EventConsumer.java 4.0 KB

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