/*******************************************************************************
* Copyright (c) 2000, 2012 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
* Gunnar Wagenknecht - Fork for Gyrex Admin UI
*******************************************************************************/
package org.eclipse.gyrex.admin.ui.internal.widgets;
import java.text.BreakIterator;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.eclipse.gyrex.admin.ui.internal.helper.StringMatcher;
import org.eclipse.jface.viewers.AbstractTreeViewer;
import org.eclipse.jface.viewers.ILabelProvider;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.StructuredViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerFilter;
/**
* 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 1.0
*/
public class PatternFilter extends ViewerFilter {
/** serialVersionUID */
private static final long serialVersionUID = 1L;
/*
* Cache of filtered elements in the tree
*/
private final Map<Object, Object[]> cache = new HashMap<Object, Object[]>();
/*
* Maps parent elements to TRUE or FALSE
*/
private final Map<Object, Boolean> foundAnyCache = new HashMap<Object, Boolean>();
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 StringMatcher matcher;
private boolean useEarlyReturnIfMatcherIsNull = true;
private static Object[] EMPTY = new Object[0];
/**
* Clears the caches used for optimizing this filter. Needs to be called
* whenever the tree content changes.
*/
/* package */void clearCaches() {
cache.clear();
foundAnyCache.clear();
}
/**
* 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(final Viewer viewer, final Object[] elements) {
boolean elementFound = false;
for (int i = 0; (i < elements.length) && !elementFound; i++) {
final Object element = elements[i];
elementFound = isElementVisible(viewer, element);
}
return elementFound;
}
/* (non-Javadoc)
* @see org.eclipse.jface.viewers.ViewerFilter#filter(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object[])
*/
@Override
public final Object[] filter(final Viewer viewer, final Object parent, final 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 = cache.get(parent);
if (filtered == null) {
final 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;
}
/**
* Take the given filter text and break it down into words using a
* BreakIterator.
*
* @param text
* @return an array of words
*/
private String[] getWords(final String text) {
final List<String> words = new ArrayList<String>();
// Break the text up into words, separating based on whitespace and
// common punctuation.
// Previously used String.split(..., "\\W"), where "\W" is a regular
// expression (see the Javadoc for class Pattern).
// Need to avoid both String.split and regular expressions, in order to
// compile against JCL Foundation (bug 80053).
// Also need to do this in an NL-sensitive way. The use of BreakIterator
// was suggested in bug 90579.
final BreakIterator iter = BreakIterator.getWordInstance();
iter.setText(text);
int i = iter.first();
while ((i != java.text.BreakIterator.DONE) && (i < text.length())) {
int j = iter.following(i);
if (j == java.text.BreakIterator.DONE) {
j = text.length();
}
// match the word
if (Character.isLetterOrDigit(text.charAt(i))) {
final String word = text.substring(i, j);
words.add(word);
}
i = j;
}
return words.toArray(new String[words.size()]);
}
/**
* 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(final Viewer viewer, final Object parent, final Object[] elements) {
if (matcher == null)
return true;
if (!useCache)
return computeAnyVisible(viewer, elements);
final Object[] filtered = 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();
}
/**
* 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(final 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(final Viewer viewer, final Object element) {
return isParentMatch(viewer, element) || isLeafMatch(viewer, element);
}
/**
* 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(final Viewer viewer, final Object element) {
final String labelText = ((ILabelProvider) ((StructuredViewer) viewer).getLabelProvider()).getText(element);
if (labelText == null)
return false;
return wordMatches(labelText);
}
/**
* 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(final Viewer viewer, final Object element) {
final Object[] children = ((ITreeContentProvider) ((AbstractTreeViewer) viewer).getContentProvider()).getChildren(element);
if ((children != null) && (children.length > 0))
return isAnyVisible(viewer, element, children);
return false;
}
/**
* Answers whether the given String matches the pattern.
*
* @param string
* the String to test
* @return whether the string matches the pattern
*/
private boolean match(final String string) {
if (matcher == null)
return true;
return matcher.match(string);
}
/* (non-Javadoc)
* @see org.eclipse.jface.viewers.ViewerFilter#select(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object)
*/
@Override
public final boolean select(final Viewer viewer, final Object parentElement, final 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(final 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 StringMatcher(pattern, true, false);
}
}
/**
* Can be called by the filtered tree to turn on caching.
*
* @param useCache
* The useCache to set.
*/
void setUseCache(final boolean useCache) {
this.useCache = useCache;
}
/**
* 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(final 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
final String[] words = getWords(text);
for (int i = 0; i < words.length; i++) {
final String word = words[i];
if (match(word))
return true;
}
return false;
}
}