gomp-20050608-branch/libjava/classpath/gnu/xml/pipeline/EventConsumer.java

   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 }