Spawners are entities, that are used to create other entities or structures. Normally, they are inaccessible in survival mode, unless given to a player by a command, a command block, or a dispenser. In creative mode, the spawners can be accessed, and their properties altered.
There are several types of spawners included in the Mod:
Mob Spawner[]
The LotR Mod mob spawner looks and works quite similar to the classic vanilla monster (or mob) spawner. It spawns a single type of mob, continuously according to its settings. It can be given to the player using the commands:
/give @p mob_spawner 1 <ID>
/setblock ~ ~-1 ~ mob_spawner 0 replace {EntityId:<mob name>}
for vanilla spawners and
/give @p lotr:tile.mobSpawner 1 <ID>
/setblock ~ ~-1 ~ lotr:tile.mobSpawner 0 replace
{id:LOTRMobSpawner, EntityID:lotr.<mob name>}
for LotR Mod spawners. The <ID> is the id number of the desired mob, and <mob name> is the name of the mob to be spawned.
The entity properties in a LotR Mod mob spawner GUI.
If you want to install a LotR Mod mob spawner, enter creative mode, put it into your inventory as described above and place it, or use the setblock command. Then right-click on it, to access its GUI and configure it. Note, that there are 2 settings: Entity and spawner properties, which can be toggled by the top right button ("Spawner Properties" in the image). To remove the spawner from the world, just left-click on it in creative mode.
NPC Respawner[]
The NPC respawner, which is nearly the same as the monster spawner, except that is invisible in survival mode, can spawn two different types of mobs and keep those within a certain range. It can be accessed in creative mode, or using the command:
/give @p lotr:item.npcRespawner /lotr_summon lotr.NPCRespawner
The NPC respawner GUI.
It is indestructible when placed in the world, only the "Destroy" button in its GUI can remove it in creative mode. This spawner is described in more detail here.
Trader Respawner[]
The trader respawner, a big floating coin, which can be seen in survival mode. It is generated by the game, when a trader is slain, and is not accessible via creative mode. It can be created using the command:
/summon lotr.TraderRespawn ~ ~ ~ {TraderClassID:lotr.<trader name>}
The <trader name> is the name of the trader to be respawned. It can be broken by left-clicking in creative mode and has no GUI.
Invasion Spawner[]
The invasion spawner, which is symbolized by a floating weapon, generates various mobs of a given faction in multiple waves. The spawner can be triggered by an in-game event (see invasion), summoned by a warhorn or created by a command:
/give @p lotr:item.conquestHorn 1 0 {HornFaction:<FACTION>}
/summon lotr.InvasionSpawner ~ ~ ~
{Faction:<FACTION>, MobsRemaining:<number>}
The <FACTION> is the desired faction in capital letters, and the <number> is the total number of mobs to be spawned. It can be broken in creative mode by left-clicking and has no GUI.
Spawn Egg[]
The spawn egg is a one-use item in survival mode. It spawns a single mob of the given kind. It can be accessed in creative mode, or using the command:
/give @p lotr:item.spawnEgg 1 <ID>
The <ID> is the id number of the mob to be spawned.
On servers, it is a good idea, to make those eggs somehow obtainable for normal players. Perhaps give them some regularly, depending of their alignment level, sell them for coins, or make them craftable. But keep them rare! That way, players are able to populate their buildings, put traders into self-built market stalls, use them as receptionist for hostels, or whatever they may come up with. As soldiers and farmhands are hirable, it's not so important to obtain those spawn eggs.
If you put spawn eggs into a dispenser, it will rather spawn the mob than shooting out the egg, when activated.
Structure Spawner[]
The structure spawner is a one-use item in survival mode. It builds a single structure of the given kind. It can be accessed in creative mode, or using the command:
/give @p lotr:item.structureSpawner 1 <ID>
The <ID> is the id number of the building to be spawned.
On servers, it might be a good idea, to give those out to players, in case they want to build a structure outside its home biome. The same systems as for the spawn eggs can be used.
If you put structure spawners into a dispenser, it will not spawn the structure, but just shoot out the spawner, when activated.
Settlement Spawner[]
The settlement spawner is the same as above, except that it spawns a whole settlement, instead of a single building. It can be accessed in creative mode, or using the command:
/give @p lotr:item.structureSpawner 1 <ID>
The <ID> is the id number of the settlement structure to be spawned.
If you want players to even be able to spawn whole settlements on servers, you can give out those too. Kings and Queens may even be found towns occasionally, won't they?