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https://issues.apache.org/jira/browse/BEAM-6701?focusedWorklogId=200434&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-200434
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ASF GitHub Bot logged work on BEAM-6701:
----------------------------------------
Author: ASF GitHub Bot
Created on: 19/Feb/19 09:56
Start Date: 19/Feb/19 09:56
Worklog Time Spent: 10m
Work Description: amaliujia commented on pull request #7865: [BEAM-6701]
Add logical types to schema
URL: https://github.com/apache/beam/pull/7865#discussion_r257956360
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File path: sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/Schema.java
##########
@@ -398,6 +443,50 @@ public boolean isSupertypeOf(TypeName other) {
}
}
+ /**
+ * A LogicalType allows users to define a custom schema type.
+ *
+ * <p>A LogicalType is a way to define a new type that can be stored in a
schema field using an
+ * underlying FieldType as storage. A LogicalType must specify a base
FieldType used to store the
+ * data by overriding the {@link #getBaseType()} method. Usually the
FieldType returned will be
+ * one of the standard ones implemented by Schema. It is legal to return
another LogicalType, but
+ * the storage types must eventually resolve to one of the standard Schema
types; it is not
+ * allowed to have LogicalTypes reference each other recursively via
getBaseType. The {@link
+ * #toBaseType} and {@link #toInputType} should convert back and forth
between the Java type for
+ * the LogicalType (InputT) and the Java type appropriate for the underlying
base type (BaseT).
+ *
+ * <p>{@link #getIdentifier} must define a globally unique identifier for
this LogicalType. A
Review comment:
It seems that there is no verification on globally uniqueness of
identifiers. What's the effect if identifiers are not unique (seems to me that
there is no any effect)?
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Issue Time Tracking
-------------------
Worklog Id: (was: 200434)
Time Spent: 2h 10m (was: 2h)
> Create LogicalType for Schema fields
> ------------------------------------
>
> Key: BEAM-6701
> URL: https://issues.apache.org/jira/browse/BEAM-6701
> Project: Beam
> Issue Type: Sub-task
> Components: sdk-java-core
> Reporter: Reuven Lax
> Assignee: Reuven Lax
> Priority: Major
> Time Spent: 2h 10m
> Remaining Estimate: 0h
>
> This will allow users to create their own logical types to store in schema
> fields, backed by one of the fundamental schema field types. Today SQL hacks
> on top of the field metadata to distinguish its types. LogicalTypes would
> allow for a more principled way of doing this.
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