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https://issues.apache.org/jira/browse/HADOOP-2555?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12557096#action_12557096
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Peter Dolan commented on HADOOP-2555:
-------------------------------------
Ok, I'm taking this one. I own it. No Touchy!
Maybe someone will eventually fulfill my dreams and add me to the list of
developers so I can officially own an issue... sniff... sniff...
> Refactor the HTable#get and HTable#getRow methods to avoid repetition of
> retry-on-failure logic
> -----------------------------------------------------------------------------------------------
>
> Key: HADOOP-2555
> URL: https://issues.apache.org/jira/browse/HADOOP-2555
> Project: Hadoop
> Issue Type: Improvement
> Components: contrib/hbase
> Reporter: Peter Dolan
> Priority: Minor
>
> The following code is repeated in every one of HTable#get and HTable#getRow
> methods:
> {code:title=HTable.java|borderStyle=solid}
> MapWritable value = null;
> for (int tries = 0; tries < numRetries; tries++) {
> HRegionLocation r = getRegionLocation(row);
> HRegionInterface server =
> connection.getHRegionConnection(r.getServerAddress());
>
> try {
> value = server.getRow(r.getRegionInfo().getRegionName(), row, ts);
> // This is the only line of code that changes significantly between methods
> break;
>
> } catch (IOException e) {
> if (e instanceof RemoteException) {
> e = RemoteExceptionHandler.decodeRemoteException((RemoteException)
> e);
> }
> if (tries == numRetries - 1) {
> // No more tries
> throw e;
> }
> if (LOG.isDebugEnabled()) {
> LOG.debug("reloading table servers because: " + e.getMessage());
> }
> tableServers = connection.reloadTableServers(tableName);
> }
> try {
> Thread.sleep(this.pause);
>
> } catch (InterruptedException x) {
> // continue
> }
> }
> {code}
> This should be factored out into a protected method that handles
> retry-on-failure logic to facilitate more robust testing and the development
> of new API methods.
> Proposed modification:
> // Execute the provided Callable against the server
> protected <T> callServerWithRetries(Callable<T> callable) throws
> RemoteException;
> The above code could then be reduced to:
> {code:title=HTable.java|borderStyle=solid}
> MapWritable value = null;
> final connection;
> try {
> value = callServerWithRetries(new Callable<MapWritable>() {
> HRegionLocation r = getRegionLocation(row);
> HRegionInterface server =
> connection.getHRegionConnection(r.getServerAddress());
> server.getRow(r.getRegionInfo().getRegionName(), row, ts);
> });
> } catch (RemoteException e) {
> // handle unrecoverable remote exceptions
> }
> {code}
> This would greatly ease the development of new API methods by reducing the
> amount of code needed to implement a new method and reducing the amount of
> logic that needs to be tested per method.
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