Github user hyunsik commented on a diff in the pull request:
https://github.com/apache/tajo/pull/512#discussion_r27850825
--- Diff:
tajo-core/src/main/java/org/apache/tajo/engine/function/json/JsonExtractPathText.java
---
@@ -0,0 +1,86 @@
+/**
+ * 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
+ * <p/>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p/>
+ * 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.tajo.engine.function.json;
+
+import com.jayway.jsonpath.JsonPath;
+import net.minidev.json.JSONObject;
+import net.minidev.json.parser.JSONParser;
+import org.apache.tajo.catalog.Column;
+import org.apache.tajo.common.TajoDataTypes;
+import org.apache.tajo.datum.Datum;
+import org.apache.tajo.datum.DatumFactory;
+import org.apache.tajo.datum.NullDatum;
+import org.apache.tajo.engine.function.annotation.Description;
+import org.apache.tajo.engine.function.annotation.ParamTypes;
+import org.apache.tajo.plan.function.GeneralFunction;
+import org.apache.tajo.storage.Tuple;
+
+/**
+ * json_extract_path_text(string, string) -
+ * Extracts JSON string from a JSON string based on json path specified,
+ * and returns JSON string pointed to by xPath.
+ *
+ *
+ * Returns null if either argument is null.
+ *
+ * Example:
+ * SELECT json_extract_path_text('{"sample" : {"name" :
"tajo"}}','$.sample.name') FROM src LIMIT 1;\n"
+ * -> result: 'tajo'
+ */
+@Description(
+ functionName = "json_extract_path_text",
+ description = "Returns JSON string pointed to by xPath",
+ detail = "Extracts JSON string from a JSON string based on json path
specified,\n"
+ + "and returns JSON string pointed to by xPath.",
+ example = "> SELECT json_extract_path_text('{\"sample\" : {\"name\" :
\"tajo\"}}','$.sample.name');\n"
+ + "tajo",
+ returnType = TajoDataTypes.Type.TEXT,
+ paramTypes = {@ParamTypes(paramTypes = {TajoDataTypes.Type.TEXT,
TajoDataTypes.Type.TEXT})}
+)
+public class JsonExtractPathText extends GeneralFunction {
+ private JSONParser parser;
+
+ public JsonExtractPathText() {
+ super(new Column[]{
+ new Column("string", TajoDataTypes.Type.TEXT),
+ new Column("string", TajoDataTypes.Type.TEXT),
+ });
+ parser = new JSONParser(JSONParser.MODE_JSON_SIMPLE |
JSONParser.IGNORE_CONTROL_CHAR);
--- End diff --
I misunderstood it. It's just a function. So, it does not have bind()
method. We may need pre-initialization method like bind in Eval.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
