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https://issues.apache.org/jira/browse/BEAM-4461?focusedWorklogId=383100&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-383100
]
ASF GitHub Bot logged work on BEAM-4461:
----------------------------------------
Author: ASF GitHub Bot
Created on: 06/Feb/20 19:33
Start Date: 06/Feb/20 19:33
Worklog Time Spent: 10m
Work Description: reuvenlax commented on pull request #10766: [BEAM-4461]
Add Selected.flattenedSchema
URL: https://github.com/apache/beam/pull/10766#discussion_r376038435
##########
File path:
sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/transforms/Select.java
##########
@@ -69,55 +75,117 @@
* }</pre>
*/
@Experimental(Kind.SCHEMAS)
-public class Select<T> extends PTransform<PCollection<T>, PCollection<Row>> {
- private final FieldAccessDescriptor fieldAccessDescriptor;
-
- private Select(FieldAccessDescriptor fieldAccessDescriptor) {
- this.fieldAccessDescriptor = fieldAccessDescriptor;
+public class Select {
+ public static <T> Select.Fields<T> create() {
+ return new Fields<>(FieldAccessDescriptor.create());
}
/** Select a set of top-level field ids from the row. */
- public static <T> Select<T> fieldIds(Integer... ids) {
- return new Select<>(FieldAccessDescriptor.withFieldIds(ids));
+ public static <T> Fields<T> fieldIds(Integer... ids) {
+ return new Fields<>(FieldAccessDescriptor.withFieldIds(ids));
}
/** Select a set of top-level field names from the row. */
- public static <T> Select<T> fieldNames(String... names) {
- return new Select<>(FieldAccessDescriptor.withFieldNames(names));
+ public static <T> Fields<T> fieldNames(String... names) {
+ return new Fields<>(FieldAccessDescriptor.withFieldNames(names));
}
/**
* Select a set of fields described in a {@link FieldAccessDescriptor}.
*
* <p>This allows for nested fields to be selected as well.
*/
- public static <T> Select<T> fieldAccess(FieldAccessDescriptor
fieldAccessDescriptor) {
- return new Select<>(fieldAccessDescriptor);
+ public static <T> Fields<T> fieldAccess(FieldAccessDescriptor
fieldAccessDescriptor) {
+ return new Fields<>(fieldAccessDescriptor);
+ }
+
+ /**
+ * Selects every leaf-level field. This results in a a nested schema being
flattened into a single
+ * top-level schema.
+ */
+ public static <T> Flattened<T> flattenedSchema() {
+ return new Flattened<>();
+ }
+
+ private static class SelectDoFn<T> extends DoFn<T, Row> {
+ private FieldAccessDescriptor fieldAccessDescriptor;
+ private Schema inputSchema;
+ private Schema outputSchema;
+
+ // TODO: This should be the same as resolved so that Beam knows which
fields
+ // are being accessed. Currently Beam only supports wildcard descriptors.
+ // Once BEAM-4457 is fixed, fix this.
+ @FieldAccess("selectFields")
+ final FieldAccessDescriptor fieldAccess =
FieldAccessDescriptor.withAllFields();
+
+ public SelectDoFn(
+ FieldAccessDescriptor fieldAccessDescriptor, Schema inputSchema,
Schema outputSchema) {
+ this.fieldAccessDescriptor = fieldAccessDescriptor;
+ this.inputSchema = inputSchema;
+ this.outputSchema = outputSchema;
+ }
+
+ @ProcessElement
+ public void process(@FieldAccess("selectFields") @Element Row row,
OutputReceiver<Row> r) {
+ r.output(SelectHelpers.selectRow(row, fieldAccessDescriptor,
inputSchema, outputSchema));
+ }
+ }
+
+ public static class Fields<T> extends PTransform<PCollection<T>,
PCollection<Row>> {
+ private FieldAccessDescriptor fieldAccessDescriptor;
+
+ public Fields(FieldAccessDescriptor fieldAccessDescriptor) {
+ this.fieldAccessDescriptor = fieldAccessDescriptor;
+ }
+
+ @Override
+ public PCollection<Row> expand(PCollection<T> input) {
+ Schema inputSchema = input.getSchema();
+ FieldAccessDescriptor resolved =
fieldAccessDescriptor.resolve(inputSchema);
+ Schema outputSchema = SelectHelpers.getOutputSchema(inputSchema,
resolved);
+ return input
+ .apply(ParDo.of(new SelectDoFn<>(resolved, inputSchema,
outputSchema)))
+ .setRowSchema(outputSchema);
+ }
}
- @Override
- public PCollection<Row> expand(PCollection<T> input) {
- Schema inputSchema = input.getSchema();
- FieldAccessDescriptor resolved =
fieldAccessDescriptor.resolve(inputSchema);
- Schema outputSchema = SelectHelpers.getOutputSchema(inputSchema, resolved);
-
- return input
- .apply(
- ParDo.of(
- new DoFn<T, Row>() {
- // TODO: This should be the same as resolved so that Beam
knows which fields
- // are being accessed. Currently Beam only supports wildcard
descriptors.
- // Once BEAM-4457 is fixed, fix this.
- @FieldAccess("selectFields")
- final FieldAccessDescriptor fieldAccessDescriptor =
- FieldAccessDescriptor.withAllFields();
-
- @ProcessElement
- public void process(
- @FieldAccess("selectFields") @Element Row row,
OutputReceiver<Row> r) {
- r.output(SelectHelpers.selectRow(row, resolved,
inputSchema, outputSchema));
- }
- }))
- .setRowSchema(outputSchema);
+ /** A {@link PTransform} representing a flattened schema. */
+ public static class Flattened<T> extends PTransform<PCollection<T>,
PCollection<Row>> {
+ private SerializableFunction<List<String>, String> nameFn;
+
+ Flattened() {
+ this(CONCAT_FIELD_NAMES);
+ }
+
+ Flattened(SerializableFunction<List<String>, String> nameFn) {
+ this.nameFn = nameFn;
+ }
+
+ /**
+ * For nested fields, concatenate all the names separated by a _ character
in the flattened
+ * schema.
Review comment:
Added withFieldNameAs to allow the user to rename fields
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Issue Time Tracking
-------------------
Worklog Id: (was: 383100)
Time Spent: 29h 50m (was: 29h 40m)
> Create a library of useful transforms that use schemas
> ------------------------------------------------------
>
> Key: BEAM-4461
> URL: https://issues.apache.org/jira/browse/BEAM-4461
> Project: Beam
> Issue Type: Sub-task
> Components: sdk-java-core
> Reporter: Reuven Lax
> Assignee: Reuven Lax
> Priority: Major
> Time Spent: 29h 50m
> Remaining Estimate: 0h
>
> e.g. JoinBy(fields). Project, Filter, etc.
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