Update PreprocessSchemas with interface implementation

Signed-off-by: Jalander Ramagiri <jalander.ramagiri@est.tech>

preprocessor/pom.xml

@@ -56,7 +56,7 @@
                             <goal>java</goal>
                         </goals>
                         <configuration>
-                            <mainClass>dev.cdevents.preprocessor.PreprocessSchemas</mainClass>
+                            <mainClass>dev.cdevents.PreprocessSchemas</mainClass>
                             <arguments>
                                 <argument>${spec.schemas.dir}</argument>
                             </arguments>

preprocessor/src/main/java/dev/cdevents/PreprocessSchemas.java

@@ -0,0 +1,38 @@
+package dev.cdevents;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import dev.cdevents.process.ProcessSchemas;
+import dev.cdevents.process.ProcessSchemasImpl;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Iterator;
+
+/**
+ * Adapts incoming schemas to a format that jsonschema2pojo
+ */
+public final class PreprocessSchemas {
+
+    private PreprocessSchemas() {
+    }
+    /**
+     *
+     * Main method to update schema files.
+     * @param args [0] - spec schemas directory for the cdevents-sdk-java
+     */
+    public static void main(String[] args) {
+        if (args == null || args.length != 1) {
+            System.err.println("Usage: PreprocessSchemas <spec_schemas_directory_path>");
+            throw new IllegalArgumentException("spec schemas directory path argument not passed to PreprocessSchemas");
+        }
+        String specSchemasDir = args[0];
+        ProcessSchemas processSchemas = new ProcessSchemasImpl();
+        processSchemas.updateSchemas(specSchemasDir);
+    }
+}

preprocessor/src/main/java/dev/cdevents/preprocessor/package-info.java → preprocessor/src/main/java/dev/cdevents/package-info.java

@@ -14,4 +14,4 @@
  *
  */
 
-package dev.cdevents.preprocessor;
+package dev.cdevents;

preprocessor/src/main/java/dev/cdevents/process/ProcessSchemas.java

@@ -0,0 +1,10 @@
+package dev.cdevents.process;
+
+public interface ProcessSchemas {
+
+    /**
+     * Updates schemas in the specified input schemasPath.
+     * @param schemasPath
+     */
+    void updateSchemas(String schemasPath);
+}

preprocessor/src/main/java/dev/cdevents/process/ProcessSchemasImpl.java

@@ -0,0 +1,69 @@
+package dev.cdevents.process;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Iterator;
+
+public class ProcessSchemasImpl implements ProcessSchemas {
+
+    private static Logger log = LoggerFactory.getLogger(ProcessSchemasImpl.class);
+
+    /**
+     * Updates schemas in the specified input schemasPath.
+     * @param schemasPath
+     */
+    @Override
+    public void updateSchemas(String schemasPath) {
+        try {
+            Files.walk(Paths.get(schemasPath))
+                    .filter(Files::isRegularFile)
+                    .filter(path -> path.toString().endsWith(".json"))
+                    .forEach(ProcessSchemasImpl::processFile);
+        } catch (IOException e) {
+            log.error("Exception occurred while processing schema directory {}", e.getMessage());
+            throw new IllegalStateException("Exception occurred while processing schema directory", e);
+        }
+    }
+
+
+private static void processFile(Path filePath) {
+    log.info("processing schema file {} to update $ref path with json extension.", filePath.getFileName());
+    ObjectMapper objectMapper = new ObjectMapper();
+    try {
+        JsonNode rootNode = objectMapper.readTree(filePath.toFile());
+        updateRefs(rootNode);
+        objectMapper.writerWithDefaultPrettyPrinter().writeValue(filePath.toFile(), rootNode);
+    } catch (IOException e) {
+        log.error("Exception occurred while process schema file to update ref {}", e.getMessage());
+        throw new IllegalStateException("Exception occurred while process schema file to update ref ", e);
+    }
+}
+
+private static void updateRefs(JsonNode node) {
+    if (node.isObject()) {
+        ObjectNode objectNode = (ObjectNode) node;
+        Iterator<String> fieldNames = objectNode.fieldNames();
+        while (fieldNames.hasNext()) {
+            String fieldName = fieldNames.next();
+            JsonNode childNode = objectNode.get(fieldName);
+            if ("$ref".equals(fieldName) && !childNode.asText().endsWith(".json")) {
+                objectNode.put(fieldName, childNode.asText() + ".json");
+            } else {
+                updateRefs(childNode);
+            }
+        }
+    } else if (node.isArray()) {
+        for (JsonNode arrayItem : node) {
+            updateRefs(arrayItem);
+        }
+    }
+}
+}

preprocessor/src/main/java/dev/cdevents/process/package-info.java

@@ -0,0 +1,17 @@
+/**
+ * Copyright 2024-Present https://cdevents.dev/
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ *
+ */
+
+package dev.cdevents.process;