try {
DataInputStream input = new DataInputStream(stream);
int size = WritableUtils.readVInt(input);
List<Expression> selectExpressions = Lists.newArrayListWithExpectedSize(size);
for (int i = 0; i < size; i++) {
ExpressionType type = ExpressionType.values()[WritableUtils.readVInt(input)];
Expression selectExpression = type.newInstance();
selectExpression.readFields(input);
selectExpressions.add(selectExpression);
}
return selectExpressions;
} catch (IOException e) {