A framework that read data from jni scanner, which can support the data source from java ecosystem(java API).
## Java Interface
Java scanner should extends `org.apache.doris.jni.JniScanner`, implements the following methods:
```
// Initialize JniScanner
public abstract void open() throws IOException;
// Close JniScanner and release resources
public abstract void close() throws IOException;
// Scan data and save as vector table
public abstract int getNext() throws IOException;
```
See demo usage in `org.apache.doris.jni.MockJniScanner`
## c++ interface
C++ reader should use `doris::JniConnector` to get data from `org.apache.doris.jni.JniScanner`. See demo usage in `doris::MockJniReader`.
## Pushed-down predicates
Java scanner can get pushed-down predicates by `org.apache.doris.jni.vec.ScanPredicate`.
## Remaining works:
1. Implement complex nested types.
2. Read hudi MOR table as the end-to-end demo usage.
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