/*
* @(#)GTKEngineParser.java 1.7 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package com.sun.java.swing.plaf.gtk;
import java.io.IOException;
/**
* The abstract base class for all theme engine parsers.
*
* @author Shannon Hickey
* @version 1.7 12/19/03
*/
abstract class GTKEngineParser {
protected final int uniqueScopeID = GTKScanner.getUniqueScopeID();
/**
* Parse the body of an 'engine' section of an rc file and store
* the results in a <CODE>GTKParser.EngineInfo<CODE> object.
* <P>
* This method takes three parameters. The first is a scanner to
* retrieve tokens from. Configuration options on the scanner may be
* changed by this method, but it must be sure to restore the previous
* values when it has completed. A typical implementation will also
* want to register its own symbols with the scanner. To do so, it should
* save the current scope of the scanner, and then set the scanner's scope
* to the value of 'uniqueScopeID'. Then, it should register its own
* symbols with the scanner if they don't already exist. The int value
* of every symbol registered must be > GTKScanner.TOKEN_LAST.
* At the successful completion of this method, the old scope should be
* restored, but the registered symbols can be left for the next use.
* <P>
* When this method is called, the scanner will be ready to return the first
* token inside the opening '{' of an engine section. Therefore, with the
* exception of returning early in error, this method must continue parsing
* until it sees a matching outer '}', even if it no longer has interest in
* the tokens returned.
* <P>
* The second parameter is the parser that called this method. It should
* not be modified in any way, and has been included only to make available
* its <CODE>resolvePixmapPath</CODE> method for resolving paths to images.
* <P>
* The last parameter will always be a single element array, for returning a
* <CODE>GTKParser.EngineInfo</CODE> object representing the information
* that was parsed. Upon invocation of this method, the array may already
* contain an info object. If so, it is guaranteed that it was created by this
* <CODE>GTKEngineParser</CODE> on a previous call to <CODE>parse</CODE>.
* As such, its type can be assumed. Typically, an implementation will
* want to append to, or merge with the information contained in any passed in
* info object.
* <P>
* Upon successful completion, the information parsed should be stored in
* a <CODE>GTKParser.EngineInfo</CODE> object as element 0 in the array
* parameter. This can be null if we wish to signify, for any reason, that
* that this entire engine section be thrown out and to use the default
* engine instead.
* <P>
* This method should return <CODE>GTKScanner.TOKEN_NONE</CODE>, if successful,
* otherwise the token that it expected but didn't get.
*
* @param scanner The scanner to retrieve tokens from.
* @param parser The parser that called us.
* @param retVal A single element array to store an object containing the
* information parsed.
*
* @return <CODE>GTKScanner.TOKEN_NONE</CODE> if the parse was successful,
* otherwise the token that was expected but not received.
*/
abstract int parse(GTKScanner scanner,
GTKParser parser,
GTKParser.EngineInfo[] retVal) throws IOException;
}
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