@Override
public Schema getOutputSchema(Schema input) {
ArrayList<String> bagNames = new ArrayList<String>(input.size() / 2);
Map<String, String> bagNameToJoinPrefix = new HashMap<String, String>(input.size() / 2);
Map<String, Integer> bagNameToSize = new HashMap<String, Integer>(input.size() / 2);
Schema outputSchema = null;
Schema bagSchema = new Schema();
try {
int i = 0;
// all even fields should be bags, odd fields are key names
String bagName = null;
String tupleName = null;
for (FieldSchema outerField : input.getFields()) {
if (i++ % 2 == 1) continue;
bagName = outerField.alias;
bagNames.add(bagName);
if (bagName == null) bagName = "null";
if (outerField.schema == null)
throw new RuntimeException(
"Expected input format of (bag, 'field') pairs. "
+ "Did not receive a bag at index: "
+ i
+ ", alias: "
+ bagName
+ ". "
+ "Instead received type: "
+ DataType.findTypeName(outerField.type)
+ " in schema:"
+ input.toString());
FieldSchema tupleField = outerField.schema.getField(0);
tupleName = tupleField.alias;
bagNameToJoinPrefix.put(bagName, getPrefixedAliasName(outerField.alias, tupleName));
if (tupleField.schema == null) {
log.error(
String.format(
"could not get schema for inner tuple %s in bag %s", tupleName, bagName));
} else {
bagNameToSize.put(bagName, tupleField.schema.size());
for (FieldSchema innerField : tupleField.schema.getFields()) {
String innerFieldName = innerField.alias;
if (innerFieldName == null) innerFieldName = "null";
String outputFieldName = bagName + "::" + innerFieldName;
bagSchema.add(new FieldSchema(outputFieldName, innerField.type));
}
}
}
outputSchema = new Schema(new Schema.FieldSchema("joined", bagSchema, DataType.BAG));
log.debug("output schema: " + outputSchema.toString());
} catch (FrontendException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
Properties properties = getInstanceProperties();
properties.put(BAG_NAMES_PROPERTY, bagNames);
properties.put(BAG_NAME_TO_JOIN_PREFIX_PROPERTY, bagNameToJoinPrefix);
properties.put(BAG_NAME_TO_SIZE_PROPERTY, bagNameToSize);
return outputSchema;
}
@Override
public Schema outputSchema(Schema input) {
try {
Schema.FieldSchema inputFieldSchema = input.getField(0);
if (inputFieldSchema.type != DataType.BAG) {
throw new RuntimeException("Expected a BAG as input");
}
return new Schema(
new Schema.FieldSchema(
getSchemaName(this.getClass().getName().toLowerCase(), input),
inputFieldSchema.schema,
DataType.BAG));
} catch (FrontendException e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}