From d709577991110bdd3ce3f839bbb06a4225de351a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Hohwiller?= <joerg.hohwiller@capgemini.com>
Date: Thu, 14 Dec 2023 00:25:24 +0100
Subject: [PATCH] added support for app config

---
 .../io/github/mmm/base/metainfo/MetaInfo.java |  8 +++
 .../base/metainfo/impl/AppConfigHolder.java   | 49 +++++++++++++++++++
 2 files changed, 57 insertions(+)
 create mode 100644 metainfo/src/main/java/io/github/mmm/base/metainfo/impl/AppConfigHolder.java

diff --git a/metainfo/src/main/java/io/github/mmm/base/metainfo/MetaInfo.java b/metainfo/src/main/java/io/github/mmm/base/metainfo/MetaInfo.java
index d6947c0..3b2c81f 100644
--- a/metainfo/src/main/java/io/github/mmm/base/metainfo/MetaInfo.java
+++ b/metainfo/src/main/java/io/github/mmm/base/metainfo/MetaInfo.java
@@ -309,4 +309,12 @@ static MetaInfo empty() {
 
     return MetaInfoEmpty.INSTANCE;
   }
+
+  /**
+   * @return the {@link MetaInfo} with the configuration for the running application.
+   */
+  static MetaInfo config() {
+
+    return io.github.mmm.base.metainfo.impl.AppConfigHolder.CONFIG;
+  }
 }
diff --git a/metainfo/src/main/java/io/github/mmm/base/metainfo/impl/AppConfigHolder.java b/metainfo/src/main/java/io/github/mmm/base/metainfo/impl/AppConfigHolder.java
new file mode 100644
index 0000000..3e705d0
--- /dev/null
+++ b/metainfo/src/main/java/io/github/mmm/base/metainfo/impl/AppConfigHolder.java
@@ -0,0 +1,49 @@
+package io.github.mmm.base.metainfo.impl;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Properties;
+
+import io.github.mmm.base.exception.RuntimeIoException;
+import io.github.mmm.base.metainfo.MetaInfo;
+
+/**
+ * Holder for the {@link MetaInfo#config() app config}.
+ */
+public class AppConfigHolder {
+
+  /** @see MetaInfo#config() */
+  public static final MetaInfo CONFIG;
+
+  static {
+    MetaInfo metaInfo = MetaInfo.empty();
+    metaInfo = metaInfo.with(System.getenv());
+    metaInfo = withApplicationProperties(metaInfo);
+    metaInfo = metaInfo.with(System.getProperties());
+    CONFIG = metaInfo;
+  }
+
+  @SuppressWarnings({ "unchecked", "rawtypes" })
+  private static MetaInfo withApplicationProperties(MetaInfo metaInfo) {
+
+    Path configPath = Paths.get("./config/application.properties");
+    if (!Files.exists(configPath)) {
+      return metaInfo;
+    }
+    Properties properties = new Properties();
+    try (BufferedReader reader = Files.newBufferedReader(configPath, StandardCharsets.UTF_8)) {
+      properties.load(reader);
+    } catch (IOException e) {
+      throw new RuntimeIoException(e);
+    }
+    Map<String, String> map = new HashMap<>((Map) properties);
+    return metaInfo.with(map);
+  }
+
+}