[xtext][generator] Additional abstract base class

Helps to implement generator fragments that write
to other locations on the disk, e.g to generate
plugins for other editors

plugins/org.eclipse.xtext.xtext.generator/src/org/eclipse/xtext/xtext/generator/AbstractExternalFolderAwareFragment.xtend

@@ -0,0 +1,50 @@
+/*******************************************************************************
+ * Copyright (c) 2015 itemis AG (http://www.itemis.eu) and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.xtext.xtext.generator
+
+import com.google.inject.Injector
+import org.eclipse.xtend.lib.annotations.Accessors
+import org.eclipse.xtext.xtext.generator.model.IXtextGeneratorFileSystemAccess
+import org.eclipse.xtext.xtext.generator.model.XtextGeneratorFileSystemAccess
+import org.eclipse.emf.mwe2.runtime.Mandatory
+
+/**
+ * Generator fragment that allows to write files to arbitrary, user configurable
+ * locations.
+ * 
+ * @author Sebastian Zarnekow - Initial contribution and API
+ */
+abstract class AbstractExternalFolderAwareFragment extends AbstractXtextGeneratorFragment {
+	
+	String absolutePath
+	
+	@Accessors(PROTECTED_GETTER, PUBLIC_SETTER)
+	boolean ^override = false
+	
+	IXtextGeneratorFileSystemAccess outputLocation
+	
+	protected def getOutputLocation() {
+		return outputLocation
+	}
+	
+	override initialize(Injector injector) {
+		super.initialize(injector)
+		this.outputLocation = new XtextGeneratorFileSystemAccess(absolutePath, override)
+		injector.injectMembers(outputLocation)
+	}
+	
+	protected def getAbsolutePath() {
+		return absolutePath
+	}
+	
+	@Mandatory
+	def void setAbsolutePath(String absolutePath) {
+		this.absolutePath = absolutePath
+	}
+	
+}