[#476] Support EMF's ResourceLocators in XtextResourceSet.

Signed-off-by: Arne Deutsch <Arne.Deutsch@itemis.de>

org.eclipse.xtext.tests/src/org/eclipse/xtext/resource/XtextResourceSetTest.xtend

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2012 itemis AG (http://www.itemis.eu) and others.
+ * Copyright (c) 2012, 2018 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
@@ -17,6 +17,7 @@ import org.eclipse.emf.ecore.resource.impl.ResourceSetImpl
 import org.junit.Test
 
 import static org.junit.Assert.*
+import org.eclipse.emf.ecore.resource.impl.ResourceSetImpl.ResourceLocator
 
 /**
  * @author Sven Efftinge - Initial contribution and API
@@ -35,7 +36,7 @@ abstract class AbstractResourceSetTest {
 		]
 		rs.resourceFactoryRegistry.extensionToFactoryMap.put('xmi', nullFactory)
 		assertEquals(0, rs.URIResourceMap.size)
-		val uri = URI::createURI('file:/does/not/exist.xmi')
+		val uri = URI.createURI('file:/does/not/exist.xmi')
 		val demandLoaded = rs.getResource(uri, true)
 		assertNotNull(demandLoaded)
 		val second = rs.getResource(uri, true)
@@ -44,6 +45,34 @@ abstract class AbstractResourceSetTest {
 		assertEquals(1, rs.URIResourceMap.size)
 	}
 	
+	@Test
+	def void testResourceLocatorIsUsed() {
+		val rs = createEmptyResourceSet
+		
+		val resource = new XtextResource
+		resource.URI = URI.createFileURI(new File('foo').absolutePath)
+		
+		// resource locators register themselves on the resource set as a side effect in their constructor
+		new ResourceLocator(rs) {
+			override getResource(URI uri, boolean loadOnDemand) {
+				if (uri == resource.URI) {
+					return resource;
+				}
+				throw new IllegalArgumentException(uri.toString)
+			}
+		}
+		assertSame(resource, rs.getResource(resource.URI, true))
+		assertTrue(rs.resources.isEmpty)
+		assertNull(resource.resourceSet)
+		
+		try {
+			rs.getResource(resource.URI.appendSegment("doesNotExist"), true)
+			fail()
+		} catch(IllegalArgumentException e) {
+			assertTrue(e.message.endsWith("doesNotExist"))
+		}
+	}
+	
 }
 
 abstract class AbstractXtextResourceSetTest extends AbstractResourceSetTest {

org.eclipse.xtext.tests/xtend-gen/org/eclipse/xtext/resource/AbstractResourceSetTest.java

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2012 itemis AG (http://www.itemis.eu) and others.
+ * Copyright (c) 2012, 2018 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
@@ -7,10 +7,14 @@
  */
 package org.eclipse.xtext.resource;
 
+import com.google.common.base.Objects;
+import java.io.File;
 import org.eclipse.emf.common.util.URI;
 import org.eclipse.emf.ecore.resource.Resource;
 import org.eclipse.emf.ecore.resource.impl.ResourceSetImpl;
 import org.eclipse.xtext.resource.NullResource;
+import org.eclipse.xtext.resource.XtextResource;
+import org.eclipse.xtext.xbase.lib.Exceptions;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -43,4 +47,37 @@ public abstract class AbstractResourceSetTest {
     Assert.assertSame(demandLoaded, second);
     Assert.assertEquals(1, rs.getURIResourceMap().size());
   }
+  
+  @Test
+  public void testResourceLocatorIsUsed() {
+    final ResourceSetImpl rs = this.createEmptyResourceSet();
+    final XtextResource resource = new XtextResource();
+    resource.setURI(URI.createFileURI(new File("foo").getAbsolutePath()));
+    new ResourceSetImpl.ResourceLocator(rs) {
+      @Override
+      public Resource getResource(final URI uri, final boolean loadOnDemand) {
+        URI _uRI = resource.getURI();
+        boolean _equals = Objects.equal(uri, _uRI);
+        if (_equals) {
+          return resource;
+        }
+        String _string = uri.toString();
+        throw new IllegalArgumentException(_string);
+      }
+    };
+    Assert.assertSame(resource, rs.getResource(resource.getURI(), true));
+    Assert.assertTrue(rs.getResources().isEmpty());
+    Assert.assertNull(resource.getResourceSet());
+    try {
+      rs.getResource(resource.getURI().appendSegment("doesNotExist"), true);
+      Assert.fail();
+    } catch (final Throwable _t) {
+      if (_t instanceof IllegalArgumentException) {
+        final IllegalArgumentException e = (IllegalArgumentException)_t;
+        Assert.assertTrue(e.getMessage().endsWith("doesNotExist"));
+      } else {
+        throw Exceptions.sneakyThrow(_t);
+      }
+    }
+  }
 }

org.eclipse.xtext.tests/xtend-gen/org/eclipse/xtext/resource/AbstractXtextResourceSetTest.java

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2012 itemis AG (http://www.itemis.eu) and others.
+ * Copyright (c) 2012, 2018 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

org.eclipse.xtext.tests/xtend-gen/org/eclipse/xtext/resource/NullResource.java

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2012 itemis AG (http://www.itemis.eu) and others.
+ * Copyright (c) 2012, 2018 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

org.eclipse.xtext.tests/xtend-gen/org/eclipse/xtext/resource/ResourceSetTest.java

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2012 itemis AG (http://www.itemis.eu) and others.
+ * Copyright (c) 2012, 2018 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

org.eclipse.xtext.tests/xtend-gen/org/eclipse/xtext/resource/SynchronizedXtextResourceSetTest.java

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2012 itemis AG (http://www.itemis.eu) and others.
+ * Copyright (c) 2012, 2018 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

org.eclipse.xtext.tests/xtend-gen/org/eclipse/xtext/resource/XtextResourceSetTest.java

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2012 itemis AG (http://www.itemis.eu) and others.
+ * Copyright (c) 2012, 2018 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

org.eclipse.xtext/src/org/eclipse/xtext/resource/XtextResourceSet.java

@@ -232,7 +232,7 @@ public class XtextResourceSet extends ResourceSetImpl {
     @Override
 	public Resource getResource(URI uri, boolean loadOnDemand) {
 		Map<URI, Resource> map = getURIResourceMap();
-		if (map == null)
+		if (map == null || resourceLocator != null)
 			return super.getResource(uri, loadOnDemand);
 		Resource resource = map.get(uri);
 		if (resource == null) {