bundles/org.eclipse.equinox.p2.ui.discovery/src/org/eclipse/equinox/internal/p2/ui/discovery/util/PatternFilter.java - equinox/rt.equinox.p2 - Git at Google

 /*******************************************************************************
  * Copyright (c) 2004, 2020 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *     Tasktop Technologies - generalization for structured viewers
  *******************************************************************************/
 package org.eclipse.equinox.internal.p2.ui.discovery.util;

 import java.util.HashMap;
 import java.util.Map;
 import java.util.regex.Pattern;
 import org.eclipse.jface.viewers.*;
 import org.eclipse.ui.internal.misc.TextMatcher;

 /**
  * A filter used in conjunction with <code>FilteredTree</code>. In order to
  * determine if a node should be filtered it uses the content and label provider
  * of the tree to do pattern matching on its children. This causes the entire
  * tree structure to be realized. Note that the label provider must implement
  * ILabelProvider.
  *
  * @see org.eclipse.ui.dialogs.FilteredTree
  * @since 3.2
  */
 @SuppressWarnings("restriction")
 public class PatternFilter extends ViewerFilter {
 	/*
 	 * Cache of filtered elements in the tree
 	 */
 	private final Map<Object, Object> cache = new HashMap<>();

 	/*
 	 * Maps parent elements to TRUE or FALSE
 	 */
 	private final Map<Object, Boolean> foundAnyCache = new HashMap<>();

 	private boolean useCache = false;

 	/**
 	 * Whether to include a leading wildcard for all provided patterns. A trailing
 	 * wildcard is always included.
 	 */
 	private boolean includeLeadingWildcard = false;

 	/**
 	 * The string pattern matcher used for this pattern filter.
 	 */
 	private TextMatcher matcher;

 	private boolean useEarlyReturnIfMatcherIsNull = true;

 	private static Object[] EMPTY = new Object[0];

 	private static final Pattern NON_WORD = Pattern.compile("\\W+", Pattern.UNICODE_CHARACTER_CLASS); //$NON-NLS-1$

 	@Override
 	public final Object[] filter(Viewer viewer, Object parent, Object[] elements) {
 		// we don't want to optimize if we've extended the filter ... this
 		// needs to be addressed in 3.4
 		// https://bugs.eclipse.org/bugs/show_bug.cgi?id=186404
 		if (matcher == null && useEarlyReturnIfMatcherIsNull) {
 			return elements;
 		}

 		if (!useCache) {
 			return super.filter(viewer, parent, elements);
 		}

 		Object[] filtered = (Object[]) cache.get(parent);
 		if (filtered == null) {
 			Boolean foundAny = foundAnyCache.get(parent);
 			if (foundAny != null && !foundAny.booleanValue()) {
 				filtered = EMPTY;
 			} else {
 				filtered = super.filter(viewer, parent, elements);
 			}
 			cache.put(parent, filtered);
 		}
 		return filtered;
 	}

 	/**
 	 * Returns true if any of the elements makes it through the filter. This method
 	 * uses caching if enabled; the computation is done in computeAnyVisible.
 	 *
 	 * @param viewer
 	 * @param parent
 	 * @param elements the elements (must not be an empty array)
 	 * @return true if any of the elements makes it through the filter.
 	 */
 	private boolean isAnyVisible(Viewer viewer, Object parent, Object[] elements) {
 		if (matcher == null) {
 			return true;
 		}

 		if (!useCache) {
 			return computeAnyVisible(viewer, elements);
 		}

 		Object[] filtered = (Object[]) cache.get(parent);
 		if (filtered != null) {
 			return filtered.length > 0;
 		}
 		Boolean foundAny = foundAnyCache.get(parent);
 		if (foundAny == null) {
 			foundAny = computeAnyVisible(viewer, elements) ? Boolean.TRUE : Boolean.FALSE;
 			foundAnyCache.put(parent, foundAny);
 		}
 		return foundAny.booleanValue();
 	}

 	/**
 	 * Returns true if any of the elements makes it through the filter.
 	 *
 	 * @param viewer   the viewer
 	 * @param elements the elements to test
 	 * @return <code>true</code> if any of the elements makes it through the filter
 	 */
 	private boolean computeAnyVisible(Viewer viewer, Object[] elements) {
 		boolean elementFound = false;
 		for (int i = 0; i < elements.length && !elementFound; i++) {
 			Object element = elements[i];
 			elementFound = isElementVisible(viewer, element);
 		}
 		return elementFound;
 	}

 	@Override
 	public final boolean select(Viewer viewer, Object parentElement, Object element) {
 		return isElementVisible(viewer, element);
 	}

 	/**
 	 * Sets whether a leading wildcard should be attached to each pattern string.
 	 *
 	 * @param includeLeadingWildcard Whether a leading wildcard should be added.
 	 */
 	public final void setIncludeLeadingWildcard(final boolean includeLeadingWildcard) {
 		this.includeLeadingWildcard = includeLeadingWildcard;
 	}

 	/**
 	 * The pattern string for which this filter should select elements in the
 	 * viewer.
 	 *
 	 * @param patternString
 	 */
 	public void setPattern(String patternString) {
 		// these 2 strings allow the PatternFilter to be extended in
 		// 3.3 - https://bugs.eclipse.org/bugs/show_bug.cgi?id=186404
 		if ("org.eclipse.ui.keys.optimization.true".equals(patternString)) { //$NON-NLS-1$
 			useEarlyReturnIfMatcherIsNull = true;
 			return;
 		} else if ("org.eclipse.ui.keys.optimization.false".equals(patternString)) { //$NON-NLS-1$
 			useEarlyReturnIfMatcherIsNull = false;
 			return;
 		}
 		clearCaches();
 		if (patternString == null || patternString.equals("")) { //$NON-NLS-1$
 			matcher = null;
 		} else {
 			String pattern = patternString + "*"; //$NON-NLS-1$
 			if (includeLeadingWildcard) {
 				pattern = "*" + pattern; //$NON-NLS-1$
 			}
 			matcher = new TextMatcher(pattern, true, false);
 		}
 	}

 	/**
 	 * Clears the caches used for optimizing this filter. Needs to be called
 	 * whenever the tree content changes.
 	 */
 	/* package */void clearCaches() {
 		cache.clear();
 		foundAnyCache.clear();
 	}

 	/**
 	 * Answers whether the given String matches the pattern.
 	 *
 	 * @param string the String to test
 	 * @return whether the string matches the pattern
 	 */
 	private boolean match(String string) {
 		if (matcher == null) {
 			return true;
 		}
 		return matcher.match(string);
 	}

 	/**
 	 * Answers whether the given element is a valid selection in the filtered tree.
 	 * For example, if a tree has items that are categorized, the category itself
 	 * may not be a valid selection since it is used merely to organize the
 	 * elements.
 	 *
 	 * @param element
 	 * @return true if this element is eligible for automatic selection
 	 */
 	public boolean isElementSelectable(Object element) {
 		return element != null;
 	}

 	/**
 	 * Answers whether the given element in the given viewer matches the filter
 	 * pattern. This is a default implementation that will show a leaf element in
 	 * the tree based on whether the provided filter text matches the text of the
 	 * given element's text, or that of it's children (if the element has any).
 	 * Subclasses may override this method.
 	 *
 	 * @param viewer  the tree viewer in which the element resides
 	 * @param element the element in the tree to check for a match
 	 * @return true if the element matches the filter pattern
 	 */
 	public boolean isElementVisible(Viewer viewer, Object element) {
 		return isParentMatch(viewer, element) || isLeafMatch(viewer, element);
 	}

 	/**
 	 * Check if the parent (category) is a match to the filter text. The default
 	 * behavior returns true if the element has at least one child element that is a
 	 * match with the filter text. Subclasses may override this method.
 	 *
 	 * @param viewer  the viewer that contains the element
 	 * @param element the tree element to check
 	 * @return true if the given element has children that matches the filter text
 	 */
 	protected boolean isParentMatch(Viewer viewer, Object element) {
 		Object[] children = getChildren(element);

 		if ((children != null) && (children.length > 0)) {
 			return isAnyVisible(viewer, element, children);
 		}
 		return false;
 	}

 	protected Object[] getChildren(Object element) {
 		return null;
 	}

 	/**
 	 * Check if the current (leaf) element is a match with the filter text. The
 	 * default behavior checks that the label of the element is a match. Subclasses
 	 * should override this method.
 	 *
 	 * @param viewer  the viewer that contains the element
 	 * @param element the tree element to check
 	 * @return true if the given element's label matches the filter text
 	 */
 	protected boolean isLeafMatch(Viewer viewer, Object element) {
 		String labelText = ((ILabelProvider) ((StructuredViewer) viewer).getLabelProvider()).getText(element);

 		if (labelText == null) {
 			return false;
 		}
 		return wordMatches(labelText);
 	}

 	/**
 	 * Take the given filter text and break it down into words using a
 	 * BreakIterator.
 	 *
 	 * @param text
 	 * @return an array of words
 	 */
 	private String[] getWords(String text) {
 		return NON_WORD.split(text, 0);
 	}

 	/**
 	 * Return whether or not if any of the words in text satisfy the match critera.
 	 *
 	 * @param text the text to match
 	 * @return boolean <code>true</code> if one of the words in text satisifes the
 	 *         match criteria.
 	 */
 	protected boolean wordMatches(String text) {
 		if (text == null) {
 			return false;
 		}

 		// If the whole text matches we are all set
 		if (match(text)) {
 			return true;
 		}

 		// Otherwise check if any of the words of the text matches
 		String[] words = getWords(text);
 		for (String word : words) {
 			if (match(word)) {
 				return true;
 			}
 		}

 		return false;
 	}

 	/**
 	 * Can be called by the filtered tree to turn on caching.
 	 *
 	 * @param useCache The useCache to set.
 	 */
 	void setUseCache(boolean useCache) {
 		this.useCache = useCache;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2004, 2020 IBM Corporation and others.
	*
	* This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License 2.0
	* which accompanies this distribution, and is available at
	* https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	* Tasktop Technologies - generalization for structured viewers
	*******************************************************************************/
	package org.eclipse.equinox.internal.p2.ui.discovery.util;

	import java.util.HashMap;
	import java.util.Map;
	import java.util.regex.Pattern;
	import org.eclipse.jface.viewers.*;
	import org.eclipse.ui.internal.misc.TextMatcher;

	/**
	* A filter used in conjunction with <code>FilteredTree</code>. In order to
	* determine if a node should be filtered it uses the content and label provider
	* of the tree to do pattern matching on its children. This causes the entire
	* tree structure to be realized. Note that the label provider must implement
	* ILabelProvider.
	*
	* @see org.eclipse.ui.dialogs.FilteredTree
	* @since 3.2
	*/
	@SuppressWarnings("restriction")
	public class PatternFilter extends ViewerFilter {
	/*
	* Cache of filtered elements in the tree
	*/
	private final Map<Object, Object> cache = new HashMap<>();

	/*
	* Maps parent elements to TRUE or FALSE
	*/
	private final Map<Object, Boolean> foundAnyCache = new HashMap<>();

	private boolean useCache = false;

	/**
	* Whether to include a leading wildcard for all provided patterns. A trailing
	* wildcard is always included.
	*/
	private boolean includeLeadingWildcard = false;

	/**
	* The string pattern matcher used for this pattern filter.
	*/
	private TextMatcher matcher;

	private boolean useEarlyReturnIfMatcherIsNull = true;

	private static Object[] EMPTY = new Object[0];

	private static final Pattern NON_WORD = Pattern.compile("\\W+", Pattern.UNICODE_CHARACTER_CLASS); //$NON-NLS-1$

	@Override
	public final Object[] filter(Viewer viewer, Object parent, Object[] elements) {
	// we don't want to optimize if we've extended the filter ... this
	// needs to be addressed in 3.4
	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=186404
	if (matcher == null && useEarlyReturnIfMatcherIsNull) {
	return elements;
	}

	if (!useCache) {
	return super.filter(viewer, parent, elements);
	}

	Object[] filtered = (Object[]) cache.get(parent);
	if (filtered == null) {
	Boolean foundAny = foundAnyCache.get(parent);
	if (foundAny != null && !foundAny.booleanValue()) {
	filtered = EMPTY;
	} else {
	filtered = super.filter(viewer, parent, elements);
	}
	cache.put(parent, filtered);
	}
	return filtered;
	}

	/**
	* Returns true if any of the elements makes it through the filter. This method
	* uses caching if enabled; the computation is done in computeAnyVisible.
	*
	* @param viewer
	* @param parent
	* @param elements the elements (must not be an empty array)
	* @return true if any of the elements makes it through the filter.
	*/
	private boolean isAnyVisible(Viewer viewer, Object parent, Object[] elements) {
	if (matcher == null) {
	return true;
	}

	if (!useCache) {
	return computeAnyVisible(viewer, elements);
	}

	Object[] filtered = (Object[]) cache.get(parent);
	if (filtered != null) {
	return filtered.length > 0;
	}
	Boolean foundAny = foundAnyCache.get(parent);
	if (foundAny == null) {
	foundAny = computeAnyVisible(viewer, elements) ? Boolean.TRUE : Boolean.FALSE;
	foundAnyCache.put(parent, foundAny);
	}
	return foundAny.booleanValue();
	}

	/**
	* Returns true if any of the elements makes it through the filter.
	*
	* @param viewer the viewer
	* @param elements the elements to test
	* @return <code>true</code> if any of the elements makes it through the filter
	*/
	private boolean computeAnyVisible(Viewer viewer, Object[] elements) {
	boolean elementFound = false;
	for (int i = 0; i < elements.length && !elementFound; i++) {
	Object element = elements[i];
	elementFound = isElementVisible(viewer, element);
	}
	return elementFound;
	}

	@Override
	public final boolean select(Viewer viewer, Object parentElement, Object element) {
	return isElementVisible(viewer, element);
	}

	/**
	* Sets whether a leading wildcard should be attached to each pattern string.
	*
	* @param includeLeadingWildcard Whether a leading wildcard should be added.
	*/
	public final void setIncludeLeadingWildcard(final boolean includeLeadingWildcard) {
	this.includeLeadingWildcard = includeLeadingWildcard;
	}

	/**
	* The pattern string for which this filter should select elements in the
	* viewer.
	*
	* @param patternString
	*/
	public void setPattern(String patternString) {
	// these 2 strings allow the PatternFilter to be extended in
	// 3.3 - https://bugs.eclipse.org/bugs/show_bug.cgi?id=186404
	if ("org.eclipse.ui.keys.optimization.true".equals(patternString)) { //$NON-NLS-1$
	useEarlyReturnIfMatcherIsNull = true;
	return;
	} else if ("org.eclipse.ui.keys.optimization.false".equals(patternString)) { //$NON-NLS-1$
	useEarlyReturnIfMatcherIsNull = false;
	return;
	}
	clearCaches();
	if (patternString == null \|\| patternString.equals("")) { //$NON-NLS-1$
	matcher = null;
	} else {
	String pattern = patternString + "*"; //$NON-NLS-1$
	if (includeLeadingWildcard) {
	pattern = "*" + pattern; //$NON-NLS-1$
	}
	matcher = new TextMatcher(pattern, true, false);
	}
	}

	/**
	* Clears the caches used for optimizing this filter. Needs to be called
	* whenever the tree content changes.
	*/
	/* package */void clearCaches() {
	cache.clear();
	foundAnyCache.clear();
	}

	/**
	* Answers whether the given String matches the pattern.
	*
	* @param string the String to test
	* @return whether the string matches the pattern
	*/
	private boolean match(String string) {
	if (matcher == null) {
	return true;
	}
	return matcher.match(string);
	}

	/**
	* Answers whether the given element is a valid selection in the filtered tree.
	* For example, if a tree has items that are categorized, the category itself
	* may not be a valid selection since it is used merely to organize the
	* elements.
	*
	* @param element
	* @return true if this element is eligible for automatic selection
	*/
	public boolean isElementSelectable(Object element) {
	return element != null;
	}

	/**
	* Answers whether the given element in the given viewer matches the filter
	* pattern. This is a default implementation that will show a leaf element in
	* the tree based on whether the provided filter text matches the text of the
	* given element's text, or that of it's children (if the element has any).
	* Subclasses may override this method.
	*
	* @param viewer the tree viewer in which the element resides
	* @param element the element in the tree to check for a match
	* @return true if the element matches the filter pattern
	*/
	public boolean isElementVisible(Viewer viewer, Object element) {
	return isParentMatch(viewer, element) \|\| isLeafMatch(viewer, element);
	}

	/**
	* Check if the parent (category) is a match to the filter text. The default
	* behavior returns true if the element has at least one child element that is a
	* match with the filter text. Subclasses may override this method.
	*
	* @param viewer the viewer that contains the element
	* @param element the tree element to check
	* @return true if the given element has children that matches the filter text
	*/
	protected boolean isParentMatch(Viewer viewer, Object element) {
	Object[] children = getChildren(element);

	if ((children != null) && (children.length > 0)) {
	return isAnyVisible(viewer, element, children);
	}
	return false;
	}

	protected Object[] getChildren(Object element) {
	return null;
	}

	/**
	* Check if the current (leaf) element is a match with the filter text. The
	* default behavior checks that the label of the element is a match. Subclasses
	* should override this method.
	*
	* @param viewer the viewer that contains the element
	* @param element the tree element to check
	* @return true if the given element's label matches the filter text
	*/
	protected boolean isLeafMatch(Viewer viewer, Object element) {
	String labelText = ((ILabelProvider) ((StructuredViewer) viewer).getLabelProvider()).getText(element);

	if (labelText == null) {
	return false;
	}
	return wordMatches(labelText);
	}

	/**
	* Take the given filter text and break it down into words using a
	* BreakIterator.
	*
	* @param text
	* @return an array of words
	*/
	private String[] getWords(String text) {
	return NON_WORD.split(text, 0);
	}

	/**
	* Return whether or not if any of the words in text satisfy the match critera.
	*
	* @param text the text to match
	* @return boolean <code>true</code> if one of the words in text satisifes the
	* match criteria.
	*/
	protected boolean wordMatches(String text) {
	if (text == null) {
	return false;
	}

	// If the whole text matches we are all set
	if (match(text)) {
	return true;
	}

	// Otherwise check if any of the words of the text matches
	String[] words = getWords(text);
	for (String word : words) {
	if (match(word)) {
	return true;
	}
	}

	return false;
	}

	/**
	* Can be called by the filtered tree to turn on caching.
	*
	* @param useCache The useCache to set.
	*/
	void setUseCache(boolean useCache) {
	this.useCache = useCache;
	}
	}