DataFrame (datafusion-java 0.7.1 API)

```
public interface DataFrame
```
A dataframe is a rectangle shaped data that holds columns and rows, and can be collected into batches and read via reader.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`java.util.concurrent.CompletableFuture<org.apache.arrow.vector.ipc.ArrowReader>`	`collect(org.apache.arrow.memory.BufferAllocator allocator)`	Collect dataframe into a list of record batches
`long`	`getPointer()`
`java.util.concurrent.CompletableFuture<java.lang.Void>`	`show()`	Print results.

- Method Detail
  - collect
```
java.util.concurrent.CompletableFuture<org.apache.arrow.vector.ipc.ArrowReader> collect(org.apache.arrow.memory.BufferAllocator allocator)
```
    Collect dataframe into a list of record batches
    
    Parameters:
    
    allocator - buffer allocator to allocate vectors within Reader
    
    Returns:
    
    reader instance to extract the data, you are expected to ArrowReader.close() it after usage to release memory
  - show
```
java.util.concurrent.CompletableFuture<java.lang.Void> show()
```
    Print results.
    
    Returns:
    
    null
  - getPointer
```
long getPointer()
```