Changes

=== Sided Setup Events ===

=== Sided Setup Events ===

There are different events which are fired at different stages during the [[Modloading|modloading process]]. Most of these events are fired on both physical sides, except for the '''sided setup events''': <code>FMLClientSetupEvent</code> and <code>FMLDedicatedServerSetupEvent</code>, which is fired on the physical client and the physical/dedicated server respectively.

There are different events which are fired at different stages during the [[Stages_of_Modloading|modloading process]]. Most of these events are fired on both physical sides, except for the '''sided setup events''': <code>FMLClientSetupEvent</code> and <code>FMLDedicatedServerSetupEvent</code>, which is fired on the physical client and the physical/dedicated server respectively.

These events should be used for running side-specific initialization code. It is recommended to either put your sided event handler registration behind a <code>DistExecutor</code> call, or use the <code>@Mod.EventBusSubscriber</code> anntoation with '<code>value = Dist.CLIENT</code> for clients (or <code>value = Dist.DEDICATED_SERVER</code> for the dedicated server) to conditionally register your event handlers and prevent the classes referenced within from crashing upon being loaded.

These events should be used for running side-specific initialization code. It is recommended to either put your sided event handler registration behind a <code>DistExecutor</code> call, or use the <code>@Mod.EventBusSubscriber</code> anntoation with '<code>value = Dist.CLIENT</code> for clients (or <code>value = Dist.DEDICATED_SERVER</code> for the dedicated server) to conditionally register your event handlers and prevent the classes referenced within from crashing upon being loaded.

=== Reaching Across Logical Sides ===

=== Reaching Across Logical Sides ===

Whenever you want to send information from one logical side to another, you must '''always''' use network packets. It is incredibly tempting, when in a single player scenario, to directly transfer data from the logical server to the logical client.

Whenever you want to send information from one logical side to another, you must '''always''' use [[SimpleChannel|network packets]]. It is incredibly tempting, when in a single player scenario, to directly transfer data from the logical server to the logical client.

This is actually very commonly inadvertently done through static fields. Since the logical client and logical server share the same JVM instance in a single player scenario, both threads writing to and reading from static fields will cause all sorts of race conditions and classical issues associated with threading.

This is actually very commonly inadvertently done through static fields. Since the logical client and logical server share the same JVM instance in a single player scenario, both threads writing to and reading from static fields will cause all sorts of race conditions and classical issues associated with threading.

Your mods are expected to always load, regardless of if they are loaded on the client or the server. For one-sided mods, this means that they must still run on the opposite physical side.

Your mods are expected to always load, regardless of if they are loaded on the client or the server. For one-sided mods, this means that they must still run on the opposite physical side.

So for one-sided mods, you would typically register your event handlers using [[#DistExecutor|<code>DistExecutor</code>]] or ''@EventBusSubscriber(value = Dist.*)'', instead of directly calling the relevant registration methods in the constructor. The idea is that, if your mod is loaded on the wrong side, it should simply do nothing: listen to no events, do no special behaviors, and so on. A one-sided mod by nature should not register blocks, items, … since they would need to be available on the other side, too.

So for one-sided mods, you would typically register your event handlers using [[#DistExecutor|<code>DistExecutor</code>]] or <code>@EventBusSubscriber(value = Dist.*)</code>, instead of directly calling the relevant registration methods in the constructor. The idea is that, if your mod is loaded on the wrong side, it should simply do nothing: listen to no events, do no special behaviors, and so on. A one-sided mod by nature should not register blocks, items, … since they would need to be available on the other side, too.

Additionally, if your mod is one-sided, it typically does not forbid the user from joining a server that is lacking that mod, but the server menu will display the server as being incompatible (with a red <code>X</code> at the side). Therefore, you should override the <code>DISPLAYTEST</code> extension point to make sure that Forge does not think your mod is required on the server: (this is usually done in the mod constructor)

Additionally, if your mod is one-sided, it typically does not forbid the user from joining a server that is lacking that mod, but the server menu will display the server as being incompatible (with a red <code>X</code> at the side). Therefore, you should override the <code>DISPLAYTEST</code> extension point to make sure that Forge does not think your mod is required on the server: (this is usually done in the mod constructor)