public class Triggers {
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/**
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Enum representing each of before/after CRUD events on Sobjects
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*/
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public enum Evt {
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afterdelete, afterinsert, afterundelete,
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afterupdate, beforedelete, beforeinsert, beforeupdate
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}
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/**
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Simplistic handler to implement on any of the event. It doesn't requires or enforces any patter except the
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method name to be "handle()", a developer is free to use any Trigger context variable or reuse any other
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apex class here.
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*/
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public interface Handler {
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void handle();
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}
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// Internal mapping of handlers
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Map<String, List<Handler>> eventHandlerMapping = new Map<String, List<Handler>>();
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/**
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Core API to bind handlers with events
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*/
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public Triggers bind(Evt event, Handler eh) {
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List<Handler> handlers = eventHandlerMapping.get(event.name());
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if (handlers == null) {
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handlers = new List<Handler>();
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eventHandlerMapping.put(event.name(), handlers);
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}
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handlers.add(eh);
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return this;
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}
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/**
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Invokes correct handlers as per the context of trigger and available registered handlers
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*/
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public void manage() {
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Evt ev = null;
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if(Trigger.isInsert && Trigger.isBefore){
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ev = Evt.beforeinsert;
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} else if(Trigger.isInsert && Trigger.isAfter){
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ev = Evt.afterinsert;
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} else if(Trigger.isUpdate && Trigger.isBefore){
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ev = Evt.beforeupdate;
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} else if(Trigger.isUpdate && Trigger.isAfter){
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ev = Evt.afterupdate;
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} else if(Trigger.isDelete && Trigger.isBefore){
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ev = Evt.beforedelete;
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} else if(Trigger.isDelete && Trigger.isAfter){
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ev = Evt.afterdelete;
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} else if(Trigger.isundelete){
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ev = Evt.afterundelete;
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}
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List<Handler> handlers = eventHandlerMapping.get(ev.name());
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if (handlers != null && !handlers.isEmpty()) {
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for (Handler h : handlers) {
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h.handle();
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}
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}
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}
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}
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