/*******************************************************************************
* Copyright (c) 2005, 2015 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.ui.internal.services;
import java.util.HashMap;
import java.util.Map;
import org.eclipse.core.expressions.Expression;
import org.eclipse.core.expressions.ExpressionInfo;
import org.eclipse.ui.ISources;
/**
* <p>
* A static class linking the names of variables in an IEvaluationContext to the
* priority they should be given when doing conflict resolution.
* </p>
* <p>
* In the future, it will possible to define a new variable (i.e., piece of
* application state) that you want to use inside of the
* <code>org.eclipse.ui.contexts</code>, <code>org.eclipse.ui.handlers</code>
* or <code>org.eclipse.ui.menus</code> extension points. As it stands right
* now, it is not possible to run code soon enough for the
* <code>IHandlerService</code>, <code>IMenuService</code> or
* <code>IContextService</code> to become aware of the new variables. This
* will likely be fixed with a new extension point.
* </p>
* <p>
* TODO Move to "org.eclipse.ui" and resolve the above issue.
* </p>
*
* @since 3.2
* @see org.eclipse.ui.ISources
* @see org.eclipse.ui.contexts.IContextService
* @see org.eclipse.ui.handlers.IHandlerService
* @see org.eclipse.ui.menus.IMenuService
*/
public final class SourcePriorityNameMapping implements ISources {
/**
* The variable name to use when boosting priority on an activation.
*/
public static final String LEGACY_LEGACY_NAME = "LEGACY"; //$NON-NLS-1$
/**
* The value returned if there is source priority for the given name
*
* @see SourcePriorityNameMapping#getMapping(String)
*/
public static final int NO_SOURCE_PRIORITY = 0;
/**
* The map of source priorities indexed by name. This value is never
* <code>null</code>.
*/
private static final Map sourcePrioritiesByName = new HashMap();
static {
addMapping(ACTIVE_ACTION_SETS_NAME, ACTIVE_ACTION_SETS);
addMapping(ACTIVE_CONTEXT_NAME, ACTIVE_CONTEXT);
addMapping(ACTIVE_CURRENT_SELECTION_NAME, ACTIVE_CURRENT_SELECTION);
addMapping(ACTIVE_EDITOR_NAME, ACTIVE_EDITOR);
addMapping(ACTIVE_EDITOR_INPUT_NAME, ACTIVE_EDITOR);
addMapping(ACTIVE_EDITOR_ID_NAME, ACTIVE_EDITOR_ID);
addMapping(ACTIVE_MENU_NAME, ACTIVE_MENU);
addMapping(ACTIVE_MENU_SELECTION_NAME, ACTIVE_MENU);
addMapping(ACTIVE_MENU_EDITOR_INPUT_NAME, ACTIVE_MENU);
addMapping(ACTIVE_FOCUS_CONTROL_ID_NAME, ACTIVE_MENU);
addMapping(ACTIVE_FOCUS_CONTROL_NAME, ACTIVE_MENU);
addMapping(ACTIVE_PART_NAME, ACTIVE_PART);
addMapping(ACTIVE_PART_ID_NAME, ACTIVE_PART_ID);
addMapping(ACTIVE_SHELL_NAME, ACTIVE_SHELL);
addMapping(ACTIVE_SITE_NAME, ACTIVE_SITE);
addMapping(ACTIVE_WORKBENCH_WINDOW_NAME, ACTIVE_WORKBENCH_WINDOW);
addMapping(ACTIVE_WORKBENCH_WINDOW_SHELL_NAME,
ACTIVE_WORKBENCH_WINDOW_SHELL);
addMapping(ACTIVE_WORKBENCH_WINDOW_IS_COOLBAR_VISIBLE_NAME,
ACTIVE_WORKBENCH_WINDOW_SUBORDINATE);
addMapping(ACTIVE_WORKBENCH_WINDOW_ACTIVE_PERSPECTIVE_NAME,
ACTIVE_WORKBENCH_WINDOW_SUBORDINATE);
addMapping(ACTIVE_WORKBENCH_WINDOW_IS_PERSPECTIVEBAR_VISIBLE_NAME,
ACTIVE_WORKBENCH_WINDOW_SUBORDINATE);
addMapping(LEGACY_LEGACY_NAME, LEGACY_LEGACY);
addMapping("workbench", WORKBENCH); //$NON-NLS-1$
}
/**
* Adds a mapping between a source name and a source priority. This method
* also cleans up any existing mappings using the same name or priority.
* There is a one-to-one relationship between name and priority.
*
* @param sourceName
* The name of the variable as it would appear in an XML
* expression; must not be <code>null</code>.
* @param sourcePriority
* The priority of the source with respect to other sources. A
* higher value means that expressions including this priority
* will win ties more often. It is recommended that this value is
* simply a single bit shifted to a particular place.
* @see ISources
*/
public static final void addMapping(final String sourceName,
final int sourcePriority) {
if (sourceName == null) {
throw new NullPointerException("The source name cannot be null."); //$NON-NLS-1$
}
if (!sourcePrioritiesByName.containsKey(sourceName)) {
final Integer priority = Integer.valueOf(sourcePriority);
sourcePrioritiesByName.put(sourceName, priority);
}
}
/**
* Computes the source priority for the given expression. The source
* priority is a bit mask of all of the variables references by the
* expression. The default variable is considered to be
* {@link ISources#ACTIVE_CURRENT_SELECTION}. The source priority is used
* to minimize recomputations of the expression, and it can also be used for
* conflict resolution.
*
* @param expression
* The expression for which the source priority should be
* computed; may be <code>null</code>.
* @return The bit mask of all the sources required for this expression;
* <code>0</code> if none.
*/
public static final int computeSourcePriority(final Expression expression) {
int sourcePriority = ISources.WORKBENCH;
if (expression == null) {
return sourcePriority;
}
final ExpressionInfo info = expression.computeExpressionInfo();
// Add the default variable, if any.
if (info.hasDefaultVariableAccess()) {
sourcePriority |= ISources.ACTIVE_CURRENT_SELECTION;
}
// Add all of the reference variables.
final String[] sourceNames = info.getAccessedVariableNames();
for (final String sourceName : sourceNames) {
sourcePriority |= getMapping(sourceName);
}
return sourcePriority;
}
/**
* Gets the priority for the source with the given name.
*
* @param sourceName
* The name of the variable as it would appear in an XML
* expression; should not be <code>null</code>.
* @return The source priority that matches, if any;
* <code>NO_SOURCE_PRIORITY</code> if none is found.
*/
public static final int getMapping(final String sourceName) {
final Object object = sourcePrioritiesByName.get(sourceName);
if (object instanceof Integer) {
return ((Integer) object).intValue();
}
return NO_SOURCE_PRIORITY;
}
/**
* This class should not be instantiated.
*/
private SourcePriorityNameMapping() {
// This class should not be instantiated.
}
}