KeyBindingInterceptor (for Minecraft Forge mods). The purpose of this class is to intercept key presses (especially left and right mouse button clicks) before they are passed to the vanilla code. This gives the mod code greater flexibility in responding to them. For example- a staff which, when held: (1) left click performs an immediate attack (…

KeyBindingInterceptor.java

package speedytools.client;

/**
 * The purpose of this class is to intercept key presses (especially left and right mouse button clicks) and allow
 *    greater flexibility in responding to them.
 *   The class replaces KeyBindings in GameSettings.  When interception is on:
 *      .isPressed() is overridden to return false so that the vanilla code never receives the clicks.
 *      .pressed is always false.
 *      The true .isPressed() and .pressed are available using .retrieveClick() and .isKeyDown()
 *   Usage:
 *    (1) replace KeyBinding with a newly generated interceptor
 *        eg
 *        KeyBindingInterceptor attackButtonInterceptor(GameSettings.keyBindAttack);
 *        GameSettings.keyBindAttack = attackButtonInterceptor;
 *        This creates an interceptor linked to the existing keyBindAttack.  The original keyBindAttack remains in the
 *          KeyBinding hashmap and keyBindArray.
 *    (2) Set the interception mode (eg true = on)
 *        eg  setInterceptionActive(false);
 *    (3) read the underlying clicks using .retrieveClick() or .isKeyDown();
 *    (4) when Interceptor is no longer required, call .getOriginalKeyBinding();
 *        eg GameSettings.keyBindAttack = attackButtonInterceptor.getOriginalKeyBinding();
 *
 *  NOTES -
 *    (a) the interceptor does not update the .pressed field until .isPressed() is called.  The vanilla Minecraft.runTick
 *        currently always accesses .isPressed() before attempting to read .pressed.
 *    (b) In the current vanilla code, if the bindings are changed it will affect the original keybinding.  The new binding will
 *        be copied to the interceptor at the first call to .retrieveClick(), .isKeyDown(), or .isPressed().
 *    (c) Will not work in GUI
 *  7 Nov 2013: bugfix (.retrieveClick) 
 */   
import cpw.mods.fml.relauncher.Side;
import cpw.mods.fml.relauncher.SideOnly;
import net.minecraft.client.Minecraft;
import net.minecraft.client.settings.KeyBinding;

@SideOnly(Side.CLIENT)
public class KeyBindingInterceptor extends KeyBinding
{
  /**
   *  Create an Interceptor based on an existing binding.
   *  The initial interception mode is OFF.
   *  If existingKeyBinding is already a KeyBindingInterceptor, a reinitialised copy will be created but no further effect.
   * @param existingKeyBinding - the binding that will be intercepted.
   */
  public KeyBindingInterceptor(KeyBinding existingKeyBinding)
  {
    super(existingKeyBinding.keyDescription, existingKeyBinding.keyCode);
    // the base constructor automatically adds the class to the keybindArray and hash, which we don't want, so undo it
    keybindArray.remove(this);

    this.interceptionActive = false;
    this.pressed = false;
    this.pressTime = 0;
    this.interceptedPressTime = 0;

    if (existingKeyBinding instanceof KeyBindingInterceptor) {
      interceptedKeyBinding = ((KeyBindingInterceptor)existingKeyBinding).getOriginalKeyBinding();
    } else {
      interceptedKeyBinding = existingKeyBinding;
    }

    KeyBinding.resetKeyBindingArrayAndHash();
  }

  public void setInterceptionActive(boolean newMode)
  {
    if (newMode && !interceptionActive) {
      this.interceptedPressTime = 0;
    }
    interceptionActive = newMode;
  }

  public boolean isKeyDown()
  {
    copyKeyCodeToOriginal();
    return interceptedKeyBinding.pressed;
  }

  /**
   *
   * @return returns false if interception isn't active.  Otherwise, retrieves one of the clicks (true) or false if no clicks left
   */
  public boolean retrieveClick()
  {
    copyKeyCodeToOriginal();
    if (interceptionActive) {
      copyClickInfoFromOriginal();

      if (this.interceptedPressTime == 0) {
        return false;
      } else {
        --this.interceptedPressTime;
        return true;
      }
    } else {
      return false;
    }
  }

  /** A better name for this method would be retrieveClick.
   * If interception is on, resets .pressed and .pressTime to zero.
   * Otherwise, copies these from the intercepted KeyBinding.
   * @return If interception is on, this will return false; Otherwise, it will pass on any clicks in the intercepted KeyBinding
   */
  @Override
  public boolean isPressed()
  {
    copyKeyCodeToOriginal();
    copyClickInfoFromOriginal();

    if (interceptionActive) {
      this.pressTime = 0;
      this.pressed = false;
      return false;
    } else {
      if (this.pressTime == 0) {
        return false;
      } else {
        --this.pressTime;
        return true;
      }
    }
  }

  public KeyBinding getOriginalKeyBinding() {
    return interceptedKeyBinding;
  }

  protected KeyBinding interceptedKeyBinding;
  private boolean interceptionActive;

  private int interceptedPressTime;

  protected void copyClickInfoFromOriginal()
  {
    this.pressTime += interceptedKeyBinding.pressTime;
    this.interceptedPressTime += interceptedKeyBinding.pressTime;
    interceptedKeyBinding.pressTime = 0;
    this.pressed = interceptedKeyBinding.pressed;
  }

  protected void copyKeyCodeToOriginal()
  {
    // only copy if necessary
    if (this.keyCode != interceptedKeyBinding.keyCode) {
      this.keyCode = interceptedKeyBinding.keyCode;
      resetKeyBindingArrayAndHash();
    }
  }

}