1 /*
   2  * Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package org.xml.sax;
  27 
  28 
  29 /**
  30  * Interface for an XML filter.
  31  *
  32  * <p>An XML filter is like an XML reader, except that it obtains its
  33  * events from another XML reader rather than a primary source like
  34  * an XML document or database.  Filters can modify a stream of
  35  * events as they pass on to the final application.</p>
  36  *
  37  * <p>The XMLFilterImpl helper class provides a convenient base
  38  * for creating SAX2 filters, by passing on all {@link org.xml.sax.EntityResolver
  39  * EntityResolver}, {@link org.xml.sax.DTDHandler DTDHandler},
  40  * {@link org.xml.sax.ContentHandler ContentHandler} and {@link org.xml.sax.ErrorHandler
  41  * ErrorHandler} events automatically.</p>
  42  *
  43  * @since 1.4, SAX 2.0
  44  * @author David Megginson
  45  * @see org.xml.sax.helpers.XMLFilterImpl
  46  */
  47 public interface XMLFilter extends XMLReader
  48 {
  49 
  50     /**
  51      * Set the parent reader.
  52      *
  53      * <p>This method allows the application to link the filter to
  54      * a parent reader (which may be another filter).  The argument
  55      * may not be null.</p>
  56      *
  57      * @param parent The parent reader.
  58      */
  59     public abstract void setParent (XMLReader parent);
  60 
  61 
  62     /**
  63      * Get the parent reader.
  64      *
  65      * <p>This method allows the application to query the parent
  66      * reader (which may be another filter).  It is generally a
  67      * bad idea to perform any operations on the parent reader
  68      * directly: they should all pass through this filter.</p>
  69      *
  70      * @return The parent filter, or null if none has been set.
  71      */
  72     public abstract XMLReader getParent ();
  73 
  74 }
  75 
  76 // end of XMLFilter.java