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https://issues.apache.org/jira/browse/PHOENIX-1661?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14641860#comment-14641860
]
ASF GitHub Bot commented on PHOENIX-1661:
-----------------------------------------
Github user JamesRTaylor commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/102#discussion_r35489782
--- Diff:
phoenix-core/src/main/java/org/apache/phoenix/expression/function/JsonArrayElementsFunction.java
---
@@ -0,0 +1,110 @@
+/*
+ * 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.phoenix.expression.function;
+
+import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
+import org.apache.phoenix.compile.KeyPart;
+import org.apache.phoenix.exception.SQLExceptionCode;
+import org.apache.phoenix.exception.SQLExceptionInfo;
+import org.apache.phoenix.expression.Expression;
+import org.apache.phoenix.parse.FunctionParseNode.Argument;
+import org.apache.phoenix.parse.FunctionParseNode.BuiltInFunction;
+import org.apache.phoenix.schema.IllegalDataException;
+import org.apache.phoenix.schema.json.PhoenixJson;
+import org.apache.phoenix.schema.tuple.Tuple;
+import org.apache.phoenix.schema.types.*;
+import org.apache.phoenix.util.ByteUtil;
+
+import java.sql.SQLException;
+import java.util.List;
+
+@BuiltInFunction(name = JsonArrayElementsFunction.NAME, args = {
+ @Argument(allowedTypes = { PJson.class })})
+public class JsonArrayElementsFunction extends ScalarFunction {
+ public static final String NAME = "JSON_ARRAY_ELEMENTS";
+
+ public JsonArrayElementsFunction() {
+ super();
+ }
+
+ public JsonArrayElementsFunction(List<Expression> children) {
+ super(children);
+ }
+
+ @Override
+ public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
+
+ Expression jsonExpression = this.children.get(0);
+ if (!jsonExpression.evaluate(tuple, ptr)) {
+ return false;
+ }
+ if (ptr.getLength() == 0) {
+ return false;
--- End diff --
This (and other occurences of the same) should return true, meaning "yes,
there was enough information available for me to evaluate this expression, but
it returned null (which is what a ptr.getLength() of 0 means)"
> Implement built-in functions for JSON
> -------------------------------------
>
> Key: PHOENIX-1661
> URL: https://issues.apache.org/jira/browse/PHOENIX-1661
> Project: Phoenix
> Issue Type: Sub-task
> Reporter: James Taylor
> Labels: JSON, Java, SQL, gsoc2015, mentor
> Attachments: PhoenixJSONSpecification-First-Draft.pdf
>
>
> Take a look at the JSON built-in functions that are implemented in Postgres
> (http://www.postgresql.org/docs/9.3/static/functions-json.html) and implement
> the same for Phoenix in Java following this guide:
> http://phoenix-hbase.blogspot.com/2013/04/how-to-add-your-own-built-in-function.html
> Examples of functions include ARRAY_TO_JSON, ROW_TO_JSON, TO_JSON, etc. The
> implementation of these built-in functions will be impacted by how JSON is
> stored in Phoenix. See PHOENIX-628. An initial implementation could work off
> of a simple text-based JSON representation and then when a native JSON type
> is implemented, they could be reworked to be more efficient.
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