Generate tags from JSON file

pom.xml

@@ -40,6 +40,21 @@
     </issueManagement>
 
     <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>3.7</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>2.8.5</version>
+        </dependency>
+        <dependency>
+            <groupId>com.squareup</groupId>
+            <artifactId>javapoet</artifactId>
+            <version>1.11.1</version>
+        </dependency>
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
@@ -52,12 +67,6 @@
             <version>1.3</version>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>org.apache.commons</groupId>
-            <artifactId>commons-lang3</artifactId>
-            <version>3.0</version>
-            <scope>test</scope>
-        </dependency>
         <dependency>
             <groupId>com.carrotsearch</groupId>
             <artifactId>junit-benchmarks</artifactId>
@@ -149,6 +158,19 @@
                     </execution>
                 </executions>
             </plugin>
+            <plugin>
+                <groupId>com.j2html</groupId>
+                <artifactId>j2html-maven-plugin</artifactId>
+                <version>1.0-SNAPSHOT</version>
+                <executions>
+                    <execution>
+                        <id>generate-tags</id>
+                        <goals>
+                            <goal>generate-tags</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
         </plugins>
     </build>
 

src/main/java/j2html/tags/ContainerTag.java

@@ -6,7 +6,7 @@
 import java.util.List;
 import java.util.stream.Stream;
 
-public class ContainerTag extends Tag<ContainerTag> {
+public class ContainerTag<T extends ContainerTag<T>> extends Tag<T> {
 
     private List<DomContent> children;
 
@@ -22,15 +22,15 @@ public ContainerTag(String tagName) {
      * @param child DomContent-object to be appended
      * @return itself for easy chaining
      */
-    public ContainerTag with(DomContent child) {
+    public T with(DomContent child) {
         if (this == child) {
             throw new RuntimeException("Cannot append a tag to itself.");
         }
         if (child == null) {
-            return this; // in some cases, like when using iff(), we ignore null children
+            return (T) this; // in some cases, like when using iff(), we ignore null children
         }
         children.add(child);
-        return this;
+        return (T) this;
     }
 
 
@@ -121,7 +121,7 @@ public ContainerTag condWith(boolean condition, DomContent... children) {
      * @param text the text to be appended
      * @return itself for easy chaining
      */
-    public ContainerTag withText(String text) {
+    public T withText(String text) {
         return with(new Text(text));
     }
 

src/main/java/j2html/tags/EmptyTag.java

@@ -4,7 +4,7 @@
 import j2html.attributes.Attribute;
 import java.io.IOException;
 
-public class EmptyTag extends Tag<EmptyTag> {
+public class EmptyTag<T extends EmptyTag<T>> extends Tag<T> {
 
     public EmptyTag(String tagName) {
         super(tagName);

src/main/java/j2html/tags/Tag.java

@@ -132,7 +132,7 @@ public T attr(String attribute) {
      * @param value     the attribute value
      * @return itself for easy chaining
      */
-    public T condAttr(boolean condition, String attribute, String value) {
+    public T condAttr(boolean condition, String attribute, Object value) {
         return (condition ? attr(attribute, value) : (T) this);
     }
 

src/main/java/j2html/tags/TagCreatorCodeGeneratorFromJson.java

@@ -0,0 +1,78 @@
+package j2html.tags;
+
+import com.google.gson.*;
+import com.squareup.javapoet.*;
+import j2html.attributes.Attr;
+
+import javax.lang.model.element.Modifier;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.OutputStreamWriter;
+import java.io.StringWriter;
+
+import static org.apache.commons.lang3.StringUtils.capitalize;
+
+public class TagCreatorCodeGeneratorFromJson {
+
+    public static void main(String[] args) throws Exception {
+        StringWriter output = new StringWriter();
+
+        try (FileReader fileReader = new FileReader("src/main/resources/tagClasses.json")) {
+            JsonObject json = new Gson().fromJson(fileReader, JsonObject.class);
+            ClassName containerTagClassName = ClassName.get(ContainerTag.class);
+            json.getAsJsonArray("tags").forEach(element -> {
+                JsonObject tagJson = element.getAsJsonObject();
+
+                String tag = tagJson.get("tag").getAsString();
+                ClassName tagClassName = ClassName.get("j2html.tags", capitalize(tag + "Tag"));
+                TypeSpec.Builder typeSpec = TypeSpec.classBuilder(tagClassName)
+                    .superclass(ParameterizedTypeName.get(containerTagClassName, tagClassName))
+                    .addMethod(
+                        MethodSpec.constructorBuilder()
+                            .addModifiers(Modifier.PUBLIC)
+                            .addStatement("super(\"" + tag + "\")")
+                            .build());
+
+                JsonArray attrs = tagJson.getAsJsonArray("attrs");
+                attrs.forEach(attrElement -> {
+                    String attrName = attrElement.isJsonObject() ? attrElement.getAsJsonObject().get("name").getAsString() : attrElement.getAsString();
+                    String attrNameCapitalized = capitalize(attrName);
+
+                    MethodSpec.Builder methodSpec = MethodSpec.methodBuilder("with" + attrNameCapitalized)
+                        .addModifiers(Modifier.PUBLIC)
+                        .returns(tagClassName);
+
+                    MethodSpec.Builder condMethodSpec = MethodSpec.methodBuilder("withCond" + attrNameCapitalized)
+                        .addModifiers(Modifier.PUBLIC)
+                        .addParameter(boolean.class, "condition")
+                        .returns(tagClassName);
+
+                    if (attrElement.isJsonObject() && new JsonPrimitive(true).equals(attrElement.getAsJsonObject().get("empty"))) {
+                        methodSpec.addStatement("return attr(\"" + attrName + "\")");
+                        condMethodSpec.addStatement("return condAttr(condition, \"" + attrName + "\", \"" + attrName + "\")");
+                    } else {
+                        methodSpec
+                            .addParameter(String.class, attrName)
+                            .addStatement("return attr(\"" + attrName + "\", " + attrName + ")");
+                        condMethodSpec
+                            .addParameter(boolean.class, "condition")
+                            .addParameter(String.class, attrName)
+                            .addStatement("return condAttr(condition, \"" + attrName + "\", " + attrName + ")");
+                    }
+                    typeSpec.addMethod(methodSpec.build())
+                        .addMethod(condMethodSpec.build());
+                });
+
+                try {
+                    JavaFile.builder("j2html.tags", typeSpec.build())
+                        .build()
+                        .writeTo(output);
+                } catch (IOException e) {
+                    throw new RuntimeException(e);
+                }
+            });
+        }
+
+        System.out.println(output);
+    }
+}

src/main/resources/globalAttributes.json

@@ -0,0 +1,7 @@
+[
+  {
+    "name": "tabindex",
+    "type": "Integer"
+  },
+  "title"
+]

src/main/resources/tagClasses.json

@@ -0,0 +1,18 @@
+{
+    "tags": [
+        {
+            "tag": "a",
+            "attrs": [
+                "href",
+                "charset"
+            ]
+        },
+        {
+            "tag": "video",
+            "attrs": [
+                { "name": "autoplay", "empty": true }, "controls", "height", "loop", "muted", "poster", "preload", "src", "width"
+            ]
+        },
+        "abbr"
+    ]
+}