addressviewercategoryfilter.java

eclipse开发笔记

package com.plugindev.addressbook.views;

import org.eclipse.jface.viewers.StructuredViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerFilter;
import org.eclipse.ui.IMemento;

import com.plugindev.addressbook.models.AddressItem;
import com.plugindev.addressbook.util.StringMatcher;

public class AddressViewerCategoryFilter extends ViewerFilter {

	@Override
	public boolean select(Viewer viewer, Object parentElement, Object element) {
	      return matcher.match(
	 	         ((AddressItem) element).getCategory().getCategoryName());
	}
	//保存在IMemento中的标记名称
	private static final String TAG_PATTERN = "pattern";
	private static final String TAG_TYPE = "CategoryFilterInfo";
	   
	private final StructuredViewer viewer;
	private String pattern = "";
	private StringMatcher matcher;
	   
	public AddressViewerCategoryFilter(StructuredViewer viewer) {
		this.viewer = viewer;
	}

	public String getPattern() {
		return pattern;
	}

	public void setPattern(String newPattern) {
		boolean filtering = matcher != null;
		if (newPattern != null && newPattern.trim().length() > 0) {
			pattern = newPattern;
			matcher = new StringMatcher(pattern, true, false);
			if (!filtering)
				viewer.addFilter(this);
			else
	            viewer.refresh();
		}
		else {
			pattern = "";
			matcher = null;
			if (filtering)
				viewer.removeFilter(this);
		}
	}
	//保存过滤状态
	public void saveState(IMemento memento) {
		if (pattern.length() == 0)
			return;
		IMemento mem = memento.createChild(TAG_TYPE);
			mem.putString(TAG_PATTERN, pattern);
		}
	//获得保存的过滤状态
	public void init(IMemento memento) {
		IMemento mem = memento.getChild(TAG_TYPE);
		if (mem == null)
			return;
		setPattern(mem.getString(TAG_PATTERN));
	}
}