/*******************************************************************************
* Copyright (c) 2005, 2011 IBM Corporation 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
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.internal.ui.text.java;
import java.util.Collections;
import java.util.List;
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.Status;
import org.eclipse.jface.text.contentassist.ICompletionProposal;
import org.eclipse.jdt.internal.corext.util.Messages;
import org.eclipse.jdt.ui.text.java.AbstractProposalSorter;
import org.eclipse.jdt.ui.text.java.ContentAssistInvocationContext;
import org.eclipse.jdt.internal.ui.JavaPlugin;
/**
* The description of an extension to the
* <code>org.eclipse.jdt.ui.javaCompletionProposalSorters</code> extension point. Instances are
* immutable.
*
* @since 3.2
*/
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 name of the performance event used to trace extensions. */
private static final String PERFORMANCE_EVENT= JavaPlugin.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 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
* @throws CoreException if the configuration does not contain mandatory attributes
*/
ProposalSorterHandle(IConfigurationElement element) throws InvalidRegistryObjectException, CoreException {
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;
fClass= element.getAttribute(CLASS);
checkNotNull(fClass, CLASS);
}
/**
* Checks that the given attribute value is not <code>null</code>.
*
* @param value the value to check if not null
* @param attribute the attribute
* @throws InvalidRegistryObjectException if the registry element is no longer valid
* @throws CoreException if <code>value</code> is <code>null</code>
*/
private void checkNotNull(Object value, String attribute) throws InvalidRegistryObjectException, CoreException {
if (value == null) {
Object[] args= { getId(), fElement.getContributor().getName(), attribute };
String message= Messages.format(JavaTextMessages.CompletionProposalComputerDescriptor_illegal_attribute_message, args);
IStatus status= new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, message, null);
throw new CoreException(status);
}
}
/**
* 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;
}
/**
* 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)
fSorter= createSorter();
return fSorter;
}
/**
* 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);
}
/**
* 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
*/
public void sortProposals(ContentAssistInvocationContext context, List<ICompletionProposal> 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);
}
JavaPlugin.log(status);
return;
}
private IStatus stopMeter(final PerformanceStats stats, String operation) {
if (MEASURE_PERFORMANCE) {
stats.endRun();
if (stats.isFailure())
return createPerformanceStatus(operation);
}
return null;
}
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 Status createExceptionStatus(InvalidRegistryObjectException x) {
// extension has become invalid - log & disable
String disable= createBlameMessage();
String reason= JavaTextMessages.CompletionProposalComputerDescriptor_reason_invalid;
return new Status(IStatus.INFO, JavaPlugin.getPluginId(), IStatus.OK, disable + " " + reason, x); //$NON-NLS-1$
}
private Status createExceptionStatus(CoreException x) {
// unable to instantiate the extension - log & disable
String disable= createBlameMessage();
String reason= JavaTextMessages.CompletionProposalComputerDescriptor_reason_instantiation;
return new Status(IStatus.ERROR, JavaPlugin.getPluginId(), IStatus.OK, disable + " " + reason, x); //$NON-NLS-1$
}
private Status createExceptionStatus(RuntimeException x) {
// misbehaving extension - log & disable
String disable= createBlameMessage();
String reason= JavaTextMessages.CompletionProposalComputerDescriptor_reason_runtime_ex;
return new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, disable + " " + reason, x); //$NON-NLS-1$
}
private Status createAPIViolationStatus(String operation) {
String disable= createBlameMessage();
Object[] args= {operation};
String reason= Messages.format(JavaTextMessages.CompletionProposalComputerDescriptor_reason_API, args);
return new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, disable + " " + reason, null); //$NON-NLS-1$
}
private Status createPerformanceStatus(String operation) {
String disable= createBlameMessage();
Object[] args= {operation};
String reason= Messages.format(JavaTextMessages.CompletionProposalComputerDescriptor_reason_performance, args);
return new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, disable + " " + reason, null); //$NON-NLS-1$
}
private String createBlameMessage() {
Object[] args= { getName(), getId() };
String disable= Messages.format(JavaTextMessages.ProposalSorterHandle_blame, args);
return disable;
}
/**
* 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;
}
}