Class FilterBase

java/org/apache/catalina/filters/FilterBase.java:32–88

Base class for filters that provides generic initialisation and a simple no-op destruction.

     * Base class for filters that provides generic initialisation and a simple no-op destruction.
     */
public abstract class FilterBase implements Filter {

    /**
     * Default constructor for FilterBase.
     */
    public FilterBase() {
        // Default constructor
    }

    /**
     * StringManager for internationalized strings.
     */
    protected static final StringManager sm = StringManager.getManager(FilterBase.class);

    /**
     * Returns the logger for this filter.
     *
     * @return the logger
     */
    protected abstract Log getLogger();


    /**
     * Iterates over the configuration parameters and either logs a warning, or throws an exception for any parameter
     * that does not have a matching setter in this filter.
     *
     * @param filterConfig The configuration information associated with the filter instance being initialised
     *
     * @throws ServletException if {@link #isConfigProblemFatal()} returns {@code true} and a configured parameter does
     *                              not have a matching setter
     */
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        Enumeration<String> paramNames = filterConfig.getInitParameterNames();
        while (paramNames.hasMoreElements()) {
            String paramName = paramNames.nextElement();
            if (!IntrospectionUtils.setProperty(this, paramName, filterConfig.getInitParameter(paramName))) {
                String msg = sm.getString("filterbase.noSuchProperty", paramName, this.getClass().getName());
                if (isConfigProblemFatal()) {
                    throw new ServletException(msg);
                } else {
                    getLogger().warn(msg);
                }
            }
        }
    }

    /**
     * Determines if an exception when calling a setter or an unknown configuration attribute triggers the failure of
     * this filter which in turn will prevent the web application from starting.
     *
     * @return <code>true</code> if a problem should trigger the failure of this filter, else <code>false</code>
     */
    protected boolean isConfigProblemFatal() {
        return false;
    }
}