YAML to JSON

src/main/java/com/amihaiemil/eoyaml/YamlMapping.java

@@ -27,6 +27,7 @@
  */
 package com.amihaiemil.eoyaml;
 
+import javax.json.JsonObject;
 import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeParseException;
@@ -471,4 +472,12 @@ default List<YamlNode> children() {
         }
         return children;
     }
+
+    /**
+     * Turn this YamlMapping to a JsonObject.
+     * @return JsonObject.
+     */
+    default JsonObject toJsonObject() {
+        return (JsonObject) this.accept(new YamlToJsonVisitor());
+    }
 }

src/main/java/com/amihaiemil/eoyaml/YamlNode.java

@@ -29,6 +29,7 @@
 
 import com.amihaiemil.eoyaml.exceptions.YamlReadingException;
 
+import javax.json.JsonValue;
 import java.util.List;
 
 /**
@@ -129,4 +130,11 @@ default <T> T accept(YamlVisitor<? extends T> visitor) {
         return visitor.visitYamlNode(this);
     }
 
+    /**
+     * Turn this YamlNode to JsonValue.
+     * @return JsonValue.
+     */
+    default JsonValue toJsonValue() {
+        return this.accept(new YamlToJsonVisitor());
+    }
 }

src/main/java/com/amihaiemil/eoyaml/YamlSequence.java

@@ -27,6 +27,7 @@
  */
 package com.amihaiemil.eoyaml;
 
+import javax.json.JsonArray;
 import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeParseException;
@@ -274,4 +275,12 @@ default LocalDateTime dateTime(final int index) {
         }
         return datetime;
     }
+
+    /**
+     * Turn this YamlSequence to a JsonArray.
+     * @return JsonArray.
+     */
+    default JsonArray toJsonArray() {
+        return (JsonArray) this.accept(new YamlToJsonVisitor());
+    }
 }

src/main/java/com/amihaiemil/eoyaml/YamlStream.java

@@ -27,6 +27,7 @@
  */
 package com.amihaiemil.eoyaml;
 
+import javax.json.JsonArray;
 import java.util.*;
 import java.util.function.*;
 import java.util.stream.*;
@@ -223,4 +224,12 @@ default Optional<YamlNode> findFirst() {
     default Optional<YamlNode> findAny() {
         return this.values().stream().findAny();
     }
+
+    /**
+     * Turn this YamlSequence to a JsonArray.
+     * @return JsonArray.
+     */
+    default JsonArray toJsonArray() {
+        return (JsonArray) this.accept(new YamlToJsonVisitor());
+    }
 }

src/main/java/com/amihaiemil/eoyaml/YamlToJsonVisitor.java

@@ -0,0 +1,101 @@
+/**
+ * Copyright (c) 2016-2024, Mihai Emil Andronache
+ * All rights reserved.
+ * <p>
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * Neither the name of the copyright holder nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+package com.amihaiemil.eoyaml;
+
+import javax.json.Json;
+import javax.json.JsonArrayBuilder;
+import javax.json.JsonObjectBuilder;
+import javax.json.JsonValue;
+
+/**
+ * Visitor which converts the Yaml to JSON.
+ * @author Mihai Andronache (amihaiemil@gmail.com)
+ * @version $Id$
+ * @checkstyle ExecutableStatementCount (1000 lines)
+ * @since 8.0.2
+ */
+final class YamlToJsonVisitor implements YamlVisitor<JsonValue> {
+
+    @Override
+    public JsonValue visitYamlMapping(final YamlMapping node) {
+        final JsonObjectBuilder object = Json.createObjectBuilder();
+        node.keys().forEach(
+            k -> {
+                if(k instanceof Scalar) {
+                    final String stringKey = ((Scalar) k).value();
+                    object.add(
+                        stringKey,
+                        this.visitYamlNode(node.value(stringKey))
+                    );
+                } else {
+                    throw new IllegalArgumentException(
+                        "YamlMapping contains key which is not a Scalar. "
+                        + "Cannot convert to JSON!"
+                    );
+                }
+            }
+        );
+        return object.build();
+    }
+
+    @Override
+    public JsonValue visitYamlSequence(final YamlSequence node) {
+        final JsonArrayBuilder array = Json.createArrayBuilder();
+        node.values().forEach(
+            v -> array.add(this.visitYamlNode(v))
+        );
+        return array.build();
+    }
+
+    @Override
+    public JsonValue visitYamlStream(final YamlStream node) {
+        final JsonArrayBuilder array = Json.createArrayBuilder();
+        node.values().forEach(
+            v -> array.add(this.visitYamlNode(v))
+        );
+        return array.build();
+    }
+
+    @Override
+    public JsonValue visitScalar(final Scalar node) {
+        return Json.createValue(node.value());
+    }
+
+    @Override
+    public JsonValue defaultResult() {
+        return JsonValue.EMPTY_JSON_OBJECT;
+    }
+
+    @Override
+    public JsonValue aggregateResult(
+        final JsonValue aggregate,
+        final JsonValue nextResult
+    ) {
+        return null;
+    }
+}

src/main/java/com/amihaiemil/eoyaml/YamlVisitor.java

@@ -44,7 +44,19 @@ public interface YamlVisitor<T> {
      * @return T returned type.
      */
     default T visitYamlNode(final YamlNode node) {
-        return this.visitChildren(node);
+        T result;
+        if (node instanceof Scalar) {
+            result = this.visitScalar((Scalar) node);
+        } else if (node instanceof YamlSequence) {
+            result = this.visitYamlSequence((YamlSequence) node);
+        } else if (node instanceof YamlMapping) {
+            result = this.visitYamlMapping((YamlMapping) node);
+        } else if (node instanceof YamlStream) {
+            result = this.visitYamlStream((YamlStream) node);
+        } else {
+            result = this.visitChildren(node);
+        }
+        return result;
     }
 
     /**

src/test/java/com/amihaiemil/eoyaml/RtYamlMappingTest.java

@@ -401,9 +401,16 @@ public void prettyPrintsSimpleYaml() throws Exception {
             .add("name", "eo-yaml")
             .add("conditions", "- none")
             .build();
-        System.out.print(yaml.toString());
+        System.out.println(yaml.toString());
+        System.out.println(yaml.toJsonObject());
         String expected = this.readTestResource("simpleMapping.yml");
         MatcherAssert.assertThat(yaml.toString(), Matchers.equalTo(expected));
+        MatcherAssert.assertThat(
+            yaml.toJsonObject().toString(),
+            Matchers.equalTo(
+                "{\"architect\":\"mihai\",\"developers\":[\"rultor\",\"salikjan\",\"sherif\"],\"name\":\"eo-yaml\",\"conditions\":\"- none\"}"
+            )
+        );
     }
 
     /**