org.jwall.web.audit.util.VariableContext Maven / Gradle / Ivy

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/*
 *  Copyright (C) 2007-2014 Christian Bockermann 
 *
 *  This file is part of the  web-audit  library.
 *
 *  web-audit library is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  The  web-audit  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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see .
 *
 */
package org.jwall.web.audit.util;

import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author chris
 *
 */
public class VariableContext {
	
	/* A global logger for this class */
	static Logger log = LoggerFactory.getLogger( VariableContext.class );
	
	public final static String VAR_PREFIX = "${";
	public final static String VAR_SUFFIX = "}";
	
	/* The variables available in this context */
	Map variables = new HashMap();

	
	public VariableContext( VariableContext root ){
		variables = new HashMap();
		if( root.variables != null )
			variables.putAll( root.variables );
	}
	

	public VariableContext( Map variables ){
		this.variables = variables;
	}
	
	public VariableContext( Properties p ){
		this.variables = new HashMap();
		for( Object k : p.keySet() )
			variables.put( k.toString(), p.getProperty( k.toString() ) );
	}


	public void addVariables( Map vars ){
		for( String key : vars.keySet() )
			variables.put( key, vars.get( key ) );
	}

	
	public void set( String key, String val ){
		variables.put( key, val );
	}
	
	
	public String expand( String str ){
		return substitute( str );
	}
	

	private String substitute( String str ){
		String content = str;
		int start = content.indexOf( VAR_PREFIX, 0 );
		while( start >= 0 ){
			int end = content.indexOf( VAR_SUFFIX, start );
			if( end >= start + 2 ){
				String variable = content.substring( start + 2, end );
				log.debug( "Found variable: {}", variable );
				log.trace( "   content is: {}", content );
				if( variables.containsKey( variable ) )
					content = content.substring( 0, start ) + variables.get( variable ) + content.substring( end + 1 );
				else
					content = content.substring( 0, start ) + "" + content.substring( end + 1 );

				if( end < content.length() )
					start = content.indexOf( VAR_PREFIX, end );
				else
					start = -1;
			} else
				start = -1;
		}
		return content;
	}
}