check needed classpath for engines

Author: nidi3

graphviz-java/src/main/java/guru/nidi/graphviz/engine/AbstractJsGraphvizEngine.java

@@ -33,7 +33,7 @@
 
 public abstract class AbstractJsGraphvizEngine extends AbstractGraphvizEngine {
     private static final String VIZ_BASE = "META-INF/resources/webjars/viz.js-for-graphviz-java/2.1.2/";
-    static boolean AVAILABLE = isOnClasspath(VIZ_BASE + "viz.js");
+    static final boolean AVAILABLE = isOnClasspath(VIZ_BASE + "viz.js");
     private static final Pattern FONT_NAME_PATTERN = Pattern.compile("\"?fontname\"?\\s*=\\s*\"?(.*?)[\",;\\]]");
     private static final Map<Class<?>, ThreadLocal<JavascriptEngine>> ENGINES = new HashMap<>();
     private final Supplier<JavascriptEngine> engineSupplier;

graphviz-java/src/main/java/guru/nidi/graphviz/engine/Graphviz.java

@@ -82,8 +82,8 @@ private static List<GraphvizEngine> availableEngines() {
             engines.add(new GraphvizJdkEngine());
         }
         if (engines.size() == 1) {
-            LOG.warn("Only GraphvizServerEngine is available." +
-                    " If you want to use other engines, please put the needed dependencies on the classpath.");
+            LOG.warn("Only GraphvizServerEngine is available."
+                    + " If you want to use other engines, please put the needed dependencies on the classpath.");
         }
         return engines;
     }

graphviz-java/src/main/java/guru/nidi/graphviz/engine/GraphvizCmdLineEngine.java

@@ -37,7 +37,7 @@
  */
 public class GraphvizCmdLineEngine extends AbstractGraphvizEngine {
     private static final Logger LOG = LoggerFactory.getLogger(AbstractGraphvizEngine.class);
-    static boolean AVAILABLE = isOnClasspath("org.apache.commons.exec.CommandLine");
+    static final boolean AVAILABLE = isOnClasspath("org/apache/commons/exec/CommandLine.class");
 
     private final String envPath;
     private final CommandRunner cmdRunner;

graphviz-java/src/main/java/guru/nidi/graphviz/engine/GraphvizJdkEngine.java

@@ -20,8 +20,8 @@
 import static guru.nidi.graphviz.engine.IoUtils.isOnClasspath;
 
 public class GraphvizJdkEngine extends AbstractJsGraphvizEngine {
-    static boolean AVAILABLE = AbstractJsGraphvizEngine.AVAILABLE &&
-            (tryGraal() != null || isOnClasspath("net.arnx.nashorn.lib.PromiseException"));
+    static final boolean AVAILABLE = AbstractJsGraphvizEngine.AVAILABLE
+            && (tryGraal() != null || isOnClasspath("net/arnx/nashorn/lib/PromiseException.class"));
 
     public GraphvizJdkEngine() {
         super(false, GraphvizJdkEngine::newEngine);
@@ -32,7 +32,7 @@ public GraphvizJdkEngine() {
 
     private static JavascriptEngine newEngine() {
         final GraalJavascriptEngine graal = tryGraal();
-        return graal != null ? graal : new NashornJavascriptEngine();
+        return graal == null ? new NashornJavascriptEngine() : graal;
     }
 
     @Nullable

graphviz-java/src/main/java/guru/nidi/graphviz/engine/GraphvizV8Engine.java

@@ -20,7 +20,8 @@
 import static guru.nidi.graphviz.engine.IoUtils.isOnClasspath;
 
 public class GraphvizV8Engine extends AbstractJsGraphvizEngine {
-    static boolean AVAILABLE = AbstractJsGraphvizEngine.AVAILABLE && isOnClasspath("com.eclipsesource.v8.V8");
+    static final boolean AVAILABLE = AbstractJsGraphvizEngine.AVAILABLE
+            && isOnClasspath("com/eclipsesource/v8/V8.class");
 
     public GraphvizV8Engine() {
         this(null);

graphviz-java/src/main/java/guru/nidi/graphviz/engine/IoUtils.java

@@ -32,13 +32,8 @@ static String readStream(InputStream in) throws IOException {
         return new String(buf, StandardCharsets.UTF_8);
     }
 
-    static boolean isOnClasspath(String clazz) {
-        try {
-            Class.forName(clazz);
-            return true;
-        } catch (ClassNotFoundException e) {
-            return false;
-        }
+    static boolean isOnClasspath(String resource) {
+        return Thread.currentThread().getContextClassLoader().getResourceAsStream(resource) != null;
     }
 
     static void closeQuietly(AutoCloseable c) {

graphviz-java/src/main/java/guru/nidi/graphviz/engine/Rasterizer.java

@@ -26,9 +26,9 @@
 
 public interface Rasterizer {
     @Nullable
-    Rasterizer BATIK = isOnClasspath("org.apache.batik.transcoder.Transcoder") ? new BatikRasterizer() : null;
+    Rasterizer BATIK = isOnClasspath("org/apache/batik/transcoder/Transcoder.class") ? new BatikRasterizer() : null;
     @Nullable
-    Rasterizer SALAMANDER = isOnClasspath("com.kitfox.svg.SVGDiagram") ? new SalamanderRasterizer() : null;
+    Rasterizer SALAMANDER = isOnClasspath("com/kitfox/svg/SVGDiagram.class") ? new SalamanderRasterizer() : null;
     @Nullable
     Rasterizer DEFAULT = getDefault();
 

graphviz-java/src/test/java/guru/nidi/graphviz/CodeAnalysisTest.java

@@ -114,7 +114,7 @@ protected PmdResult analyzePmd() {
                                 .ignore("CyclomaticComplexity", "StdCyclomaticComplexity", "ModifiedCyclomaticComplexity", "NPathComplexity"),
                         In.classes(GraphvizJdkEngine.class, GraphvizV8Engine.class, GraphvizServerEngine.class, AbstractGraphvizEngine.class)
                                 .ignore("PreserveStackTrace", "SignatureDeclareThrowsException", "AvoidCatchingGenericException"),
-                        In.locs("MutableGraph", "Serializer", "ParserImpl", "Label").ignore("GodClass"),
+                        In.locs("MutableGraph", "Serializer", "ParserImpl", "Label", "Graphviz").ignore("GodClass"),
                         In.locs("ImmutableGraph", "MutableGraph").ignore("ExcessiveMethodLength", "ExcessiveParameterList", "LooseCoupling"),
                         In.locs("Format", "ImmutableGraph$GraphAttributed").ignore("AccessorMethodGeneration"),
                         In.locs("AttributeConfigs", "AttributeValidator", "FontTools").ignore("TooManyStaticImports"),
@@ -142,7 +142,7 @@ protected CpdResult analyzeCpd() {
                 .apply(PmdConfigs.cpdIgnoreEqualsHashCodeToString())
                 .because("It's java",
                         In.loc("*Graph").ignore("Graph(strict, directed, cluster, name,", "if (strict != graph.strict) {"),
-                        In.loc("Format").ignore("String preProcess(String src) {"))
+                        In.loc("Format").ignore("EngineResult postProcess("))
                 .just(In.locs("GraphvizGraalEngine", "GraphvizNashornEngine").ignore("void doInit()"));
         return new CpdAnalyzer(AnalyzerConfig.maven().main(), 36, collector).analyze();
     }