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https://issues.apache.org/jira/browse/FLINK-2033?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14559213#comment-14559213
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PJ Van Aeken commented on FLINK-2033:
-------------------------------------
I will add overloaded methods to the Java API on a need-to-have basis for
implementing the Scala Gelly API. Progress can be followed here:
https://github.com/PieterJanVanAeken/flink/tree/scala-gelly-api/
> Add overloaded methods with explicit TypeInformation parameters to Gelly
> ------------------------------------------------------------------------
>
> Key: FLINK-2033
> URL: https://issues.apache.org/jira/browse/FLINK-2033
> Project: Flink
> Issue Type: Task
> Components: Gelly
> Affects Versions: 0.9
> Reporter: PJ Van Aeken
> Assignee: PJ Van Aeken
>
> For the implementation of the Scala API for Gelly (FLINK-1962), we need to
> pass explicit TypeInformation since the Java TypeExtractor does not work for
> all Scala Types (see FLINK-2023).
> To do this, the java Gelly API needs to be expanded with methods that allow
> for explicit passing of TypeInformation.
> An example with mapVertices:
> {code}
> public <NV> Graph<K, NV, EV> mapVertices(final MapFunction<Vertex<K, VV>,
> NV> mapper) {
> TypeInformation<K> keyType = ((TupleTypeInfo<?>)
> vertices.getType()).getTypeAt(0);
> String callLocation = Utils.getCallLocationName();
> TypeInformation<NV> valueType =
> TypeExtractor.getMapReturnTypes(mapper, vertices.getType(), callLocation,
> false);
> TypeInformation<Vertex<K, NV>> returnType =
> (TypeInformation<Vertex<K, NV>>) new TupleTypeInfo(
> Vertex.class, keyType, valueType);
> return mapVertices(mapper,returnType);
> }
> public <NV> Graph<K, NV, EV> mapVertices(final MapFunction<Vertex<K, VV>,
> NV> mapper, TypeInformation<Vertex<K, NV>> returnType) {
> DataSet<Vertex<K, NV>> mappedVertices = vertices.map(
> new MapFunction<Vertex<K, VV>, Vertex<K, NV>>() {
> public Vertex<K, NV> map(Vertex<K, VV> value) throws
> Exception {
> return new Vertex<K, NV>(value.f0, mapper.map(value));
> }
> }).returns(returnType);
> return new Graph<K, NV, EV>(mappedVertices, this.edges, this.context);
> }
> {code}
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