--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/org.symbian.tools.wrttools.previewer/src/org/symbian/tools/tmw/previewer/internal/PreviewerExtensionsManagerImpl.java	Thu Aug 19 16:13:44 2010 -0700
@@ -0,0 +1,114 @@
+/**
+ * Copyright (c) 2010 Symbian Foundation and/or its subsidiary(-ies).
+ * All rights reserved.
+ * This component and the accompanying materials are made available
+ * under the terms of the License "Eclipse Public License v1.0"
+ * which accompanies this distribution, and is available
+ * at the URL "http://www.eclipse.org/legal/epl-v10.html".
+ *
+ * Initial Contributors:
+ * Symbian Foundation - initial contribution.
+ * Contributors:
+ * Description:
+ * Overview:
+ * Details:
+ * Platforms/Drives/Compatibility:
+ * Assumptions/Requirement/Pre-requisites:
+ * Failures and causes:
+ */
+package org.symbian.tools.tmw.previewer.internal;
+
+import java.io.InputStream;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.eclipse.core.resources.IFile;
+import org.eclipse.core.resources.IProject;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IConfigurationElement;
+import org.eclipse.core.runtime.IPath;
+import org.eclipse.core.runtime.Platform;
+import org.symbian.tools.tmw.core.TMWCore;
+import org.symbian.tools.tmw.core.projects.ITMWProject;
+import org.symbian.tools.tmw.core.runtimes.IMobileWebRuntime;
+import org.symbian.tools.tmw.previewer.core.IApplicationLayoutProvider;
+import org.symbian.tools.tmw.previewer.core.IPreviewerExtensionsManager;
+import org.symbian.tools.wrttools.previewer.PreviewerPlugin;
+
+public class PreviewerExtensionsManagerImpl implements IPreviewerExtensionsManager {
+    public static final class LazyProvider implements IApplicationLayoutProvider {
+        private final IConfigurationElement element;
+        private IApplicationLayoutProvider instance;
+
+        public LazyProvider(IConfigurationElement element) {
+            this.element = element;
+        }
+
+        public IPath getResourcePath(IFile file) {
+            return getDelegate().getResourcePath(file);
+        }
+
+        private IApplicationLayoutProvider getDelegate() {
+            if (instance == null) {
+                try {
+                    instance = (IApplicationLayoutProvider) element.createExecutableExtension("class");
+                } catch (CoreException e) {
+                    PreviewerPlugin.log(e);
+                    instance = new IApplicationLayoutProvider() {
+
+                        public IPath getResourcePath(IFile file) {
+                            return null;
+                        }
+
+                        public InputStream getResourceFromPath(IProject project, IPath path) {
+                            return null;
+                        }
+
+                        public IFile getWorkspaceFile(IProject project, IPath applicationPath) {
+                            return null;
+                        }
+                    };
+                }
+            }
+            return instance;
+        }
+
+        public InputStream getResourceFromPath(IProject project, IPath path) throws CoreException {
+            return getDelegate().getResourceFromPath(project, path);
+        }
+
+        public IFile getWorkspaceFile(IProject project, IPath applicationPath) throws CoreException {
+            return getDelegate().getWorkspaceFile(project, applicationPath);
+        }
+    }
+
+    private Map<IMobileWebRuntime, IApplicationLayoutProvider> providers;
+
+    public IApplicationLayoutProvider getLayoutProvider(IProject project) {
+        final ITMWProject p = TMWCore.create(project);
+        if (p != null && p.getTargetRuntime() != null) {
+            checkRegistry();
+            return providers.get(p.getTargetRuntime());
+        }
+        return null;
+    }
+
+    private synchronized void checkRegistry() {
+        if (providers == null) {
+            providers = new HashMap<IMobileWebRuntime, IApplicationLayoutProvider>();
+            final IConfigurationElement[] configuration = Platform.getExtensionRegistry().getConfigurationElementsFor(
+                    PreviewerPlugin.PLUGIN_ID, "layoutProviders");
+            for (IConfigurationElement element : configuration) {
+                final String runtimeId = element.getAttribute("runtime-id");
+                final String version = element.getAttribute("runtime-version");
+                final IMobileWebRuntime runtime = TMWCore.getRuntimesManager().getRuntime(runtimeId, version);
+                if (runtime != null) {
+                    providers.put(runtime, new LazyProvider(element));
+                } else {
+                    PreviewerPlugin.log(String.format("Runtime %s:$s referenced from %s was not found", runtimeId,
+                            version, element.getContributor().getName()), null);
+                }
+            }
+        }
+    }
+}