Refactor providers to a generic implementation in preparation for future spawn egg APIs

Author: vemacs

Essentials/src/com/earth2me/essentials/Essentials.java

@@ -28,14 +28,18 @@
 import com.earth2me.essentials.textreader.KeywordReplacer;
 import com.earth2me.essentials.textreader.SimpleTextInput;
 import com.earth2me.essentials.utils.DateUtil;
-import com.earth2me.essentials.utils.SpawnerProviderFactory;
 import com.google.common.base.Function;
 import com.google.common.base.Throwables;
 import com.google.common.collect.Iterables;
 import net.ess3.api.*;
 import net.ess3.api.IEssentials;
 import net.ess3.api.ISettings;
 import net.ess3.nms.SpawnerProvider;
+import net.ess3.nms.blockmeta.BlockMetaSpawnerProvider;
+import net.ess3.nms.legacy.LegacySpawnerProvider;
+import net.ess3.nms.v1_8_R1.v1_8_R1SpawnerProvider;
+import net.ess3.nms.v1_8_R2.v1_8_R2SpawnerProvider;
+import net.ess3.providers.ProviderFactory;
 import org.bukkit.Bukkit;
 import org.bukkit.ChatColor;
 import org.bukkit.Server;
@@ -74,7 +78,6 @@
 
 
 public class Essentials extends JavaPlugin implements net.ess3.api.IEssentials {
-    public static final int BUKKIT_VERSION = 3050;
     private static final Logger LOGGER = Logger.getLogger("Essentials");
     private transient ISettings settings;
     private final transient TNTExplodeListener tntListener = new TNTExplodeListener(this);
@@ -194,7 +197,13 @@ public void onEnable() {
                 execTimer.mark("Init(Worth/ItemDB)");
                 jails = new Jails(this);
                 confList.add(jails);
-                spawnerProvider = new SpawnerProviderFactory(this).getProvider();
+                spawnerProvider = new ProviderFactory<>(getLogger(),
+                        Arrays.asList(
+                                BlockMetaSpawnerProvider.class,
+                                v1_8_R2SpawnerProvider.class,
+                                v1_8_R1SpawnerProvider.class,
+                                LegacySpawnerProvider.class
+                        ), "mob spawner").getProvider();
                 reload();
             } catch (YAMLException exception) {
                 if (pm.getPlugin("EssentialsUpdate") != null) {

Essentials/src/com/earth2me/essentials/utils/SpawnerProviderFactory.java

@@ -1,5 +1,6 @@
 package net.ess3.nms;
 
+import net.ess3.providers.Provider;
 import com.google.common.collect.ImmutableMap;
 import org.bukkit.ChatColor;
 import org.bukkit.Material;
@@ -9,7 +10,7 @@
 
 import java.util.Map;
 
-public abstract class SpawnerProvider {
+public abstract class SpawnerProvider implements Provider {
     protected Map<EntityType, String> entityToDisplayName = ImmutableMap.<EntityType, String>builder()
             .put(EntityType.CAVE_SPIDER, "Cave Spider")
             .put(EntityType.PIG_ZOMBIE, "Zombie Pigman")
@@ -25,8 +26,8 @@ public abstract class SpawnerProvider {
 
     public abstract ItemStack setEntityType(ItemStack is, EntityType type) throws IllegalArgumentException;
     public abstract EntityType getEntityType(ItemStack is) throws IllegalArgumentException;
-    public abstract String getHumanName();
 
+    @Override
     public boolean tryProvider() {
         try {
             EntityType type = EntityType.CREEPER;

nms/NMSProvider/src/net/ess3/nms/SpawnerProvider.java

@@ -0,0 +1,7 @@
+package net.ess3.providers;
+
+public interface Provider {
+    boolean tryProvider();
+
+    String getHumanName();
+}

nms/NMSProvider/src/net/ess3/providers/Provider.java

@@ -0,0 +1,36 @@
+package net.ess3.providers;
+
+import java.util.logging.Logger;
+
+public class ProviderFactory<T extends Provider> {
+    private Logger logger;
+    private String providerType;
+    private Iterable<Class <? extends T>> availableProviders;
+
+    public ProviderFactory(Logger logger, Iterable<Class <? extends T>> availableProviders, String providerType) {
+        this.logger = logger;
+        this.providerType = providerType;
+        this.availableProviders = availableProviders;
+    }
+
+    public T getProvider() {
+        T finalProvider = null;
+        for (Class<? extends T> providerClass : availableProviders) {
+            finalProvider = loadProvider(providerClass);
+            if (finalProvider != null && finalProvider.tryProvider()) {
+                break;
+            }
+        }
+        assert finalProvider != null;
+        logger.info("Using " + finalProvider.getHumanName() + " as " + providerType + " provider.");
+        return finalProvider;
+    }
+
+    private T loadProvider(Class<? extends T> providerClass) {
+        try {
+            return providerClass.newInstance();
+        } catch (Throwable ignored) {
+            return null;
+        }
+    }
+}