[BEAM-225] Create Class for Common TypeDescriptors

• Type: Bug
• Status: Resolved
• Priority: P4
• Resolution: Fixed
• Fix Version/s: 0.1.0-incubating
• Component/s: sdk-java-core
• Labels: Done starter
• Assignee: Jesse Anderson
• Reporter: Jesse Anderson
• Created: 25/Apr/16 18:13
• Updated: 06/Oct/20 21:53
• Resolved: 11/May/16 20:08

Description

There should be a built-in class for common types like String, Float, etc.

Right now, all types have to create an inline TypeDescriptor:

        PCollection<String> words = suits.apply(
                FlatMapElements.via(
                        (String line) -> Arrays.asList(line.split(" "))
                ).withOutputType(new TypeDescriptor<String>() {}));

The should be a built-in class with common types like String so you don't have to create a TypeDescriptor each time like:

              PCollection<String> words = suits.apply(
                FlatMapElements.via(
                        (String line) -> Arrays.asList(line.split(" "))
                ).withOutputType(TypeDescriptors.STRINGS));

Another possibility is to make it a static method:

              PCollection<String> words = suits.apply(
                FlatMapElements.via(
                        (String line) -> Arrays.asList(line.split(" "))
                ).withOutputType(TypeDescriptors.strings()));

An example of this is Apache Crunch's Writables class https://crunch.apache.org/apidocs/0.11.0/org/apache/crunch/types/writable/Writables.html.