package org.erlide.ui.internal.folding;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.core.runtime.Platform;
import org.erlide.ui.editors.erl.folding.IErlangFoldingStructureProvider;
import org.erlide.ui.internal.ErlideUIPlugin;
import org.erlide.ui.prefs.PreferenceConstants;
public class ErlangFoldingStructureProviderRegistry {
private static final String EXTENSION_POINT = "foldingStructureProviders"; //$NON-NLS-1$
/** The map of descriptors, indexed by their identifiers. */
private Map<String, ErlangFoldingStructureProviderDescriptor> fDescriptors;
/**
* Creates a new instance.
*/
public ErlangFoldingStructureProviderRegistry() {
}
/**
* Returns an array of <code>ErlangFoldingStructureProviderDescriptor</code>
* describing all extension to the <code>foldingProviders</code> extension
* point.
*
* @return the list of extensions to the
* <code>quickDiffReferenceProvider</code> extension point.
*/
public ErlangFoldingStructureProviderDescriptor[] getFoldingProviderDescriptors() {
synchronized (this) {
ensureRegistered();
return fDescriptors.values().toArray(
new ErlangFoldingStructureProviderDescriptor[fDescriptors.size()]);
}
}
/**
* Returns the folding provider descriptor with identifier <code>id</code>
* or <code>null</code> if no such provider is registered.
*
* @param id
* the identifier for which a provider is wanted
* @return the corresponding provider descriptor, or <code>null</code> if
* none can be found
*/
public ErlangFoldingStructureProviderDescriptor getFoldingProviderDescriptor(
final String id) {
synchronized (this) {
ensureRegistered();
return fDescriptors.get(id);
}
}
/**
* Instantiates and returns the provider that is currently configured in the
* preferences.
*
* @return the current provider according to the preferences
*/
public IErlangFoldingStructureProvider getCurrentFoldingProvider() {
final String id = ErlideUIPlugin.getDefault().getPreferenceStore()
.getString(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
final ErlangFoldingStructureProviderDescriptor desc = getFoldingProviderDescriptor(id);
if (desc != null) {
try {
return desc.createProvider();
} catch (final CoreException e) {
ErlideUIPlugin.log(e);
}
}
return null;
}
/**
* Ensures that the extensions are read and stored in
* <code>fDescriptors</code>.
*/
private void ensureRegistered() {
if (fDescriptors == null) {
reloadExtensions();
}
}
/**
* Reads all extensions.
* <p>
* This method can be called more than once in order to reload from a
* changed extension registry.
* </p>
*/
public void reloadExtensions() {
final IExtensionRegistry registry = Platform.getExtensionRegistry();
final Map<String, ErlangFoldingStructureProviderDescriptor> map = new HashMap<String, ErlangFoldingStructureProviderDescriptor>();
final IConfigurationElement[] elements = registry.getConfigurationElementsFor(
ErlideUIPlugin.PLUGIN_ID, EXTENSION_POINT);
for (final IConfigurationElement element : elements) {
final ErlangFoldingStructureProviderDescriptor desc = new ErlangFoldingStructureProviderDescriptor(
element);
map.put(desc.getId(), desc);
}
synchronized (this) {
fDescriptors = Collections.unmodifiableMap(map);
}
}
}