Spring property placeholder configurer which exposes properties

ExposePropertyPlaceholderConfigurer.java

/**
 * Use instead of {@link PropertyPlaceholderConfigurer}
 * to get access to properties loaded by spring.
 * <p>
 * Note: there is support to define file with list of properties which should stay unexposed. 
 * 
 */
public class ExposePropertyPlaceholderConfigurer extends PropertyPlaceholderConfigurer implements InitializingBean {

    private Map<String, String> resolvedProps = new TreeMap<String, String>();
    private Set<String> hiddenProps = Collections.emptySet();
    private PropertyPlaceholderHelper helper = new PropertyPlaceholderHelper(DEFAULT_PLACEHOLDER_PREFIX, DEFAULT_PLACEHOLDER_SUFFIX);
    private Resource hiddenProperties;

    @Override
    protected void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess, Properties props)
            throws BeansException {
        super.processProperties(beanFactoryToProcess, props);

        for (Object propertyKey : props.keySet()) {
            String propertyKeyStr = propertyKey.toString();

            // filter out properties that should be hidden
            if (hiddenProps.contains(propertyKeyStr)) {
                continue;
            }
            
            resolvedProps.put(propertyKeyStr, helper.replacePlaceholders(props.getProperty(propertyKeyStr), props));
        }
    }

    /**
     * @return resolved properties with excluded hidden properties
     */
    public Map<String, String> getResolvedProps() {
        return Collections.unmodifiableMap(resolvedProps);
    }

    /**
     * Optional hidden properties
     * @param hiddenProperties file with properties to hide
     */
    public void setHiddenProperties(Resource hiddenProperties) {
        this.hiddenProperties = hiddenProperties;
    }

    public void afterPropertiesSet() throws Exception {
        if (hiddenProperties != null) {
            InputSupplier<InputStreamReader> supplier = Resources.newReaderSupplier(hiddenProperties.getURL(), Charsets.UTF_8);
            hiddenProps = Sets.newHashSet(CharStreams.readLines(supplier)); 
        }
    }

}