提交 cb7f7c1b authored 作者: LaughingMan's avatar LaughingMan

Use a Future so exceptions thrown in another thread don't get ignored

上级 3ae7d1e4
......@@ -13,10 +13,12 @@ import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import org.h2.api.ErrorCode;
import org.h2.engine.Constants;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import org.h2.util.IOUtils;
import org.h2.util.JdbcUtils;
import org.h2.util.Tool;
/**
......@@ -124,20 +126,6 @@ public class CreateCluster extends Tool {
private static void performTransfer(Statement statSource, String urlTarget,
String user, String password, String serverList) throws SQLException {
try (PipedReader pipeReader = new PipedReader()) {
/*
* Pipe writer is used + closed in the inner class, in a
* separate thread (needs to be final). It should be initialized
* within try{} so an exception could be caught if creation
* fails. In that scenario, the the writer should be null and
* needs no closing, and the main goal is that finally{} should
* bring the source DB out of exclusive mode, and close the
* reader.
*/
final PipedWriter pipeWriter = new PipedWriter(pipeReader);
// Backup data from source database in script form.
// Start writing to pipe writer in separate thread.
final ResultSet rs = statSource.executeQuery("SCRIPT");
// Delete the target database first.
try (Connection connTarget = DriverManager.getConnection(
......@@ -147,24 +135,7 @@ public class CreateCluster extends Tool {
statTarget.execute("DROP ALL OBJECTS DELETE FILES");
}
new Thread(
new Runnable() {
@Override
public void run() {
try {
while (rs.next()) {
pipeWriter.write(rs.getString(1) + "\n");
}
} catch (SQLException ex) {
throw new IllegalStateException("Producing script from the source DB is failing.", ex);
} catch (IOException ex) {
throw new IllegalStateException("Producing script from the source DB is failing.", ex);
} finally {
IOUtils.closeSilently(pipeWriter);
}
}
}
).start();
Future<?> threadFuture = startWriter(pipeReader, statSource);
// Read data from pipe reader, restore on target.
try (Connection connTarget = DriverManager.getConnection(
......@@ -177,9 +148,62 @@ public class CreateCluster extends Tool {
statSource.executeUpdate("SET CLUSTER '" + serverList + "'");
statTarget.executeUpdate("SET CLUSTER '" + serverList + "'");
}
// Check if the writer encountered any exception
try {
threadFuture.get();
} catch (ExecutionException ex) {
throw new SQLException(ex.getCause());
} catch (InterruptedException ex) {
throw new SQLException(ex);
}
} catch (IOException ex) {
throw new SQLException(ex);
}
}
private static Future<?> startWriter(PipedReader pipeReader, Statement statSource)
throws SQLException, IOException {
final ExecutorService thread = Executors.newFixedThreadPool(1);
/*
* Pipe writer is used + closed in the inner class, in a
* separate thread (needs to be final). It should be initialized
* within try{} so an exception could be caught if creation
* fails. In that scenario, the the writer should be null and
* needs no closing, and the main goal is that finally{} should
* bring the source DB out of exclusive mode, and close the
* reader.
*/
final PipedWriter pipeWriter = new PipedWriter(pipeReader);
// Backup data from source database in script form.
// Start writing to pipe writer in separate thread.
final ResultSet rs = statSource.executeQuery("SCRIPT");
// Since exceptions cannot be thrown across thread boundaries, return
// the task's future so we can check manually
Future<?> threadFuture = thread.submit(new Runnable() {
@Override
public void run() {
try {
while (rs.next()) {
pipeWriter.write(rs.getString(1) + "\n");
}
} catch (SQLException ex) {
throw new IllegalStateException("Producing script from the source DB is failing.", ex);
} catch (IOException ex) {
throw new IllegalStateException("Producing script from the source DB is failing.", ex);
} finally {
IOUtils.closeSilently(pipeWriter);
}
}
});
thread.shutdown();
return threadFuture;
}
}
Markdown 格式
0%
您添加了 0 到此讨论。请谨慎行事。
请先完成此评论的编辑!
注册 或者 后发表评论