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https://issues.apache.org/jira/browse/TAJO-1529?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14482580#comment-14482580
]
ASF GitHub Bot commented on TAJO-1529:
--------------------------------------
Github user jinossy commented on a diff in the pull request:
https://github.com/apache/tajo/pull/512#discussion_r27851381
--- 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 agree, we need pre-initialization with const params
> Implement json_extract_path_text(string, string) function
> ---------------------------------------------------------
>
> Key: TAJO-1529
> URL: https://issues.apache.org/jira/browse/TAJO-1529
> Project: Tajo
> Issue Type: Sub-task
> Components: function/udf
> Reporter: Jinho Kim
> Assignee: Jinho Kim
> Priority: Minor
> Fix For: 0.11.0, 0.10.1
>
> Attachments: TAJO-1529.patch, TAJO-1529_2.patch
>
>
> See the below sample:
> {code}
> SELECT json_extract_path_text('{"sample" : {"name" :
> "tajo"}}','$.sample.name')
> {code}
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