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Example 1 with Handler

use of org.openmrs.annotation.Handler in project openmrs-core by openmrs.

the class HandlerUtil method getHandlersForType.

/**
 * Retrieves a List of all registered components from the Context that are of the passed
 * handlerType and one or more of the following is true:
 * <ul>
 * <li>The handlerType is annotated as a {@link Handler} that supports the passed type</li>
 * <li>The passed type is null - this effectively returns all components of the passed
 * handlerType</li>
 * </ul>
 * The returned handlers are ordered in the list based upon the order property.
 *
 * @param handlerType Indicates the type of class to return
 * @param type Indicates the type that the given handlerType must support (or null for any)
 * @return a List of all matching Handlers for the given parameters, ordered by Handler#order
 * @should return a list of all classes that can handle the passed type
 * @should return classes registered in a module
 * @should return an empty list if no classes can handle the passed type
 */
public static <H, T> List<H> getHandlersForType(Class<H> handlerType, Class<T> type) {
    List<?> list = cachedHandlers.get(new Key(handlerType, type));
    if (list != null) {
        return (List<H>) list;
    }
    List<H> handlers = new ArrayList<>();
    // First get all registered components of the passed class
    log.debug("Getting handlers of type " + handlerType + (type == null ? "" : " for class " + type.getName()));
    for (H handler : Context.getRegisteredComponents(handlerType)) {
        Handler handlerAnnotation = handler.getClass().getAnnotation(Handler.class);
        // Only consider those that have been annotated as Handlers
        if (handlerAnnotation != null) {
            // If no type is passed in return all handlers
            if (type == null) {
                log.debug("Found handler " + handler.getClass());
                handlers.add(handler);
            } else // Otherwise, return all handlers that support the passed type
            {
                for (int i = 0; i < handlerAnnotation.supports().length; i++) {
                    Class<?> clazz = handlerAnnotation.supports()[i];
                    if (clazz.isAssignableFrom(type)) {
                        log.debug("Found handler: " + handler.getClass());
                        handlers.add(handler);
                    }
                }
            }
        }
    }
    // Return the list of handlers based on the order specified in the Handler annotation
    handlers.sort(Comparator.comparing(o -> getOrderOfHandler(o.getClass())));
    Map<Key, List<?>> newCachedHandlers = new WeakHashMap<>(cachedHandlers);
    newCachedHandlers.put(new Key(handlerType, type), handlers);
    cachedHandlers = newCachedHandlers;
    return handlers;
}
Also used : Logger(org.slf4j.Logger) APIException(org.openmrs.api.APIException) LoggerFactory(org.slf4j.LoggerFactory) ApplicationListener(org.springframework.context.ApplicationListener) ArrayList(java.util.ArrayList) List(java.util.List) ContextRefreshedEvent(org.springframework.context.event.ContextRefreshedEvent) Component(org.springframework.stereotype.Component) Map(java.util.Map) Handler(org.openmrs.annotation.Handler) Comparator(java.util.Comparator) Context(org.openmrs.api.context.Context) WeakHashMap(java.util.WeakHashMap) ArrayList(java.util.ArrayList) Handler(org.openmrs.annotation.Handler) ArrayList(java.util.ArrayList) List(java.util.List) WeakHashMap(java.util.WeakHashMap)

Aggregations

ArrayList (java.util.ArrayList)1 Comparator (java.util.Comparator)1 List (java.util.List)1 Map (java.util.Map)1 WeakHashMap (java.util.WeakHashMap)1 Handler (org.openmrs.annotation.Handler)1 APIException (org.openmrs.api.APIException)1 Context (org.openmrs.api.context.Context)1 Logger (org.slf4j.Logger)1 LoggerFactory (org.slf4j.LoggerFactory)1 ApplicationListener (org.springframework.context.ApplicationListener)1 ContextRefreshedEvent (org.springframework.context.event.ContextRefreshedEvent)1 Component (org.springframework.stereotype.Component)1