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https://issues.apache.org/jira/browse/FLINK-3702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15434753#comment-15434753
]
ASF GitHub Bot commented on FLINK-3702:
---------------------------------------
Github user ggevay commented on a diff in the pull request:
https://github.com/apache/flink/pull/2094#discussion_r76040532
--- Diff:
flink-core/src/main/java/org/apache/flink/api/java/typeutils/FieldAccessor.java
---
@@ -0,0 +1,295 @@
+/*
+ * 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.flink.api.java.typeutils;
+
+import org.apache.flink.annotation.PublicEvolving;
+import org.apache.flink.api.common.operators.Keys;
+import org.apache.flink.api.common.typeinfo.BasicTypeInfo;
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.typeutils.runtime.FieldSerializer;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+import java.lang.reflect.Array;
+import java.lang.reflect.Field;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+
+/**
+ * These classes encapsulate the logic of accessing a field specified by
the user as either an index
+ * or a field expression string. TypeInformation can also be requested for
the field.
+ * The position index might specify a field of a Tuple, an array, or a
simple type (only "0th field").
+ *
+ * Field expressions that specify nested fields (e.g. "f1.a.foo") result
in nested field accessors.
+ * These penetrate one layer, and then delegate the rest of the work to an
"innerAccesor".
+ * (see PojoFieldAccessor, RecursiveTupleFieldAccessor,
ProductFieldAccessor)
+ */
+@PublicEvolving
+public abstract class FieldAccessor<T, F> implements Serializable {
+
+ private static final long serialVersionUID = 1L;
+
+ protected TypeInformation fieldType;
+
+ /**
+ * Gets the TypeInformation for the type of the field.
+ * Note: For an array of a primitive type, it returns the corresponding
basic type (Integer for int[]).
+ */
+ @SuppressWarnings("unchecked")
+ public TypeInformation<F> getFieldType() {
+ return fieldType;
+ }
+
+
+ /**
+ * Gets the value of the field (specified in the constructor) of the
given record.
+ * @param record
+ * @return The value of the field.
+ */
+ public abstract F get(T record);
+
+ /**
+ * Sets the field (specified in the constructor) of the given record to
the given value.
+ *
+ * Warning: This might modify the original object, or might return a
new object instance.
+ * (This is necessary, because the record might be immutable.)
+ *
+ * @param record The record to modify
+ * @param fieldValue The new value of the field
+ * @return A record that has the given field value. (this might be a
new instance or the original)
+ */
+ public abstract T set(T record, F fieldValue);
+
+
+ //
==================================================================================================
--- End diff --
8f191a91d202c6e25d8e0ccf8e68c4d39c397315
> DataStream API PojoFieldAccessor doesn't support nested POJOs
> -------------------------------------------------------------
>
> Key: FLINK-3702
> URL: https://issues.apache.org/jira/browse/FLINK-3702
> Project: Flink
> Issue Type: Improvement
> Components: DataStream API
> Affects Versions: 1.0.0
> Reporter: Robert Metzger
> Assignee: Gabor Gevay
>
> The {{PojoFieldAccessor}} (which is used by {{.sum(String)}} and similar
> methods) doesn't support nested POJOs right now.
> As part of FLINK-3697 I'll add a check for a nested POJO and fail with an
> exception.
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