package org.springframework.data.cassandra.convert;
import java.util.List;
import org.springframework.cassandra.core.cql.CqlIdentifier;
import com.datastax.driver.core.ColumnDefinitions;
import com.datastax.driver.core.DataType;
import com.datastax.driver.core.Row;
/**
* Helpful class to read a column's value from a row, with possible type conversion.
*
* @author Matthew T. Adams
*/
public class ColumnReader {
protected Row row;
protected ColumnDefinitions columns;
public ColumnReader(Row row) {
this.row = row;
this.columns = row.getColumnDefinitions();
}
/**
* Returns the row's column value.
*/
public Object get(CqlIdentifier name) {
return get(name.toCql());
}
/**
* Returns the row's column value.
*/
public Object get(String name) {
int indexOf = getColumnIndex(name);
return get(indexOf);
}
public Object get(int i) {
if (row.isNull(i)) {
return null;
}
DataType type = columns.getType(i);
if (type.isCollection()) {
List<DataType> collectionTypes = type.getTypeArguments();
if (collectionTypes.size() == 2) {
return row.getMap(i, collectionTypes.get(0).asJavaClass(), collectionTypes.get(1).asJavaClass());
}
if (type.equals(DataType.list(collectionTypes.get(0)))) {
return row.getList(i, collectionTypes.get(0).asJavaClass());
}
if (type.equals(DataType.set(collectionTypes.get(0)))) {
return row.getSet(i, collectionTypes.get(0).asJavaClass());
}
throw new IllegalStateException("Unknown Collection type encountered. Valid collections are Set, List and Map.");
}
if (type.equals(DataType.text()) || type.equals(DataType.ascii()) || type.equals(DataType.varchar())) {
return row.getString(i);
}
if (type.equals(DataType.cint()) || type.equals(DataType.varint())) {
return new Integer(row.getInt(i));
}
if (type.equals(DataType.cdouble())) {
return new Double(row.getDouble(i));
}
if (type.equals(DataType.bigint()) || type.equals(DataType.counter())) {
return new Long(row.getLong(i));
}
if (type.equals(DataType.cfloat())) {
return new Float(row.getFloat(i));
}
if (type.equals(DataType.decimal())) {
return row.getDecimal(i);
}
if (type.equals(DataType.cboolean())) {
return new Boolean(row.getBool(i));
}
if (type.equals(DataType.timestamp())) {
return row.getDate(i);
}
if (type.equals(DataType.blob())) {
return row.getBytes(i);
}
if (type.equals(DataType.inet())) {
return row.getInet(i);
}
if (type.equals(DataType.uuid()) || type.equals(DataType.timeuuid())) {
return row.getUUID(i);
}
return row.getBytesUnsafe(i);
}
public Row getRow() {
return row;
}
/**
* Returns the row's column value as an instance of the given type.
*
* @throws ClassCastException if the value cannot be converted to the requested type.
*/
public <T> T get(CqlIdentifier name, Class<T> requestedType) {
return get(getColumnIndex(name.toCql()), requestedType);
}
/**
* Returns the row's column value as an instance of the given type.
*
* @throws ClassCastException if the value cannot be converted to the requested type.
*/
public <T> T get(String name, Class<T> requestedType) {
return get(columns.getIndexOf(name), requestedType);
}
/**
* Returns the row's column value as an instance of the given type.
*
* @throws ClassCastException if the value cannot be converted to the requested type.
*/
@SuppressWarnings("unchecked")
public <T> T get(int i, Class<T> requestedType) {
Object o = get(i);
if (o == null) {
return null;
}
return (T) o;
}
private int getColumnIndex(String name) {
int indexOf = columns.getIndexOf(name);
if (indexOf == -1) {
throw new IllegalArgumentException("Column does not exist in Cassandra table: " + name);
}
return indexOf;
}
}