[Bleeding] Added Potions API. Fixes BUKKIT-389

By: fullwall <fullwall@optusnet.com>

paper-api/src/main/java/org/bukkit/potion/PotionEffect.java

@@ -0,0 +1,85 @@
+package org.bukkit.potion;
+
+import org.apache.commons.lang.Validate;
+import org.bukkit.entity.LivingEntity;
+
+/**
+ * Represents a potion effect, that can be added to a {@link LivingEntity}. A
+ * potion effect has a duration that it will last for, an amplifier that will
+ * enhance its effects, and a {@link PotionEffectType}, that represents its
+ * effect on an entity.
+ */
+public class PotionEffect {
+    private final int amplifier;
+    private final int duration;
+    private final PotionEffectType type;
+
+    public PotionEffect(PotionEffectType type, int duration, int amplifier) {
+        Validate.notNull(type, "effect type cannot be null");
+        this.type = type;
+        this.duration = duration;
+        this.amplifier = amplifier;
+    }
+
+    /**
+     * Attempts to add the effect represented by this object to the given
+     * {@link LivingEntity}.
+     *
+     * @see LivingEntity#addPotionEffect(PotionEffect)
+     * @param entity
+     *            The entity to add this effect to
+     */
+    public boolean apply(LivingEntity entity) {
+        return entity.addPotionEffect(this);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        PotionEffect other = (PotionEffect) obj;
+        if (type == null) {
+            if (other.type != null) {
+                return false;
+            }
+        } else if (!type.equals(other.type)) {
+            return false;
+        }
+        return true;
+    }
+
+    /**
+     * Returns the amplifier of this effect. A higher amplifier means the potion
+     * effect happens more often over its duration and in some cases has more
+     * effect on its target.
+     */
+    public int getAmplifier() {
+        return amplifier;
+    }
+
+    /**
+     * Returns the duration (in ticks) that this effect will run for when
+     * applied to a {@link LivingEntity}.
+     */
+    public int getDuration() {
+        return duration;
+    }
+
+    /**
+     * Returns the {@link PotionEffectType} of this effect.
+     *
+     * @return The potion type of this effect
+     */
+    public PotionEffectType getType() {
+        return type;
+    }
+
+    @Override
+    public int hashCode() {
+        return 31 + ((type == null) ? 0 : type.hashCode());
+    };
+}