How to use

allFields

method

in

org.apache.beam.sdk.schemas.FieldAccessDescriptor

@Test
public void testAllFields() {
 FieldAccessDescriptor fieldAccessDescriptor = FieldAccessDescriptor.withAllFields();
 assertTrue(fieldAccessDescriptor.resolve(SIMPLE_SCHEMA).allFields());
}

static Schema getOutputSchema(Schema inputSchema, FieldAccessDescriptor fieldAccessDescriptor) {
 if (fieldAccessDescriptor.allFields()) {
  return inputSchema;
 }
 Schema.Builder builder = new Schema.Builder();
 for (int fieldId : fieldAccessDescriptor.fieldIdsAccessed()) {
  builder.addField(inputSchema.getField(fieldId));
 }
 for (Map.Entry<Integer, FieldAccessDescriptor> nested :
   fieldAccessDescriptor.nestedFields().entrySet()) {
  Field field = inputSchema.getField(nested.getKey());
  FieldAccessDescriptor nestedDescriptor = nested.getValue();
  FieldType nestedType =
    FieldType.row(getOutputSchema(field.getType().getRowSchema(), nestedDescriptor));
  if (field.getNullable()) {
   builder.addNullableField(field.getName(), nestedType);
  } else {
   builder.addField(field.getName(), nestedType);
  }
 }
 return builder.build();
}

 static Row selectRow(
   Row input,
   FieldAccessDescriptor fieldAccessDescriptor,
   Schema inputSchema,
   Schema outputSchema) {
  if (fieldAccessDescriptor.allFields()) {
   return input;
  } else {
   Row.Builder output = Row.withSchema(outputSchema);
   for (int fieldId : fieldAccessDescriptor.fieldIdsAccessed()) {
    output.addValue(input.getValue(fieldId));
   }
   for (Map.Entry<Integer, FieldAccessDescriptor> nested :
     fieldAccessDescriptor.nestedFields().entrySet()) {
    String fieldName = inputSchema.nameOf(nested.getKey());
    Schema nestedInputSchema = inputSchema.getField(nested.getKey()).getType().getRowSchema();
    Schema nestedOutputSchema = outputSchema.getField(fieldName).getType().getRowSchema();
    output.addValue(
      selectRow(
        input.getValue(fieldName),
        nested.getValue(),
        nestedInputSchema,
        nestedOutputSchema));
   }
   return output.build();
  }
 }
}

@Test
public void testNestedFieldByName() {
 FieldAccessDescriptor fieldAccessDescriptor =
   FieldAccessDescriptor.withFieldNames("field1")
     .withNestedField("field1", FieldAccessDescriptor.withAllFields());
 fieldAccessDescriptor = fieldAccessDescriptor.resolve(NESTED_SCHEMA2);
 assertTrue(fieldAccessDescriptor.fieldIdsAccessed().isEmpty());
 assertEquals(1, fieldAccessDescriptor.nestedFields().size());
 FieldAccessDescriptor nestedAccess = fieldAccessDescriptor.nestedFields().get(1);
 assertTrue(nestedAccess.allFields());
}

@Test
public void testNestedFieldById() {
 FieldAccessDescriptor fieldAccessDescriptor =
   FieldAccessDescriptor.withFieldNames("field1")
     .withNestedField(1, FieldAccessDescriptor.withAllFields());
 fieldAccessDescriptor = fieldAccessDescriptor.resolve(NESTED_SCHEMA2);
 assertTrue(fieldAccessDescriptor.fieldIdsAccessed().isEmpty());
 assertEquals(1, fieldAccessDescriptor.nestedFields().size());
 FieldAccessDescriptor nestedAccess = fieldAccessDescriptor.nestedFields().get(1);
 assertTrue(nestedAccess.allFields());
}