package org.dresdenocl.tools.template.internal;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.log4j.Logger;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.IRegistryEventListener;
import org.eclipse.core.runtime.ListenerList;
import org.eclipse.core.runtime.Platform;
import org.dresdenocl.tools.template.ITemplate;
import org.dresdenocl.tools.template.ITemplateEngine;
import org.dresdenocl.tools.template.ITemplateEngineRegistry;
import org.dresdenocl.tools.template.TemplatePlugin;
import org.dresdenocl.tools.template.event.ITemplateEngineRegistryListener;
import org.dresdenocl.tools.template.event.TemplateEngineRegistryEvent;
import org.dresdenocl.tools.template.exception.TemplateException;
/**
* Default implementation of the {@link ITemplateEngineRegistr}
*
* @author Bjoern Freitag
*
*/
public class TemplateEngineRegistry implements ITemplateEngineRegistry,
IRegistryEventListener {
/** {@link Logger} for this class. */
private static final Logger LOGGER = TemplatePlugin
.getLogger(TemplateEngineRegistry.class);
/**
* the map of template engines
*/
private Map<String, ITemplateEngine> templateEngines;
/** The full identifier of the {@link ITemplateEngine}s' extension point. */
private static final String TEMPLATEENGINE_EXTENSION_POINT_ID = TemplatePlugin.ID
+ ".templateEngines";
/** A list of listeners. */
private ListenerList listeners;
/**
* The constructor
*/
public TemplateEngineRegistry() {
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("TemplateEngineRegistry() - enter"); //$NON-NLS-1$
}
// no else.
this.templateEngines = new HashMap<String, ITemplateEngine>();
if (Platform.isRunning()) {
this.added(this.getExtensionPoint().getExtensions());
/* Register this registry as a listener for plug-in events. */
Platform.getExtensionRegistry().addListener(this,
TEMPLATEENGINE_EXTENSION_POINT_ID);
}
else {
LOGGER.warn("Platform is not running. TemplateEngines must be registered manually.");
}
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("TemplateEngineRegistry() - exit"); //$NON-NLS-1$
}
}
/**
* @see org.dresdenocl.tools.template.ITemplateEngineRegistry#addTemplateEngine(ITemplateEngine)
*/
public void addTemplateEngine(ITemplateEngine templateEngine)
throws TemplateException {
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("addTemplateEngine(templateEngine=" + templateEngine + ") - enter"); //$NON-NLS-1$ //$NON-NLS-2$
}
// no else.
if (templateEngine == null) {
throw new TemplateException(
"The parameter 'templateEngine' must not be null."); //$NON-NLS-1$
}
// no else.
/*
* Check if model is already contained in the registry; this is meant to
* be captured and dealt with on the UI, e.g., by showing an error
* message; this is better than silently do nothing.
*/
if (this.templateEngines.containsValue(templateEngine)) {
LOGGER.warn("TemplateEngine '" + templateEngine.getDisplayName() + "' is already loaded. The templateEngine will be replaced."); //$NON-NLS-1$//$NON-NLS-2$
}
// no else.
/* Add the model. */
this.templateEngines.put(templateEngine.getDisplayName(),
templateEngine);
/* Inform listeners. */
this.fireTemplateEngineAdded(templateEngine);
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("addTemplateEngine() - exit"); //$NON-NLS-1$
}
// no else.
}
/**
* @see org.dresdenocl.tools.template.ITemplateEngineRegistry#dispose()
*/
public void dispose() {
if (this.templateEngines.size() != 0) {
this.templateEngines.clear();
}
}
/**
* @see org.dresdenocl.tools.template.ITemplateEngineRegistry#getNewTemplateEngine(String)
*/
public ITemplateEngine getNewTemplateEngine(String templateEngineName)
throws TemplateException {
if (templateEngineName == null) {
throw new TemplateException(
"The parameter templateEngineName must not be null.");
}
// no else.
ITemplateEngine templateEngine;
try {
templateEngine = this.templateEngines.get(templateEngineName)
.getClass().newInstance();
} catch (InstantiationException e) {
templateEngine = null;
} catch (IllegalAccessException e) {
templateEngine = null;
} catch (NullPointerException e) {
templateEngine = null;
}
if (templateEngine == null) {
throw new TemplateException("The template engine can't load.");
}
return templateEngine;
}
/**
* @see org.dresdenocl.tools.template.ITemplateEngineRegistry#getTemplateEngines()
*/
public List<ITemplateEngine> getTemplateEngines() {
List<ITemplateEngine> tempGroup = new ArrayList<ITemplateEngine>();
for (ITemplateEngine tGroup : this.templateEngines.values()) {
tempGroup.add(tGroup);
}
return tempGroup;
}
/**
* @see org.dresdenocl.tools.template.ITemplateEngineRegistry#removeTemplateEngine(ITemplateEngine)
*/
public void removeTemplateEngine(ITemplateEngine templateEngine) {
if (templateEngine == null) {
throw new IllegalArgumentException(
"The parameter templateEngineName must not be null.");
}
// no else.
this.templateEngines.remove(templateEngine.getDisplayName());
this.fireTemplateEngineRemoved(this.templateEngines
.remove(templateEngine.getDisplayName()));
}
/**
* @see org.dresdenocl.tools.template.ITemplateEngineRegistry#removeTemplateEngine(String)
*/
public void removeTemplateEngine(String templateEngineName) {
if (templateEngineName == null) {
throw new IllegalArgumentException(
"The parameter templateEngineName must not be null.");
}
// no else.
this.templateEngines.remove(templateEngineName);
}
/**
* @see org.dresdenocl.tools.template.ITemplateEngineRegistry#addTemplateEngineRegistryListener(ITemplateEngineRegistryListener)
*/
public void addTemplateEngineRegistryListener(
ITemplateEngineRegistryListener listener) {
this.getListeners().add(listener);
}
/**
* <p>
* A helper method that informs all listeners about an added
* {@link ITemplateEngine}.
* </p>
*
* @param model
* The {@link ITemplateEngine} that has been added.
*/
private void fireTemplateEngineAdded(ITemplateEngine model) {
TemplateEngineRegistryEvent event;
event = null;
if (this.listeners != null) {
Object[] listeners;
listeners = this.listeners.getListeners();
for (int index = 0; index < listeners.length; index++) {
/* Lazily create the event. */
if (event == null) {
event = new TemplateEngineRegistryEvent(this, model);
}
// no else.
((ITemplateEngineRegistryListener) listeners[index])
.templateEngineAdded(event);
}
// end for.
}
// no else.
}
/**
* <p>
* A helper method that informs all listeners about a removed
* {@link ITemplateEngine}.
* </p>
*
* @param templateEngine
* The {@link ITemplate} that has been removed.
*/
private void fireTemplateEngineRemoved(ITemplateEngine templateEngine) {
TemplateEngineRegistryEvent event = null;
if (this.listeners != null) {
Object[] listeners;
listeners = this.listeners.getListeners();
for (int index = 0; index < listeners.length; index++) {
/* Lazily create the event. */
if (event == null) {
event = new TemplateEngineRegistryEvent(this,
templateEngine);
}
// no else.
((ITemplateEngineRegistryListener) listeners[index])
.templateEngineRemoved(event);
}
// end for.
}
// no else.
}
/**
* @see org.dresdenocl.tools.template.ITemplateEngineRegistry#removeTemplateEngineRegistryListener(ITemplateEngineRegistryListener)
*
*/
public void removeTemplateEngineRegistryListener(
ITemplateEngineRegistryListener listener) {
if (this.listeners != null) {
this.listeners.remove(listener);
}
// no else.
}
/**
* <p>
* A helper method that lazily creates the {@link ListenerList}.
* </p>
*/
private ListenerList getListeners() {
if (this.listeners == null) {
this.listeners = new ListenerList(ListenerList.IDENTITY);
}
// no else.
return this.listeners;
}
/**
* Add a new {@link ITemplateEngine} from an extension
*
* @see org.eclipse.core.runtime.IRegistryEventListener#added(IExtension[])
*/
public void added(IExtension[] extensions) {
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("added(extensions=" + extensions + ") - enter"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
}
// no else.
/* Remove all registered objects from the meta-model cache. */
if (this.templateEngines != null) {
for (IExtension extension : extensions) {
for (IConfigurationElement configurationElement : extension
.getConfigurationElements()) {
ITemplateEngine templateEngine;
try {
templateEngine = (ITemplateEngine) configurationElement
.createExecutableExtension("class");
} catch (CoreException e) {
continue;
}
if (templateEngine != null) {
try {
this.addTemplateEngine(templateEngine);
} catch (TemplateException e) {
LOGGER.warn("The element of the extension can't load.");
}
}
// no else.
}
// end for (configurationElements).
}
// end for (extensions).
}
// no else.
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("added(IExtension[]) - exit"); //$NON-NLS-1$
}
// no else.
}
/**
* This method do nothing.
*
* @see org.eclipse.core.runtime.IRegistryEventListener#added(IExtensionPoint[])
*/
public void added(IExtensionPoint[] extensionPoints) {
// Do nothing
}
/**
* Remove an {@link ITemplateEngine} from the extension
*
* @see org.eclipse.core.runtime.IRegistryEventListener#removed(IExtension[])
*/
public void removed(IExtension[] extensions) {
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("removed(extensions=" + extensions + ") - enter"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
}
// no else.
/* Remove all registered objects from the meta-model cache. */
if (this.templateEngines != null) {
for (IExtension extension : extensions) {
for (IConfigurationElement configurationElement : extension
.getConfigurationElements()) {
String templateEngineID;
try {
templateEngineID = ((ITemplateEngine) (Class
.forName(this.getAttribute("class",
configurationElement)).newInstance()))
.getDisplayName();
} catch (InstantiationException e) {
templateEngineID = null;
} catch (IllegalAccessException e) {
templateEngineID = null;
} catch (ClassNotFoundException e) {
templateEngineID = null;
}
if (templateEngineID != null) {
this.removeTemplateEngine(templateEngineID);
}
// no else.
}
// end for (configurationElements).
}
// end for (extensions).
}
// no else.
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("removed(IExtension[]) - exit"); //$NON-NLS-1$
}
// no else.
}
/**
* This method do nothing.
*
* @see org.eclipse.core.runtime.IRegistryEventListener#removed(IExtensionPoint[])
*/
public void removed(IExtensionPoint[] extensionPoints) {
// Do nothing
}
/**
* <p>
* A helper method to get the worklist task {@link IExtensionPoint}.
* </p>
*
* @return The {@link ITemplateEngine} {@link IExtensionPoint}.
*/
private IExtensionPoint getExtensionPoint() {
IExtensionPoint result;
/* Get the point from the registry. */
result = Platform.getExtensionRegistry().getExtensionPoint(
TEMPLATEENGINE_EXTENSION_POINT_ID);
/* This should not happen unless the id changes. */
if (result == null) {
throw new IllegalStateException(
"The extension point for new template engines could not be found under the id " //$NON-NLS-1$
+ TEMPLATEENGINE_EXTENSION_POINT_ID);
}
// no else.
return result;
}
/**
* <p>
* Helper method that returns the value of an attribute of the given
* {@link IConfigurationElement}. Throws an
* {@link InvalidDescriptorException} if the attribute is empty and
* required.
* </p>
*
* @param attributeName
* The name of the extension point attribute.
* @param configurationElement
* The {@link IllegalClassException} whose attribute shall be
* returned.
*
* @throws InvalidDescriptorException
* If the value of the attribute is invalid.
*/
private String getAttribute(String attributeName,
IConfigurationElement configurationElement) {
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("getAttribute(attributeName=" + attributeName + ", configurationElement=" + configurationElement //$NON-NLS-1$ //$NON-NLS-2$
+ ") - enter"); //$NON-NLS-1$
}
// no else.
String value = configurationElement.getAttribute(attributeName);
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("getAttribute() - exit - return value=" + value); //$NON-NLS-1$
}
// no else.
return value;
}
}