Spring Cloud Dataflow Application Properties to Show a dropdown in Dataflow Ui - spring

Question

I want to know how to specify a property here so that i can get a dropdown in Spring Cloud Dataflow ui when ill register my app. I am adding screeshot of my app modal
This is the property file of my app
import java.nio.charset.Charset;
import org.springframework.boot.context.properties.ConfigurationProperties;
import java.util.*;
#ConfigurationProperties("filestream")
public class FileStreamProperties {
/* filePath for file stream */
private String filePath;
private List<String> list = new ArrayList<String>().add("option1");
/* delayMillis the delay between checks of the file for new content in milliseconds */
private long delayMillis = 1000;
private long bufferSize = 4096;
private Charset charset = Charset.defaultCharset();
public String getFilePath() {
return filePath;
}
public void setFilePath(String filePath) {
this.filePath = filePath;
}
public long getDelayMillis() {
return delayMillis;
}
public void setDelayMillis(long delayMillis) {
this.delayMillis = delayMillis;
}
public long getBufferSize() {
return bufferSize;
}
public void setBufferSize(long bufferSize) {
this.bufferSize = bufferSize;
}
public Charset getCharset() {
return charset;
}
public void setCharset(Charset charset) {
this.charset = charset;
}
}