[
https://issues.apache.org/jira/browse/DRILL-5324?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15899873#comment-15899873
]
Paul Rogers edited comment on DRILL-5324 at 3/7/17 6:13 PM:
------------------------------------------------------------
The idea is to provide a uniform column access interface, similar to how JDBC
works (but much simpler!). Assume a row reader defined elsewhere:
{code}
public interface RowSetReader {
boolean next();
ColumnReader column(int colIndex);
}
{code}
Then, we can read values as follows. Assume a schema of (Int, VarChar):
{code}
RowSetReader reader = ...;
assertEquals(10, reader.column(0).getInt());
assertEquals("foo", reader.column(1).getString());
{code}
Proposed interfaces (without comments):
{code}
public enum ValueType {
INTEGER, LONG, DOUBLE, STRING, BYTES
}
public interface ColumnReader {
ValueType getType();
boolean isNull();
int getInt();
long getLong();
double getDouble();
String getString();
byte[] getBytes();
}
public interface ColumnWriter {
ValueType getType();
void setNull();
void setInt(int value);
void setLong(long value);
void setDouble(double value);
void setString(String value);
void setBytes(byte[] value);
}
{code}
was (Author: paul-rogers):
The idea is to provide a uniform column access interface, similar to how JDBC
works (but much simpler!). Assume a row reader defined elsewhere:
{code}
public interface RowSetReader {
boolean next();
ColumnReader column(int colIndex);
}
{code}
Then, we can read values as follows. Assume a schema of (Int, VarChar):
{code}
RowSetReader reader = ...;
assertEquals(10, reader.column(0).getInt());
assertEquals("foo", reader.column(1).getString());
{code}
Proposed interfaces (without comments):
{code}
public interface ColumnReader {
ValueType getType();
boolean isNull();
int getInt();
long getLong();
double getDouble();
String getString();
byte[] getBytes();
}
public interface ColumnWriter {
ValueType getType();
void setNull();
void setInt(int value);
void setLong(long value);
void setDouble(double value);
void setString(String value);
void setBytes(byte[] value);
}
{code}
> Provide simplified column reader/writer for use in tests
> --------------------------------------------------------
>
> Key: DRILL-5324
> URL: https://issues.apache.org/jira/browse/DRILL-5324
> Project: Apache Drill
> Issue Type: Sub-task
> Components: Tools, Build & Test
> Affects Versions: 1.11.0
> Reporter: Paul Rogers
> Assignee: Paul Rogers
> Fix For: 1.11.0
>
>
> In support of DRILL-5323, we wish to provide a very easy way to work with row
> sets. See the comment section for examples of the target API.
> Drill provides over 100 different value vectors, any of which may be required
> to perform a specific unit test. Creating these vectors, populating them, and
> retrieving values, is very tedious. The work is so complex that it acts to
> discourage developers from writing such tests.
> To simplify the task, we wish to provide a simplified row set reader and
> writer. To do that, we need to generate the corresponding column reader and
> writer for each value vector. This ticket focuses on the column-level readers
> and writers, and the required code generation.
> Drill already provides vector readers and writers derived from
> {{FieldReader}}. However, these readers do not provide a uniform get/set
> interface that is type independent on the application side. Instead,
> application code must be aware of the type of the vector, something we seek
> to avoid for test code.
> The reader and writer classes are designed to be used in many contexts, not
> just for testing. As a result, their implementation makes no assumptions
> about the broader row reader and writer, other than that a row index and the
> required value vector are both available.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
