plugins/org.eclipse.amalgam.explorer.activity/src/org/eclipse/amalgam/explorer/activity/api/editor/pages/helper/TreePatternFilter.java

/*******************************************************************************
 * Copyright (c)  2006, 2015 THALES GLOBAL SERVICES.
 * 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:
 *    Thales - initial API and implementation
 *******************************************************************************/
package org.eclipse.amalgam.explorer.activity.api.editor.pages.helper;

import java.util.HashSet;
import java.util.Set;

import org.eclipse.emf.ecore.EObject;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.StructuredViewer;
import org.eclipse.jface.viewers.TreePath;
import org.eclipse.jface.viewers.Viewer;

/**
 * Pattern filter used in Tree displaying DSL concepts.<br>
 * This pattern filter automatically selects children of a parent that matches
 * the filter even if children labels don't match.
 * 
 */
public class TreePatternFilter extends PatternFilter {
	/**
	 * Flag used to ignore matching result when set.<br>
	 * When a parent matches the filter, this flag is set to <code>true</code>
	 * to automatically select its children.
	 */
	private boolean _ignoreMatching;
	/**
	 * Set of parent that match the filter either a parent has a label text that
	 * matches the filter or it is contained by a parent that matches the
	 * filter.
	 */
	private Set<Object> _matchingParents;

	/**
	 * Constructor.
	 */
	public TreePatternFilter() {
		super();
		setUseCache(true);
		_matchingParents = new HashSet<Object>(0);
	}

	/**
	 * @see org.eclipse.amalgam.explorer.activity.api.editor.pages.helper.common.ui.toolkit.widgets.filter.PatternFilter#select(org.eclipse.jface.viewers.Viewer,
	 *      java.lang.Object, java.lang.Object)
	 */
	@Override
	public boolean select(Viewer viewer, Object parentElement_p, Object element_p) {
		boolean result = false;
		Object parent = parentElement_p;
		// Get the real object from the TreePath.
		if (parentElement_p instanceof TreePath) {
			parent = ((TreePath) parentElement_p).getLastSegment();
		}
		// If element is contained by a parent that matches, let's select it.
		if (_matchingParents.contains(parent)) {
			result = true;
			// Add it as a matching parent even if we don't know if it has
			// children...
			_matchingParents.add(element_p);
		} else {
			result = isElementVisible(viewer, parent, element_p);
		}
		return result;
	}

	/**
	 * @see org.eclipse.amalgam.explorer.activity.api.editor.pages.helper.common.ui.toolkit.widgets.filter.PatternFilter#clearCaches()
	 */
	@Override
	public void clearCaches() {
		super.clearCaches();
		_matchingParents.clear();
	}

	/**
	 * Overridden to improve performances.
	 * 
	 * @see org.eclipse.amalgam.explorer.activity.api.editor.pages.helper.common.ui.toolkit.widgets.filter.PatternFilter#isLeafMatch(org.eclipse.jface.viewers.Viewer,
	 *      java.lang.Object, java.lang.Object)
	 */
	@Override
	protected boolean isLeafMatch(Viewer viewer_p, Object parentElement_p, Object element_p) {
		// Precondition.
		if (_ignoreMatching) {
			// Automatically select the element as the flag is set.
			return true;
		}
		return doIsLeafMatch(viewer_p, parentElement_p, element_p);
	}

	/**
	 * @param viewer_p
	 * @param parentElement_p
	 * @param element_p
	 * @return
	 */
	protected boolean doIsLeafMatch(Viewer viewer_p, Object parentElement_p, Object element_p) {
		boolean result = false;
		// Get the label in a straight forward manner in case of EObject
		// elements.
		if (element_p instanceof EObject) {
			String textToMatch = getTextFromModelElement((EObject) element_p);
			if (null != textToMatch) {
				result = wordMatches(textToMatch);
			}
		} else {
			result = super.isLeafMatch(viewer_p, parentElement_p, element_p);
		}
		if (result) {
			// Get the parent from the content provider, parent and children in
			// the tree may not be based on model containment hierarchy.
			// Is current leaf, that matches the pattern filter, filtered out by
			// other filters ?
			result = !isLeafAlreadyFilteredOutByOtherFilters((StructuredViewer) viewer_p, parentElement_p, element_p);
		}
		return result;
	}

	/**
	 * Get text from specified model element.<br>
	 * Default implementation gets the label according underlying
	 * {@link LabelProvider}.
	 * 
	 * @param element_p
	 * @return
	 */
	protected String getTextFromModelElement(EObject element_p) {
		return EObjectLabelProviderHelper.getText(element_p);
	}

	/**
	 * @see org.eclipse.amalgam.explorer.activity.api.editor.pages.helper.common.ui.toolkit.widgets.filter.PatternFilter#isElementVisible(org.eclipse.jface.viewers.Viewer,
	 *      java.lang.Object, java.lang.Object)
	 */
	@Override
	public boolean isElementVisible(Viewer viewer_p, Object parentElement_p, Object element_p) {
		boolean leafMatch = isLeafMatch(viewer_p, parentElement_p, element_p);
		// Flag used to know if ignoreMatching is set within this call.
		boolean ignoreMatchingEnabled = false;
		if (leafMatch /* && !_ignoreMatching */) {
			// Element label matches the filter, set the flag and add it as a
			// parent matching.
			_ignoreMatching = true;
			ignoreMatchingEnabled = true;
			_matchingParents.add(element_p);
		}
		boolean parentMatch = isParentMatch(viewer_p, parentElement_p, element_p);
		if (ignoreMatchingEnabled) {
			// Children have been processed, reset the flag only if it was set
			// within this call.
			_ignoreMatching = false;
		}
		return leafMatch || parentMatch;
	}
}