it.unimi.dsi.parser.callback.Callback Maven / Gradle / Ivy
Show all versions of dsi-utils Show documentation
package it.unimi.dsi.parser.callback;
/*
* DSI utilities
*
* Copyright (C) 2005-2009 Sebastiano Vigna
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the Free
* Software Foundation; either version 2.1 of the License, or (at your option)
* any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
import it.unimi.dsi.lang.MutableString;
import it.unimi.dsi.parser.Attribute;
import it.unimi.dsi.parser.BulletParser;
import it.unimi.dsi.parser.Element;
import java.util.Map;
/** A callback for the {@linkplain it.unimi.dsi.parser.BulletParser bullet parser}.
*
* This interface is very loosely inspired to the SAX2 interface. However, it
* strives to be simple, and to be StringFree™.
*
*
By contract, all implementations of this interface are bound to be reusable:
* by calling {@link #startDocument()}, a callback can be used again.
* It must be safe to call {@link #startDocument()} any number of times.
*
*/
public interface Callback {
/** A singleton empty callback array. */
Callback[] EMPTY_CALLBACK_ARRAY = new Callback[ 0 ];
/** Configure the parser for usage with this callback.
*
*
When a callback is registered with a parser, it needs to set up
* the parser so that all data required by the callback is actually parsed.
* The configuration must be a monotone process—you
* can only set properties and add attribute types to
* be parsed.
*/
void configure( BulletParser parser );
/** Receive notification of the beginning of the document.
*
*
The callback must use this method to reset its internal state so
* that it can be resued. It must be safe to invoke this method
* several times.
*/
void startDocument();
/** Receive notification of the start of an element.
*
*
For simple elements, this is the only notification that the
* callback will ever receive.
*
* @param element the element whose opening tag was found.
* @param attrMap a map from {@link it.unimi.dsi.parser.Attribute}s to {@link MutableString}s.
* @return true to keep the parser parsing, false to stop it.
*/
boolean startElement( Element element, Map attrMap );
/** Receive notification of the end of an element.
*
* Warning: unless specific decorators are used, in
* general a callback will just receive notifications for elements
* whose closing tag appears explicitly in the document.
*
* This method will never be called for element without closing tags,
* even if such a tag is found.
*
* @param element the element whose closing tag was found.
* @return true to keep the parser parsing, false to stop it.
*/
boolean endElement( Element element );
/** Receive notification of character data inside an element.
*
*
You must not write into text, as it could be passed
* around to many callbacks.
*
*
flowBroken will be true iff
* the flow was broken before text. This feature makes it possible
* to extract quickly the text in a document without looking at the elements.
*
* @param text an array containing the character data.
* @param offset the start position in the array.
* @param length the number of characters to read from the array.
* @param flowBroken whether the flow is broken at the start of text.
* @return true to keep the parser parsing, false to stop it.
*/
boolean characters( char[] text, int offset, int length, boolean flowBroken );
/** Receive notification of the content of a CDATA section.
*
*
CDATA sections in an HTML document are the result of meeting
* a STYLE or SCRIPT element. In that case, the element
* will be passed as first argument.
*
*
You must not write into text, as it could be passed
* around to many callbacks.
*
* @param element the element enclosing the CDATA section, or null if the
* CDATA section was created with explicit markup.
* @param text an array containing the character data.
* @param offset the start position in the array.
* @param length the number of characters to read from the array.
* @return true to keep the parser parsing, false to stop it.
*/
boolean cdata( Element element, char[] text, int offset, int length );
/** Receive notification of the end of the document. */
void endDocument();
}