MailCountLimitMod.java

package com.joedobo27.mcl;

import com.joedobo27.libs.bytecode.BytecodeTools;
import javassist.CannotCompileException;
import javassist.CtClass;
import javassist.CtPrimitiveType;
import javassist.NotFoundException;
import javassist.bytecode.*;
import org.gotti.wurmunlimited.modloader.classhooks.HookManager;
import org.gotti.wurmunlimited.modloader.interfaces.Configurable;
import org.gotti.wurmunlimited.modloader.interfaces.Initable;
import org.gotti.wurmunlimited.modloader.interfaces.WurmServerMod;

import java.util.Properties;
import java.util.logging.Logger;


public class MailCountLimitMod implements WurmServerMod, Initable, Configurable {

    private static int maxMailCount = 100;
    static final Logger logger = Logger.getLogger(MailCountLimitMod.class.getName());

    @Override
    public void configure(Properties properties) {
        maxMailCount = Integer.parseInt(properties.getProperty("maxMailCount", Integer.toString(maxMailCount)));
    }

    @Override
    public void init() {
        try {
            String injectCode = "" +
                    "java.util.Set wurmMails1 = com.wurmonline.server.items.WurmMail.getMailsFor(pinf.wurmId);\n" +
                    "com.wurmonline.server.items.WurmMail[] wurmMails2 = new com.wurmonline.server.items.WurmMail[wurmMails1.size()];\n" +
                    "wurmMails1.toArray(wurmMails2);\n" +
                    "int inTransitCount = 0;\n" +
                    "for (int i=0; i<wurmMails2.length; i++) {\n" +
                    "\tcom.wurmonline.server.items.Item item = null;\n" +
                    "\ttry {\n" +
                    "\t\titem = com.wurmonline.server.Items.getItem(wurmMails2[i].itemId);\n" +
                    "\t} catch (com.wurmonline.server.NoSuchItemException ignore) {}\n" +
                    "\tif (item == null)\n" +
                    "\t\treturn;\n" +
                    "\tinTransitCount += item.getAllItems(false).length;\n" +
                    "\tinTransitCount ++;\n" +
                    "}\n" +
                    "if (inTransitCount + this.mailbox.getAllItems(false).length > "+maxMailCount+"){\n" +
                    "\tthis.getResponder().getCommunicator().sendNormalServerMessage(\n" +
                    "\t\t\tname + \" would have \" + java.lang.Integer.toString(inTransitCount + this.mailbox.getAllItems(false).length) +\n" +
                    "\t\t\t\t\t\" items in transit which exceed the max of \" + "+maxMailCount+");\n" +
                    "\treturn;\n" +
                    "}";

            int insertLine = BytecodeTools.getInsertLineAfterMethod("com.wurmonline.server.questions.MailSendQuestion", new String[]{
                    "answer", "(Ljava/util/Properties;)V"}, Opcode.INVOKESTATIC, new String[]{"createPlayerInfo",
                    "(Ljava/lang/String;)Lcom/wurmonline/server/players/PlayerInfo;",
                    "com.wurmonline.server.players.PlayerInfoFactory"});

            HookManager.getInstance().getClassPool().get("com.wurmonline.server.questions.MailSendQuestion")
                    .getMethod("answer", Descriptor.ofMethod(CtPrimitiveType.voidType, new CtClass[]{
                            HookManager.getInstance().getClassPool().get("java.util.Properties")})).insertAt(insertLine, injectCode);
        }catch (BadBytecode | NotFoundException | CannotCompileException e){
            logger.warning(e.getMessage());
        }
    }
}

MailCountLimitMod.properties

# suppress inspection "UnusedProperty"
classname=com.joedobo27.mcl.MailCountLimitMod
# suppress inspection "UnusedProperty"
classpath=MailCountLimitMod.jar,libs/*.jar

maxMailCount=300