Refactor Validate class, rename to Preconditions

Plugin/src/main/java/me/filoghost/chestcommands/api/IconMenu.java

@@ -21,7 +21,7 @@ import org.bukkit.inventory.Inventory;
 import me.filoghost.chestcommands.internal.MenuInventoryHolder;
 import me.filoghost.chestcommands.util.ItemUtils;
 import me.filoghost.chestcommands.util.Utils;
-import me.filoghost.chestcommands.util.Validate;
+import me.filoghost.chestcommands.util.Preconditions;
 
 import java.util.Arrays;
 
@@ -87,7 +87,7 @@ public class IconMenu {
 	}
 
 	public void open(Player player) {
-		Validate.notNull(player, "Player cannot be null");
+		Preconditions.notNull(player, "player");
 
 		Inventory inventory = Bukkit.createInventory(new MenuInventoryHolder(this), icons.length, title);
 

Plugin/src/main/java/me/filoghost/chestcommands/bridge/BarAPIBridge.java

@@ -15,6 +15,8 @@
 package me.filoghost.chestcommands.bridge;
 
 import me.confuser.barapi.BarAPI;
+import me.filoghost.chestcommands.util.Preconditions;
+
 import org.bukkit.Bukkit;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.Plugin;
@@ -40,7 +42,7 @@ public class BarAPIBridge {
 
 	@SuppressWarnings("deprecation")
 	public static void setMessage(Player player, String message, int seconds) {
-		if (!hasValidPlugin()) throw new IllegalStateException("BarAPI plugin was not found!");
+		Preconditions.checkState(hasValidPlugin(), "BarAPI plugin not found");
 		
 		BarAPI.setMessage(player, message, seconds);
 	}

Plugin/src/main/java/me/filoghost/chestcommands/bridge/EconomyBridge.java

@@ -19,6 +19,7 @@ import org.bukkit.entity.Player;
 import org.bukkit.plugin.RegisteredServiceProvider;
 
 import me.filoghost.chestcommands.MenuManager;
+import me.filoghost.chestcommands.util.Preconditions;
 import net.milkbowl.vault.economy.Economy;
 import net.milkbowl.vault.economy.EconomyResponse;
 
@@ -30,11 +31,11 @@ public class EconomyBridge {
 		if (Bukkit.getPluginManager().getPlugin("Vault") == null) {
 			return false;
 		}
-		RegisteredServiceProvider<Economy> rsp = Bukkit.getServicesManager().getRegistration(Economy.class);
+		RegisteredServiceProvider<Economy> economyServiceProvider = Bukkit.getServicesManager().getRegistration(Economy.class);
-		if (rsp == null) {
+		if (economyServiceProvider == null) {
 			return false;
 		}
-		economy = rsp.getProvider();
+		economy = economyServiceProvider.getProvider();
 		return economy != null;
 	}
 
@@ -88,15 +89,11 @@ public class EconomyBridge {
 	}
 
 	private static void checkValidEconomy() {
-		if (!hasValidEconomy()) {
+		Preconditions.checkState(hasValidEconomy(), "economy plugin not found");
-			throw new IllegalStateException("Economy plugin was not found!");
-		}
 	}
 	
 	private static void checkPositiveAmount(double amount) {
-		if (amount < 0.0) {
+		Preconditions.checkArgument(amount >= 0.0, "amount cannot be negative");
-			throw new IllegalArgumentException("Invalid amount of money: " + amount);
-		}
 	}
 
 	public static String formatMoney(double amount) {

Plugin/src/main/java/me/filoghost/chestcommands/bridge/PlaceholderAPIBridge.java

@@ -2,6 +2,8 @@ package me.filoghost.chestcommands.bridge;
 
 import me.clip.placeholderapi.PlaceholderAPI;
 import me.clip.placeholderapi.PlaceholderAPIPlugin;
+import me.filoghost.chestcommands.util.Preconditions;
+
 import org.bukkit.Bukkit;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.Plugin;
@@ -26,17 +28,13 @@ public class PlaceholderAPIBridge {
 	}
 
 	public static boolean hasPlaceholders(String message) {
-		if (!hasValidPlugin()) {
+		Preconditions.checkState(hasValidPlugin(), "PlaceholderAPI plugin not found");
-			throw new IllegalStateException("PlaceholderAPI plugin was not found!");
-		}
 		
 		return PlaceholderAPI.containsPlaceholders(message);
 	}
 
 	public static String setPlaceholders(String message, Player executor) {
-		if (!hasValidPlugin()) {
+		Preconditions.checkState(hasValidPlugin(), "PlaceholderAPI plugin not found");
-			throw new IllegalStateException("PlaceholderAPI plugin was not found!");
-		}
 
 		return PlaceholderAPI.setPlaceholders(executor, message);
 	}

Plugin/src/main/java/me/filoghost/chestcommands/internal/OpenTrigger.java

@@ -18,7 +18,7 @@ import org.bukkit.Material;
 import org.bukkit.event.block.Action;
 import org.bukkit.inventory.ItemStack;
 
-import me.filoghost.chestcommands.util.Validate;
+import me.filoghost.chestcommands.util.Preconditions;
 
 public class OpenTrigger {
 
@@ -28,9 +28,8 @@ public class OpenTrigger {
 	private boolean isRestrictiveDurability;
 
 	public OpenTrigger(Material material, ClickType clickType) {
-		Validate.notNull(material, "Material cannot be null");
+		Preconditions.checkArgumentNotAir(material, "material");
-		Validate.notNull(material, "ClickType cannot be null");
+		Preconditions.notNull(clickType, "clickType");
-		Validate.isTrue(material != Material.AIR, "Material cannot be AIR");
 		
 		this.material = material;
 		this.clickType = clickType;

Plugin/src/main/java/me/filoghost/chestcommands/internal/RequiredItem.java

@@ -18,7 +18,7 @@ import org.bukkit.Material;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 
-import me.filoghost.chestcommands.util.Validate;
+import me.filoghost.chestcommands.util.Preconditions;
 
 public class RequiredItem {
 
@@ -28,8 +28,7 @@ public class RequiredItem {
 	private boolean isDurabilityRestrictive = false;
 
 	public RequiredItem(Material material, int amount) {
-		Validate.notNull(material, "Material cannot be null");
+		Preconditions.checkArgumentNotAir(material, "material");
-		Validate.isTrue(material != Material.AIR, "Material cannot be air");
 
 		this.material = material;
 		this.amount = amount;
@@ -48,7 +47,7 @@ public class RequiredItem {
 	}
 
 	public void setRestrictiveDataValue(short data) {
-		Validate.isTrue(data >= 0, "Data value cannot be negative");
+		Preconditions.checkArgument(data >= 0, "Data value cannot be negative");
 
 		this.dataValue = data;
 		isDurabilityRestrictive = true;

Plugin/src/main/java/me/filoghost/chestcommands/parser/IconParser.java

@@ -35,7 +35,7 @@ import me.filoghost.chestcommands.parser.EnchantmentParser.EnchantmentDetails;
 import me.filoghost.chestcommands.util.ErrorCollector;
 import me.filoghost.chestcommands.util.FormatUtils;
 import me.filoghost.chestcommands.util.ItemUtils;
-import me.filoghost.chestcommands.util.Validate;
+import me.filoghost.chestcommands.util.Preconditions;
 import me.filoghost.chestcommands.util.nbt.parser.MojangsonParseException;
 import me.filoghost.chestcommands.util.nbt.parser.MojangsonParser;
 
@@ -94,7 +94,7 @@ public class IconParser {
 
 
 	public static Icon loadIconFromSection(ConfigurationSection section, String iconName, String menuFileName, ErrorCollector errorCollector) {
-		Validate.notNull(section, "ConfigurationSection cannot be null");
+		Preconditions.notNull(section, "section");
 
 		// The icon is valid even without a Material
 		ExtendedIcon icon = new ExtendedIcon();
@@ -245,7 +245,7 @@ public class IconParser {
 
 
 	public static Coords loadCoordsFromSection(ConfigurationSection section) {
-		Validate.notNull(section, "ConfigurationSection cannot be null");
+		Preconditions.notNull(section, "section");
 
 		Integer x = null;
 		Integer y = null;

Plugin/src/main/java/me/filoghost/chestcommands/parser/ItemStackParser.java

@@ -20,7 +20,7 @@ import org.bukkit.inventory.ItemStack;
 import me.filoghost.chestcommands.exception.FormatException;
 import me.filoghost.chestcommands.util.MaterialsHelper;
 import me.filoghost.chestcommands.util.Utils;
-import me.filoghost.chestcommands.util.Validate;
+import me.filoghost.chestcommands.util.Preconditions;
 
 public class ItemStackParser {
 
@@ -35,7 +35,7 @@ public class ItemStackParser {
 	 * for example wool:5, 3 is a valid input.
 	 */
 	public ItemStackParser(String input, boolean parseAmount) throws FormatException {
-		Validate.notNull(input, "input cannot be null");
+		Preconditions.notNull(input, "input");
 
 		// Remove spaces, they're not needed
 		input = input.replace(" ", "");

Plugin/src/main/java/me/filoghost/chestcommands/util/Preconditions.java

@@ -0,0 +1,48 @@
+/*
+ *  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 <https://www.gnu.org/licenses/>.
+ */
+package me.filoghost.chestcommands.util;
+
+import org.bukkit.Material;
+
+public final class Preconditions {
+
+	private Preconditions() {}
+
+	public static void notNull(Object object, String objectName) {
+		if (object == null) {
+			throw new NullPointerException(objectName + " cannot be null");
+		}
+	}
+	
+	public static void checkArgument(boolean expression, String errorMessage) {
+		if (!expression) {
+			throw new IllegalArgumentException(errorMessage);
+		}
+	}
+
+	public static void checkState(boolean expression, String errorMessage) {
+		if (!expression) {
+			throw new IllegalStateException(errorMessage);
+		}
+	}
+	
+	public static void checkArgumentNotAir(Material material, String objectName) {
+		notNull(material, objectName);
+		if (MaterialsHelper.isAir(material)) {
+			throw new IllegalArgumentException(objectName + " cannot be " + material);
+		}
+	}
+
+}

Plugin/src/main/java/me/filoghost/chestcommands/util/Registry.java

@@ -55,9 +55,7 @@ public class Registry<T> {
 	}
 	
 	public void putIfEnumExists(String key, String enumValueName) {
-		if (!valuesType.isEnum()) {
+		Preconditions.checkState(valuesType.isEnum(), "value type is not an enum");
-			throw new IllegalArgumentException("Value type is not an enum");
-		}
 		
 		try {
 			@SuppressWarnings({ "unchecked", "rawtypes" })

Plugin/src/main/java/me/filoghost/chestcommands/util/Validate.java

@@ -1,34 +0,0 @@
-/*
- *  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 <https://www.gnu.org/licenses/>.
- */
-package me.filoghost.chestcommands.util;
-
-public final class Validate {
-
-	private Validate() {
-	}
-
-	public static void notNull(Object object, String error) {
-		if (object == null) {
-			throw new NullPointerException(error);
-		}
-	}
-
-	public static void isTrue(boolean statement, String error) {
-		if (!statement) {
-			throw new IllegalArgumentException(error);
-		}
-	}
-
-}