From 4ab6b7072a2d9ab4e0726326cba3d1fb64172879 Mon Sep 17 00:00:00 2001
From: 00asdf <christoph@00asdf.dev>
Date: Sun, 9 Apr 2023 22:56:11 +0200
Subject: [PATCH] added ConfigProcessor

---
 .idea/compiler.xml                            |  12 ++
 .idea/modules.xml                             |   2 +-
 .idea/workspace.xml                           | 149 ++++++++++++++++--
 Confindibus.iml                               |  12 ++
 .../javax.annotation.processing.Processor     |   1 +
 .../confindibus/ConfigurationException.java   |   2 +-
 src/dev/asdf00/confindibus/Configurator.java  |  11 +-
 .../annotations/Configuration.java            |   2 +-
 .../confindibus/annotations/Section.java      |   2 +-
 .../asdf00/confindibus/annotations/Value.java |   2 +-
 .../processor/ConfigProcessor.java            | 122 ++++++++++++++
 .../dev/asdf00/confindibus/ProcessorTest.java |  67 ++++++++
 .../confindibus/testclasses/BrokenConfig.java |  10 ++
 .../testclasses/BrokenSection1.java           |  10 ++
 .../testclasses/BrokenSection2.java           |  11 ++
 .../confindibus/testclasses/BrokenValue1.java |  12 ++
 .../confindibus/testclasses/BrokenValue2.java |  14 ++
 .../confindibus/testclasses/BrokenValue3.java |  12 ++
 .../confindibus/testclasses/BrokenValue4.java |  12 ++
 .../testclasses/SimpleTestConfig.java         |  31 ++++
 20 files changed, 469 insertions(+), 27 deletions(-)
 create mode 100644 .idea/compiler.xml
 create mode 100644 resources/META-INF/services/javax.annotation.processing.Processor
 create mode 100644 src/dev/asdf00/confindibus/processor/ConfigProcessor.java
 create mode 100644 test/dev/asdf00/confindibus/ProcessorTest.java
 create mode 100644 test/dev/asdf00/confindibus/testclasses/BrokenConfig.java
 create mode 100644 test/dev/asdf00/confindibus/testclasses/BrokenSection1.java
 create mode 100644 test/dev/asdf00/confindibus/testclasses/BrokenSection2.java
 create mode 100644 test/dev/asdf00/confindibus/testclasses/BrokenValue1.java
 create mode 100644 test/dev/asdf00/confindibus/testclasses/BrokenValue2.java
 create mode 100644 test/dev/asdf00/confindibus/testclasses/BrokenValue3.java
 create mode 100644 test/dev/asdf00/confindibus/testclasses/BrokenValue4.java
 create mode 100644 test/dev/asdf00/confindibus/testclasses/SimpleTestConfig.java

diff --git a/.idea/compiler.xml b/.idea/compiler.xml
new file mode 100644
index 0000000..bf6e349
--- /dev/null
+++ b/.idea/compiler.xml
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <annotationProcessing>
+      <profile default="true" name="Default">
+        <processorPath useProcessorModulePath="true">
+          <entry name="$PROJECT_DIR$/src/dev/asdf00/confindibus/processor/ConfigProcessor.java" />
+        </processorPath>
+      </profile>
+    </annotationProcessing>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/modules.xml b/.idea/modules.xml
index 2fe2f58..24f1ec5 100644
--- a/.idea/modules.xml
+++ b/.idea/modules.xml
@@ -2,7 +2,7 @@
 <project version="4">
   <component name="ProjectModuleManager">
     <modules>
-      <module fileurl="file://$PROJECT_DIR$/Confidibus.iml" filepath="$PROJECT_DIR$/Confidibus.iml" />
+      <module fileurl="file://$PROJECT_DIR$/Confindibus.iml" filepath="$PROJECT_DIR$/Confindibus.iml" />
     </modules>
   </component>
 </project>
\ No newline at end of file
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index 4257bea..72f48a2 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -1,14 +1,36 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="ArtifactsWorkspaceSettings">
+    <artifacts-to-build>
+      <artifact name="Confindibus:jar" />
+    </artifacts-to-build>
+  </component>
   <component name="AutoImportSettings">
     <option name="autoReloadType" value="SELECTIVE" />
   </component>
   <component name="ChangeListManager">
     <list default="true" id="d8897652-66f5-4f30-9dbf-a6b280944ebf" name="Changes" comment="">
+      <change afterPath="$PROJECT_DIR$/.idea/libraries/google_auto_service.xml" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/resources/META-INF/services/javax.annotation.processing.Processor" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/src/dev/asdf00/confindibus/processor/ConfigProcessor.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/test/dev/asdf00/confindibus/ProcessorTest.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/test/dev/asdf00/confindibus/testclasses/BrokenConfig.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/test/dev/asdf00/confindibus/testclasses/BrokenSection1.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/test/dev/asdf00/confindibus/testclasses/BrokenSection2.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/test/dev/asdf00/confindibus/testclasses/BrokenValue1.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/test/dev/asdf00/confindibus/testclasses/BrokenValue2.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/test/dev/asdf00/confindibus/testclasses/BrokenValue3.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/test/dev/asdf00/confindibus/testclasses/BrokenValue4.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/test/dev/asdf00/confindibus/testclasses/SimpleTestConfig.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/.idea/misc.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/misc.xml" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/.idea/modules.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/modules.xml" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/src/dev/asdf00/confidibus/Confidibus.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/dev/asdf00/confidibus/Configurator.java" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/src/dev/asdf00/confidibus/annotations/Config.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/dev/asdf00/confidibus/annotations/Configuration.java" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/src/dev/asdf00/confidibus/annotations/Value.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/dev/asdf00/confidibus/annotations/Value.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/Confindibus.iml" beforeDir="false" afterPath="$PROJECT_DIR$/Confindibus.iml" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/dev/asdf00/confindibus/ConfigurationException.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/dev/asdf00/confindibus/ConfigurationException.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/dev/asdf00/confindibus/Configurator.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/dev/asdf00/confindibus/Configurator.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/dev/asdf00/confindibus/annotations/Configuration.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/dev/asdf00/confindibus/annotations/Configuration.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/dev/asdf00/confindibus/annotations/Section.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/dev/asdf00/confindibus/annotations/Section.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/dev/asdf00/confindibus/annotations/Value.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/dev/asdf00/confindibus/annotations/Value.java" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
@@ -19,6 +41,7 @@
     <option name="RECENT_TEMPLATES">
       <list>
         <option value="AnnotationType" />
+        <option value="module-info" />
         <option value="Class" />
       </list>
     </option>
@@ -32,30 +55,124 @@
     <option name="hideEmptyMiddlePackages" value="true" />
     <option name="showLibraryContents" value="true" />
   </component>
-  <component name="PropertiesComponent">{
-  &quot;keyToString&quot;: {
-    &quot;RunOnceActivity.OpenProjectViewOnStart&quot;: &quot;true&quot;,
-    &quot;RunOnceActivity.ShowReadmeOnStart&quot;: &quot;true&quot;,
-    &quot;last_opened_file_path&quot;: &quot;C:/Users/chris/Documents/HomeAuto/Confindibus&quot;,
-    &quot;project.structure.last.edited&quot;: &quot;Artifacts&quot;,
-    &quot;project.structure.proportion&quot;: &quot;0.0&quot;,
-    &quot;project.structure.side.proportion&quot;: &quot;0.2&quot;
+  <component name="PropertiesComponent"><![CDATA[{
+  "keyToString": {
+    "Downloaded.Files.Path.Enabled": "false",
+    "Repository.Attach.Annotations": "false",
+    "Repository.Attach.JavaDocs": "false",
+    "Repository.Attach.Sources": "false",
+    "RunOnceActivity.OpenProjectViewOnStart": "true",
+    "RunOnceActivity.ShowReadmeOnStart": "true",
+    "SHARE_PROJECT_CONFIGURATION_FILES": "true",
+    "last_opened_file_path": "C:/Users/Christoph/Documents/HomeAutomation/Confindibus/resources/META-INF/services",
+    "project.structure.last.edited": "Modules",
+    "project.structure.proportion": "0.15",
+    "project.structure.side.proportion": "0.2",
+    "settings.editor.selected.configurable": "reference.projectsettings.compiler.annotationProcessors"
   }
-}</component>
+}]]></component>
   <component name="RecentsManager">
+    <key name="CopyFile.RECENT_KEYS">
+      <recent name="C:\Users\Christoph\Documents\HomeAutomation\Confindibus\resources\META-INF\services" />
+    </key>
+    <key name="MoveFile.RECENT_KEYS">
+      <recent name="C:\Users\Christoph\Documents\HomeAutomation\Confindibus" />
+    </key>
     <key name="MoveClassesOrPackagesDialog.RECENTS_KEY">
       <recent name="dev.asdf00.confidibus.config" />
       <recent name="dev.asdf00.confidibus" />
     </key>
   </component>
-  <component name="RunManager">
-    <configuration name="MainTest" type="Application" factoryName="Application">
-      <option name="MAIN_CLASS_NAME" value="dev.asdf00.confidibus.Main" />
-      <module name="Confidibus" />
+  <component name="RunManager" selected="JUnit.Test">
+    <configuration name="ProcessorTest.testBrokenSection" type="JUnit" factoryName="JUnit" temporary="true" nameIsGenerated="true">
+      <module name="Confindibus" />
+      <extension name="coverage">
+        <pattern>
+          <option name="PATTERN" value="dev.asdf00.confindibus.*" />
+          <option name="ENABLED" value="true" />
+        </pattern>
+      </extension>
+      <option name="PACKAGE_NAME" value="dev.asdf00.confindibus" />
+      <option name="MAIN_CLASS_NAME" value="dev.asdf00.confindibus.ProcessorTest" />
+      <option name="METHOD_NAME" value="testBrokenSection" />
+      <option name="TEST_OBJECT" value="method" />
       <method v="2">
         <option name="Make" enabled="true" />
       </method>
     </configuration>
+    <configuration name="ProcessorTest.testBrokenValue2" type="JUnit" factoryName="JUnit" temporary="true" nameIsGenerated="true">
+      <module name="Confindibus" />
+      <extension name="coverage">
+        <pattern>
+          <option name="PATTERN" value="dev.asdf00.confindibus.*" />
+          <option name="ENABLED" value="true" />
+        </pattern>
+      </extension>
+      <option name="PACKAGE_NAME" value="dev.asdf00.confindibus" />
+      <option name="MAIN_CLASS_NAME" value="dev.asdf00.confindibus.ProcessorTest" />
+      <option name="METHOD_NAME" value="testBrokenValue2" />
+      <option name="TEST_OBJECT" value="method" />
+      <method v="2">
+        <option name="Make" enabled="true" />
+      </method>
+    </configuration>
+    <configuration name="ProcessorTest.testProcSimpleConfig" type="JUnit" factoryName="JUnit" temporary="true" nameIsGenerated="true">
+      <module name="Confindibus" />
+      <extension name="coverage">
+        <pattern>
+          <option name="PATTERN" value="dev.asdf00.confindibus.*" />
+          <option name="ENABLED" value="true" />
+        </pattern>
+      </extension>
+      <option name="PACKAGE_NAME" value="dev.asdf00.confindibus" />
+      <option name="MAIN_CLASS_NAME" value="dev.asdf00.confindibus.ProcessorTest" />
+      <option name="METHOD_NAME" value="testProcSimpleConfig" />
+      <option name="TEST_OBJECT" value="method" />
+      <method v="2">
+        <option name="Make" enabled="true" />
+      </method>
+    </configuration>
+    <configuration name="ProcessorTest.testSimpleConfig" type="JUnit" factoryName="JUnit" temporary="true" nameIsGenerated="true">
+      <module name="Confindibus" />
+      <extension name="coverage">
+        <pattern>
+          <option name="PATTERN" value="dev.asdf00.confindibus.*" />
+          <option name="ENABLED" value="true" />
+        </pattern>
+      </extension>
+      <option name="PACKAGE_NAME" value="dev.asdf00.confindibus" />
+      <option name="MAIN_CLASS_NAME" value="dev.asdf00.confindibus.ProcessorTest" />
+      <option name="METHOD_NAME" value="testSimpleConfig" />
+      <option name="TEST_OBJECT" value="method" />
+      <method v="2">
+        <option name="Make" enabled="true" />
+      </method>
+    </configuration>
+    <configuration name="Test" type="JUnit" factoryName="JUnit">
+      <module name="Confindibus" />
+      <option name="PACKAGE_NAME" value="dev.asdf00.confindibus" />
+      <option name="MAIN_CLASS_NAME" value="dev.asdf00.confindibus.ProcessorTest" />
+      <option name="METHOD_NAME" value="" />
+      <option name="TEST_OBJECT" value="class" />
+      <method v="2">
+        <option name="Make" enabled="true" />
+      </method>
+    </configuration>
+    <list>
+      <item itemvalue="JUnit.Test" />
+      <item itemvalue="JUnit.ProcessorTest.testBrokenSection" />
+      <item itemvalue="JUnit.ProcessorTest.testBrokenValue2" />
+      <item itemvalue="JUnit.ProcessorTest.testSimpleConfig" />
+      <item itemvalue="JUnit.ProcessorTest.testProcSimpleConfig" />
+    </list>
+    <recent_temporary>
+      <list>
+        <item itemvalue="JUnit.ProcessorTest.testSimpleConfig" />
+        <item itemvalue="JUnit.ProcessorTest.testBrokenSection" />
+        <item itemvalue="JUnit.ProcessorTest.testBrokenValue2" />
+        <item itemvalue="JUnit.ProcessorTest.testProcSimpleConfig" />
+      </list>
+    </recent_temporary>
   </component>
   <component name="SpellCheckerSettings" RuntimeDictionaries="0" Folders="0" CustomDictionaries="0" DefaultDictionary="application-level" UseSingleDictionary="true" transferred="true" />
   <component name="TaskManager">
diff --git a/Confindibus.iml b/Confindibus.iml
index c90834f..a47d190 100644
--- a/Confindibus.iml
+++ b/Confindibus.iml
@@ -3,9 +3,21 @@
   <component name="NewModuleRootManager" inherit-compiler-output="true">
     <exclude-output />
     <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/resources" type="java-resource" />
       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="module-library" scope="TEST">
+      <library name="JUnit4">
+        <CLASSES>
+          <root url="jar://$MAVEN_REPOSITORY$/junit/junit/4.13.1/junit-4.13.1.jar!/" />
+          <root url="jar://$MAVEN_REPOSITORY$/org/hamcrest/hamcrest-core/1.3/hamcrest-core-1.3.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+      </library>
+    </orderEntry>
   </component>
 </module>
\ No newline at end of file
diff --git a/resources/META-INF/services/javax.annotation.processing.Processor b/resources/META-INF/services/javax.annotation.processing.Processor
new file mode 100644
index 0000000..fa29b95
--- /dev/null
+++ b/resources/META-INF/services/javax.annotation.processing.Processor
@@ -0,0 +1 @@
+dev.asdf00.confindibus.processor.ConfigProcessor
diff --git a/src/dev/asdf00/confindibus/ConfigurationException.java b/src/dev/asdf00/confindibus/ConfigurationException.java
index 667e372..ac16e74 100644
--- a/src/dev/asdf00/confindibus/ConfigurationException.java
+++ b/src/dev/asdf00/confindibus/ConfigurationException.java
@@ -1,4 +1,4 @@
-package dev.asdf00.confidibus;
+package dev.asdf00.confindibus;
 
 public class ConfigurationException extends RuntimeException {
     public ConfigurationException(String format, Object... params) {
diff --git a/src/dev/asdf00/confindibus/Configurator.java b/src/dev/asdf00/confindibus/Configurator.java
index 0c7bca8..48cd184 100644
--- a/src/dev/asdf00/confindibus/Configurator.java
+++ b/src/dev/asdf00/confindibus/Configurator.java
@@ -1,8 +1,8 @@
-package dev.asdf00.confidibus;
+package dev.asdf00.confindibus;
 
-import dev.asdf00.confidibus.annotations.Configuration;
-import dev.asdf00.confidibus.annotations.Section;
-import dev.asdf00.confidibus.annotations.Value;
+import dev.asdf00.confindibus.annotations.Configuration;
+import dev.asdf00.confindibus.annotations.Section;
+import dev.asdf00.confindibus.annotations.Value;
 
 import java.io.IOException;
 import java.io.PrintStream;
@@ -40,8 +40,7 @@ import java.util.Iterator;
  *         @Value(comment = "enables debug mode", standard = "false")
  *         public static boolean DEBUG;
  *     }
- * }
- * </pre>
+ * }}</pre>
  */
 public class Configurator {
     private final Class<?> _class;
diff --git a/src/dev/asdf00/confindibus/annotations/Configuration.java b/src/dev/asdf00/confindibus/annotations/Configuration.java
index fbd7ed8..f59c505 100644
--- a/src/dev/asdf00/confindibus/annotations/Configuration.java
+++ b/src/dev/asdf00/confindibus/annotations/Configuration.java
@@ -1,4 +1,4 @@
-package dev.asdf00.confidibus.annotations;
+package dev.asdf00.confindibus.annotations;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
diff --git a/src/dev/asdf00/confindibus/annotations/Section.java b/src/dev/asdf00/confindibus/annotations/Section.java
index aacae58..68e4df0 100644
--- a/src/dev/asdf00/confindibus/annotations/Section.java
+++ b/src/dev/asdf00/confindibus/annotations/Section.java
@@ -1,4 +1,4 @@
-package dev.asdf00.confidibus.annotations;
+package dev.asdf00.confindibus.annotations;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
diff --git a/src/dev/asdf00/confindibus/annotations/Value.java b/src/dev/asdf00/confindibus/annotations/Value.java
index 938182a..84dbdf7 100644
--- a/src/dev/asdf00/confindibus/annotations/Value.java
+++ b/src/dev/asdf00/confindibus/annotations/Value.java
@@ -1,4 +1,4 @@
-package dev.asdf00.confidibus.annotations;
+package dev.asdf00.confindibus.annotations;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
diff --git a/src/dev/asdf00/confindibus/processor/ConfigProcessor.java b/src/dev/asdf00/confindibus/processor/ConfigProcessor.java
new file mode 100644
index 0000000..0a8f864
--- /dev/null
+++ b/src/dev/asdf00/confindibus/processor/ConfigProcessor.java
@@ -0,0 +1,122 @@
+package dev.asdf00.confindibus.processor;
+
+import dev.asdf00.confindibus.annotations.Configuration;
+import dev.asdf00.confindibus.annotations.Section;
+import dev.asdf00.confindibus.annotations.Value;
+
+import javax.annotation.processing.*;
+import javax.lang.model.SourceVersion;
+import javax.lang.model.element.Element;
+import javax.lang.model.element.Modifier;
+import javax.lang.model.element.TypeElement;
+import javax.lang.model.type.TypeMirror;
+import javax.tools.Diagnostic;
+import java.util.Set;
+
+@SupportedAnnotationTypes("dev.asdf00.confindibus.annotations.*")
+@SupportedSourceVersion(SourceVersion.RELEASE_17)
+public class ConfigProcessor extends AbstractProcessor {
+    @Override
+    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
+        boolean processedAllAns = true;
+        for (TypeElement anno : annotations) {
+            Set<? extends Element> annotatedElements = roundEnv.getElementsAnnotatedWith(anno);
+            for (Element elem : annotatedElements) {
+                if (anno.getQualifiedName().contentEquals("dev.asdf00.confindibus.annotations.Configuration")) {
+                    configuration(elem);
+                } else if (anno.getQualifiedName().contentEquals("dev.asdf00.confindibus.annotations.Section")) {
+                    section(elem);
+                } else if (anno.getQualifiedName().contentEquals("dev.asdf00.confindibus.annotations.Value")) {
+                    value(elem);
+                } else {
+                    processedAllAns = false;
+                }
+            }
+        }
+        return processedAllAns;
+    }
+
+    private void configuration(Element config) {
+        if (config.getAnnotation(Section.class) == null) {
+            printError("Classes annotated with @Configuration also need to be annotated with @Section!", config);
+        }
+    }
+
+    private void section(Element section) {
+        Element inner = section;
+        Element outer = inner.getEnclosingElement();
+        while (outer.getClass().getName().equals("com.sun.tools.javac.code.Symbol$ClassSymbol")) {
+            if (outer.getAnnotation(Section.class) == null) {
+                printError("Subsection '%s' needs to be part of an outer @Section!".formatted(inner.getSimpleName()), section);
+            }
+            Set<Modifier> clsMods = inner.getModifiers();
+            if (!clsMods.contains(Modifier.PUBLIC) || !clsMods.contains(Modifier.STATIC)) {
+                printError("Classes that represent subsections need to be 'public static'!", section);
+            }
+            inner = outer;
+            outer = inner.getEnclosingElement();
+        }
+        if (inner.getAnnotation(Configuration.class) == null) {
+            printError("Class '%s' annotated with @Section found outside of valid configuration!".formatted(section.getSimpleName()), section);
+        }
+
+        Section sect = section.getAnnotation(Section.class);
+        if (sect.title().indexOf('{') != -1 || sect.title().indexOf('\n') != -1) {
+            printError("The title of a section must not contain '{' or '\\n'! (title = '%s')".formatted(sect.title()), section);
+        }
+    }
+
+    private void value(Element value) {
+        Set<Modifier> modifiers = value.getModifiers();
+        if (!modifiers.contains(Modifier.PUBLIC) || !modifiers.contains(Modifier.STATIC) || modifiers.contains(Modifier.FINAL)) {
+            printError("Field '%s' annotated with @Value needs to be exactly 'public static'!".formatted(value.getSimpleName()), value);
+        }
+        if (value.getEnclosingElement().getAnnotation(Section.class) == null) {
+            printError("Field '%s' annotated with @Value needs to be inside a class annotated with @Section!".formatted(value.getSimpleName()), value);
+        }
+
+        checkParsableAsType(value, value.getAnnotation(Value.class).standard());
+
+        Value val = value.getAnnotation(Value.class);
+        if (val.name().indexOf(':') != -1 || val.name().indexOf('\n') != -1) {
+            printError("The name of a field must not contain ':' or '\\n'! (name = '%s')".formatted(val.name()), value);
+        }
+    }
+
+    // =================================================================================================================
+    static volatile Object temp;
+    
+    private void checkParsableAsType(Element elem, String value) {
+        TypeMirror type = elem.asType();
+        try {
+            String tst = type.toString();
+            if (tst.equals("byte")) {
+                temp = Byte.parseByte(value);
+            } else if (tst.equals("short")) {
+                temp = Short.parseShort(value);
+            } else if (tst.equals("int")) {
+                temp = Integer.parseInt(value);
+            } else if (tst.equals("long")) {
+                temp = Long.parseLong(value);
+            } else if (tst.equals("float")) {
+                temp = Float.parseFloat(value);
+            } else if (tst.equals("double")) {
+                temp = Double.parseDouble(value);
+            } else if (tst.equals("boolean")) {
+                temp = Boolean.parseBoolean(value);
+            } else if (tst.equals("char")) {
+                temp = value.charAt(0);
+            } else if (tst.equals("java.lang.String")) {
+                temp = value;
+            } else {
+                printError("'%s' is not a valid type for a field annotated with @Value!".formatted(type), elem);
+            }
+        } catch (NumberFormatException | IndexOutOfBoundsException e) {
+            printError("Standard value of '%s' is not parsable as %s!".formatted(value, type), elem);
+        }
+    }
+
+    private void printError(CharSequence msg, Element elem) {
+        processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, msg, elem);
+    }
+}
diff --git a/test/dev/asdf00/confindibus/ProcessorTest.java b/test/dev/asdf00/confindibus/ProcessorTest.java
new file mode 100644
index 0000000..9d16a4b
--- /dev/null
+++ b/test/dev/asdf00/confindibus/ProcessorTest.java
@@ -0,0 +1,67 @@
+package dev.asdf00.confindibus;
+
+import dev.asdf00.confindibus.testclasses.*;
+import org.junit.Assert;
+import org.junit.Test;
+
+import static com.sun.tools.javac.Main.compile;
+
+public class ProcessorTest {
+    @Test
+    public void testSimpleConfig() {
+        Assert.assertEquals(0, compileWithProc(SimpleTestConfig.class));
+    }
+
+    @Test
+    public void testBrokenConfig() {
+        Assert.assertEquals(1, compileWithProc(BrokenConfig.class));
+    }
+
+    @Test
+    public void testBrokenSection1() {
+        Assert.assertEquals(1, compileWithProc(BrokenSection1.class));
+    }
+
+    @Test
+    public void testBrokenSection2() {
+        Assert.assertEquals(1, compileWithProc(BrokenSection2.class));
+    }
+
+    @Test
+    public void testBrokenValue1() {
+        Assert.assertEquals(1, compileWithProc(BrokenValue1.class));
+    }
+
+    @Test
+    public void testBrokenValue2() {
+        Assert.assertEquals(1, compileWithProc(BrokenValue2.class));
+    }
+
+    @Test
+    public void testBrokenValue3() {
+        Assert.assertEquals(1, compileWithProc(BrokenValue3.class));
+    }
+
+    @Test
+    public void testBrokenValue4() {
+        Assert.assertEquals(1, compileWithProc(BrokenValue4.class));
+    }
+
+
+    // =================================================================================================================
+    private int compileWithProc(Class<?>... classes) {
+        int fixedArgCnt = 3;
+        String[] args = new String[classes.length + fixedArgCnt];
+        args[0] = "-proc:only";
+        args[1] = "-processor";
+        args[2] = "dev.asdf00.confindibus.processor.ConfigProcessor";
+        for (int i = fixedArgCnt; i < args.length; i++) {
+            args[i] = testClass(classes[i - fixedArgCnt]);
+        }
+        return compile(args);
+    }
+
+    private String testClass(Class cls) {
+        return "test/" + cls.getName().replace('.', '/') + ".java";
+    }
+}
diff --git a/test/dev/asdf00/confindibus/testclasses/BrokenConfig.java b/test/dev/asdf00/confindibus/testclasses/BrokenConfig.java
new file mode 100644
index 0000000..3aa7d6f
--- /dev/null
+++ b/test/dev/asdf00/confindibus/testclasses/BrokenConfig.java
@@ -0,0 +1,10 @@
+package dev.asdf00.confindibus.testclasses;
+
+import dev.asdf00.confindibus.annotations.Configuration;
+import dev.asdf00.confindibus.annotations.Value;
+
+@Configuration(path = "test")
+public class BrokenConfig {
+    @Value(standard = "value")
+    public static String VALUE;
+}
diff --git a/test/dev/asdf00/confindibus/testclasses/BrokenSection1.java b/test/dev/asdf00/confindibus/testclasses/BrokenSection1.java
new file mode 100644
index 0000000..be7e839
--- /dev/null
+++ b/test/dev/asdf00/confindibus/testclasses/BrokenSection1.java
@@ -0,0 +1,10 @@
+package dev.asdf00.confindibus.testclasses;
+
+import dev.asdf00.confindibus.annotations.Section;
+import dev.asdf00.confindibus.annotations.Value;
+
+@Section(title = "test")
+public class BrokenSection1 {
+    @Value(standard = "value")
+    public static String VALUE;
+}
diff --git a/test/dev/asdf00/confindibus/testclasses/BrokenSection2.java b/test/dev/asdf00/confindibus/testclasses/BrokenSection2.java
new file mode 100644
index 0000000..7245c6c
--- /dev/null
+++ b/test/dev/asdf00/confindibus/testclasses/BrokenSection2.java
@@ -0,0 +1,11 @@
+package dev.asdf00.confindibus.testclasses;
+
+import dev.asdf00.confindibus.annotations.Configuration;
+import dev.asdf00.confindibus.annotations.Section;
+
+@Configuration(path = "test")
+@Section(title = "sect")
+public class BrokenSection2 {
+    @Section(title = "broken subsect")
+    public class Subsect { }
+}
diff --git a/test/dev/asdf00/confindibus/testclasses/BrokenValue1.java b/test/dev/asdf00/confindibus/testclasses/BrokenValue1.java
new file mode 100644
index 0000000..28bd2ac
--- /dev/null
+++ b/test/dev/asdf00/confindibus/testclasses/BrokenValue1.java
@@ -0,0 +1,12 @@
+package dev.asdf00.confindibus.testclasses;
+
+import dev.asdf00.confindibus.annotations.Configuration;
+import dev.asdf00.confindibus.annotations.Section;
+import dev.asdf00.confindibus.annotations.Value;
+
+@Configuration(path = "test")
+@Section(title = "sect")
+public class BrokenValue1 {
+    @Value(standard = "test")
+    public String TEST;
+}
diff --git a/test/dev/asdf00/confindibus/testclasses/BrokenValue2.java b/test/dev/asdf00/confindibus/testclasses/BrokenValue2.java
new file mode 100644
index 0000000..96c8d75
--- /dev/null
+++ b/test/dev/asdf00/confindibus/testclasses/BrokenValue2.java
@@ -0,0 +1,14 @@
+package dev.asdf00.confindibus.testclasses;
+
+import dev.asdf00.confindibus.annotations.Configuration;
+import dev.asdf00.confindibus.annotations.Section;
+import dev.asdf00.confindibus.annotations.Value;
+
+@Configuration(path = "test")
+@Section(title = "sect outer")
+public class BrokenValue2 {
+    public static class InnerSection {
+        @Value(standard = "value")
+        public static String VALUE;
+    }
+}
diff --git a/test/dev/asdf00/confindibus/testclasses/BrokenValue3.java b/test/dev/asdf00/confindibus/testclasses/BrokenValue3.java
new file mode 100644
index 0000000..332195d
--- /dev/null
+++ b/test/dev/asdf00/confindibus/testclasses/BrokenValue3.java
@@ -0,0 +1,12 @@
+package dev.asdf00.confindibus.testclasses;
+
+import dev.asdf00.confindibus.annotations.Configuration;
+import dev.asdf00.confindibus.annotations.Section;
+import dev.asdf00.confindibus.annotations.Value;
+
+@Configuration(path = "test")
+@Section(title = "sect")
+public class BrokenValue3 {
+    @Value(standard = "")
+    public static Object VALUE;
+}
diff --git a/test/dev/asdf00/confindibus/testclasses/BrokenValue4.java b/test/dev/asdf00/confindibus/testclasses/BrokenValue4.java
new file mode 100644
index 0000000..ae80813
--- /dev/null
+++ b/test/dev/asdf00/confindibus/testclasses/BrokenValue4.java
@@ -0,0 +1,12 @@
+package dev.asdf00.confindibus.testclasses;
+
+import dev.asdf00.confindibus.annotations.Configuration;
+import dev.asdf00.confindibus.annotations.Section;
+import dev.asdf00.confindibus.annotations.Value;
+
+@Configuration(path = "test")
+@Section(title = "sect")
+public class BrokenValue4 {
+    @Value(standard = "256")
+    public static byte VALUE;
+}
diff --git a/test/dev/asdf00/confindibus/testclasses/SimpleTestConfig.java b/test/dev/asdf00/confindibus/testclasses/SimpleTestConfig.java
new file mode 100644
index 0000000..cc6432d
--- /dev/null
+++ b/test/dev/asdf00/confindibus/testclasses/SimpleTestConfig.java
@@ -0,0 +1,31 @@
+package dev.asdf00.confindibus.testclasses;
+
+import dev.asdf00.confindibus.annotations.Configuration;
+import dev.asdf00.confindibus.annotations.Section;
+import dev.asdf00.confindibus.annotations.Value;
+
+@Configuration(path = "test")
+@Section(title = "sect")
+public class SimpleTestConfig {
+    @Value(standard = "1")
+    public static byte BYTE;
+    @Value(standard = "1")
+    public static short SHORT;
+    @Value(standard = "1")
+    public static int INT;
+    @Value(standard = "1")
+    public static long LONG;
+    @Value(standard = "1.0")
+    public static float FLOAT;
+    @Value(standard = "1.0")
+    public static double DOUBLE;
+    @Value(standard = "true")
+    public static boolean BOOLEAN;
+    @Value(standard = "c")
+    public static char CHAR;
+    @Value(standard = "string")
+    public static String STRING;
+
+    @Section(title = "test inner section")
+    public static class SubSection { }
+}