/**
* Populates an entity from a row.
*
* @param entity Entity object to populate from a row.
* @param row Kiji row to populate the entity from.
* @return the populated entity.
* @throws IllegalAccessException
* @throws IOException
*/
public T populateEntityFromRow(T entity, KijiRowData row)
throws IllegalAccessException, IOException {
// Populate fields from the row columns:
for (final Field field : mColumnFields) {
final KijiColumn column = field.getAnnotation(KijiColumn.class);
Preconditions.checkState(column != null);
if (column.qualifier().isEmpty()) {
// Field is populated from a map-type family:
populateFieldFromMapTypeFamily(entity, field, column, row);
} else {
// Field is populated from a fully-qualified column:
populateFieldFromFullyQualifiedColumn(entity, field, column, row);
}
}
// Populate fields from the row entity ID:
for (final Field field : mEntityIdFields) {
final EntityIdField eidField = field.getAnnotation(EntityIdField.class);
Preconditions.checkState(eidField != null);
final int index = mRowKeyComponentIndexMap.get(eidField.component());
field.set(entity, row.getEntityId().getComponentByIndex(index));
}
return entity;
}
/**
* Initializes a new specification for an Entity from an annotated Java class.
*
* @param klass Annotated Java class to derive an entity specification from.
* @param kiji Kiji instance where to fetch entities from.
* @throws IOException on I/O error.
*/
public EntitySpec(Class<T> klass, Kiji kiji) throws IOException {
mClass = klass;
final KijiEntity entity = klass.getAnnotation(KijiEntity.class);
Preconditions.checkArgument(
entity != null, "Class '{}' has no @KijiEntity annotation.", klass);
mTableName = entity.table();
final KijiTable table = kiji.openTable(mTableName);
try {
final KijiTableLayout layout = table.getLayout();
// TODO: Support deprecated RowKeyFormat?
final RowKeyFormat2 rowKeyFormat = (RowKeyFormat2) layout.getDesc().getKeysFormat();
final Map<String, RowKeyComponent> rkcMap = Maps.newHashMap();
final Map<String, Integer> rkcIndexMap = Maps.newHashMap();
for (int index = 0; index < rowKeyFormat.getComponents().size(); ++index) {
final RowKeyComponent rkc = rowKeyFormat.getComponents().get(index);
rkcMap.put(rkc.getName(), rkc);
rkcIndexMap.put(rkc.getName(), index);
}
mRowKeyComponentMap = ImmutableMap.copyOf(rkcMap);
mRowKeyComponentIndexMap = ImmutableMap.copyOf(rkcIndexMap);
// --------------------------------------------------------------------
// Parse fields with annotations from the entity class:
final List<Field> columnFields = Lists.newArrayList();
final List<Field> entityIdFields = Lists.newArrayList();
for (final Field field : mClass.getDeclaredFields()) {
final KijiColumn column = field.getAnnotation(KijiColumn.class);
final EntityIdField eidField = field.getAnnotation(EntityIdField.class);
if ((column != null) && (eidField != null)) {
throw new IllegalArgumentException(
String.format(
"Field '%s' cannot have both @KijiColumn and @EntityIdField annotations.",
field));
} else if (column != null) {
LOG.debug("Validating column field '{}'.", field);
field.setAccessible(true);
columnFields.add(field);
final FamilyLayout flayout = layout.getFamilyMap().get(column.family());
Preconditions.checkArgument(
flayout != null,
"Field '%s' maps to non-existing family '%s' from table '%s'.",
field,
column.family(),
mTableName);
if (column.qualifier().isEmpty()) {
// Request for a map-type family:
Preconditions.checkArgument(
flayout.isMapType(),
"Field '%s' maps to family '%s' from table '%s' which is not a map-type family.",
field,
column.family(),
mTableName);
// Validate field type:
if (column.pageSize() > 0) {
Preconditions.checkArgument(
MapFamilyVersionIterator.class.isAssignableFrom(field.getType()),
"Fields mapped to map-type family with paging enabled must be "
+ "MapFamilyVersionIterator, got '{}'.",
field.getType());
} else {
// TODO Validate type when no paging enabled on map-type family.
}
} else {
// Request for a fully-qualified column:
final ColumnLayout clayout = flayout.getColumnMap().get(column.qualifier());
Preconditions.checkArgument(
flayout != null,
"Field '%s' maps to non-existing column '%s:%s' from table '%s'.",
field,
column.family(),
column.qualifier(),
mTableName);
// Validate field type:
if (column.pageSize() > 0) {
Preconditions.checkArgument(
ColumnVersionIterator.class.isAssignableFrom(field.getType()),
"Fields mapped to column with paging enabled must be "
+ "ColumnVersionIterator, got '{}'.",
field.getType());
} else {
// TODO Validate type when no paging enabled on the column.
}
}
} else if (eidField != null) {
LOG.debug("Validating entity ID field '{}'.", field);
field.setAccessible(true);
entityIdFields.add(field);
final RowKeyComponent rkc = mRowKeyComponentMap.get(eidField.component());
Preconditions.checkArgument(
rkc != null,
"Field '%s' maps to unknown entity ID component '%s'.",
field,
eidField.component());
} else {
LOG.debug("Ignoring field '{}' with no annotation.", field);
}
}
mColumnFields = ImmutableList.copyOf(columnFields);
mEntityIdFields = ImmutableList.copyOf(entityIdFields);
} finally {
table.release();
}
}