.addModifyListener(e -> updateStatus());
     location.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false, 1, 1));
 
-    btnDirectory = new Button(container, SWT.NONE);
+    Composite btnComposite = new Composite(container, SWT.NONE);
+    btnComposite.setLayout((new GridLayout(2, true)));
+    btnDirectory = new Button(btnComposite, SWT.NONE);
     btnDirectory.addSelectionListener(SelectionListener.widgetSelectedAdapter(e -> selectLocationAction()));
     btnDirectory.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false, 1, 1));
     btnDirectory.setText(Messages.ExternalInstallPage_btnDirectory_text);
 
+    Button variablesButton = new Button(btnComposite, SWT.NONE);
+    variablesButton.setText(Messages.ExternalInstallPage_btnVariables_text);
+    variablesButton.addSelectionListener(SelectionListener.widgetSelectedAdapter(e -> {
+      StringVariableSelectionDialog dialog = new StringVariableSelectionDialog(getShell());
+      dialog.open();
+      String variable = dialog.getVariableExpression();
+      if(variable != null) {
+        location.setText(location.getText() + variable);
+      }
+    }));
+
     Label lblInstallationName = new Label(container, SWT.NONE);
     lblInstallationName.setText(Messages.ExternalInstallPage_lblInstallationName_text);
 
@@ -353,10 +367,6 @@ private boolean isValidMavenInstall(String dir) {
     if(dir == null || dir.length() == 0) {
       return false;
     }
-    File selectedDir = new File(dir);
-    if(!selectedDir.isDirectory()) {
-      return false;
-    }
     return new MavenExternalRuntime(dir).isAvailable();
   }
 

org.eclipse.m2e.core/META-INF/MANIFEST.MF

@@ -10,7 +10,8 @@ Require-Bundle: org.eclipse.m2e.maven.runtime;bundle-version="[3.8.6,4.0.0)",
  org.eclipse.m2e.workspace.cli;bundle-version="0.1.0",
  org.eclipse.core.runtime;bundle-version="3.12.0",
  org.eclipse.core.resources;bundle-version="3.9.0",
- org.eclipse.core.filesystem;bundle-version="1.7.700"
+ org.eclipse.core.filesystem;bundle-version="1.7.700",
+ org.eclipse.core.variables
 Bundle-ActivationPolicy: lazy
 Bundle-RequiredExecutionEnvironment: JavaSE-17
 Export-Package: org.eclipse.m2e.core,

org.eclipse.m2e.core/src/org/eclipse/m2e/core/internal/launch/MavenExternalRuntime.java

@@ -29,6 +29,8 @@
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.Status;
+import org.eclipse.core.variables.IStringVariableManager;
+import org.eclipse.core.variables.VariablesPlugin;
 
 import org.codehaus.plexus.classworlds.ClassWorldException;
 import org.codehaus.plexus.classworlds.launcher.ConfigurationException;
@@ -71,16 +73,22 @@ public boolean isEditable() {
 
   @Override
   public boolean isAvailable() {
-    return new File(location, "bin").exists() && getLauncherClasspath() != null && isSupportedVersion(); //$NON-NLS-1$
+    return new File(getLocation(), "bin").exists() && getLauncherClasspath() != null && isSupportedVersion(); //$NON-NLS-1$
   }
 
   @Override
   public String getLocation() {
+    IStringVariableManager manager = VariablesPlugin.getDefault().getStringVariableManager();
+    try {
+      return manager.performStringSubstitution(location);
+    } catch(CoreException ex) {
+      //if we can't parse the location we need to return the unparsed raw value...
+    }
     return location;
   }
 
   private File getLauncherConfigurationFile() {
-    return new File(location, "bin/m2.conf"); //$NON-NLS-1$
+    return new File(getLocation(), "bin/m2.conf"); //$NON-NLS-1$
   }
 
   @Override
@@ -140,7 +148,7 @@ public void setAppMain(String mainClassName, String mainRealmName) {
 
     Properties properties = new Properties();
     copyProperties(properties, System.getProperties());
-    properties.put(PROPERTY_MAVEN_HOME, location);
+    properties.put(PROPERTY_MAVEN_HOME, getLocation());
 
     ConfigurationParser parser = new ConfigurationParser(handler, properties);
 
@@ -158,7 +166,7 @@ public void setAppMain(String mainClassName, String mainRealmName) {
 
   @Override
   public String toString() {
-    return location + ' ' + getVersion();
+    return getLocation() + ' ' + getVersion();
   }
 
   private static class ExceptionWrapper extends RuntimeException {
@@ -170,7 +178,7 @@ public ExceptionWrapper(Exception cause) {
   }
 
   private String getLauncherClasspath() {
-    File mavenHome = new File(location);
+    File mavenHome = new File(getLocation());
     DirectoryScanner ds = new DirectoryScanner();
     ds.setBasedir(mavenHome);
     ds.setIncludes(new String[] {"core/boot/classworlds*.jar", // 2.0.4 //$NON-NLS-1$
@@ -255,7 +263,7 @@ public void setAppMain(String mainClassName, String mainRealmName) {
 
     Properties properties = new Properties();
     copyProperties(properties, System.getProperties());
-    properties.put(PROPERTY_MAVEN_HOME, location);
+    properties.put(PROPERTY_MAVEN_HOME, getLocation());
 
     try (FileInputStream is = new FileInputStream(getLauncherConfigurationFile())) {
       new ConfigurationParser(handler, properties).parse(is);