/*
* Copyright (C) 2012-2014 DataStax Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.datastax.driver.mapping;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import com.datastax.driver.core.ExecutionInfo;
import com.datastax.driver.core.ResultSet;
import com.datastax.driver.core.Row;
/**
* A {@code ResultSet} mapped to an entity class.
*/
public class Result<T> implements Iterable<T> {
private final ResultSet rs;
private final EntityMapper<T> mapper;
private final int protocolVersion;
Result(ResultSet rs, EntityMapper<T> mapper, int protocolVersion) {
this.rs = rs;
this.mapper = mapper;
this.protocolVersion = protocolVersion;
}
private T map(Row row) {
T entity = mapper.newEntity();
for (ColumnMapper<T> cm : mapper.allColumns()) {
ByteBuffer bytes = row.getBytesUnsafe(cm.getColumnName());
if (bytes != null)
cm.setValue(entity, cm.getDataType().deserialize(bytes, protocolVersion));
}
return entity;
}
/**
* Test whether this mapped result set has more results.
*
* @return whether this mapped result set has more results.
*/
public boolean isExhausted() {
return rs.isExhausted();
}
/**
* Returns the next result (i.e. the entity corresponding to the next row
* in the result set).
*
* @return the next result in this mapped result set or null if it is exhausted.
*/
public T one() {
Row row = rs.one();
return row == null ? null : map(row);
}
/**
* Returns all the remaining results (entities) in this mapped result set
* as a list.
*
* @return a list containing the remaining results of this mapped result
* set. The returned list is empty if and only the result set is exhausted.
*/
public List<T> all() {
List<Row> rows = rs.all();
List<T> entities = new ArrayList<T>(rows.size());
for (Row row : rows) {
entities.add(map(row));
}
return entities;
}
/**
* An iterator over the entities of this mapped result set.
*
* The {@link Iterator#next} method is equivalent to calling {@link #one}.
* So this iterator will consume results and after a full iteration, the
* mapped result set (and underlying {@code ResultSet}) will be empty.
*
* The returned iterator does not support the {@link Iterator#remove} method.
*
* @return an iterator that will consume and return the remaining rows of
* this mapped result set.
*/
public Iterator<T> iterator() {
return new Iterator<T>() {
private final Iterator<Row> rowIterator = rs.iterator();
public boolean hasNext() {
return rowIterator.hasNext();
}
public T next() {
return map(rowIterator.next());
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
/**
* Returns information on the execution of this query.
* <p>
* The returned object includes basic information such as the queried hosts,
* but also the Cassandra query trace if tracing was enabled for the query.
*
* @return the execution info for this query.
*/
public ExecutionInfo getExecutionInfo() {
return rs.getExecutionInfo();
}
}