SPIGOT-4705: Revamp Ageable interface and add Breedable interface

src/main/java/org/bukkit/craftbukkit/entity/CraftPiglinAbstract.java

@@ -52,6 +52,49 @@ public class CraftPiglinAbstract extends CraftMonster implements PiglinAbstract
         getHandle().setBaby(flag);
     }
 
+    @Override
+    public int getAge() {
+        return getHandle().isBaby() ? -1 : 0;
+    }
+
+    @Override
+    public void setAge(int i) {
+        getHandle().setBaby(i < 0);
+    }
+
+    @Override
+    public void setAgeLock(boolean b) {
+    }
+
+    @Override
+    public boolean getAgeLock() {
+        return false;
+    }
+
+    @Override
+    public void setBaby() {
+        getHandle().setBaby(true);
+    }
+
+    @Override
+    public void setAdult() {
+        getHandle().setBaby(false);
+    }
+
+    @Override
+    public boolean isAdult() {
+        return !getHandle().isBaby();
+    }
+
+    @Override
+    public boolean canBreed() {
+        return false;
+    }
+
+    @Override
+    public void setBreed(boolean b) {
+    }
+
     @Override
     public EntityPiglinAbstract getHandle() {
         return (EntityPiglinAbstract) super.getHandle();

src/main/java/org/bukkit/craftbukkit/entity/CraftZoglin.java

@@ -35,4 +35,47 @@ public class CraftZoglin extends CraftMonster implements Zoglin {
     public EntityType getType() {
         return EntityType.ZOGLIN;
     }
+
+    @Override
+    public int getAge() {
+        return getHandle().isBaby() ? -1 : 0;
+    }
+
+    @Override
+    public void setAge(int i) {
+        getHandle().setBaby(i < 0);
+    }
+
+    @Override
+    public void setAgeLock(boolean b) {
+    }
+
+    @Override
+    public boolean getAgeLock() {
+        return false;
+    }
+
+    @Override
+    public void setBaby() {
+        getHandle().setBaby(true);
+    }
+
+    @Override
+    public void setAdult() {
+        getHandle().setBaby(false);
+    }
+
+    @Override
+    public boolean isAdult() {
+        return !getHandle().isBaby();
+    }
+
+    @Override
+    public boolean canBreed() {
+        return false;
+    }
+
+    @Override
+    public void setBreed(boolean b) {
+    }
 }

src/main/java/org/bukkit/craftbukkit/entity/CraftZombie.java

@@ -80,4 +80,47 @@ public class CraftZombie extends CraftMonster implements Zombie {
             getHandle().startDrownedConversion(time);
         }
     }
+
+    @Override
+    public int getAge() {
+        return getHandle().isBaby() ? -1 : 0;
+    }
+
+    @Override
+    public void setAge(int i) {
+        getHandle().setBaby(i < 0);
+    }
+
+    @Override
+    public void setAgeLock(boolean b) {
+    }
+
+    @Override
+    public boolean getAgeLock() {
+        return false;
+    }
+
+    @Override
+    public void setBaby() {
+        getHandle().setBaby(true);
+    }
+
+    @Override
+    public void setAdult() {
+        getHandle().setBaby(false);
+    }
+
+    @Override
+    public boolean isAdult() {
+        return !getHandle().isBaby();
+    }
+
+    @Override
+    public boolean canBreed() {
+        return false;
+    }
+
+    @Override
+    public void setBreed(boolean b) {
+    }
 }