Util.java

/*
 * Dog - Core
 * 
 * Copyright (c) 2013 Dario Bonino and Luigi De Russis
 * 
 * This software is based on a bundle of the Apache Felix project.
 * See the NOTICE file distributed with this work for additional information.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License
 */
package it.polito.elite.dog.core.devicemanager.util;

import org.osgi.framework.Constants;
import org.osgi.framework.Filter;
import org.osgi.framework.FrameworkUtil;
import org.osgi.framework.InvalidSyntaxException;
import org.osgi.framework.ServiceReference;
import org.osgi.service.device.Device;

/**
 * This class provides multiple utilities for the Device Manager bundle.
 * 
 * @author <a href="mailto:dev@felix.apache.org">Felix Project Team</a>
 *         (original version)
 * @author <a href="mailto:luigi.derussis@polito.it">Luigi De Russis</a>
 *         (successive modifications)
 * @see <a href="http://elite.polito.it">http://elite.polito.it</a>
 * 
 */
public class Util
{
	/**
	 * Default (empty) constructor
	 */
	private Util()
	{
	}
	
	public static String showDriver(ServiceReference<?> ref)
	{
		Object objectClass = ref.getProperty(Constants.OBJECTCLASS);
		Object driverId = ref.getProperty(org.osgi.service.device.Constants.DRIVER_ID);
		StringBuffer buffer = new StringBuffer();
		
		buffer.append("Driver: ");
		buffer.append(Constants.OBJECTCLASS).append("=");
		
		if (String[].class.isInstance(objectClass))
		{
			buffer.append(enumerateStringArray(String[].class.cast(objectClass)));
		}
		else
		{
			buffer.append(objectClass);
		}
		buffer.append(" ");
		
		buffer.append(org.osgi.service.device.Constants.DRIVER_ID).append("=");
		buffer.append(driverId);
		return buffer.toString();
	}
	
	public static boolean isDevice(ServiceReference<?> ref)
	{
		try
		{
			Filter device = createFilter("(|(%s=%s)(%s=%s))",
					new Object[] { Constants.OBJECTCLASS, Device.class.getName(),
							org.osgi.service.device.Constants.DEVICE_CATEGORY, "*" });
			return device.match(ref);
		}
		catch (Exception e)
		{
			e.printStackTrace();
		}
		return false;
	}
	
	public static boolean isDeviceInstance(ServiceReference<?> ref)
	{
		try
		{
			Filter device = createFilter("(%s=%s)", new Object[] { Constants.OBJECTCLASS, Device.class.getName() });
			return device.match(ref);
		}
		catch (Exception e)
		{
			e.printStackTrace();
		}
		return false;
	}
	
	public static String createFilterString(String input, Object[] data)
	{
		return String.format(input, data);
	}
	
	public static Filter createFilter(String input, Object[] data) throws InvalidSyntaxException
	{
		return FrameworkUtil.createFilter(String.format(input, data));
	}
	
	public static String showDevice(ServiceReference<?> ref)
	{
		Object objectClass = ref.getProperty(Constants.OBJECTCLASS);
		Object category = ref.getProperty(org.osgi.service.device.Constants.DEVICE_CATEGORY);
		StringBuffer buffer = new StringBuffer();
		
		buffer.append("Device: ");
		buffer.append(Constants.OBJECTCLASS).append("=");
		
		appendObject(buffer, objectClass);
		buffer.append(" ");
		
		buffer.append(org.osgi.service.device.Constants.DEVICE_CATEGORY).append("=");
		appendObject(buffer, category);
		
		buffer.append("\n{ ");
		String[] keys = ref.getPropertyKeys();
		
		for (String key : keys)
		{
			if (key.equals(Constants.OBJECTCLASS))
			{
				continue;
			}
			if (key.equals(org.osgi.service.device.Constants.DEVICE_CATEGORY))
			{
				continue;
			}
			buffer.append(key).append("=");
			appendObject(buffer, ref.getProperty(key));
			buffer.append(" ");
		}
		buffer.append("}\n");
		
		return buffer.toString();
	}
	
	private static void appendObject(StringBuffer buffer, Object obj)
	{
		if (String[].class.isInstance(obj))
		{
			buffer.append(enumerateStringArray(String[].class.cast(obj)));
		}
		else
		{
			buffer.append(obj);
		}
	}
	
	private static String enumerateStringArray(String[] strings)
	{
		StringBuffer buffer = new StringBuffer();
		
		buffer.append("[");
		for (String str : strings)
		{
			buffer.append(str);
			buffer.append(" ");
		}
		buffer.deleteCharAt(buffer.length() - 1);
		buffer.append("]");
		return buffer.toString();
	}
}