From 0851c5adfd968e50227dc037a3c2175af2a5ca9e Mon Sep 17 00:00:00 2001 From: =?utf8?q?David=20=E2=80=98Bombe=E2=80=99=20Roden?= Date: Fri, 4 Jan 2013 17:54:41 +0100 Subject: [PATCH] Add loader for reactions from chains. --- .../reactor/loader/ReactionLoader.java | 177 +++++++++++++++++++++ 1 file changed, 177 insertions(+) create mode 100644 src/main/java/net/pterodactylus/reactor/loader/ReactionLoader.java diff --git a/src/main/java/net/pterodactylus/reactor/loader/ReactionLoader.java b/src/main/java/net/pterodactylus/reactor/loader/ReactionLoader.java new file mode 100644 index 0000000..7016edb --- /dev/null +++ b/src/main/java/net/pterodactylus/reactor/loader/ReactionLoader.java @@ -0,0 +1,177 @@ +/* + * Reactor - Loader.java - Copyright © 2013 David Roden + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +package net.pterodactylus.reactor.loader; + +import java.lang.reflect.Constructor; +import java.lang.reflect.InvocationTargetException; +import java.util.ArrayList; +import java.util.List; +import java.util.concurrent.TimeUnit; + +import net.pterodactylus.reactor.Action; +import net.pterodactylus.reactor.Filter; +import net.pterodactylus.reactor.Query; +import net.pterodactylus.reactor.Reaction; +import net.pterodactylus.reactor.Trigger; +import net.pterodactylus.reactor.loader.Chain.Parameter; +import net.pterodactylus.reactor.loader.Chain.Part; + +/** + * Creates {@link Reaction}s from {@link Chain}s. + * + * @author David ‘Bombe’ Roden + */ +public class ReactionLoader { + + /** + * Creates a {@link Reaction} from the given {@link Chain}. + * + * @param chain + * The chain to create a reaction from + * @return The created reaction + * @throws LoaderException + * if a class can not be loaded + */ + @SuppressWarnings("static-method") + public Reaction loadReaction(Chain chain) throws LoaderException { + + /* check if chain is enabled. */ + if (!chain.enabled()) { + throw new IllegalArgumentException("Chain is not enabled."); + } + + /* create query. */ + Query query = createObject(chain.query().name(), "net.pterodactylus.reactor.queries", extractParameters(chain.query().parameters())); + + /* create filters. */ + List filters = new ArrayList(); + for (Part filterPart : chain.filters()) { + filters.add(ReactionLoader. createObject(filterPart.name(), "net.pterodactylus.reactor.filters", extractParameters(filterPart.parameters()))); + } + + /* create trigger. */ + Trigger trigger = createObject(chain.trigger().name(), "net.pterodactylus.reactor.triggers", extractParameters(chain.trigger().parameters())); + + /* create action. */ + Action action = createObject(chain.action().name(), "net.pterodactylus.reactor.actions", extractParameters(chain.action().parameters())); + + return new Reaction(query, filters, trigger, action).setUpdateInterval(TimeUnit.SECONDS.toMillis(chain.updateInterval())); + } + + // + // STATIC METHODS + // + + /** + * Extracts all parameter values from the given parameters. + * + * @param parameters + * The parameters to extract the values from + * @return The extracted values + */ + private static List extractParameters(List parameters) { + List parameterValues = new ArrayList(); + + for (Parameter parameter : parameters) { + parameterValues.add(parameter.value()); + } + + return parameterValues; + } + + /** + * Creates a new object. + *

+ * First, {@code className} is used to try to load a {@link Class} with that + * name. If that fails, {@code packageName} is prepended to the class name. + * If no class can be found, a {@link LoaderException} will be thrown. + *

+ * If a class could be located using the described method, a constructor + * will be searched that has the same number of {@link String} parameters as + * the given parameters. The parameters from the given parameters are then + * used in a constructor call to create the new object. + * + * @param className + * The name of the class + * @param packageName + * The optional name of the package to prepend + * @param parameters + * The parameters for the constructor call + * @return The created object + * @throws LoaderException + * if the object can not be created + */ + @SuppressWarnings("unchecked") + private static T createObject(String className, String packageName, List parameters) throws LoaderException { + + /* try to load class without package name. */ + Class objectClass = null; + try { + objectClass = Class.forName(className); + } catch (ClassNotFoundException cnfe1) { + /* ignore, we’ll try again. */ + } + + if (objectClass == null) { + try { + objectClass = Class.forName(packageName + "." + className); + } catch (ClassNotFoundException cnfe1) { + /* okay, now we need to throw. */ + throw new LoaderException(String.format("Could find neither class “%s” nor class “%s.”", className, packageName + "." + className), cnfe1); + } + } + + /* locate an eligible constructor. */ + Constructor wantedConstructor = null; + for (Constructor constructor : objectClass.getConstructors()) { + Class[] parameterTypes = constructor.getParameterTypes(); + if (parameterTypes.length != parameters.size()) { + continue; + } + boolean compatibleTypes = true; + for (Class parameterType : parameterTypes) { + if (parameterType != String.class) { + compatibleTypes = false; + break; + } + } + if (!compatibleTypes) { + continue; + } + wantedConstructor = constructor; + } + + if (wantedConstructor == null) { + throw new LoaderException("Could not find eligible constructor."); + } + + try { + return (T) wantedConstructor.newInstance(parameters.toArray()); + } catch (IllegalArgumentException iae1) { + throw new LoaderException("Could not invoke constructor.", iae1); + } catch (InstantiationException ie1) { + throw new LoaderException("Could not invoke constructor.", ie1); + } catch (IllegalAccessException iae1) { + throw new LoaderException("Could not invoke constructor.", iae1); + } catch (InvocationTargetException ite1) { + throw new LoaderException("Could not invoke constructor.", ite1); + } + + } + +} -- 2.7.4