pipelinefactory.java

gcc的组建

		    + "' stage of pipeline, " + message);
	}

	EventConsumer createStage (EventConsumer next)
	throws IOException
	{
	    String	 name = id;

	    // most builtins are just class aliases
	    for (int i = 0; i < builtinStages.length; i++) {
		if (id.equals (builtinStages [i][0])) {
		    name = builtinStages [i][1];
		    break;
		}
	    }

	    // Save output as XML or XHTML text
	    if ("write".equals (name) || "xhtml".equals (name)) {
		String		filename;
		boolean		isXhtml = "xhtml".equals (name);
		OutputStream	out = null;
		TextConsumer	consumer;

		if (param == null)
		    fail ("parameter is required");

		filename = param.toString ();
		if ("stdout".equals (filename))
		    out = System.out;
		else if ("stderr".equals (filename))
		    out = System.err;
		else {
		    File f = new File (filename);

/*
		    if (!f.isAbsolute ())
			fail ("require absolute file paths");
 */
		    if (f.exists ())
			fail ("file already exists: " + f.getName ());

// XXX this races against the existence test
		    out = new FileOutputStream (f);
		}
		
		if (!isXhtml)
		    consumer = new TextConsumer (out);
		else
		    consumer = new TextConsumer (
			new OutputStreamWriter (out, "8859_1"),
			true);
		
		consumer.setPrettyPrinting (true);
		if (next == null)
		    return consumer;
		return new TeeConsumer (consumer, next);

	    } else {
		//
		// Here go all the builtins that are just aliases for
		// classes, and all stage IDs that started out as such
		// class names.  The following logic relies on several
		// documented conventions for constructor invocation.
		//
		String		msg = null;

		try {
		    Class	klass = Class.forName (name);
		    Class	argTypes [] = null;
		    Constructor	constructor = null;
		    boolean	filter = false;
		    Object	params [] = null;
		    Object	obj = null;

		    // do we need a filter stage?
		    if (next != null) {
			// "next" consumer is always passed, with
			// or without the optional string param
			if (param == null) {
			    argTypes = new Class [1];
			    argTypes [0] = EventConsumer.class;

			    params = new Object [1];
			    params [0] = next;

			    msg = "no-param filter";
			} else {
			    argTypes = new Class [2];
			    argTypes [0] = String.class;
			    argTypes [1] = EventConsumer.class;

			    params = new Object [2];
			    params [0] = param.toString ();
			    params [1] = next;

			    msg = "one-param filter";
			}


			try {
			    constructor = klass.getConstructor (argTypes);
			} catch (NoSuchMethodException e) {
			    // try creating a filter from a
			    // terminus and a tee
			    filter = true;
			    msg += " built from ";
			}
		    }

		    // build from a terminus stage, with or
		    // without the optional string param
		    if (constructor == null) {
			String	tmp;

			if (param == null) {
			    argTypes = new Class [0];
			    params = new Object [0];

			    tmp = "no-param terminus";
			} else {
			    argTypes = new Class [1];
			    argTypes [0] = String.class;

			    params = new Object [1];
			    params [0] = param.toString ();

			    tmp = "one-param terminus";
			}
			if (msg == null)
			    msg = tmp;
			else
			    msg += tmp;
			constructor = klass.getConstructor (argTypes);
			    // NOT creating terminus by dead-ending
			    // filters ... users should think about
			    // that one, something's likely wrong
		    }
		    
		    obj = constructor.newInstance (params);

		    // return EventConsumers directly, perhaps after
		    // turning them into a filter
		    if (obj instanceof EventConsumer) {
			if (filter)
			    return new TeeConsumer ((EventConsumer) obj, next);
			return (EventConsumer) obj;
		    }
		    
		    // if it's not a handler, it's an error
		    // we can wrap handlers in a filter
		    EventFilter		retval = new EventFilter ();
		    boolean		updated = false;

		    if (obj instanceof ContentHandler) {
			retval.setContentHandler ((ContentHandler) obj);
			updated = true;
		    }
		    if (obj instanceof DTDHandler) {
			retval.setDTDHandler ((DTDHandler) obj);
			updated = true;
		    }
		    if (obj instanceof LexicalHandler) {
			retval.setProperty (
			    EventFilter.PROPERTY_URI + "lexical-handler",
			    obj);
			updated = true;
		    }
		    if (obj instanceof DeclHandler) {
			retval.setProperty (
			    EventFilter.PROPERTY_URI + "declaration-handler",
			    obj);
			updated = true;
		    }

		    if (!updated)
			fail ("class is neither Consumer nor Handler");
		    
		    if (filter)
			return new TeeConsumer (retval, next);
		    return retval;

		} catch (IOException e) {
		    throw e;

		} catch (NoSuchMethodException e) {
		    fail (name + " constructor missing -- " + msg);

		} catch (ClassNotFoundException e) {
		    fail (name + " class not found");

		} catch (Exception e) {
		    // e.printStackTrace ();
		    fail ("stage not available: " + e.getMessage ());
		}
	    }
	    // NOTREACHED
	    return null;
	}
    }

    private static class Pipeline
    {
	Stage		stage;

	// rest may be null
	Pipeline	rest;
	EventConsumer	next;

	Pipeline (Stage s)
	    { stage = s; }

	public String toString ()
	{
	    if (rest == null && next == null)
		return stage.toString ();
	    if (rest != null)
		return stage + " | " + rest;
	    throw new IllegalArgumentException ("next");
	}

	EventConsumer createPipeline ()
	throws IOException
	{
	    if (next == null) {
		if (rest == null)
		    next = stage.createStage (null);
		else
		    next = stage.createStage (rest.createPipeline ());
	    }
	    return next;
	}
    }

/*
    public static void main (String argv [])
    {
	try {
	    // three basic terminus cases
	    createPipeline ("null");
	    createPipeline ("validate");
	    createPipeline ("write ( stdout )");

	    // four basic filters
	    createPipeline ("nsfix | write ( stderr )");
	    createPipeline ("wf | null");
	    createPipeline ("null | null");
	    createPipeline (
"call ( http://www.example.com/services/xml-1a ) | xhtml ( stdout )");

	    // tee junctions
	    createPipeline ("tee ( validate ) | write ( stdout )");
	    createPipeline ("tee ( nsfix | write ( stdout ) ) | validate");

	    // longer pipeline
	    createPipeline ("nsfix | tee ( validate ) | write ( stdout )");
	    createPipeline (
		"null | wf | nsfix | tee ( validate ) | write ( stdout )");

	    // try some parsing error cases
	    try {
		createPipeline ("null (");		// extra token '('
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }

	    try {
		createPipeline ("nsfix |");		// extra token '|'
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }

	    try {
		createPipeline ("xhtml ( foo");		// missing right paren
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }

	    try {
		createPipeline ("xhtml ( foo bar");	// required right paren
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }

	    try {
		createPipeline ("tee ( nsfix | validate");// missing right paren
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }

	    // try some construction error cases

	    try {
		createPipeline ("call");		// missing param
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }
	    try {
		createPipeline ("call ( foobar )");	// broken param
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }
	    try {
		createPipeline ("nsfix ( foobar )");	// illegal param
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }
	    try {
		createPipeline ("null ( foobar )");	// illegal param
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }
	    try {
		createPipeline ("wf ( foobar )");	// illegal param
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }
	    try {
		createPipeline ("xhtml ( foobar.html )");
		new File ("foobar.html").delete ();
		// now supported
	    } catch (Exception e) {
		System.err.println ("** err: " + e.getMessage ()); }
	    try {
		createPipeline ("xhtml");		// missing param
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }
	    try {
		createPipeline ("write ( stdout ) | null");	// nonterminal
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }
	    try {
		createPipeline ("validate | null");
		// now supported
	    } catch (Exception e) {
		System.err.println ("** err: " + e.getMessage ()); }
	    try {
		createPipeline ("validate ( foo )");	// illegal param
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }
	    try {
		createPipeline ("tee");			// missing param
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }
	    try {
		    // only builtins so far
		createPipeline ("com.example.xml.FilterClass");
		System.err.println ("** didn't report error");
	    } catch (Exception e) {
		System.err.println ("== err: " + e.getMessage ()); }

	} catch (Exception e) {
	    e.printStackTrace ();
	}
    }
/**/

}