Initial commit for DataLock

.gitignore

@@ -0,0 +1,121 @@
+# User-specific stuff
+.idea/
+
+*.iml
+*.ipr
+*.iws
+
+# IntelliJ
+out/
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Package Files #
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+*~
+
+# temporary files which can be created if a process still has a handle open of a deleted file
+.fuse_hidden*
+
+# KDE directory preferences
+.directory
+
+# Linux trash folder which might appear on any partition or disk
+.Trash-*
+
+# .nfs files are created when an open file is removed but is still being accessed
+.nfs*
+
+# General
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# Icon must end with two \r
+Icon
+
+# Thumbnails
+._*
+
+# Files that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+.com.apple.timemachine.donotpresent
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+# Windows thumbnail cache files
+Thumbs.db
+Thumbs.db:encryptable
+ehthumbs.db
+ehthumbs_vista.db
+
+# Dump file
+*.stackdump
+
+# Folder config file
+[Dd]esktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Windows Installer files
+*.cab
+*.msi
+*.msix
+*.msm
+*.msp
+
+# Windows shortcuts
+*.lnk
+
+.gradle
+build/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Cache of project
+.gradletasknamecache
+
+**/build/
+
+# Common working directory
+run/
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# My stuff
+gradle/

build.gradle

@@ -0,0 +1,55 @@
+plugins {
+    id 'java'
+    id 'eclipse'
+    id "org.jetbrains.gradle.plugin.idea-ext" version "1.0.1"
+}
+
+group = 'com.alttd'
+version = '1.0-SNAPSHOT'
+
+repositories {
+    mavenCentral()
+    maven {
+        name = 'velocitypowered-repo'
+        url = 'https://nexus.velocitypowered.com/repository/maven-public/'
+    }
+}
+
+dependencies {
+    compileOnly 'com.velocitypowered:velocity-api:3.1.0'
+    annotationProcessor 'com.velocitypowered:velocity-api:3.1.0'
+}
+
+def targetJavaVersion = 11
+java {
+    def javaVersion = JavaVersion.toVersion(targetJavaVersion)
+    sourceCompatibility = javaVersion
+    targetCompatibility = javaVersion
+    if (JavaVersion.current() < javaVersion) {
+        toolchain.languageVersion = JavaLanguageVersion.of(targetJavaVersion)
+    }
+}
+
+tasks.withType(JavaCompile).configureEach {
+    if (targetJavaVersion >= 10 || JavaVersion.current().isJava10Compatible()) {
+        options.release = targetJavaVersion
+    }
+}
+
+def templateSource = file('src/main/templates')
+def templateDest = layout.buildDirectory.dir('generated/sources/templates')
+def generateTemplates = tasks.register('generateTemplates', Copy) { task ->
+    def props = [
+            'version': project.version
+    ]
+    task.inputs.properties props
+
+    task.from templateSource
+    task.into templateDest
+    task.expand props
+}
+
+sourceSets.main.java.srcDir(generateTemplates.map { it.outputs })
+
+rootProject.idea.project.settings.taskTriggers.afterSync generateTemplates
+project.eclipse.synchronizationTasks(generateTemplates)

gradlew

@@ -0,0 +1,234 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'DataLock'

src/main/java/com/alttd/datalock/DataLock.java

@@ -0,0 +1,47 @@
+package com.alttd.datalock;
+
+import com.google.inject.Inject;
+import com.velocitypowered.api.event.proxy.ProxyInitializeEvent;
+import com.velocitypowered.api.event.Subscribe;
+import com.velocitypowered.api.plugin.Plugin;
+import com.velocitypowered.api.plugin.annotation.DataDirectory;
+import com.velocitypowered.api.proxy.ProxyServer;
+import org.slf4j.Logger;
+
+import java.nio.file.Path;
+
+@Plugin(
+        id = "data-lock",
+        name = "DataLock",
+        version = BuildConstants.VERSION,
+        description = "A proxy plugin that can be utilized to prevent any plugins from editing data that is currently in use elsewhere",
+        url = "https://alttd.com",
+        authors = {"Teriuihi"}
+)
+public class DataLock {
+
+    private static DataLock instance;
+    private final ProxyServer server;
+    private final Logger logger;
+    private final Path dataDirectory;
+
+    @Inject
+    public DataLock(ProxyServer proxyServer, Logger proxyLogger, @DataDirectory Path proxydataDirectory) {
+        instance = this;
+        server = proxyServer;
+        logger = proxyLogger;
+        dataDirectory = proxydataDirectory;
+    }
+
+    @Subscribe
+    public void onProxyInitialization(ProxyInitializeEvent event) {
+    }
+
+    public static DataLock getInstance() {
+        return instance;
+    }
+
+    public static Logger getLogger() {
+        return getInstance().logger;
+    }
+}

src/main/java/com/alttd/datalock/EventListener.java

@@ -0,0 +1,144 @@
+package com.alttd.datalock;
+
+import com.google.common.io.ByteArrayDataInput;
+import com.google.common.io.ByteArrayDataOutput;
+import com.google.common.io.ByteStreams;
+import com.velocitypowered.api.event.Subscribe;
+import com.velocitypowered.api.event.connection.PluginMessageEvent;
+import com.velocitypowered.api.proxy.Player;
+import com.velocitypowered.api.proxy.ServerConnection;
+import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
+
+import java.util.*;
+
+public class EventListener {
+
+    private final HashMap<ChannelIdentifier, HashSet<Lock>> channelLockMap = new HashMap<>();
+    private final static List<ChannelIdentifier> channelIdentifierList = new ArrayList<>();
+
+    public EventListener(List<ChannelIdentifier> channelIdentifierList)
+    {
+        EventListener.reload(channelIdentifierList);
+    }
+
+    public static void reload(List<ChannelIdentifier> channelIdentifierList)
+    {
+        EventListener.channelIdentifierList.clear();
+        EventListener.channelIdentifierList.addAll(channelIdentifierList);
+    }
+
+    @Subscribe
+    public void onPluginMessageEvent(PluginMessageEvent event) {
+        ChannelIdentifier identifier = event.getIdentifier();
+        if (!EventListener.channelIdentifierList.contains(identifier))
+            return;
+
+        event.setResult(PluginMessageEvent.ForwardResult.handled());
+
+        if(event.getSource() instanceof Player) {
+            Logger.warn("Received plugin message from a player");
+            return;
+        }
+
+        if (!(event.getSource() instanceof ServerConnection serverConnection)) {
+            Logger.warn("Received plugin message from something other than a server.");
+            return;
+        }
+
+        HashSet<Lock> hashLock = channelLockMap.getOrDefault(identifier, new HashSet<>());
+        ByteArrayDataInput in = ByteStreams.newDataInput(event.getData());
+        String channel;
+        try {
+            channel = in.readUTF();
+        } catch (IllegalStateException e) {
+            Logger.error("Input stream did not contain enough data, please contact %'s developer.",
+                    identifier.getId());
+            return;
+        }
+        String data;
+        try {
+            data = in.readUTF();
+        } catch (IllegalStateException e) {
+            Logger.error("Input stream did not contain enough data, please contact %'s developer.",
+                    identifier.getId());
+            return;
+        }
+
+        switch (channel.toLowerCase()) {
+            case "try-lock" -> tryLock(identifier, hashLock, data, serverConnection);
+            case "check-lock" -> checkLock(identifier, hashLock, data, serverConnection);
+            case "try-unlock" -> tryUnlock(identifier, hashLock, data, serverConnection);
+        }
+    }
+
+    private void tryLock(ChannelIdentifier identifier, HashSet<Lock> lockSet, String data, ServerConnection serverConnection) {
+        ByteArrayDataOutput out = ByteStreams.newDataOutput();
+        out.writeUTF("try-lock-result");
+
+        Lock lock = new Lock(serverConnection.getServerInfo().hashCode(), data);
+        if (lockSet.contains(lock)) //An entry from this server already exists, so we can say that it's locked
+        {
+            out.writeBoolean(true);
+            serverConnection.sendPluginMessage(identifier, out.toByteArray());
+            return;
+        }
+
+        Optional<Lock> first = lockSet.stream().filter(a -> a.compareTo(lock) == 0).findFirst();
+        if (first.isPresent()) //An entry from another server exists, so we can't lock it
+        {
+            out.writeBoolean(false);
+            serverConnection.sendPluginMessage(identifier, out.toByteArray());
+            return;
+        }
+
+        //Lock the data
+        lockSet.add(lock);
+        channelLockMap.put(identifier, lockSet);
+
+        out.writeBoolean(true);
+        serverConnection.sendPluginMessage(identifier, out.toByteArray());
+    }
+
+    private void checkLock(ChannelIdentifier identifier, HashSet<Lock> lockSet, String data, ServerConnection serverConnection) {
+        ByteArrayDataOutput out = ByteStreams.newDataOutput();
+        Lock lock = new Lock(serverConnection.hashCode(), data);
+
+        out.writeUTF("check-lock-result");
+        if (lockSet.contains(lock)) //We locked this, but we still return true since it's locked
+            out.writeBoolean(true);
+        else if (lockSet.stream().anyMatch(a -> a.compareTo(lock) == 0))
+            out.writeBoolean(true); //There is a lock (not ours, but it's still locked)
+        else
+            out.writeBoolean(false); //The data is not locked
+
+        serverConnection.sendPluginMessage(identifier, out.toByteArray());
+    }
+
+    private void tryUnlock(ChannelIdentifier identifier, HashSet<Lock> lockSet, String data, ServerConnection serverConnection) {
+        ByteArrayDataOutput out = ByteStreams.newDataOutput();
+        out.writeUTF("try-unlock-result");
+
+        Lock lock = new Lock(serverConnection.getServerInfo().hashCode(), data);
+        if (lockSet.contains(lock)) //Lock is in the list, but it's made by this server, so we can unlock it
+        {
+            out.writeBoolean(true);
+            lockSet.remove(lock);
+            channelLockMap.put(identifier, lockSet);
+            serverConnection.sendPluginMessage(identifier, out.toByteArray());
+            return;
+        }
+
+        Optional<Lock> first = lockSet.stream().filter(a -> a.compareTo(lock) == 0).findFirst();
+        if (first.isEmpty()) //There is no entry with this data, so we can say it's unlocked
+        {
+            out.writeBoolean(true);
+            serverConnection.sendPluginMessage(identifier, out.toByteArray());
+            return;
+        }
+
+        //There is an entry with this data, but it's not owned by this server, so we can't unlock it
+        out.writeBoolean(false);
+        serverConnection.sendPluginMessage(identifier, out.toByteArray());
+    }
+
+}

src/main/java/com/alttd/datalock/Lock.java

@@ -0,0 +1,40 @@
+package com.alttd.datalock;
+
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Objects;
+
+public class Lock implements Comparable {
+
+    private final int serverHash;
+    private final String data;
+
+    public Lock(int serverHash, String data) {
+        this.serverHash = serverHash;
+        this.data = data;
+    }
+
+    @Override
+    public final boolean equals(@Nullable Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        Lock other = (Lock) o;
+        return data.equals(other.data) && serverHash == other.serverHash;
+    }
+
+    @Override
+    public final int hashCode() {
+        return Objects.hash(serverHash, data);
+    }
+
+
+    @Override
+    public int compareTo(@NotNull Object o) {
+        return ((Lock) o).data.compareTo(data);
+    }
+}

src/main/java/com/alttd/datalock/Logger.java

@@ -0,0 +1,34 @@
+package com.alttd.datalock;
+
+public class Logger {
+
+    static private final org.slf4j.Logger logger;
+
+    static {
+        logger = DataLock.getLogger();
+    }
+
+    public static void info(String info, String... variables)
+    {
+        for (String variable : variables) {
+            info = info.replaceFirst("%", variable);
+        }
+        logger.info(info);
+    }
+
+    public static void warn(String warning, String... variables)
+    {
+        for (String variable : variables) {
+            warning = warning.replaceFirst("%", variable);
+        }
+        logger.warn(warning);
+    }
+
+    public static void error(String severe, String... variables)
+    {
+        for (String variable : variables) {
+            severe = severe.replaceFirst("%", variable);
+        }
+        logger.error(severe);
+    }
+}

src/main/templates/com/alttd/datalock/BuildConstants.java

@@ -0,0 +1,7 @@
+package com.alttd.datalock;
+
+// The constants are replaced before compilation
+public class BuildConstants {
+
+    public static final String VERSION = "${version}";
+}