Add lazy wrappers around diagram generators to make server init more …

…robust

ditaa/src/main/java/org/asciidoctor/diagram/ditaa/Ditaa.java

@@ -22,12 +22,6 @@ public class Ditaa implements DiagramGenerator
     public static final MimeType DEFAULT_CONTENT_TYPE = MimeType.TEXT_PLAIN_UTF8;
     public static final String DEFAULT_CHARSET = "UTF-8";
 
-    @Override
-    public String getName()
-    {
-        return "ditaa";
-    }
-
     @Override
     public ResponseData generate(Request request) throws IOException {
         MimeType format = request.headers.getValue(HTTPHeader.ACCEPT);

ditaa/src/main/java/org/asciidoctor/diagram/ditaa/DitaaDiagramGenerator.java

@@ -0,0 +1,15 @@
+package org.asciidoctor.diagram.ditaa;
+
+import org.asciidoctor.diagram.DiagramGenerator;
+import org.asciidoctor.diagram.LazyDiagramGenerator;
+
+public class DitaaDiagramGenerator extends LazyDiagramGenerator {
+    public DitaaDiagramGenerator() {
+        super("ditaa");
+    }
+
+    @Override
+    protected DiagramGenerator createGenerator() throws Exception {
+        return new Ditaa();
+    }
+}

ditaa/src/main/resources/META-INF/services/org.asciidoctor.diagram.DiagramGenerator

@@ -1 +1 @@
-org.asciidoctor.diagram.ditaa.Ditaa
+org.asciidoctor.diagram.ditaa.DitaaDiagramGenerator

plantuml/src/main/java/org/asciidoctor/diagram/plantuml/PlantUML.java

@@ -80,12 +80,6 @@ public class PlantUML implements DiagramGenerator
         }
     }
 
-    @Override
-    public String getName()
-    {
-        return "plantuml";
-    }
-
     @Override
     public ResponseData generate(Request request) throws IOException {
         File graphviz;

plantuml/src/main/java/org/asciidoctor/diagram/plantuml/PlantUMLDiagramGenerator.java

@@ -0,0 +1,15 @@
+package org.asciidoctor.diagram.plantuml;
+
+import org.asciidoctor.diagram.DiagramGenerator;
+import org.asciidoctor.diagram.LazyDiagramGenerator;
+
+public class PlantUMLDiagramGenerator extends LazyDiagramGenerator {
+    public PlantUMLDiagramGenerator() {
+        super("plantuml");
+    }
+
+    @Override
+    protected DiagramGenerator createGenerator() throws Exception {
+        return new PlantUML();
+    }
+}

plantuml/src/main/java/org/asciidoctor/diagram/plantuml/PlantUMLPreprocessor.java

@@ -21,12 +21,6 @@ public class PlantUMLPreprocessor implements DiagramGenerator
 {
     private static final MimeType DEFAULT_OUTPUT_FORMAT = MimeType.TEXT_PLAIN_UTF8;
 
-    @Override
-    public String getName()
-    {
-        return "plantumlpreprocessor";
-    }
-
     @Override
     public ResponseData generate(Request request) throws IOException {
         MimeType format = request.headers.getValue(HTTPHeader.ACCEPT);

plantuml/src/main/java/org/asciidoctor/diagram/plantuml/PlantUMLPreprocessorDiagramGenerator.java

@@ -0,0 +1,15 @@
+package org.asciidoctor.diagram.plantuml;
+
+import org.asciidoctor.diagram.DiagramGenerator;
+import org.asciidoctor.diagram.LazyDiagramGenerator;
+
+public class PlantUMLPreprocessorDiagramGenerator extends LazyDiagramGenerator {
+    public PlantUMLPreprocessorDiagramGenerator() {
+        super("plantumlpreprocessor");
+    }
+
+    @Override
+    protected DiagramGenerator createGenerator() throws Exception {
+        return new PlantUMLPreprocessorDiagramGenerator();
+    }
+}

plantuml/src/main/resources/META-INF/services/org.asciidoctor.diagram.DiagramGenerator

@@ -1,2 +1,2 @@
-org.asciidoctor.diagram.plantuml.PlantUML
-org.asciidoctor.diagram.plantuml.PlantUMLPreprocessor
+org.asciidoctor.diagram.plantuml.PlantUMLDiagramGenerator
+org.asciidoctor.diagram.plantuml.PlantUMLPreprocessorDiagramGenerator

server/src/main/java/org/asciidoctor/diagram/DiagramGenerator.java

@@ -3,7 +3,5 @@
 import java.io.IOException;
 
 public interface DiagramGenerator {
-    String getName();
-
     ResponseData generate(Request request) throws IOException;
 }

server/src/main/java/org/asciidoctor/diagram/LazyDiagramGenerator.java

@@ -0,0 +1,36 @@
+package org.asciidoctor.diagram;
+
+import java.io.IOException;
+
+public abstract class LazyDiagramGenerator implements NamedDiagramGenerator {
+    private final String name;
+    private DiagramGenerator diagramGenerator;
+    private IOException loadError;
+
+    public LazyDiagramGenerator(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    protected abstract DiagramGenerator createGenerator() throws Exception;
+
+    public ResponseData generate(Request request) throws IOException {
+        if (loadError != null) {
+            throw loadError;
+        }
+
+        if (diagramGenerator == null) {
+            try {
+                diagramGenerator = createGenerator();
+            } catch (Exception e) {
+                loadError = new IOException(getName() + " is could not be initialised", e);
+                throw loadError;
+            }
+        }
+
+        return diagramGenerator.generate(request);
+    }
+}

server/src/main/java/org/asciidoctor/diagram/NamedDiagramGenerator.java

@@ -0,0 +1,5 @@
+package org.asciidoctor.diagram;
+
+public interface NamedDiagramGenerator extends DiagramGenerator {
+    String getName();
+}

structurizr/src/main/java/org/asciidoctor/diagram/structurizr/Structurizr.java

@@ -93,12 +93,6 @@ static ParseDsl createParseDsl() {
 
     private static final MimeType DEFAULT_OUTPUT_FORMAT = PLANTUML;
 
-    @Override
-    public String getName() {
-        return "structurizr";
-    }
-
-    @Override
     public ResponseData generate(Request request) throws IOException {
         MimeType format = request.headers.getValue(HTTPHeader.ACCEPT);
 

structurizr/src/main/java/org/asciidoctor/diagram/structurizr/StructurizrDiagramGenerator.java

@@ -0,0 +1,15 @@
+package org.asciidoctor.diagram.structurizr;
+
+import org.asciidoctor.diagram.DiagramGenerator;
+import org.asciidoctor.diagram.LazyDiagramGenerator;
+
+public class StructurizrDiagramGenerator extends LazyDiagramGenerator {
+    public StructurizrDiagramGenerator() {
+        super("structurizr");
+    }
+
+    @Override
+    protected DiagramGenerator createGenerator() throws Exception {
+        return new Structurizr();
+    }
+}

structurizr/src/main/resources/META-INF/services/org.asciidoctor.diagram.DiagramGenerator

@@ -1 +1 @@
-org.asciidoctor.diagram.structurizr.Structurizr
+org.asciidoctor.diagram.structurizr.StructurizrDiagramGenerator

syntrax/src/main/java/org/asciidoctor/diagram/syntrax/Syntrax.java

@@ -16,11 +16,6 @@
 public class Syntrax implements DiagramGenerator {
     public static final MimeType DEFAULT_OUTPUT_FORMAT = MimeType.SVG;
 
-    @Override
-    public String getName() {
-        return "syntrax";
-    }
-
     @Override
     public ResponseData generate(Request request) throws IOException {
         MimeType format = request.headers.getValue(HTTPHeader.ACCEPT);

syntrax/src/main/java/org/asciidoctor/diagram/syntrax/SyntraxDiagramGenerator.java

@@ -0,0 +1,15 @@
+package org.asciidoctor.diagram.syntrax;
+
+import org.asciidoctor.diagram.DiagramGenerator;
+import org.asciidoctor.diagram.LazyDiagramGenerator;
+
+public class SyntraxDiagramGenerator extends LazyDiagramGenerator {
+    public SyntraxDiagramGenerator() {
+        super("syntrax");
+    }
+
+    @Override
+    protected DiagramGenerator createGenerator() throws Exception {
+        return new Syntrax();
+    }
+}

syntrax/src/main/resources/META-INF/services/org.asciidoctor.diagram.DiagramGenerator

@@ -1 +1 @@
-org.asciidoctor.diagram.syntrax.Syntrax
+org.asciidoctor.diagram.syntrax.SyntraxDiagramGenerator