package org.erlide.ui.editors.erl.outline.filters;
import java.text.Collator;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.core.runtime.ISafeRunnable;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.SafeRunner;
import org.eclipse.jface.util.SafeRunnable;
import org.eclipse.jface.viewers.ViewerFilter;
import org.eclipse.ui.IPluginContribution;
import org.eclipse.ui.activities.WorkbenchActivityHelper;
import org.erlide.ui.internal.ErlideUIPlugin;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
public final class FilterDescriptor implements Comparable<Object>, IPluginContribution {
private static final String EXTENSION_POINT_NAME = "erlangElementFilters"; //$NON-NLS-1$
private static final String FILTER_TAG = "filter"; //$NON-NLS-1$
private static final String PATTERN_ATTRIBUTE = "pattern"; //$NON-NLS-1$
private static final String ID_ATTRIBUTE = "id"; //$NON-NLS-1$
private static final String TARGET_ID_ATTRIBUTE = "targetId"; //$NON-NLS-1$
private static final String CLASS_ATTRIBUTE = "class"; //$NON-NLS-1$
private static final String NAME_ATTRIBUTE = "name"; //$NON-NLS-1$
private static final String ENABLED_ATTRIBUTE = "enabled"; //$NON-NLS-1$
private static final String DESCRIPTION_ATTRIBUTE = "description"; //$NON-NLS-1$
private static Collection<FilterDescriptor> fgFilterDescriptors;
private final IConfigurationElement fElement;
private ViewerFilter fCachedInstance = null;
/**
* Returns all contributed Erlang element filters.
*
* @return all contributed Erlang element filters
*/
public static Collection<FilterDescriptor> getFilterDescriptors() {
if (fgFilterDescriptors == null) {
final IExtensionRegistry registry = Platform.getExtensionRegistry();
final IConfigurationElement[] elements = registry
.getConfigurationElementsFor(ErlideUIPlugin.PLUGIN_ID,
EXTENSION_POINT_NAME);
final String extensionPointID = ErlideUIPlugin.PLUGIN_ID + "."
+ EXTENSION_POINT_NAME;
fgFilterDescriptors = createFilterDescriptors(elements, extensionPointID);
}
return fgFilterDescriptors;
}
/**
* Returns all Erlang element filters which are contributed to the given
* view.
*
* @param targetId
* the target id
* @return all contributed Erlang element filters for the given view
*/
public static List<FilterDescriptor> getFilterDescriptors(final String targetId) {
final Collection<FilterDescriptor> descs = FilterDescriptor
.getFilterDescriptors();
final List<FilterDescriptor> result = Lists.newArrayList();
for (final FilterDescriptor desc : descs) {
final String tid = desc.getTargetId();
if (WorkbenchActivityHelper.filterItem(desc)) {
continue;
}
if (tid == null || tid.equals(targetId)) {
result.add(desc);
}
}
return result;
}
/**
* Creates a new filter descriptor for the given configuration element.
*
* @param element
* configuration element
*/
private FilterDescriptor(final IConfigurationElement element) {
fElement = element;
// it is either a pattern filter or a custom filter
Assert.isTrue(
isPatternFilter() ^ isClassFilter(),
"An extension for extension-point org.erlide.ui.erlangElementFilters does not specify a correct filter"); //$NON-NLS-1$
Assert.isNotNull(
getId(),
"An extension for extension-point org.erlide.ui.erlangElementFilters does not provide a valid ID"); //$NON-NLS-1$
Assert.isNotNull(
getName(),
"An extension for extension-point org.erlide.ui.erlangElementFilters does not provide a valid name"); //$NON-NLS-1$
}
/**
* Creates a new <code>ViewerFilter</code>. This method is only valid for
* viewer filters.
*
* @return a new <code>ViewerFilter</code>
*/
public ViewerFilter getViewerFilter() {
if (!isClassFilter()) {
return null;
}
if (fCachedInstance == null) {
final ViewerFilter[] result = new ViewerFilter[1];
final String message = String
.format("The org.erlide.ui.erlangElementFilters plug-in extension \"%s\" specifies a viewer filter class which does not exist.",
getId());
final ISafeRunnable code = new SafeRunnable(message) {
/*
* @see org.eclipse.core.runtime.ISafeRunnable#run()
*/
@Override
public void run() throws Exception {
result[0] = (ViewerFilter) fElement
.createExecutableExtension(CLASS_ATTRIBUTE);
}
};
SafeRunner.run(code);
fCachedInstance = result[0];
}
return fCachedInstance;
}
// ---- XML Attribute accessors
// ---------------------------------------------
/**
* Returns the filter's id.
* <p>
* This attribute is mandatory for custom filters. The ID for pattern
* filters is PATTERN_FILTER_ID_PREFIX plus the pattern itself.
* </p>
*
* @return the filter id
*/
public String getId() {
return fElement.getAttribute(ID_ATTRIBUTE);
}
/**
* Returns the filter's name.
* <p>
* If the name of a pattern filter is missing then the pattern is used as
* its name.
* </p>
*
* @return the filter's name
*/
public String getName() {
String name = fElement.getAttribute(NAME_ATTRIBUTE);
if (name == null && isPatternFilter()) {
name = getPattern();
}
return name;
}
/**
* Returns the filter's pattern.
*
* @return the pattern string or <code>null</code> if it's not a pattern
* filter
*/
public String getPattern() {
return fElement.getAttribute(PATTERN_ATTRIBUTE);
}
/**
* Returns the filter's viewId.
*
* @return the view ID or <code>null</code> if the filter is for all views
* @since 3.0
*/
public String getTargetId() {
final String tid = fElement.getAttribute(TARGET_ID_ATTRIBUTE);
if (tid != null) {
return tid;
}
return "";
}
/**
* Returns the filter's description.
*
* @return the description or <code>null</code> if no description is
* provided
*/
public String getDescription() {
String description = fElement.getAttribute(DESCRIPTION_ATTRIBUTE);
if (description == null) {
description = ""; //$NON-NLS-1$
}
return description;
}
/**
* @return <code>true</code> if this filter is a pattern filter.
*/
public boolean isPatternFilter() {
return getPattern() != null;
}
/**
* @return <code>true</code> if this filter is a class filter.
*/
public boolean isClassFilter() {
return fElement.getAttribute(CLASS_ATTRIBUTE) != null;
}
/**
* Returns <code>true</code> if the filter is initially enabled.
*
* This attribute is optional and defaults to <code>true</code>.
*
* @return returns <code>true</code> if the filter is initially enabled
*/
public boolean isEnabled() {
final String strVal = fElement.getAttribute(ENABLED_ATTRIBUTE);
return strVal == null || Boolean.valueOf(strVal).booleanValue();
}
/*
* Implements a method from Comparable<Object>
*/
@Override
public int compareTo(final Object o) {
if (o instanceof FilterDescriptor) {
return Collator.getInstance().compare(getName(),
((FilterDescriptor) o).getName());
}
return -1;
}
@Override
public boolean equals(final Object obj) {
return compareTo(obj) == 0;
}
@Override
public int hashCode() {
return getName().hashCode();
}
// ---- initialization ---------------------------------------------------
/**
* Creates the filter descriptors.
*
* @param elements
* the configuration elements
* @param extensionPointID
* @return new filter descriptors
*/
private static Collection<FilterDescriptor> createFilterDescriptors(
final IConfigurationElement[] elements, final String extensionPointID) {
final List<FilterDescriptor> result = Lists.newArrayList();
final Set<String> descIds = Sets.newHashSet();
for (final IConfigurationElement element : elements) {
if (FILTER_TAG.equals(element.getName())) {
final FilterDescriptor[] desc = new FilterDescriptor[1];
SafeRunner.run(new SafeRunnable(
" One of the extensions for extension-point " + extensionPointID
+ " is incorrect.") {
@Override
public void run() throws Exception {
desc[0] = new FilterDescriptor(element);
}
});
if (desc[0] != null && !descIds.contains(desc[0].getId())) {
result.add(desc[0]);
descIds.add(desc[0].getId());
}
}
}
return result;
}
@Override
public String getLocalId() {
return fElement.getAttribute(ID_ATTRIBUTE);
}
@Override
public String getPluginId() {
return fElement.getContributor().getName();
}
public static FilterDescriptor getFilterDescriptor(final String id) {
for (final FilterDescriptor desc : getFilterDescriptors()) {
if (desc.getId().equals(id)) {
return desc;
}
}
return null;
}
}