BAEL-2037 - Code for mini-article (#4923)

* BAEL-2037 - Code for mini-article

* BAEL-2037 - Fixes after editors review

* Fixing dependencies

* Change File Reader

* Formatting

* Fix imports

* Rename test class

json/src/main/java/com/baeldung/jsonpointer/JsonPointerCrud.java

@@ -0,0 +1,95 @@
+package com.baeldung.jsonpointer;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+import javax.json.Json;
+import javax.json.JsonObject;
+import javax.json.JsonPointer;
+import javax.json.JsonReader;
+import javax.json.JsonString;
+import javax.json.JsonStructure;
+
+public class JsonPointerCrud {
+
+    private JsonStructure jsonStructure = null;
+
+    public JsonPointerCrud(String fileName) throws IOException {
+
+        try (JsonReader reader = Json.createReader(Files.newBufferedReader(Paths.get(fileName)))) {
+            jsonStructure = reader.read();
+        } catch (FileNotFoundException e) {
+            System.out.println("Error to open json file: " + e.getMessage());
+        }
+
+    }
+
+    public JsonPointerCrud(InputStream stream) {
+
+        JsonReader reader = Json.createReader(stream);
+        jsonStructure = reader.read();
+        reader.close();
+
+    }
+
+    public JsonStructure insert(String key, String value) {
+
+        JsonPointer jsonPointer = Json.createPointer("/" + key);
+        JsonString jsonValue = Json.createValue(value);
+        jsonStructure = jsonPointer.add(jsonStructure, jsonValue);
+
+        return jsonStructure;
+
+    }
+
+    public JsonStructure update(String key, String newValue) {
+
+        JsonPointer jsonPointer = Json.createPointer("/" + key);
+        JsonString jsonNewValue = Json.createValue(newValue);
+        jsonStructure = jsonPointer.replace(jsonStructure, jsonNewValue);
+
+        return jsonStructure;
+    }
+
+    public JsonStructure delete(String key) {
+
+        JsonPointer jsonPointer = Json.createPointer("/" + key);
+        jsonPointer.getValue(jsonStructure);
+        jsonStructure = jsonPointer.remove(jsonStructure);
+
+        return jsonStructure;
+
+    }
+
+    public String fetchValueFromKey(String key) {
+        JsonPointer jsonPointer = Json.createPointer("/" + key);
+        JsonString jsonString = (JsonString) jsonPointer.getValue(jsonStructure);
+
+        return jsonString.getString();
+    }
+
+    public String fetchListValues(String key) {
+        JsonPointer jsonPointer = Json.createPointer("/" + key);
+        JsonObject jsonObject = (JsonObject) jsonPointer.getValue(jsonStructure);
+
+        return jsonObject.toString();
+    }
+
+    public String fetchFullJSON() {
+        JsonPointer jsonPointer = Json.createPointer("");
+        JsonObject jsonObject = (JsonObject) jsonPointer.getValue(jsonStructure);
+
+        return jsonObject.toString();
+
+    }
+
+    public boolean check(String key) {
+        JsonPointer jsonPointer = Json.createPointer("/" + key);
+        boolean found = jsonPointer.containsValue(jsonStructure);
+
+        return found;
+    }
+}