/*
* Copyright (c) 2012, the Dart project authors.
*
* Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.eclipse.org/legal/epl-v10.html
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.dart.tools.ui.internal.text.dart;
import com.google.dart.tools.ui.DartToolsPlugin;
import com.google.dart.tools.ui.Messages;
import com.google.dart.tools.ui.text.dart.AbstractProposalSorter;
import com.google.dart.tools.ui.text.dart.ContentAssistInvocationContext;
import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.InvalidRegistryObjectException;
import org.eclipse.core.runtime.PerformanceStats;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.Status;
import org.osgi.framework.Bundle;
import java.util.Collections;
import java.util.List;
/**
* The description of an extension to the
* <code>com.google.dart.tools.ui.javaCompletionProposalSorters</code> extension point. Instances
* are immutable.
*/
public final class ProposalSorterHandle {
/** The extension schema name of the id attribute. */
private static final String ID = "id"; //$NON-NLS-1$
/** The extension schema name of the name attribute. */
private static final String NAME = "name"; //$NON-NLS-1$
/** The extension schema name of the class attribute. */
private static final String CLASS = "class"; //$NON-NLS-1$
/** The extension schema name of the activate attribute. */
private static final String ACTIVATE = "activate"; //$NON-NLS-1$
/** The name of the performance event used to trace extensions. */
private static final String PERFORMANCE_EVENT = DartToolsPlugin.getPluginId()
+ "/perf/content_assist_sorters/extensions"; //$NON-NLS-1$
/**
* If <code>true</code>, execution time of extensions is measured and extensions may be disabled
* if execution takes too long.
*/
private static final boolean MEASURE_PERFORMANCE = PerformanceStats.isEnabled(PERFORMANCE_EVENT);
/** The one and only operation name. */
private static final String SORT = "sort"; //$NON-NLS-1$
/** The identifier of the extension. */
private final String fId;
/** The name of the extension. */
private final String fName;
/** The class name of the provided <code>AbstractProposalSorter</code>. */
private final String fClass;
/** The activate attribute value. */
private final boolean fActivate;
/** The configuration element of this extension. */
private final IConfigurationElement fElement;
/** The computer, if instantiated, <code>null</code> otherwise. */
private AbstractProposalSorter fSorter;
/**
* Creates a new descriptor.
*
* @param element the configuration element to read
* @throws InvalidRegistryObjectException if the configuration element is not valid any longer or
* does not contain mandatory attributes
*/
ProposalSorterHandle(IConfigurationElement element) throws InvalidRegistryObjectException {
Assert.isLegal(element != null);
fElement = element;
fId = element.getAttribute(ID);
checkNotNull(fId, ID);
String name = element.getAttribute(NAME);
if (name == null) {
fName = fId;
} else {
fName = name;
}
String activateAttribute = element.getAttribute(ACTIVATE);
fActivate = Boolean.valueOf(activateAttribute).booleanValue();
fClass = element.getAttribute(CLASS);
checkNotNull(fClass, CLASS);
}
/**
* Returns the error message from the described extension, <code>null</code> for no error.
*
* @return the error message from the described extension, <code>null</code> for no error
*/
public String getErrorMessage() {
return null;
}
/**
* Returns the identifier of the described extension.
*
* @return Returns the id
*/
public String getId() {
return fId;
}
/**
* Returns the name of the described extension.
*
* @return Returns the name
*/
public String getName() {
return fName;
}
/**
* Safely computes completion proposals through the described extension. If the extension throws
* an exception or otherwise does not adhere to the contract described in
* {@link AbstractProposalSorter}, the list is returned as is.
*
* @param context the invocation context passed on to the extension
* @param proposals the list of computed completion proposals to be sorted (element type:
* {@link org.eclipse.jface.text.contentassist.ICompletionProposal}), must be writable
*/
@SuppressWarnings("unchecked")
public void sortProposals(ContentAssistInvocationContext context,
@SuppressWarnings("rawtypes") List proposals) {
IStatus status;
try {
AbstractProposalSorter sorter = getSorter();
PerformanceStats stats = startMeter(SORT, sorter);
sorter.beginSorting(context);
Collections.sort(proposals, sorter);
sorter.endSorting();
status = stopMeter(stats, SORT);
// valid result
if (status == null) {
return;
}
status = createAPIViolationStatus(SORT);
} catch (InvalidRegistryObjectException x) {
status = createExceptionStatus(x);
} catch (CoreException x) {
status = createExceptionStatus(x);
} catch (RuntimeException x) {
status = createExceptionStatus(x);
}
DartToolsPlugin.log(status);
return;
}
/**
* Checks an element that must be defined according to the extension point schema. Throws an
* <code>InvalidRegistryObjectException</code> if <code>obj</code> is <code>null</code>.
*/
private void checkNotNull(Object obj, String attribute) throws InvalidRegistryObjectException {
if (obj == null) {
Object[] args = {getId(), fElement.getContributor().getName(), attribute};
String message = Messages.format(
DartTextMessages.CompletionProposalComputerDescriptor_illegal_attribute_message,
args);
IStatus status = new Status(
IStatus.WARNING,
DartToolsPlugin.getPluginId(),
IStatus.OK,
message,
null);
DartToolsPlugin.log(status);
throw new InvalidRegistryObjectException();
}
}
private Status createAPIViolationStatus(String operation) {
String disable = createBlameMessage();
Object[] args = {operation};
String reason = Messages.format(
DartTextMessages.CompletionProposalComputerDescriptor_reason_API,
args);
return new Status(IStatus.WARNING, DartToolsPlugin.getPluginId(), IStatus.OK, disable
+ " " + reason, null); //$NON-NLS-1$
}
private String createBlameMessage() {
Object[] args = {getName(), getId()};
String disable = Messages.format(DartTextMessages.ProposalSorterHandle_blame, args);
return disable;
}
private Status createExceptionStatus(CoreException x) {
// unable to instantiate the extension - log & disable
String disable = createBlameMessage();
String reason = DartTextMessages.CompletionProposalComputerDescriptor_reason_instantiation;
return new Status(IStatus.ERROR, DartToolsPlugin.getPluginId(), IStatus.OK, disable
+ " " + reason, x); //$NON-NLS-1$
}
private Status createExceptionStatus(InvalidRegistryObjectException x) {
// extension has become invalid - log & disable
String disable = createBlameMessage();
String reason = DartTextMessages.CompletionProposalComputerDescriptor_reason_invalid;
return new Status(IStatus.INFO, DartToolsPlugin.getPluginId(), IStatus.OK, disable
+ " " + reason, x); //$NON-NLS-1$
}
private Status createExceptionStatus(RuntimeException x) {
// misbehaving extension - log & disable
String disable = createBlameMessage();
String reason = DartTextMessages.CompletionProposalComputerDescriptor_reason_runtime_ex;
return new Status(IStatus.WARNING, DartToolsPlugin.getPluginId(), IStatus.OK, disable
+ " " + reason, x); //$NON-NLS-1$
}
private Status createPerformanceStatus(String operation) {
String disable = createBlameMessage();
Object[] args = {operation};
String reason = Messages.format(
DartTextMessages.CompletionProposalComputerDescriptor_reason_performance,
args);
return new Status(IStatus.WARNING, DartToolsPlugin.getPluginId(), IStatus.OK, disable
+ " " + reason, null); //$NON-NLS-1$
}
/**
* Returns a new instance of the sorter as described in the extension's xml.
*
* @return a new instance of the completion proposal computer as described by this descriptor
* @throws CoreException if the creation fails
* @throws InvalidRegistryObjectException if the extension is not valid any longer (e.g. due to
* plug-in unloading)
*/
private AbstractProposalSorter createSorter() throws CoreException,
InvalidRegistryObjectException {
return (AbstractProposalSorter) fElement.createExecutableExtension(CLASS);
}
private Bundle getBundle() throws InvalidRegistryObjectException {
String symbolicName = fElement.getContributor().getName();
Bundle bundle = Platform.getBundle(symbolicName);
return bundle;
}
/**
* Returns a cached instance of the sorter as described in the extension's xml. The sorter is
* {@link #createSorter() created} the first time that this method is called and then cached.
*
* @return a new instance of the proposal sorter as described by this descriptor
* @throws CoreException if the creation fails
* @throws InvalidRegistryObjectException if the extension is not valid any longer (e.g. due to
* plug-in unloading)
*/
private synchronized AbstractProposalSorter getSorter() throws CoreException,
InvalidRegistryObjectException {
if (fSorter == null && (fActivate || isPluginLoaded())) {
fSorter = createSorter();
}
return fSorter;
}
private boolean isPluginLoaded() throws InvalidRegistryObjectException {
Bundle bundle = getBundle();
return bundle != null && bundle.getState() == Bundle.ACTIVE;
}
private PerformanceStats startMeter(String context, AbstractProposalSorter sorter) {
final PerformanceStats stats;
if (MEASURE_PERFORMANCE) {
stats = PerformanceStats.getStats(PERFORMANCE_EVENT, sorter);
stats.startRun(context);
} else {
stats = null;
}
return stats;
}
private IStatus stopMeter(final PerformanceStats stats, String operation) {
if (MEASURE_PERFORMANCE) {
stats.endRun();
if (stats.isFailure()) {
return createPerformanceStatus(operation);
}
}
return null;
}
}