| 1 | package com.hammurapi.eventbus.local; |
| 2 | |
| 3 | import java.lang.ref.Reference; |
| 4 | import java.lang.ref.SoftReference; |
| 5 | import java.lang.ref.WeakReference; |
| 6 | import java.util.Collection; |
| 7 | import java.util.concurrent.ConcurrentLinkedQueue; |
| 8 | |
| 9 | import com.hammurapi.eventbus.AbstractEventBus; |
| 10 | import com.hammurapi.eventbus.AbstractEventBus.Handle; |
| 11 | import com.hammurapi.eventbus.Derivation; |
| 12 | import com.hammurapi.eventbus.EventHandler; |
| 13 | import com.hammurapi.eventbus.EventStore; |
| 14 | import com.hammurapi.eventbus.InferenceContext; |
| 15 | import com.hammurapi.eventbus.local.LocalEventBusBase.LocalHandle; |
| 16 | import com.hammurapi.store.Store; |
| 17 | import com.hammurapi.store.local.LocalHandle.HandleStrength; |
| 18 | |
| 19 | /** |
| 20 | * Facade handles are used by event joiners and derivations. When master handle is invalidated, it sends notifications to facades and they get invalidated. |
| 21 | * @author Pavel Vlasov |
| 22 | * |
| 23 | * @param <E> |
| 24 | * @param <P> |
| 25 | * @param <C> |
| 26 | * @param <S> |
| 27 | */ |
| 28 | class FacadeHandle<E, P extends Comparable<P>, C, S extends EventStore<E, P, C, AbstractEventBus.Handle<E, P, C, Long>, S>> implements LocalHandle<E,P,C,S> { |
| 29 | private MasterHandle<E,P,C,S> master; |
| 30 | private E event; // Never read - just to create strong reference. |
| 31 | private Reference<E> eventRef; |
| 32 | private Collection<Derivation<E,P,C>> derivatives = new ConcurrentLinkedQueue<Derivation<E,P,C>>(); |
| 33 | private long masterId; |
| 34 | |
| 35 | public FacadeHandle(MasterHandle<E,P,C,S> master, HandleStrength handleStrength) { |
| 36 | this.master = master; |
| 37 | this.masterId = master.getId(); |
| 38 | master.addFacade(this); |
| 39 | switch (handleStrength) { |
| 40 | case STRONG: |
| 41 | event = master.getEvent(); |
| 42 | break; |
| 43 | case SOFT: |
| 44 | eventRef = new SoftReference<E>(master.getEvent()); |
| 45 | break; |
| 46 | case WEAK: |
| 47 | eventRef = new WeakReference<E>(master.getEvent()); |
| 48 | break; |
| 49 | } |
| 50 | } |
| 51 | |
| 52 | void addDerivative(Derivation<E,P,C> derivative) { |
| 53 | derivatives.add(derivative); |
| 54 | } |
| 55 | |
| 56 | public Long getId() { |
| 57 | return masterId; |
| 58 | } |
| 59 | |
| 60 | public Collection<Derivation<E,P,C>> getDerivations() { |
| 61 | return master.getDerivations(); |
| 62 | } |
| 63 | |
| 64 | public E getEvent() { |
| 65 | return master.getEvent(); |
| 66 | } |
| 67 | |
| 68 | @Override |
| 69 | public void remove() { |
| 70 | if (master!=null) { |
| 71 | master.remove(); |
| 72 | } |
| 73 | } |
| 74 | |
| 75 | public void remove(boolean forUpdate, InferenceContext<E,P,C,Long,AbstractEventBus.Handle<E,P,C,Long>,S> inferenceContext) { |
| 76 | if (master!=null) { |
| 77 | master.remove(forUpdate, inferenceContext); |
| 78 | } |
| 79 | } |
| 80 | |
| 81 | public boolean isDerivedFrom(E event) { |
| 82 | return master.isDerivedFrom(event); |
| 83 | } |
| 84 | |
| 85 | public boolean isValid() { |
| 86 | return master!=null && master.isValid(); |
| 87 | } |
| 88 | |
| 89 | // public void setEvent(E event) { |
| 90 | // master.setEvent(event); |
| 91 | // } |
| 92 | |
| 93 | public void update() { |
| 94 | master.update(); |
| 95 | } |
| 96 | |
| 97 | public MasterHandle<E,P,C,S> getMaster() { |
| 98 | return master; |
| 99 | } |
| 100 | |
| 101 | /** |
| 102 | * Invoked by master. |
| 103 | */ |
| 104 | void invalidateFacade(InferenceContext<E,P,C,Long,AbstractEventBus.Handle<E,P,C,Long>,S> inferenceContext) { |
| 105 | event = null; |
| 106 | if (eventRef!=null) { |
| 107 | eventRef.clear(); |
| 108 | eventRef = null; |
| 109 | } |
| 110 | master = null; |
| 111 | |
| 112 | for (Derivation<E,P,C> derivative: derivatives) { |
| 113 | derivative.invalidate(inferenceContext); |
| 114 | } |
| 115 | derivatives.clear(); |
| 116 | } |
| 117 | |
| 118 | @Override |
| 119 | public void join() throws InterruptedException { |
| 120 | master.join(); |
| 121 | } |
| 122 | |
| 123 | @Override |
| 124 | public boolean join(long timeout) throws InterruptedException { |
| 125 | return master.join(timeout); |
| 126 | } |
| 127 | |
| 128 | @Override |
| 129 | public <H extends AbstractEventBus.Handle<E,P,C,Long>, S extends EventStore<E, P, C, H, S>> void setStoreHandle(Store.Handle<H, E, S> storeHandle) { |
| 130 | throw new UnsupportedOperationException("This operation shall not be invoked for FacadeHandle"); |
| 131 | } |
| 132 | |
| 133 | @Override |
| 134 | public String toString() { |
| 135 | return "FacadeHandle [getId()="+getId()+", master=" + master + "]"; |
| 136 | } |
| 137 | |
| 138 | @Override |
| 139 | public void handleException(Exception e) { |
| 140 | master.handleException(e); |
| 141 | } |
| 142 | |
| 143 | @Override |
| 144 | public boolean isDirectPost() { |
| 145 | return master.isDirectPost(); |
| 146 | } |
| 147 | |
| 148 | @Override |
| 149 | public void setDirectPost() { |
| 150 | master.setDirectPost(); |
| 151 | } |
| 152 | |
| 153 | @Override |
| 154 | public void addDerivation(Long handlerId, EventHandler<E, P, C, ?, ?> handler, Handle<E, P, C, Long>[] inputs) { |
| 155 | master.addDerivation(handlerId, handler, inputs); |
| 156 | |
| 157 | } |
| 158 | |
| 159 | @Override |
| 160 | public void addRemoveListener(RemoveListener<E, P, C, S> removeListener) { |
| 161 | master.addRemoveListener(removeListener); |
| 162 | } |
| 163 | |
| 164 | } |
| 165 | |