Thread: [718] Instant Buy/Sell Grand Exchange at Market Value

Hello, it has been a few years since I've been away from the rsps scene, and I was wondering if anyone had any pointers on how to configure the grand exchange system to auto buy/sell items at market value, below I will post the Grand exchange configs, loader and system. If at all anyone could help I would greatly appreciate it.

Spoiler for Configs:

package com.rs.game.player.content.grandExchange;

public class GrandExchangeConfigurations {

/**
* The interface id of the main interface
*/
protected static final int MAIN_INTERFACE = 105;

/**
* The interface id of the sell interface
*/
protected static final int SELL_INTERFACE = 107;

/**
* The array of the buttons used to send the buying interfaces
*/
public static final int[] BUY_BUTTON_IDS = { 31, 82, 101, 47, 63, 120 };

/**
* The array of the buttons used to initaliaze the selling process
*/
public static final int[] SELL_BUTTON_IDS = { 83, 32, 48, 102, 121, 64 };

public enum Progress {

BUY_ABORTED(5),
SELL_ABORTED(-3),
RESET(0),
BUY_PROGRESSING(4),
FINISHED_BUYING(5),
SELL_PROGRESSING(11),
FINISHED_SELLING(13);

Progress(int value) {
this.value = value;
}

public int getValue() {
return value;
}

private final int value;
}
}

Spoiler for Loader:

package com.rs.game.player.content.grandExchange;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.ArrayList;
import java.util.List;
import java.util.ListIterator;
import java.util.logging.Logger;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.reflect.TypeToken;
import com.rs.game.World;
import com.rs.game.item.Item;
import com.rs.game.player.Player;

public class GrandExchangeLoader {

public static void initialize() {
List<GrandExchangeOffer> offerList = load();
if (offerList == null)
offerList = new ArrayList<GrandExchangeOffer>();
ListIterator<GrandExchangeOffer> it = offerList.listIterator();
while(it.hasNext()) {
GrandExchangeOffer offer = it.next();
if (offer.getPrimaryAmount() == 0
&& offer.getSecondaryAmount() == 0
&& offer.getExtraCash() == 0) {
//System.out.println(offer + " had 0 amount so removed");
it.remove();
}
}
save(offerList);
for (GrandExchangeOffer offer : offerList) {
offers.add(offer);
}
logger.info("Completely loaded " + offers.size() + " grand exchange offers.");
}

public static void addOffer(GrandExchangeOffer offer) {
offers.add(offer);
save(offers);
}

public static void removeOffer(GrandExchangeOffer offer) {
ListIterator<GrandExchangeOffer> it = offers.listIterator();
while(it.hasNext()) {
GrandExchangeOffer o = it.next();
if (o.equals(offer))
it.remove();
}
save(offers);
}

public static void saveOffer(GrandExchangeOffer offer) {
ListIterator<GrandExchangeOffer> it = offers.listIterator();
while(it.hasNext()) {
GrandExchangeOffer o = it.next();
if (o.equals(offer)) {
it.remove();
offers.add(offer);
}
}
save(offers);
}

/**
* Gets the offers by the player
* @param owner The player who you are getting the offers of
* @return A {@code List} {@code Object} with all of the players offers
*/
public static List<GrandExchangeOffer> getOffersForPlayer(String owner) {
List<GrandExchangeOffer> playerOffers = new ArrayList<GrandExchangeOffer>();
ListIterator<GrandExchangeOffer> it = offers.listIterator();
while(it.hasNext()) {
GrandExchangeOffer offer = it.next();
if (offer.getOwner().equals(owner))
playerOffers.add(offer);
}
return playerOffers;
}

/**
* Where the data will save/read from
* @return An {@code String} object of the location
*/
private static String getFileLocation() {
return "data/grandExchange.json";
}

/**
* Populates a list with all of the data in the {@link #getFileLocation()}
*
* @return The list with data
*/
public static List<GrandExchangeOffer> load() {
List<GrandExchangeOffer> autospawns = null;
String json = null;
try {
File file = new File(getFileLocation());
if (!file.exists())
return null;
FileReader reader = new FileReader(file);
char[] chars = new char[(int) file.length()];
reader.read(chars);
json = new String(chars);
reader.close();
} catch (Exception e) {
e.printStackTrace();
}
autospawns = gson.fromJson(json, new TypeToken<List<GrandExchangeOffer>>() {
}.getType());
return autospawns;
}

/**
* Saves the list to the file
*
* @param spawns
* The list to save
*/
public static void save(List<GrandExchangeOffer> spawns) {
try {
FileWriter fw = new FileWriter(getFileLocation());
BufferedWriter bw = new BufferedWriter(fw);
bw.write(gson.toJson(spawns));
bw.close();
} catch (Exception e) {
e.printStackTrace();
}
}

/**
* The list of offers
* @return
*/
public static List<GrandExchangeOffer> getOffers() {
return offers;
}

/**
* The gson instance
*/
private static Gson gson = new GsonBuilder().setPrettyPrinting().create();

private static Logger logger = Logger.getLogger(GrandExchangeLoader.class.getName ());

private static final List<GrandExchangeOffer> offers = new ArrayList<GrandExchangeOffer>();

public static class GrandExchangeOffer {

/**
* The constructor for the grand exchange offer
*
* @param owner
* The owner of the offer
* @param slot
* The slot of the offer
* @param item
* The {@code Item} {@code Object} of the offer
* @param amount
* The amount of the item you wish to exchange
* @param type
* The {@code Type} enum value of the offer
*/
public GrandExchangeOffer(String owner, int slot, Item item, int amount, int price, Type type) {
this.owner = owner;
this.slot = slot;
this.item = item;
this.primaryAmount = amount;
this.setSecondaryAmount(0);
this.setPrice(price);
this.type = type;
}

public String getOwner() {
return owner;
}

public Item getItem() {
return item;
}

/**
* The amount the offer was set to buy/sell for. This value does not change!
* @return
*/
public int getPrimaryAmount() {
return primaryAmount;
}

/**
* The amount of the item that has been bought/sold so far. This value changes when the offer updates
* @return
*/
public int getSecondaryAmount() {
return secondaryAmount;
}

/**
* Sets the amount of the item that has been bought/sold so far.
* @param secondaryAmount The amount to set it to.
*/
public void setSecondaryAmount(int secondaryAmount) {
this.secondaryAmount = secondaryAmount;
}

public Type getType() {
return type;
}

public boolean isFinished() {
return secondaryAmount == getPrimaryAmount();
}

public int getSlot() {
return slot;
}

public int getPrice() {
return price;
}

public void setPrice(int price) {
long price2 = (long) primaryAmount * price;
if (price2 > Integer.MAX_VALUE || price2 == Integer.MAX_VALUE
|| price2 >= Integer.MAX_VALUE || price2 < 0 || price <= 0) {
//System.out.println("Attempted to set a bad price.");
return;
}
this.price = price;
}

public void setPrimaryAmount(int primaryAmount) {
long price = (long) primaryAmount * (long) this.price;
if (price > Integer.MAX_VALUE || price == Integer.MAX_VALUE
|| price >= Integer.MAX_VALUE || price < 0 || price <= 0) {
//System.out.println("Attempted to set a bad amount.");
return;
}
this.primaryAmount = primaryAmount;
}

public void forcePrimaryAmount(int primaryAmount) {
this.primaryAmount = primaryAmount;
}

/**
* The extra cash from the offer, this is incremented if while
* exchanging, either player is overpaying
*
* @return
*/
public int getExtraCash() {
return extraCash;
}

public void setExtraCash(int extraCash) {
this.extraCash = extraCash;
}

@Override
public boolean equals(Object o) {
GrandExchangeOffer o2 = (GrandExchangeOffer) o;
return owner.equals(o2.getOwner()) && item.getId() == o2.getItem().getId() && slot == o2.getSlot() && price == o2.getPrice() && primaryAmount == o2.getPrimaryAmount() && type == o2.getType();
}

public enum Type {
BUY, SELL
}

@Override
public String toString() {
return "[owner=" + owner + ", type=" + type + ", slot=" + slot + ", price=" + price + ", primaryAmount=" + getPrimaryAmount() + ", secondaryAmount=" + secondaryAmount + "]";
}

public void notifyUpdated() {
Player player = World.getPlayerByDisplayName(owner);
if (player != null) {
if (player.getInterfaceManager().containsInterface(10 5) || player.getInterfaceManager().containsTab(105))
GrandExchangeSystem.get().display(player);
player.sendMessage("One or more of your grand exchange offers have been updated!");
}
}

public boolean isAborted() {
if (isFinished())
return false;
return aborted;
}

public void setAborted(boolean aborted) {
this.aborted = aborted;
}


public boolean isProcessing() {
return processing;
}

public void setProcessing(boolean processing) {
this.processing = processing;
}

private final String owner;
private final Item item;
private final int slot;
private int price;
private int primaryAmount;
private int secondaryAmount;
private int extraCash;
private final Type type;
private boolean aborted;
private boolean processing;
}
}

Spoiler for System:

package com.rs.game.player.content.grandExchange;

import com.rs.cache.loaders.ItemDefinitions;
import com.rs.game.item.Item;
import com.rs.game.item.ItemsContainer;
import com.rs.game.player.Player;
import com.rs.game.player.content.Commands;
import com.rs.game.player.content.ItemConstants;
import com.rs.game.player.content.grandExchange.GrandExch angeLoader.GrandExchangeOffer;
import com.rs.game.player.content.grandExchange.GrandExch angeLoader.GrandExchangeOffer.Type;
import com.rs.utils.ItemExamines;
import com.rs.utils.SerializableFilesManager;
import com.rs.utils.Utils;

public class GrandExchangeSystem extends GrandExchangeConfigurations {

/**
* Displays the main screen interface, this contains the default
* configurations, unlocking, aborted information, and progress bar
* information
*
* @param player
* The player to display the information to
*/
public void display(final Player player) {
if (!player.getBank().setLastCount().bln()) {
if (player.getBank().setLastCount().vkg()) {
player.getAttributes().put("entering_pin_to_bank", true);
player.getBank().setLastCount().void5();
return;
}
}
player.stopAll();
player.setCloseInterfacesEvent(new Runnable() {

@Override
public void run() {
closeSearchBar(player);
}
});
sendMainScreenConfigs(player);
player.getInterfaceManager().closeChatBoxInterface ();
player.getInterfaceManager().closeInventoryInterfa ce();
player.getInterfaceManager().sendInterface(MAIN_IN TERFACE);
player.getPackets().sendUnlockIComponentOptionSlot s(MAIN_INTERFACE, 209, -1, -1, 1, 2, 3, 5, 6);
player.getPackets().sendUnlockIComponentOptionSlot s(MAIN_INTERFACE, 211, -1, -1, 1, 2, 3, 5, 6);
for (int i = 0; i < 6; i++) {
player.getPackets().sendGrandExchangeBar(player, i, 0, Progress.RESET, 0, 0, 0);
}
for (GrandExchangeOffer offer : GrandExchangeLoader.getOffersForPlayer(player.getD isplayName())) {
switch(offer.getType()) {
case BUY:
if (!offer.isAborted())
player.getPackets().sendGrandExchangeBar(player, offer.getSlot(), offer.getItem().getId(), offer.isFinished() ? Progress.FINISHED_BUYING : Progress.BUY_PROGRESSING, offer.getPrice(), offer.getSecondaryAmount(), offer.getPrimaryAmount());
else {
player.getPackets().sendGrandExchangeBar(player, offer.getSlot(), offer.getItem().getId(), Progress.BUY_ABORTED, offer.getPrice(), offer.getSecondaryAmount(), offer.getPrimaryAmount());
}
break;
case SELL:
if (!offer.isAborted())
player.getPackets().sendGrandExchangeBar(player, offer.getSlot(), offer.getItem().getId(), offer.isFinished() ? Progress.FINISHED_SELLING : Progress.SELL_PROGRESSING, offer.getPrice(), offer.getSecondaryAmount(), offer.getPrimaryAmount());
else {
player.getPackets().sendGrandExchangeBar(player, offer.getSlot(), offer.getItem().getId(), Progress.SELL_ABORTED, offer.getPrice(), offer.getSecondaryAmount(), offer.getPrimaryAmount());
}
break;
}
}
}

public void closeSearchBar(Player player) {
player.getPackets().closeInterface(7);
player.getInterfaceManager().sendTab(player.getInt erfaceManager().getWindowsPane() == 746 ? 21 : 161, 752);
}

/**
* Handles the clicking of a grand exchange button
*
* @param player
* The player clicking
* @param interfaceId
* The interface being clicked
* @param buttonId
* The id of the button clicked
* @param packetId
* The packet id of the button clicked
* @param slotId
* The slot id clicked
* @param slotId2
* The second slot id, usually item
* @return {@code true} if successful.
*/
@SuppressWarnings("unchecked")
public boolean handleButtonEvent(Player player, int interfaceId, int buttonId, int packetId, int slotId, int slotId2) {
switch(interfaceId) {
case MAIN_INTERFACE:
GrandExchangeOffer offer;
switch(buttonId) {
case 200:
offer = getOfferBySlot(player, (Integer) player.getAttributes().get("grand_exchange_slot_cl icked"));
if (!offer.isAborted()) {
if (offer.isProcessing()) {
//System.out
// .println(player
// + " attempted to abort offer while processing.");
return true;
}
if (offer.isFinished()) {
player.sendMessage("That offer has just been completed! You are too late.");
return true;
}
if (offer.getSecondaryAmount() > 0) {
player.sendMessage("You need to collect items from the offer before aborting it.");
return true;
}
offer.setAborted(true);
display(player);
sendCollectInformation(player, (Integer) player.getAttributes().get("grand_exchange_slot_cl icked"));
}
break;
case 208:
case 206: // collecting
boolean noting = false;
GrandExchangeOffer o = getOfferBySlot(player, (Integer) player.getAttributes().get("grand_exchange_slot_cl icked"));
if (o == null)
return true;
if (o.isAborted()) {
if (packetId == 67)
noting = true;
}
if (o.isProcessing()) {
//System.out.println(player + " attempted to abort offer while processing.");
return true;
}
ItemsContainer<Item> ic = (ItemsContainer<Item>) player.getAttributes().get("grand_exchange_items") ;
Item item = null;
try {
item = buttonId == 206 ? ic.get(0) : ic.get(1);
} catch (Exception e) {
player.getDialogueManager().startDialogue("SimpleM essage", "You have already received that item!");
return true;
}
if (item == null) {
player.sendMessage("You have already received that item.");
return true;
}
if (player.getInventory().getFreeSlots() == 0) {
player.getPackets().sendGameMessage("You don't have enough space in your inventory to collect this item");
return true;
}
if (item.getAmount() > 1 && item.getId() != 995 && packetId == 14)
noting = true;
if (noting && item.getDefinitions().getCertId() != -1)
item.setId(item.getDefinitions().getCertId());
ic.remove(item);
player.getInventory().addItem(item);
player.getPackets().sendItems(523 + o.getSlot(), ic);
if (o.getType() != Type.SELL && item.getId() == 995)
o.setExtraCash(0);
if ((o.isFinished() || o.isAborted()) && ic.getUsedSlots() == 0) {
GrandExchangeLoader.removeOffer(o);
display(player);
} else {
if (o.isAborted()) {

} else {
o.forcePrimaryAmount(o.getPrimaryAmount() - o.getSecondaryAmount());
o.setSecondaryAmount(0);
}
if (ic.getUsedSlots() == 0) { // all of the items have been removed from the container
player.getAttributes().remove("grand_exchange_item s");
}
}
break;
case 19:
case 35:
case 51:
case 108:
case 89:
case 70:
player.getAttributes().put("grand_exchange_slot_cl icked", getSlot(buttonId));
offer = getOfferBySlot(player, getSlot(buttonId));
if (offer.isProcessing()) {
//System.out.println(player + " attempted to abort offer while processing.");
return true;
}
if (packetId == 67) {// abort
if (offer.isFinished()) {
player.sendMessage("That offer has just been completed! You are too late.");
return true;
}
if (offer.getSecondaryAmount() > 0) {
player.sendMessage("You need to collect items from the offer before aborting it.");
return true;
}
offer.setAborted(true);
display(player);
}
sendCollectInformation(player, getSlot(buttonId));
//player.getDialogueManager().startDialogue("GrandEx changeBarter", getSlot(buttonId));
break;
case 31:
case 82:
case 101:
case 47:
case 63:
case 120:
player.getAttributes().put("grand_exchange_slot_cl icked", getSlot(buttonId));
sendBuyScreen(player);
break;
case 83:
case 32:
case 48:
case 102:
case 121:
case 64:
player.getAttributes().put("grand_exchange_slot_cl icked", getSlot(buttonId));
sendSellScreen(player);
break;
case 169:
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
offer.setPrice(offer.getPrice() - 1);
player.getPackets().sendConfig(1111, offer.getPrice());
break;
case 171:
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
offer.setPrice(offer.getPrice() + 1);
player.getPackets().sendConfig(1111, offer.getPrice());
break;
case 179: // +5%
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
offer.setPrice((int) (offer.getPrice() + (offer.getPrice() * 0.05)));
player.getPackets().sendConfig(1111, offer.getPrice());
break;
case 181: // -5%
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
offer.setPrice((int) (offer.getPrice() - (offer.getPrice() * 0.05)));
player.getPackets().sendConfig(1111, offer.getPrice());
break;
case 168: // custom amount
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
player.getPackets().sendRunScript(108, new Object[] { "Enter Amount:" });
player.getAttributes().put("setting_geoffer_amount ", true);
break;
case 177: // custom price
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
player.getPackets().sendRunScript(108, new Object[] { "Enter Price:" });
player.getAttributes().put("setting_geoffer_price" , true);
break;
case 175: //guide price
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
offer.setPrice(ItemDefinitions.getItemDefinitions( offer.getItem().getId()).getValue());
player.getPackets().sendConfig(1111, offer.getPrice());
break;
case 155:
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
if (offer.getPrimaryAmount() - 1 > Integer.MAX_VALUE) {
player.sendMessage("You cannot buy that many...");
return true;
}
offer.setPrimaryAmount(offer.getPrimaryAmount() - 1);
player.getPackets().sendConfig(1110, offer.getPrimaryAmount());
break;
case 157:
case 160:
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
if (offer.getPrimaryAmount() + 1 > Integer.MAX_VALUE) {
player.sendMessage("You cannot buy that many...");
return true;
}
offer.setPrimaryAmount(offer.getPrimaryAmount() + 1);
player.getPackets().sendConfig(1110, offer.getPrimaryAmount());
break;
case 162:
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
if (offer.getPrimaryAmount() + 10 > Integer.MAX_VALUE) {
player.sendMessage("You cannot buy that many...");
return true;
}
offer.setPrimaryAmount(offer.getPrimaryAmount() + 10);
player.getPackets().sendConfig(1110, offer.getPrimaryAmount());
break;
case 164:
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
if (offer.getPrimaryAmount() + 100 > Integer.MAX_VALUE) {
player.sendMessage("You cannot buy that many...");
return true;
}
offer.setPrimaryAmount(offer.getPrimaryAmount() + 100);
player.getPackets().sendConfig(1110, offer.getPrimaryAmount());
break;
case 166:
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
switch(offer.getType()) {
case BUY:
if (offer.getPrimaryAmount() + 1000 > Integer.MAX_VALUE) {
player.sendMessage("You cannot buy that many...");
return true;
}
offer.setPrimaryAmount(offer.getPrimaryAmount() + 1000);
player.getPackets().sendConfig(1110, offer.getPrimaryAmount());
break;
case SELL:
int amount = 0;
if (!player.getInventory().contains(offer.getItem().g etId())) { // means the item is noted
amount = player.getInventory().getNumerOf(offer.getItem().g etDefinitions().getCertId());
} else {
amount = player.getInventory().getNumerOf(offer.getItem().g etId());
}
offer.setPrimaryAmount(amount);
player.getPackets().sendConfig(1110, amount);
break;
}
break;
case 128: // back
resetInterfaceConfigs(player);
display(player);
player.getInterfaceManager().closeInventory();
player.getInterfaceManager().sendInventory();
final int lastGameTab = player.getInterfaceManager().openGameTab(4); // inventory
final Player player2 = player;
player.setCloseInterfacesEvent(new Runnable() {
@Override
public void run() {
player2.getInterfaceManager().sendInventory();
player2.getInventory().unlockInventoryOptions();
player2.getInterfaceManager().sendEquipment();
player2.getInterfaceManager().openGameTab(lastGame Tab);
}
});
break;
case 186: // confirm
offer = (GrandExchangeOffer) player.getAttributes().get("grand_exchange_offer") ;
if (offer == null)
return true;
int price = offer.getPrimaryAmount() * offer.getPrice();
if (price > Integer.MAX_VALUE ||
price == Integer.MAX_VALUE ||
price >= Integer.MAX_VALUE ||
price < 0 || price <= 0
|| offer.getPrimaryAmount() == 0
|| offer.getPrice() == 0) {
player.getPackets().sendGameMessage("Invalid input.");
return true;
}
switch(offer.getType()) {
case BUY:
if (player.takeMoney(price)) {
player.getAttributes().remove("grand_exchange_offe r");
SerializableFilesManager.savePlayer(player);
/**
* Adds the offer to the system so it can be processed
*/
GrandExchangeLoader.addOffer(offer);
/**
* Displays the main offer screen
*/
display(player);
} else
player.sendMessage("You do not have " + Utils.format(price) + " coins to make this exchange.");
break;
case SELL:
int id = player.getInventory().getNumerOf(offer.getItem().g etId()) == offer.getPrimaryAmount() ? offer.getItem().getId() : offer.getItem().getDefinitions().getCertId();
int amt = offer.getPrimaryAmount();
if (offer.getPrimaryAmount() > player.getInventory().getNumerOf(id)) {
player.sendMessage("You do not have " + Utils.format(offer.getPrimaryAmount()) + " of this item to sell.");;
return true;
}
player.getInventory().deleteItem(id, amt);
player.getAttributes().remove("grand_exchange_offe r");
SerializableFilesManager.savePlayer(player);
/**
* Adds the offer to the system so it can be processed
*/
GrandExchangeLoader.addOffer(offer);
/**
* Displays the main offer screen
*/
display(player);
break;
}
break;
case 190: //choose item button
sendSearchScript(player);
break;
default:
//System.out.println("Unhandled button event: [interfaceId=" + interfaceId + ", buttonId=" + buttonId + ", packetId=" + packetId + "]");
break;
}
return true;
case SELL_INTERFACE:
Item item = new Item(slotId2);
if (!ItemConstants.isTradeable(item) || item.getId() == 995) {
player.sendMessage("You can't sell such an item.");
return true;
}
if (item.getDefinitions().isNoted()) {
item.setId(item.getDefinitions().getCertId());
}
offer = new GrandExchangeOffer(player.getDisplayName(), (int) player.getAttributes().get("grand_exchange_slot_cl icked"), item, getAmountOfItem(player, item), ItemDefinitions.getItemDefinitions(item.getId()).g etValue(), Type.SELL);
player.getPackets().sendConfig(1109, offer.getItem().getId());
player.getPackets().sendConfig(1110, offer.getPrimaryAmount());
player.getPackets().sendConfig(1111, offer.getPrice());
player.getPackets().sendConfig(1114, offer.getPrice());
player.getPackets().sendIComponentText(105, 143, ItemExamines.getExamine(item));
player.getAttributes().put("grand_exchange_offer", offer);
return true;
}
return false;
}

/**
* Gets the amount of an item that the player has, checks for noting in inventory as well
* @param player The player who is offering the item
* @param offer The offer that is being checked
* @return A {@code Integer} {@code Object}
*/
private int getAmountOfItem(Player player, Item offer) {
int amount = 0;
int id = offer.getId();
if (offer.getDefinitions().isStackable()) {
amount = player.getInventory().getNumerOf(id);
} else {
for (Item item : player.getInventory().getItems().toArray()) {
if (item == null)
continue;
if (item.getId() == id)
amount++;
}
}
return amount;
}

/**
* Gets the offer on a slot for the player
* @param player The player to check for
* @param slot The slot to check in
* @return
*/
private GrandExchangeOffer getOfferBySlot(Player player, int slot) {
for (GrandExchangeOffer offer : GrandExchangeLoader.getOffersForPlayer(player.getD isplayName())) {
if (offer.getSlot() == slot)
return offer;
}
return null;
}

/**
* Sends the collection interface with two slots, also checks if the offer
* has been aborted. Items are sent in a {@code ItemsContainer}
* {@code Object} which is temporarily placed in the player's attributes as
* "grand_exchange_items"
*
* @param player
* The player to send it to
* @param slotId
* The button clicked
*/
private void sendCollectInformation(Player player, int slotId) {
player.getPackets().sendConfig(1112, slotId);
player.getPackets().sendIComponentSettings(105, 206, -1, -1, 6);
player.getPackets().sendIComponentSettings(105, 208, -1, -1, 6);
GrandExchangeOffer offer = getOfferBySlot(player, slotId);
if (offer == null)
return;
ItemsContainer<Item> ic = new ItemsContainer<Item>(2, true);
if (!offer.isAborted()) {
if (offer.getSecondaryAmount() > 0)
switch(offer.getType()) {
case BUY:
ic.add(new Item(offer.getItem().getId(), offer.getSecondaryAmount()));
break;
case SELL:
ic.add(new Item(995, offer.getSecondaryAmount() * offer.getPrice()));
break;
}
} else {
switch(offer.getType()) {
case BUY:
ic.add(new Item(995, offer.getPrimaryAmount() * offer.getPrice()));
break;
case SELL:
ic.add(new Item(offer.getItem().getId(), offer.getPrimaryAmount()));
break;
}
}
if (offer.getExtraCash() >= 1) {
ic.add(new Item(995, offer.getExtraCash()));
}
player.getAttributes().put("grand_exchange_items", ic);
player.getPackets().sendConfig(1113, offer.getType().ordinal());
player.getPackets().sendItems(523 + slotId, ic);
}

/**
* Sends the main screen configs and sets them to their default value
* @param player The player to send it to
*/
private void sendMainScreenConfigs(Player player) {
player.getPackets().sendConfig(1112, -1);
player.getPackets().sendConfig(1113, -1);
player.getPackets().sendConfig(1109, -1);
player.getPackets().sendConfig(1110, 0);
player.getPackets().sendConfig(563, 4194304);
player.getPackets().sendConfig(1112, -1);
player.getPackets().sendConfig(1113, -1);
player.getPackets().sendConfig(1114, 0);
player.getPackets().sendConfig(1109, -1);
player.getPackets().sendConfig(1110, 0);
player.getPackets().sendConfig(1111, 1);
closeSearchBar(player);
}

/**
* Finds the slot of the button you are clicking
* @param buttonId The button you are clicking
* @return
*/
private int getSlot(int buttonId) {
switch (buttonId) {
case 31:
case 32:
case 19:
return 0;
case 47:
case 35:
case 48:
return 1;
case 63:
case 51:
case 64:
return 2;
case 82:
case 83:
case 70:
return 3;
case 101:
case 102:
case 89:
return 4;
case 120:
case 108:
case 121:
return 5;
default:
return -1;
}
}

/**
* Sends the sell interfaces to the player
* @param player The player to send it to
*/
private void sendSellScreen(Player player) {
int total = 0;
int reqTotal = 1;
for (int i = 0; i < 25; i++) {
total += player.getSkills().getLevel(i);
}
if (!player.isOwner() && total < reqTotal) {
player.sendMessage("No req neededany more.");
return;
}
if (Commands.isAllowedToSpawn(player)) {
player.getPackets().sendGameMessage("trying to sell.");
return;
}
resetInterfaceConfigs(player);
player.getPackets().sendConfig(1113, 1);
player.getInterfaceManager().sendInventoryInterfac e(107);
final Object[] params = new Object[]{ "", "", "", "", "Offer", -1, 0, 7, 4, 93, 7012370 };
player.getPackets().sendRunScript(149, params);
player.getPackets().sendItems(93, player.getInventory().getItems());
player.getPackets().sendHideIComponent(107, 0, false);
player.getPackets().sendIComponentSettings(107, 18, 0, 27, 1026);
player.getPackets().sendConfig(1112, (Integer) player.getAttributes().get("grand_exchange_slot_cl icked"));
player.getPackets().sendHideIComponent(105, 196, true);
}

/**
* Displays the buy screen to the player
* @param player The player to display it to.
*/
public void sendBuyScreen(Player player) {
if (Commands.isAllowedToSpawn(player)) {
player.getPackets().sendGameMessage("trying to buy.");
return;
}
resetInterfaceConfigs(player);
sendSearchScript(player);
}

/**
* Resets interface configurations to prepare for displaying the buy screen
* @param player The player to reset it for
*/
private void resetInterfaceConfigs(Player player) {
player.getPackets().sendConfig2(1109, -1);
player.getPackets().sendConfig2(1110, 0);
player.getPackets().sendConfig2(1111, 1);
player.getPackets().sendConfig2(1112, -1);
player.getPackets().sendConfig2(1113, 0);
}

/**
* Sends the search script at the bottom of the client box.
*/
private void sendSearchScript(Player player) {
player.getPackets().sendConfig1(744, 0);
player.getPackets().sendConfig(1112, (Integer) player.getAttributes().get("grand_exchange_slot_cl icked"));
player.getPackets().sendConfig(1113, 0);
player.getPackets().sendInterface(true, 752, 7, 389);
player.getPackets().sendRunScript(570, new Object[] { "Grand Exchange Item Search" });
}

public static GrandExchangeSystem get() {
return INSTANCE;
}

private static final GrandExchangeSystem INSTANCE = new GrandExchangeSystem();

}

At the moment you sell your item(s) and you wait for someone to buy them, or you put in a buy request and wait for someone to sell that item, however this is not viable due to the fact you would need a ton of players for this to get much use, and I was wanting to use it for a quick and easy method for players to be able to buy the items they need or sell the items they don't. Instead of several shops scattered around home, just a few grand exchange npc's and the rest is history.

Fixed thanks to @Andreas!