Refactor/cleanup and modernize

.github/workflows/ant.yml

@@ -1,17 +1,32 @@
 name: Java CI
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
-  build:
+  build-and-test:
 
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v1
-    - name: Set up JDK 1.8
-      uses: actions/setup-java@v1
+    - uses: actions/checkout@v4
+
+    - name: Set up JDK 11
+      uses: actions/setup-java@v4
       with:
-        java-version: 1.8
+        java-version: '11'
+        distribution: 'temurin'
+
+    - name: Download JUnit 5 dependencies
+      run: |
+        mvn dependency:get -q -Dartifact=org.junit.jupiter:junit-jupiter-api:5.9.3
+        mvn dependency:get -q -Dartifact=org.junit.jupiter:junit-jupiter-engine:5.9.3
+        mvn dependency:get -q -Dartifact=org.junit.platform:junit-platform-engine:1.9.3
+        mvn dependency:get -q -Dartifact=org.junit.platform:junit-platform-commons:1.9.3
+        mvn dependency:get -q -Dartifact=org.junit.platform:junit-platform-launcher:1.9.3
+        mvn dependency:get -q -Dartifact=org.opentest4j:opentest4j:1.2.0
+
     - name: Build with Ant
-      run: ant -noinput -buildfile build.xml
+      run: ant -noinput
+
+    - name: Run tests
+      run: ant -noinput test

CLAUDE.md

@@ -0,0 +1,105 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Build & Run
+
+```bash
+# Full clean build + run (with JDWP debug port 8000)
+./make.sh
+
+# Build only
+ant clean && ant
+
+# Run the built JAR
+java -jar binary/graphtea-main.jar
+
+# Platform-specific launchers
+./GraphTea-linux.sh
+./GraphTea-mac.sh
+./GraphTea-windows.bat
+
+# Create distribution packages (macOS .dmg, Windows .exe, Linux .deb)
+./create_packages.sh
+```
+
+Build output goes to `build/` (compiled classes) and `binary/` (JARs, plugins, extensions).
+
+## Tests
+
+Tests use JUnit 5 and live in `/test/`. There is no dedicated test runner script — run tests through your IDE or a JUnit runner with the classpath from `src/scripts/lib/`.
+
+## Code Style (Checkstyle)
+
+Checkstyle 10 enforces style on all **new** source files. Existing files are grandfathered
+in `config/checkstyle-suppressions.xml` and are exempt until cleaned up.
+
+```bash
+# Report violations (never fails the build — good for local inspection)
+ant checkstyle
+
+# Strict mode — fails the build on any violation (use in CI)
+ant checkstyle-strict
+
+# CLI equivalent (exit code = number of errors; 0 = clean)
+java -jar tools/checkstyle.jar -c config/checkstyle.xml \
+     -p config/checkstyle.properties  src/graphtea
+```
+
+Key rules enforced on new code (`config/checkstyle.xml`):
+- Braces required on all `if`/`for`/`while` bodies (`NeedBraces`)
+- No `==` for string comparison (`StringLiteralEquality`)
+- No unused or redundant imports
+- `L` suffix on long literals, not `l`
+- One statement per line; array brackets on type (`String[]` not `String []`)
+- Whitespace around operators and after keywords
+- Modifier order (`public static final`, not `static public final`)
+- Complexity limits: cyclomatic ≤ 15, nesting depth ≤ 4
+
+To **add a new file** to the suppression baseline (only if truly needed):
+```xml
+<!-- in config/checkstyle-suppressions.xml -->
+<suppress files="MyNewFile.java" checks=".*"/>
+```
+Prefer fixing violations over suppressing them.
+
+## Architecture
+
+GraphTea is a **Java Swing desktop application** for graph theory, built around a plugin-extension architecture.
+
+### Core Concepts
+
+**BlackBoard** (`src/graphtea/platform/core/BlackBoard.java`)
+The central event bus and state store. All inter-component communication flows through it. Components call `blackboard.setData(key, value)` to publish and `blackboard.addListener(key, listener)` to subscribe. This replaces direct dependencies between plugins.
+
+**Plugin System** (`src/graphtea/platform/plugin/Plugger.java`)
+Plugins are JAR files in `binary/plugins/`. Each JAR's manifest declares `plugin-name`, `plugin-version`, and `plugin-depends`. Plugger resolves load order via DFS topological sort. Each plugin has an `Init` class at `graphtea.plugins.<name>.Init` (or a custom manifest-specified class).
+
+**Extension System** (`src/graphtea/platform/extension/`)
+Extensions are JARs in `binary/extensions/`, dynamically loaded at startup. They implement typed interfaces:
+- `AlgorithmExtension` — graph algorithms
+- `GraphGeneratorExtension` — graph generators
+- `ReportExtension` — computed graph properties/reports
+- `ActionExtension` — graph transformations (products, line graphs, etc.)
+
+### Module Layout
+
+| Package | Role |
+|---|---|
+| `graphtea.platform` | Bootstrapping, BlackBoard, plugin/extension loading, preferences |
+| `graphtea.graph` | Core graph model (`GraphModel`, `Vertex`, `Edge`), rendering, events |
+| `graphtea.library` | Pure graph algorithm library, utilities |
+| `graphtea.plugins` | Main UI, visualization, generators, algorithm animator, reports UI |
+| `graphtea.extensions` | Concrete algorithms, generators, reports, actions (the bulk of domain logic) |
+| `graphtea.ui` | Swing UI components: property editors, sidebars, menus |
+| `graphtea.samples` | Example extension implementations |
+
+### Entry Point
+
+`graphtea.platform.Application.main()` → initializes BlackBoard → loads Preferences → loads Plugins (from `binary/plugins/`) → loads Extensions (from `binary/extensions/`) → fires `POST_INIT_EVENT`.
+
+### Adding a New Extension
+
+1. Implement the appropriate interface (e.g., `ReportExtension<GraphModel, String>`).
+2. Build it as a JAR and drop it in `binary/extensions/`.
+3. See `src/graphtea/samples/` for working examples.

build.xml

@@ -37,7 +37,71 @@
     <description>
         The ant build file of GraphTea Project.
     </description>
-    <target name="test">
+    <property name="m2.repo" value="${user.home}/.m2/repository"/>
+    <property name="junit5.api"      value="${m2.repo}/org/junit/jupiter/junit-jupiter-api/5.9.3/junit-jupiter-api-5.9.3.jar"/>
+    <property name="junit5.engine"   value="${m2.repo}/org/junit/jupiter/junit-jupiter-engine/5.9.3/junit-jupiter-engine-5.9.3.jar"/>
+    <property name="junit5.platform.engine"   value="${m2.repo}/org/junit/platform/junit-platform-engine/1.9.3/junit-platform-engine-1.9.3.jar"/>
+    <property name="junit5.platform.commons"  value="${m2.repo}/org/junit/platform/junit-platform-commons/1.9.3/junit-platform-commons-1.9.3.jar"/>
+    <property name="junit5.platform.launcher" value="${m2.repo}/org/junit/platform/junit-platform-launcher/1.9.3/junit-platform-launcher-1.9.3.jar"/>
+    <property name="opentest4j"      value="${m2.repo}/org/opentest4j/opentest4j/1.2.0/opentest4j-1.2.0.jar"/>
+
+    <target name="test" depends="compile" description="Compile and run JUnit 5 tests">
+        <mkdir dir="${basedir}/build/test-classes"/>
+        <javac srcdir="${basedir}/test" destdir="${basedir}/build/test-classes"
+               source="11" target="11" includeantruntime="false">
+            <classpath>
+                <path refid="project.lib"/>
+                <pathelement location="${basedir}/build"/>
+                <pathelement location="${junit5.api}"/>
+                <pathelement location="${opentest4j}"/>
+                <pathelement location="${junit5.platform.commons}"/>
+            </classpath>
+            <include name="GraphModelTest.java"/>
+            <include name="GraphUtilsTest.java"/>
+            <include name="GraphOperationsTest.java"/>
+            <include name="TraversalTest.java"/>
+            <include name="BasicReportsTest.java"/>
+            <include name="GeneratorsTest.java"/>
+            <include name="ProductsTest.java"/>
+            <include name="ReportsTest.java"/>
+            <include name="TestActions.java"/>
+            <include name="TestChemicalGraphIndices.java"/>
+            <include name="TestHomomorphism.java"/>
+            <include name="TestNewEdge.java"/>
+            <include name="AlgorithmsTest.java"/>
+        </javac>
+        <junitlauncher haltOnFailure="false" printSummary="true">
+            <classpath>
+                <path refid="project.lib"/>
+                <pathelement location="${basedir}/build"/>
+                <pathelement location="${basedir}/build/test-classes"/>
+                <pathelement location="${junit5.api}"/>
+                <pathelement location="${junit5.engine}"/>
+                <pathelement location="${junit5.platform.engine}"/>
+                <pathelement location="${junit5.platform.commons}"/>
+                <pathelement location="${junit5.platform.launcher}"/>
+                <pathelement location="${opentest4j}"/>
+            </classpath>
+            <testclasses outputdir="${basedir}/build/test-classes">
+                <fileset dir="${basedir}/build/test-classes">
+                    <include name="GraphModelTest.class"/>
+                    <include name="GraphUtilsTest.class"/>
+                    <include name="GraphOperationsTest.class"/>
+                    <include name="TraversalTest.class"/>
+                    <include name="BasicReportsTest.class"/>
+                    <include name="GeneratorsTest.class"/>
+                    <include name="ProductsTest.class"/>
+                    <include name="ReportsTest.class"/>
+                    <include name="TestActions.class"/>
+                    <include name="TestChemicalGraphIndices.class"/>
+                    <include name="TestHomomorphism.class"/>
+                    <include name="TestNewEdge.class"/>
+                    <include name="AlgorithmsTest.class"/>
+                </fileset>
+                <listener type="legacy-xml" outputdir="${basedir}/build/test-classes" sendSysOut="true" sendSysErr="true"/>
+                <listener type="legacy-plain" sendSysOut="true"/>
+            </testclasses>
+        </junitlauncher>
     </target>
     <!-- - - - - - - - - - - - - - - - - -
           target: depends
@@ -65,7 +129,7 @@
           target: compile
          ================================= -->
     <target name="compile" depends="depends" description="--> The ant build file of GraphTea Project.">
-        <javac srcdir="${src.dir}" destdir="${build.dir}">
+        <javac srcdir="${src.dir}" destdir="${build.dir}" source="11" target="11" includeantruntime="false">
             <classpath>
                 <path refid="project.lib"/>
             </classpath>
@@ -270,6 +334,55 @@
         <!--<gzip destfile="${basedir}/../developer_resources/binary.tar.gz" src="${basedir}/../developer_resources/binary.tar"/>-->
     </target>
 
+    <!-- =================================
+          target: checkstyle
+         ================================= -->
+
+    <!--
+      Checkstyle targets.
+
+      checkstyle        — runs style checks and reports violations but never fails
+                          the build. Use this to inspect the current state.
+      checkstyle-strict — same checks, fails the build on any violation. Use this
+                          in CI or as a pre-commit gate.
+
+      Existing code is grandfathered via config/checkstyle-suppressions.xml.
+      Only files NOT listed there must comply.
+
+      CLI equivalent:
+        java -jar tools/checkstyle.jar -c config/checkstyle.xml \
+             -p config/checkstyle.properties  src/graphtea
+    -->
+    <target name="checkstyle" depends="depends" description="Report Checkstyle violations (never fails build)">
+        <taskdef resource="com/puppycrawl/tools/checkstyle/ant/checkstyle-ant-task.properties"
+                 classpath="${basedir}/tools/checkstyle.jar"/>
+        <mkdir dir="${build.dir}/checkstyle"/>
+        <checkstyle config="${basedir}/config/checkstyle.xml"
+                    failOnViolation="false"
+                    maxErrors="0"
+                    maxWarnings="9999999">
+            <property key="config_loc" value="${basedir}/config"/>
+            <formatter type="plain"/>
+            <formatter type="xml" tofile="${build.dir}/checkstyle/report.xml"/>
+            <fileset dir="${src.dir}" includes="graphtea/**/*.java"/>
+        </checkstyle>
+        <echo message="Checkstyle report written to ${build.dir}/checkstyle/report.xml"/>
+    </target>
+
+    <target name="checkstyle-strict" depends="depends" description="Run Checkstyle; fail build on any violation">
+        <taskdef resource="com/puppycrawl/tools/checkstyle/ant/checkstyle-ant-task.properties"
+                 classpath="${basedir}/tools/checkstyle.jar"/>
+        <mkdir dir="${build.dir}/checkstyle"/>
+        <checkstyle config="${basedir}/config/checkstyle.xml"
+                    failOnViolation="true"
+                    maxErrors="0">
+            <property key="config_loc" value="${basedir}/config"/>
+            <formatter type="plain"/>
+            <formatter type="xml" tofile="${build.dir}/checkstyle/report.xml"/>
+            <fileset dir="${src.dir}" includes="graphtea/**/*.java"/>
+        </checkstyle>
+    </target>
+
     <!-- =================================
           target: clean
          ================================= -->