private int registerSourceFile(String file) {
        if (sourceFiles.contains(file))
            return -1;
	sourceFiles.add(file);
	this.size++;
	return sourceFiles.size() - 1;
    }
private int registerSourceFile(String file) {
        if (sourceFiles.contains(file))
            return -1;
	sourceFiles.add(file);
	this.size++;
	return sourceFiles.size() - 1;
    }
private int registerSourceFile ( String file ) { if ( sourceFiles . contains ( file ) ) return - 1 ; sourceFiles . add ( file ) ; this . size ++ ; return sourceFiles . size ( ) - 1 ; }
Register a new source file.
This method is used to implement file inclusion. Each included file
gets a unique identifier (which is the index in the array of source
files).

@return The index of the now registered file.
Register a new source file . This method is used to implement file inclusion . Each included file gets a unique identifier ( which is the index in the array of source files ) .