Source for gnu.xml.pipeline.EventConsumer

   1: /* EventConsumer.java --
   2:    Copyright (C) 1999,2000,2001 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: package gnu.xml.pipeline;
  39: 
  40: import org.xml.sax.*;
  41: 
  42: 
  43: /**
  44:  * Collects the event consumption apparatus of a SAX pipeline stage.
  45:  * Consumers which permit some handlers or other characteristics to be
  46:  * configured will provide methods to support that configuration.
  47:  *
  48:  * <p> Two important categories of consumers include <em>filters</em>, which
  49:  * process events and pass them on to other consumers, and <em>terminus</em>
  50:  * (or <em>terminal</em>) stages, which don't pass events on.  Filters are not
  51:  * necessarily derived from the {@link EventFilter} class, although that
  52:  * class can substantially simplify their construction by automating the
  53:  * most common activities.
  54:  *
  55:  * <p> Event consumers which follow certain conventions for the signatures
  56:  * of their constructors can be automatically assembled into pipelines
  57:  * by the {@link PipelineFactory} class.
  58:  *
  59:  * @author David Brownell
  60:  */
  61: public interface EventConsumer
  62: {
  63:     /** Most stages process these core SAX callbacks. */
  64:     public ContentHandler getContentHandler ();
  65: 
  66:     /** Few stages will use unparsed entities. */
  67:     public DTDHandler getDTDHandler ();
  68: 
  69:     /**
  70:      * This method works like the SAX2 XMLReader method of the same name,
  71:      * and is used to retrieve the optional lexical and declaration handlers
  72:      * in a pipeline.
  73:      *
  74:      * @param id This is a URI identifying the type of property desired.
  75:      * @return The value of that property, if it is defined.
  76:      *
  77:      * @exception SAXNotRecognizedException Thrown if the particular
  78:      *  pipeline stage does not understand the specified identifier.
  79:      */
  80:     public Object getProperty (String id)
  81:     throws SAXNotRecognizedException;
  82: 
  83:     /**
  84:      * This method provides a filter stage with a handler that abstracts
  85:      * presentation of warnings and both recoverable and fatal errors.
  86:      * Most pipeline stages should share a single policy and mechanism
  87:      * for such reports, since application components require consistency
  88:      * in such activities.  Accordingly, typical responses to this method
  89:      * invocation involve saving the handler for use; filters will pass
  90:      * it on to any other consumers they use.
  91:      *
  92:      * @param handler encapsulates error handling policy for this stage
  93:      */
  94:     public void setErrorHandler (ErrorHandler handler);
  95: }