| 1 | package com.hammurapi.eventbus; |
| 2 | |
| 3 | import java.lang.reflect.InvocationHandler; |
| 4 | import java.lang.reflect.Method; |
| 5 | import java.lang.reflect.Proxy; |
| 6 | |
| 7 | import com.hammurapi.extract.CommutativeAnd; |
| 8 | import com.hammurapi.extract.Predicate; |
| 9 | import com.hammurapi.extract.True; |
| 10 | |
| 11 | public final class ReflectiveEventHandler<E, C, H extends EventBus.Handle<E,Integer,C>, S extends EventStore<E,Integer,C,H,S>> implements EventHandler<E, Integer, C, H, S> { |
| 12 | private final C instance; |
| 13 | private final int offset; |
| 14 | private final Method mthd; |
| 15 | private final Class<E>[] pt; |
| 16 | private final Handler ha; |
| 17 | private Class<E> eventType; |
| 18 | private Class<?> contextType; |
| 19 | private Predicate<E,C> predicate; |
| 20 | |
| 21 | ReflectiveEventHandler( |
| 22 | C instance, |
| 23 | int offset, |
| 24 | Method mthd, |
| 25 | Class<E>[] pt, |
| 26 | Handler ha, |
| 27 | Class<E> eventType, |
| 28 | Predicate<E,C>... predicates) { |
| 29 | |
| 30 | this.instance = instance; |
| 31 | this.offset = offset; |
| 32 | this.mthd = mthd; |
| 33 | this.pt = pt; |
| 34 | this.ha = ha; |
| 35 | this.eventType = eventType; |
| 36 | if (offset>0) { |
| 37 | contextType=mthd.getParameterTypes()[0]; |
| 38 | if (!contextType.isInterface()) { |
| 39 | throw new IllegalArgumentException("Event dispatch context parameter type should be interface: "+mthd); |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | if (predicates.length==0) { |
| 44 | predicate = True.getInstance(); |
| 45 | } else if (predicates.length==1) { |
| 46 | predicate = predicates[0]; |
| 47 | } else { |
| 48 | predicate = new CommutativeAnd<E,C>(0, null, predicates).normalize(); |
| 49 | } |
| 50 | } |
| 51 | |
| 52 | public Method getMethod() { |
| 53 | return mthd; |
| 54 | } |
| 55 | |
| 56 | public C getInstance() { |
| 57 | return instance; |
| 58 | } |
| 59 | |
| 60 | @Override |
| 61 | public boolean consumes() { |
| 62 | return ha.consumes(); |
| 63 | } |
| 64 | |
| 65 | @Override |
| 66 | public int getCardinality() { |
| 67 | return pt.length; |
| 68 | } |
| 69 | |
| 70 | @Override |
| 71 | public C getContext() { |
| 72 | return instance; |
| 73 | } |
| 74 | |
| 75 | @Override |
| 76 | public Integer getPriority() { |
| 77 | return ha.priority(); |
| 78 | } |
| 79 | |
| 80 | @SuppressWarnings("unchecked") |
| 81 | @Override |
| 82 | public void post(final EventDispatchContext<E, Integer, C, H, S> context, E... events) { |
| 83 | int expectedEventsLength = pt.length; |
| 84 | if (events.length!=expectedEventsLength) { |
| 85 | throw new EventDispatchException("Expected "+expectedEventsLength+" input events for method "+mthd+", got "+events.length); |
| 86 | } |
| 87 | Object[] args = new Object[pt.length+offset]; |
| 88 | if (offset>0) { |
| 89 | if (contextType.isInstance(context)) { |
| 90 | args[0] = context; |
| 91 | } else { |
| 92 | // Dynamic proxy for event dispatch context. |
| 93 | InvocationHandler ih = new InvocationHandler() { |
| 94 | |
| 95 | @Override |
| 96 | public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { |
| 97 | return method.invoke(context, args); |
| 98 | } |
| 99 | }; |
| 100 | |
| 101 | Class<?>[] contextInterfaces = context.getClass().getInterfaces(); |
| 102 | Class<?>[] proxyInterfaces = new Class[contextInterfaces.length+1]; |
| 103 | System.arraycopy(contextInterfaces, 0, proxyInterfaces, 0, contextInterfaces.length); |
| 104 | proxyInterfaces[contextInterfaces.length] = contextType; |
| 105 | args[0] = Proxy.newProxyInstance(contextType.getClassLoader(), proxyInterfaces, ih); |
| 106 | } |
| 107 | } |
| 108 | for (int i=0; i<events.length; ++i) { |
| 109 | args[i+offset] = events[i]; |
| 110 | } |
| 111 | try { |
| 112 | Object toPost = mthd.invoke(instance, args); |
| 113 | if (eventType.isInstance(toPost)) { |
| 114 | context.post((E) toPost); |
| 115 | } |
| 116 | } catch (Exception e) { |
| 117 | throw new EventDispatchException("Failed to invoke event handler method "+mthd+": "+e, e); |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | @Override |
| 122 | public void reset() { |
| 123 | if (instance instanceof Resettable) { |
| 124 | ((Resettable) instance).reset(); |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | @Override |
| 129 | public String toString() { |
| 130 | return "Reflective Handler(cardinality = "+getCardinality()+", method = "+mthd+", instance = "+instance+")"; |
| 131 | } |
| 132 | |
| 133 | @Override |
| 134 | public boolean isOneOff() { |
| 135 | return ha.oneOff(); |
| 136 | } |
| 137 | |
| 138 | @Override |
| 139 | public com.hammurapi.eventbus.EventHandlerBase.Mode getMode() { |
| 140 | return ha.mode(); |
| 141 | } |
| 142 | |
| 143 | @Override |
| 144 | public Predicate<E, C> getPredicate() { |
| 145 | return predicate; |
| 146 | } |
| 147 | } |