this.temporarySymbols.clear();
	public void setSymbols(HashMap symbols) {		// check symbols:		Set keySet = symbols.keySet();		for (Iterator iter = keySet.iterator(); iter.hasNext();) {			String symbol = (String) iter.next();			if ("false".equals(symbol)) {				throw new BuildException("The symbol [false] must not be defined. Please check your settings in your build.xml, devices.xml, groups.xml and vendors.xml");			}		}		this.symbols = symbols;		this.booleanEvaluator.setEnvironment(symbols, this.variables);	}