package backtype.storm.tuple;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.io.Serializable;
public class Fields implements Iterable<String>, Serializable {
private List<String> _fields;
private Map<String, Integer> _index = new HashMap<String, Integer>();
public Fields(String... fields) {
this(Arrays.asList(fields));
}
public Fields(List<String> fields) {
_fields = new ArrayList<String>(fields.size());
for (String field : fields) {
if (_fields.contains(field))
throw new IllegalArgumentException(String.format(
"duplicate field '%s'", field));
_fields.add(field);
}
index();
}
public List<Object> select(Fields selector, List<Object> tuple) {
List<Object> ret = new ArrayList<Object>(selector.size());
for (String s : selector) {
ret.add(tuple.get(_index.get(s)));
}
return ret;
}
public List<String> toList() {
return new ArrayList<String>(_fields);
}
public int size() {
return _fields.size();
}
public String get(int index) {
return _fields.get(index);
}
public Iterator<String> iterator() {
return _fields.iterator();
}
/**
* Returns the position of the specified field.
*/
public int fieldIndex(String field) {
Integer ret = _index.get(field);
if (ret == null) {
throw new IllegalArgumentException(field + " does not exist");
}
return ret;
}
/**
* Returns true if this contains the specified name of the field.
*/
public boolean contains(String field) {
return _index.containsKey(field);
}
private void index() {
for (int i = 0; i < _fields.size(); i++) {
_index.put(_fields.get(i), i);
}
}
@Override
public String toString() {
return _fields.toString();
}
}