pluginmanager.java

FMJ（freedom media for java)是java视频开发的新选择

package net.sf.fmj.test.compat.plugins;

import java.util.Iterator;
import java.util.Vector;

import javax.media.Format;

/**
 * Copy of javax.media.pim.PlugInManager, used to test.
 * @author Ken Larson
 *
 */
public class PlugInManager extends javax.media.PlugInManager
{
	// TODO: what exactly is stored in the properties?  just the class names, or the formats as well?
	// the properties files appears to be binary, an appears to be created using java serialization.
	// seems like it contains the formats.
	// TODO: implement efficiently using maps
	// Vectors of PlugInInfo.
	private static final Vector[] vectors = new Vector[] {new Vector(), new Vector(), new Vector(), new Vector(), new Vector()};
	private static final Vector[] filteredVectors = new Vector[] {null, null, null, null, null};
	
	
	static
	{
		PlugInManagerInitializer.init();	// populate initial values
	}
	public PlugInManager()
	{
		
	}

	
	private static Vector getVector(int type)
	{
		if (filteredVectors[type - 1] != null)
			return filteredVectors[type - 1];
		
		return vectors[type - 1];
		
	}
	
	public static synchronized Vector getPlugInList(Format input, Format output, int type)
	{
		final Vector v = getVector(type);
		
		final Vector result = new Vector();
		for (int i = 0; i < v.size(); ++i)
		{
			final PlugInInfo plugInInfo = (PlugInInfo) v.get(i);
			
			if (input != null)
			{
				if (plugInInfo.inputFormats == null)
					continue;
				boolean match = false;
				for (int j = 0; j < plugInInfo.inputFormats.length; ++j)
				{
					if (input.matches(plugInInfo.inputFormats[j]))
					{	match = true;
						break;
					}
				}
				if (!match)
					continue;
			}
			
			
			if (output != null)
			{
				if (plugInInfo.outputFormats == null)
					continue;
				boolean match = false;
				for (int j = 0; j < plugInInfo.outputFormats.length; ++j)
				{
					if (output.matches(plugInInfo.outputFormats[j]))
					{	match = true;
						break;
					}
				}
				if (!match)
					continue;
			}

			
			result.add(plugInInfo.className);
		}
		
		return result;
		
	}

	// according to the docs, sets the search order.  does not appear to add new plugins.
	public static synchronized void setPlugInList(Vector plugins, int type)
	{
		final Vector vNew = new Vector();
		for (int i = 0; i < plugins.size(); ++i)
		{
			final String s = (String) plugins.get(i);
			final PlugInInfo plugInInfo = find(s, type);
			if (plugInInfo != null)
			{
				vNew.add(plugInInfo);
			}
			
		}
		filteredVectors[type - 1] = vNew;	
	}

	public static synchronized void commit() throws java.io.IOException
	{
		System.err.println("PlugInManager.commit not implemented");	// TODO
	}

	public static synchronized boolean addPlugIn(String classname, Format[] in, Format[] out, int type)
	{
		try
		{
			Class.forName(classname);
		} catch (ClassNotFoundException e)
		{
			return false;	// class does not exist.
		}
		catch (Throwable t) 
		{
			System.err.println("Unable to addPlugIn for " + classname + " due to inability to get its class: " + t);
			t.printStackTrace();
			return false;
		}
		if (find(classname, type) != null)
			return false;	// already there.
		
		final PlugInInfo plugInInfo = new PlugInInfo(classname, in, out);
		
		final boolean result = vectors[type - 1].add(plugInInfo);
		if (filteredVectors[type - 1] != null)
		{
			filteredVectors[type - 1].add(plugInInfo);
		}
		return result;
			

	}

	public static synchronized boolean removePlugIn(String classname, int type)
	{
		final Iterator i = vectors[type - 1].iterator();
		boolean found = false;
		while (i.hasNext())
		{	PlugInInfo plugInInfo = (PlugInInfo) i.next();
			if (plugInInfo.className.equals(classname))
			{	
				i.remove();
				found = true;
			}
		}
		return found;
		

	}

	private static synchronized PlugInInfo find(String classname, int type)
	{
		final Iterator i = vectors[type - 1].iterator();
		boolean found = false;
		while (i.hasNext())
		{	PlugInInfo plugInInfo = (PlugInInfo) i.next();
			if (plugInInfo.className.equals(classname))
			{	
				return plugInInfo;
			}
		}
		return null;
	}
	public static synchronized Format[] getSupportedInputFormats(String className, int type)
	{
		final PlugInInfo pi = find(className, type);
		if (pi == null)
			return null;
		return pi.inputFormats;
	}

	public static synchronized Format[] getSupportedOutputFormats(String className, int type)
	{
		final PlugInInfo pi = find(className, type);
		if (pi == null)
			return null;
		return pi.outputFormats;

	}
}