Add Schema-based validation operations

Author: zhossain-info

src/main/java/com/relogiclabs/json/schema/JsonSchema.java

@@ -0,0 +1,66 @@
+package com.relogiclabs.json.schema;
+
+import com.relogiclabs.json.schema.message.MessageFormatter;
+import com.relogiclabs.json.schema.tree.JsonTree;
+import com.relogiclabs.json.schema.tree.RuntimeContext;
+import com.relogiclabs.json.schema.tree.SchemaTree;
+import com.relogiclabs.json.schema.util.DebugUtils;
+import lombok.Getter;
+
+import java.util.Queue;
+
+/**
+ * {@code JsonSchema} provides Schema validation functionalities for JSON document.
+ */
+@Getter
+public class JsonSchema {
+    private final RuntimeContext runtime;
+    private final SchemaTree schemaTree;
+    private final Queue<Exception> exceptions;
+
+    /**
+     * Initializes a new instance of the {@link JsonSchema} class for the
+     * specified Schema string.
+     * @param schema A Schema string for validation
+     */
+    public JsonSchema(String schema) {
+        runtime = new RuntimeContext(MessageFormatter.SCHEMA_VALIDATION, false);
+        exceptions = runtime.getExceptions();
+        schemaTree = new SchemaTree(runtime, schema);
+    }
+
+    /**
+     * Indicates whether the input JSON string conforms to the Schema specified
+     * in the {@link JsonSchema} constructor.
+     * @param json The JSON to validate with Schema
+     * @return Returns {@code true} if the JSON string conforms to the Schema and {@code false} otherwise.
+     */
+    public boolean isValid(String json) {
+        exceptions.clear();
+        var jsonTree = new JsonTree(runtime, json);
+        DebugUtils.print(schemaTree, jsonTree);
+        return schemaTree.getRoot().match(jsonTree.getRoot());
+    }
+
+    /**
+     *  Writes error messages that occur during Schema validation process, to the
+     *  standard error output stream.
+     */
+    public void writeError() {
+        for(var exception : exceptions)
+            System.err.println(exception.getMessage());
+    }
+
+    /**
+     * Indicates whether the input JSON string conforms to the given Schema string.
+     * @param schema The Schema string to conform or validate
+     * @param json The JSON string to conform or validate
+     * @return Returns {@code true} if the JSON string conforms to the Schema and {@code false} otherwise.
+     */
+    public static boolean isValid(String schema, String json) {
+        var jsonSchema = new JsonSchema(schema);
+        var result = jsonSchema.isValid(json);
+        if(!result) jsonSchema.writeError();
+        return result;
+    }
+}