Github user markap14 commented on a diff in the pull request:
https://github.com/apache/nifi/pull/1918#discussion_r122736750
--- Diff:
nifi-nar-bundles/nifi-redis-bundle/nifi-redis-extensions/src/main/java/org/apache/nifi/redis/state/RedisStateMapJsonSerDe.java
---
@@ -0,0 +1,103 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.nifi.redis.state;
+
+import com.fasterxml.jackson.core.JsonFactory;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonToken;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * A RedisStateMapSerDe that uses JSON as the underlying representation.
+ */
+public class RedisStateMapJsonSerDe implements RedisStateMapSerDe {
+
+ public static final String FIELD_VERSION = "version";
+ public static final String FIELD_ENCODING = "encodingVersion";
+ public static final String FIELD_STATE_VALUES = "stateValues";
+
+ private final JsonFactory jsonFactory = new JsonFactory();
+
+ @Override
+ public byte[] serialize(final RedisStateMap stateMap) throws
IOException {
+ if (stateMap == null) {
+ return null;
+ }
+
+ try (final ByteArrayOutputStream out = new
ByteArrayOutputStream()) {
+ final JsonGenerator jsonGenerator =
jsonFactory.createGenerator(out);
+ jsonGenerator.writeStartObject();
+ jsonGenerator.writeNumberField(FIELD_VERSION,
stateMap.getVersion());
+ jsonGenerator.writeNumberField(FIELD_ENCODING,
stateMap.getEncodingVersion());
+
+ jsonGenerator.writeObjectFieldStart(FIELD_STATE_VALUES);
+ for (Map.Entry<String,String> entry :
stateMap.toMap().entrySet()) {
+ jsonGenerator.writeStringField(entry.getKey(),
entry.getValue());
+ }
+ jsonGenerator.writeEndObject();
+
+ jsonGenerator.writeEndObject();
+ jsonGenerator.flush();
+
+ return out.toByteArray();
+ }
+ }
+
+ @Override
+ public RedisStateMap deserialize(final byte[] data) throws IOException
{
+ if (data == null || data.length == 0) {
+ return null;
+ }
+
+ final RedisStateMap.Builder builder = new RedisStateMap.Builder();
+
+ try (final JsonParser jsonParser = jsonFactory.createParser(data))
{
+ while (jsonParser.nextToken() != JsonToken.END_OBJECT) {
--- End diff --
This code can probably be a lot simpler if we just use
jsonParser.readValueAsTree() here. That returns a JsonNode object. We could
then just call jsonNode.get(FIELD_VERSION), jsonNode.get(FIELD_ENCODING),
jsonNode.get(FIELD_STATE_VALUES)... but will leave it up to you if you think
the current approach is better. Just wanted to ensure that you know that this
exists :)
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