feat: add project files

.gitattributes

@@ -0,0 +1,11 @@
+#region Gradle
+/gradlew        text eol=lf
+#endregion 
+
+#region Java
+*.jar           binary
+#endregion 
+
+#region Windows
+*.bat           text eol=crlf
+#endregion 

.gitignore

@@ -0,0 +1,17 @@
+#region Visual Studio Code
+.vscode/
+*.code-workspace
+#endregion
+
+#region Java
+bin/
+build/
+run/
+#endregion
+
+#region Gradle
+.gradle/
+
+!gradle-wrapper.jar
+!gradle-wrapper.properties
+#endregion

gradle.properties

@@ -0,0 +1,6 @@
+group=org.axolotsh
+version=1.0-SNAPSHOT
+
+org.gradle.configuration-cache=true
+org.gradle.parallel=true
+org.gradle.caching=true

gradle/libs.versions.toml

@@ -0,0 +1,12 @@
+# This file was generated by the Gradle 'init' task.
+# https://docs.gradle.org/current/userguide/version_catalogs.html#sec::toml-dependencies-format
+
+[versions]
+commons-math3 = "3.6.1"
+guava = "33.5.0-jre"
+junit-jupiter = "6.0.1"
+
+[libraries]
+commons-math3 = { module = "org.apache.commons:commons-math3", version.ref = "commons-math3" }
+guava = { module = "com.google.guava:guava", version.ref = "guava" }
+junit-jupiter = { module = "org.junit.jupiter:junit-jupiter", version.ref = "junit-jupiter" }

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,9 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.5.1-bin.zip
+networkTimeout=10000
+retries=0
+retryBackOffMs=500
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,248 @@
+#!/bin/sh
+
+#
+# Copyright © 2015 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.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   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/<unknown>/platforms/jvm/plugins-application/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
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
+
+# 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 "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$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: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$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 "$APP_HOME" )
+
+    JAVACMD=$( 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
+
+
+# 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"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$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 +1,82 @@
+@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
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables, and ensure extensions are enabled
+setlocal EnableExtensions
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+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% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+"%COMSPEC%" /c exit 1
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+"%COMSPEC%" /c exit 1
+
+:execute
+@rem Setup the command line
+
+
+
+@rem Execute Gradle
+@rem endlocal doesn't take effect until after the line is parsed and variables are expanded
+@rem which allows us to clear the local environment before executing the java command
+endlocal & "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %* & call :exitWithErrorLevel
+
+:exitWithErrorLevel
+@rem Use "%COMSPEC%" /c exit to allow operators to work properly in scripts
+"%COMSPEC%" /c exit %ERRORLEVEL%

localizationlib-abstraction/build.gradle.kts

@@ -0,0 +1,38 @@
+plugins {
+    id("java-library")
+    id("maven-publish")
+}
+
+group = providers.gradleProperty("group").get()
+version = providers.gradleProperty("version").get()
+
+java {
+    toolchain.languageVersion = JavaLanguageVersion.of(25)
+}
+
+publishing {
+    publications {
+        create<MavenPublication>("mavenJava") {
+            from(components["java"])
+
+            groupId = project.group.toString()
+            artifactId = project.name
+            version = project.version.toString()
+        }
+    }
+
+    repositories {
+        maven {
+            name = "Reposilite"
+            
+            val releasesUrl = "https://maven.axolotsh.org/releases"
+            val snapshotsUrl = "https://maven.axolotsh.org/snapshots"
+            url = uri(if (version.toString().endsWith("SNAPSHOT")) snapshotsUrl else releasesUrl)
+
+            credentials {
+                username = providers.gradleProperty("reposiliteUser").orNull ?: "admin"
+                password = providers.gradleProperty("reposilitePassword").orNull ?: "password"
+            }
+        }
+    }
+}

localizationlib-abstraction/src/main/java/org/axolotsh/localizationlib/abstraction/ILocalizationEntry.java

@@ -0,0 +1,11 @@
+package org.axolotsh.localizationlib.abstraction;
+
+import java.util.Locale;
+
+public interface ILocalizationEntry {
+    public Locale locale();
+
+    public String key();
+
+    public String value();
+}

localizationlib-abstraction/src/main/java/org/axolotsh/localizationlib/abstraction/ILocalizationFactory.java

@@ -0,0 +1,9 @@
+package org.axolotsh.localizationlib.abstraction;
+
+import java.util.Locale;
+
+public interface ILocalizationFactory {
+    public ILocalizationService service();
+
+    public ILocalizationService service(Locale locale);
+}

localizationlib-abstraction/src/main/java/org/axolotsh/localizationlib/abstraction/ILocalizationService.java

@@ -0,0 +1,14 @@
+package org.axolotsh.localizationlib.abstraction;
+
+import java.util.Locale;
+import java.util.Optional;
+
+public interface ILocalizationService {
+    public Optional<String> get(String key);
+
+    public Optional<String> get(String key, Locale locale);
+
+    public String translate(String key);
+
+    public String translate(String key, Locale locale);
+}

localizationlib/build.gradle.kts

@@ -0,0 +1,72 @@
+plugins {
+    id("java-library")
+    id("maven-publish")
+    id("com.gradleup.shadow") version "9.4.1"
+}
+
+group = providers.gradleProperty("group").get()
+version = providers.gradleProperty("version").get()
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    compileOnly("org.projectlombok:lombok:1.18.46")
+    annotationProcessor("org.projectlombok:lombok:1.18.46")
+
+    implementation("org.jetbrains:annotations:26.1.0")
+    implementation("com.google.code.gson:gson:2.14.0")
+
+    implementation(project(":localizationlib-abstraction"))
+    shadow(project(":localizationlib-abstraction"))
+
+    testImplementation(libs.junit.jupiter)
+    testRuntimeOnly("org.junit.platform:junit-platform-launcher")
+}
+
+java {
+    toolchain.languageVersion = JavaLanguageVersion.of(25)
+}
+
+tasks {
+    build {
+        dependsOn(shadowJar)
+    }
+
+    shadowJar {
+        archiveClassifier.set("")
+        configurations = listOf(project.configurations.shadow.get())
+    }
+
+    named<Test>("test") {
+        useJUnitPlatform()
+    }
+}
+
+publishing {
+    publications {
+        create<MavenPublication>("mavenJava") {
+            from(components["shadow"])
+
+            groupId = project.group.toString()
+            artifactId = project.name
+            version = project.version.toString()
+        }
+    }
+
+    repositories {
+        maven {
+            name = "Reposilite"
+            
+            val releasesUrl = "https://maven.axolotsh.org/releases"
+            val snapshotsUrl = "https://maven.axolotsh.org/snapshots"
+            url = uri(if (version.toString().endsWith("SNAPSHOT")) snapshotsUrl else releasesUrl)
+
+            credentials {
+                username = providers.gradleProperty("reposiliteUser").orNull ?: "admin"
+                password = providers.gradleProperty("reposilitePassword").orNull ?: "password"
+            }
+        }
+    }
+}

localizationlib/src/main/java/org/axolotsh/localizationlib/LocalizationEntry.java

@@ -0,0 +1,32 @@
+package org.axolotsh.localizationlib;
+
+import java.util.Locale;
+
+import org.axolotsh.localizationlib.abstraction.ILocalizationEntry;
+import org.jetbrains.annotations.Nullable;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.NonNull;
+import lombok.experimental.Accessors;
+
+@Getter
+@EqualsAndHashCode
+@Accessors(chain = true, fluent = true)
+@Builder(toBuilder = true)
+@AllArgsConstructor
+public class LocalizationEntry implements ILocalizationEntry {
+    @Nullable
+    private Locale locale;
+
+    @NonNull
+    private String key;
+    @NonNull
+    private String value;
+
+    public LocalizationEntry(String key, String value) {
+        this(null, key, value);
+    }
+}

localizationlib/src/main/java/org/axolotsh/localizationlib/LocalizationFactory.java

@@ -0,0 +1,83 @@
+package org.axolotsh.localizationlib;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Set;
+
+import org.axolotsh.localizationlib.abstraction.ILocalizationEntry;
+import org.axolotsh.localizationlib.abstraction.ILocalizationFactory;
+import org.axolotsh.localizationlib.abstraction.ILocalizationService;
+import org.axolotsh.localizationlib.providers.CollectionProvider;
+import org.axolotsh.localizationlib.providers.ILocalizationEntriesProvider;
+
+import lombok.AccessLevel;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.experimental.Accessors;
+
+@Getter
+@Accessors(chain = true, fluent = true)
+public class LocalizationFactory implements ILocalizationFactory {
+    public static final Locale DEFAULT_LOCALE = Locale.US;
+
+    @Getter(AccessLevel.NONE)
+    private Collection<ILocalizationEntriesProvider> providers;
+
+    private volatile Map<Locale, Map<String, String>> storage = Collections.emptyMap();
+    private Locale defaultLocale = DEFAULT_LOCALE;
+
+    @Builder(toBuilder = true)
+    public LocalizationFactory(Collection<ILocalizationEntriesProvider> providers, Locale defaultLocale) {
+        this.providers = providers != null ? Set.copyOf(providers) : Collections.emptySet();
+
+        if (defaultLocale != null)
+            this.defaultLocale = defaultLocale;
+    }
+
+    public static class LocalizationFactoryBuilder {
+        public LocalizationFactoryBuilder provider(ILocalizationEntry... entries) {
+            return provider(new CollectionProvider(entries));
+        }
+
+        public LocalizationFactoryBuilder provider(ILocalizationEntriesProvider provider) {
+            if (providers == null)
+                providers = new HashSet<>();
+            this.providers.add(provider);
+            return this;
+        }
+    }
+
+    public synchronized LocalizationFactory reloadProviders() {
+        Map<Locale, Map<String, String>> newStorage = new HashMap<>();
+
+        for (ILocalizationEntriesProvider provider : providers) {
+            for (ILocalizationEntry entry : provider.provide()) {
+                var locale = entry.locale() != null ? entry.locale() : defaultLocale;
+
+                newStorage.computeIfAbsent(locale, k -> new HashMap<>())
+                        .put(entry.key(), entry.value());
+            }
+        }
+
+        newStorage.replaceAll((k, v) -> Collections.unmodifiableMap(v));
+        this.storage = Collections.unmodifiableMap(newStorage);
+
+        return this;
+    }
+
+    public ILocalizationService service() {
+        return service(defaultLocale);
+    }
+
+    public ILocalizationService service(Locale locale) {
+        return service(locale, defaultLocale);
+    }
+
+    public ILocalizationService service(Locale locale, Locale fallbackLocale) {
+        return new LocalizationService(this, locale, fallbackLocale);
+    }
+}

localizationlib/src/main/java/org/axolotsh/localizationlib/LocalizationService.java

@@ -0,0 +1,70 @@
+package org.axolotsh.localizationlib;
+
+import java.util.Locale;
+import java.util.Objects;
+import java.util.Optional;
+
+import org.axolotsh.localizationlib.abstraction.ILocalizationService;
+
+import lombok.Getter;
+import lombok.experimental.Accessors;
+
+@Getter
+@Accessors(chain = true, fluent = true)
+public class LocalizationService implements ILocalizationService {
+    private LocalizationFactory factory;
+
+    private Locale locale = LocalizationFactory.DEFAULT_LOCALE;
+
+    private Locale fallbackLocale = LocalizationFactory.DEFAULT_LOCALE;
+
+    LocalizationService(LocalizationFactory factory) {
+        this.factory = factory;
+    }
+
+    LocalizationService(LocalizationFactory factory, Locale locale) {
+        this.factory = factory;
+        this.locale = locale;
+    }
+
+    LocalizationService(LocalizationFactory factory, Locale locale, Locale fallbackLocale) {
+        this.factory = factory;
+        this.locale = locale;
+        this.fallbackLocale = fallbackLocale;
+    }
+
+    public String translate(String key) {
+        return translate(key, locale);
+    }
+
+    public String translate(String key, Locale locale) {
+        var result = get(key, locale);
+
+        if (result.isEmpty()) {
+            if (fallbackLocale == null || Objects.equals(locale, fallbackLocale))
+                return key;
+            return translate(key, fallbackLocale);
+        }
+
+        return result.get();
+    }
+
+    public Optional<String> get(String key) {
+        return get(key, locale);
+    }
+
+    public Optional<String> get(String key, Locale locale) {
+        var storage = factory.storage();
+        var map = storage.get(locale);
+        if (map == null)
+            return Optional.empty();
+
+        var result = map.get(key);
+
+        if (result == null)
+            return Optional.empty();
+
+        return Optional.of(result);
+    }
+
+}

localizationlib/src/main/java/org/axolotsh/localizationlib/providers/CollectionProvider.java

@@ -0,0 +1,31 @@
+package org.axolotsh.localizationlib.providers;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Set;
+
+import org.axolotsh.localizationlib.abstraction.ILocalizationEntry;
+
+import lombok.Builder;
+import lombok.Getter;
+import lombok.Singular;
+import lombok.experimental.Accessors;
+
+@Getter
+@Accessors(chain = true, fluent = true)
+@Builder(toBuilder = true)
+public class CollectionProvider implements ILocalizationEntriesProvider {
+    private Collection<ILocalizationEntry> entries;
+
+    public Collection<ILocalizationEntry> provide() {
+        return Collections.unmodifiableCollection(entries);
+    }
+
+    public CollectionProvider(ILocalizationEntry... entries) {
+        this.entries = Set.of(entries);
+    }
+
+    public CollectionProvider(@Singular Collection<ILocalizationEntry> entries) {
+        this.entries = entries;
+    }
+}

localizationlib/src/main/java/org/axolotsh/localizationlib/providers/DirectoryProvider.java

@@ -0,0 +1,67 @@
+package org.axolotsh.localizationlib.providers;
+
+import java.io.File;
+import java.nio.charset.Charset;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+
+import org.axolotsh.localizationlib.abstraction.ILocalizationEntry;
+import org.jetbrains.annotations.Nullable;
+
+import com.google.gson.Gson;
+
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NonNull;
+import lombok.experimental.Accessors;
+
+@Getter
+@Accessors(chain = true, fluent = true)
+@Builder(toBuilder = true)
+public class DirectoryProvider implements ILocalizationEntriesProvider {
+    @NonNull
+    private File directory;
+    @Builder.Default
+    private Charset charset = Charset.defaultCharset();
+    @Builder.Default
+    private Gson gson = JsonProvider.DEFAULT_GSON;
+
+    @Nullable
+    private Runnable onEmptyInitializer;
+
+    public Collection<ILocalizationEntry> provide() {
+        if (isEmptyDirectory()) {
+            if (onEmptyInitializer == null)
+                return Collections.emptySet();
+            onEmptyInitializer.run();
+        }
+
+        var files = directory.listFiles();
+        Collection<ILocalizationEntry> allEntries = new HashSet<>();
+
+        for (var file : files) {
+            if (file.isFile()) {
+                var fileProvider = FileProvider.builder()
+                        .file(file)
+                        .charset(this.charset)
+                        .gson(this.gson)
+                        .build();
+
+                allEntries.addAll(fileProvider.provide());
+            }
+        }
+
+        return allEntries;
+    }
+
+    private boolean isEmptyDirectory() {
+        if (directory == null || !directory.exists())
+            return true;
+        if (directory.isDirectory()) {
+            var files = directory.listFiles();
+            return files == null || files.length == 0;
+        }
+        return false;
+    }
+}

localizationlib/src/main/java/org/axolotsh/localizationlib/providers/FileProvider.java

@@ -0,0 +1,76 @@
+package org.axolotsh.localizationlib.providers;
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Locale;
+import java.util.Map;
+
+import org.axolotsh.localizationlib.LocalizationEntry;
+import org.axolotsh.localizationlib.abstraction.ILocalizationEntry;
+import org.jetbrains.annotations.Nullable;
+
+import com.google.gson.Gson;
+import com.google.gson.reflect.TypeToken;
+
+import lombok.Builder;
+import lombok.Getter;
+import lombok.experimental.Accessors;
+
+@Getter
+@Accessors(chain = true, fluent = true)
+@Builder(toBuilder = true)
+public class FileProvider implements ILocalizationEntriesProvider {
+    private File file;
+    @Builder.Default
+    private Charset charset = Charset.defaultCharset();
+
+    @Nullable
+    private Locale locale;
+
+    @Nullable
+    private Runnable onEmptyInitializer;
+    @Builder.Default
+    private Gson gson = JsonProvider.DEFAULT_GSON;
+
+    public Collection<ILocalizationEntry> provide() {
+        if (isEmptyFile())
+            onEmptyInitializer.run();
+
+        var fileLocale = locale == null ? Locale.forLanguageTag(fileName()) : locale;
+
+        try (var reader = new FileReader(file, charset)) {
+            var mapType = new TypeToken<Map<String, String>>() {
+            }.getType();
+            Map<String, String> map = gson.fromJson(reader, mapType);
+            if (map == null)
+                return Collections.emptySet();
+
+            Collection<ILocalizationEntry> result = new HashSet<>();
+            map.forEach((key, value) -> {
+                result.add(new LocalizationEntry(fileLocale, key, value));
+            });
+
+            return result;
+        } catch (IOException e) {
+            throw new IllegalArgumentException(e);
+        }
+    }
+
+    private String fileName() {
+        var fileName = file.getName();
+        var dotIndex = fileName.lastIndexOf('.');
+
+        return (dotIndex == -1) ? fileName : fileName.substring(0, dotIndex);
+    }
+
+    private boolean isEmptyFile() {
+        if (file == null || !file.exists())
+            return true;
+        return false;
+    }
+}

localizationlib/src/main/java/org/axolotsh/localizationlib/providers/ILocalizationEntriesProvider.java

@@ -0,0 +1,9 @@
+package org.axolotsh.localizationlib.providers;
+
+import java.util.Collection;
+
+import org.axolotsh.localizationlib.abstraction.ILocalizationEntry;
+
+public interface ILocalizationEntriesProvider {
+    public Collection<ILocalizationEntry> provide();
+}

localizationlib/src/main/java/org/axolotsh/localizationlib/providers/JsonProvider.java

@@ -0,0 +1,53 @@
+package org.axolotsh.localizationlib.providers;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Locale;
+import java.util.Map;
+
+import org.axolotsh.localizationlib.LocalizationEntry;
+import org.axolotsh.localizationlib.abstraction.ILocalizationEntry;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.Strictness;
+import com.google.gson.reflect.TypeToken;
+
+import lombok.Builder;
+import lombok.Getter;
+import lombok.experimental.Accessors;
+
+@Getter
+@Accessors(chain = true, fluent = true)
+@Builder(toBuilder = true)
+public class JsonProvider implements ILocalizationEntriesProvider {
+    static final Gson DEFAULT_GSON = new GsonBuilder()
+            .setStrictness(Strictness.LENIENT)
+            .create();
+
+    private String json;
+    private Locale locale;
+
+    @Builder.Default
+    private Gson gson = DEFAULT_GSON;
+
+    public Collection<ILocalizationEntry> provide() {
+        return provide(locale, json, gson);
+    }
+
+    public static Collection<ILocalizationEntry> provide(Locale locale, String json, Gson gson) {
+        var mapType = new TypeToken<Map<String, String>>() {
+        }.getType();
+        Map<String, String> map = gson.fromJson(json, mapType);
+        if (map == null)
+            return Collections.emptySet();
+
+        Collection<ILocalizationEntry> result = new HashSet<>();
+        map.forEach((key, value) -> {
+            result.add(new LocalizationEntry(locale, key, value));
+        });
+
+        return result;
+    }
+}

localizationlib/src/test/java/org/axolotsh/localizationlib/LocalizationLibTest.java

@@ -0,0 +1,178 @@
+package org.axolotsh.localizationlib;
+
+import com.google.gson.Gson;
+
+import org.axolotsh.localizationlib.abstraction.ILocalizationEntry;
+import org.axolotsh.localizationlib.abstraction.ILocalizationService;
+import org.axolotsh.localizationlib.providers.CollectionProvider;
+import org.axolotsh.localizationlib.providers.DirectoryProvider;
+import org.axolotsh.localizationlib.providers.FileProvider;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Path;
+import java.util.Collection;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class LocalizationLibTest {
+
+    private static final Gson GSON = new Gson();
+
+    @TempDir
+    Path tempDir;
+
+    private File enFile;
+    private File ruFile;
+
+    @BeforeEach
+    public void setup() throws IOException {
+        enFile = tempDir.resolve("en.json").toFile();
+        ruFile = tempDir.resolve("ru.json").toFile();
+
+        try (FileWriter writer = new FileWriter(enFile, StandardCharsets.UTF_8)) {
+            GSON.toJson(Map.of("message.greeting", "Hello World!", "btn.save", "Save"), writer);
+        }
+
+        try (FileWriter writer = new FileWriter(ruFile, StandardCharsets.UTF_8)) {
+            GSON.toJson(Map.of("message.greeting", "Привет, Мир!"), writer);
+        }
+    }
+
+    @Test
+    public void testLocalizationEntryCreation() {
+        LocalizationEntry entry = new LocalizationEntry(Locale.ENGLISH, "key", "value");
+        assertEquals(Locale.ENGLISH, entry.locale());
+        assertEquals("key", "key");
+        assertEquals("value", entry.value());
+
+        LocalizationEntry entryNoLocale = new LocalizationEntry("key2", "value2");
+        assertNull(entryNoLocale.locale());
+
+        assertThrows(NullPointerException.class, () -> new LocalizationEntry(null, null));
+    }
+
+    @Test
+    public void testCollectionProvider() {
+        LocalizationEntry entry1 = new LocalizationEntry(Locale.ENGLISH, "k1", "v1");
+        LocalizationEntry entry2 = new LocalizationEntry(Locale.ENGLISH, "k2", "v2");
+
+        CollectionProvider provider = new CollectionProvider(entry1, entry2);
+        Collection<ILocalizationEntry> entries = provider.provide();
+
+        assertEquals(2, entries.size());
+        assertTrue(entries.contains(entry1));
+
+        assertThrows(UnsupportedOperationException.class, () -> entries.add(new LocalizationEntry("k3", "v3")));
+    }
+
+    @Test
+    public void testFileProviderAutomaticLocale() {
+        FileProvider fileProvider = FileProvider.builder()
+                .file(enFile)
+                .charset(StandardCharsets.UTF_8)
+                .gson(GSON)
+                .build();
+
+        Collection<ILocalizationEntry> entries = fileProvider.provide();
+        assertEquals(2, entries.size());
+
+        ILocalizationEntry greetingEntry = entries.stream()
+                .filter(e -> e.key().equals("message.greeting"))
+                .findFirst()
+                .orElseThrow();
+
+        assertEquals(Locale.ENGLISH, greetingEntry.locale());
+        assertEquals("Hello World!", greetingEntry.value());
+    }
+
+    @Test
+    public void testDirectoryProvider() {
+        DirectoryProvider directoryProvider = DirectoryProvider.builder()
+                .directory(tempDir.toFile())
+                .charset(StandardCharsets.UTF_8)
+                .gson(GSON)
+                .build();
+
+        Collection<ILocalizationEntry> entries = directoryProvider.provide();
+        assertEquals(3, entries.size());
+    }
+
+    @Test
+    public void testFactoryAndServiceWithCollectionProvider() {
+        LocalizationEntry enGreeting = new LocalizationEntry(Locale.US, "message.greeting", "Hello World!");
+        LocalizationEntry ruGreeting = new LocalizationEntry(Locale.forLanguageTag("ru"), "message.greeting",
+                "Привет, Мир!");
+
+        LocalizationEntry defaultGreeting = new LocalizationEntry("message.fallback", "Default Fallback");
+
+        LocalizationFactory factory = LocalizationFactory.builder()
+                .defaultLocale(Locale.US)
+                .provider(enGreeting, ruGreeting, defaultGreeting)
+                .build();
+
+        assertTrue(factory.storage().isEmpty());
+
+        factory.reloadProviders();
+        assertFalse(factory.storage().isEmpty());
+
+        assertEquals("Default Fallback", factory.storage().get(Locale.US).get("message.fallback"));
+
+        ILocalizationService serviceEn = factory.service(Locale.US);
+        assertEquals("Hello World!", serviceEn.translate("message.greeting"));
+
+        ILocalizationService serviceRu = factory.service(Locale.forLanguageTag("ru"));
+        assertEquals("Привет, Мир!", serviceRu.translate("message.greeting"));
+    }
+
+    @Test
+    public void testServiceFallbackLogic() {
+        CollectionProvider provider = new CollectionProvider(
+                new LocalizationEntry(Locale.US, "message.greeting", "Hello World!"),
+                new LocalizationEntry(Locale.US, "btn.save", "Save"),
+                new LocalizationEntry(Locale.forLanguageTag("ru"), "message.greeting", "Привет, Мир!"));
+
+        LocalizationFactory factory = LocalizationFactory.builder()
+                .defaultLocale(Locale.US)
+                .provider(provider)
+                .build()
+                .reloadProviders();
+
+        ILocalizationService service = factory.service(Locale.forLanguageTag("ru"), Locale.US);
+
+        assertEquals("Привет, Мир!", service.translate("message.greeting"));
+
+        assertEquals("Save", service.translate("btn.save"));
+
+        assertEquals("non.existent.key", service.translate("non.existent.key"));
+    }
+
+    @Test
+    public void testServiceGetOptional() {
+        CollectionProvider provider = new CollectionProvider(
+                new LocalizationEntry(Locale.US, "message.greeting", "Hello World!"));
+
+        LocalizationFactory factory = LocalizationFactory.builder()
+                .defaultLocale(Locale.US)
+                .provider(provider)
+                .build()
+                .reloadProviders();
+
+        ILocalizationService service = factory.service(Locale.US);
+
+        Optional<String> existing = service.get("message.greeting");
+        assertTrue(existing.isPresent());
+        assertEquals("Hello World!", existing.get());
+
+        Optional<String> nonExisting = service.get("unknown.key");
+        assertTrue(nonExisting.isEmpty());
+    }
+}

settings.gradle.kts

@@ -0,0 +1,3 @@
+rootProject.name = "LocalizationLib"
+include("localizationlib")
+include("localizationlib-abstraction")