431eaf6df8
PropertySourcesPlaceholderConfigurer accommodates recent changes in Environment and PropertySource APIs, e.g. no longer assuming enumerability of property names. PSPC reuses as much functionality as possible from AbstractPropertyPlaceholderConfigurer, but overrides postProcessBeanFactory() and defines its own variation on processProperties() in order to accept a PropertyResolver rather than a PropertySource. AbstractPropertyPlaceholderConfigurer introduces doProcessProperties() method to encapsulate that which is actually common, such as the visiting of each bean definition once a StringValueResolver has been created in the subclass.