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| <h2 title="Class DFSInotifyEventInputStream" class="title">Class DFSInotifyEventInputStream</h2> |
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| <li>org.apache.hadoop.hdfs.DFSInotifyEventInputStream</li> |
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| <pre>@InterfaceAudience.Public |
| @InterfaceStability.Unstable |
| public class <span class="typeNameLabel">DFSInotifyEventInputStream</span> |
| extends <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html?is-external=true" title="class or interface in java.lang">Object</a></pre> |
| <div class="block">Stream for reading inotify events. DFSInotifyEventInputStreams should not |
| be shared among multiple threads.</div> |
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| <td class="colFirst"><code>static org.slf4j.Logger</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../org/apache/hadoop/hdfs/DFSInotifyEventInputStream.html#LOG">LOG</a></span></code> </td> |
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| <td class="colFirst"><code>long</code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../org/apache/hadoop/hdfs/DFSInotifyEventInputStream.html#getTxidsBehindEstimate--">getTxidsBehindEstimate</a></span>()</code> |
| <div class="block">Return a estimate of how many transaction IDs behind the NameNode's |
| current state this stream is.</div> |
| </td> |
| </tr> |
| <tr id="i1" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../org/apache/hadoop/hdfs/inotify/EventBatch.html" title="class in org.apache.hadoop.hdfs.inotify">EventBatch</a></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../org/apache/hadoop/hdfs/DFSInotifyEventInputStream.html#poll--">poll</a></span>()</code> |
| <div class="block">Returns the next batch of events in the stream or null if no new |
| batches are currently available.</div> |
| </td> |
| </tr> |
| <tr id="i2" class="altColor"> |
| <td class="colFirst"><code><a href="../../../../org/apache/hadoop/hdfs/inotify/EventBatch.html" title="class in org.apache.hadoop.hdfs.inotify">EventBatch</a></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../org/apache/hadoop/hdfs/DFSInotifyEventInputStream.html#poll-long-java.util.concurrent.TimeUnit-">poll</a></span>(long time, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/TimeUnit.html?is-external=true" title="class or interface in java.util.concurrent">TimeUnit</a> tu)</code> |
| <div class="block">Returns the next event batch in the stream, waiting up to the specified |
| amount of time for a new batch.</div> |
| </td> |
| </tr> |
| <tr id="i3" class="rowColor"> |
| <td class="colFirst"><code><a href="../../../../org/apache/hadoop/hdfs/inotify/EventBatch.html" title="class in org.apache.hadoop.hdfs.inotify">EventBatch</a></code></td> |
| <td class="colLast"><code><span class="memberNameLink"><a href="../../../../org/apache/hadoop/hdfs/DFSInotifyEventInputStream.html#take--">take</a></span>()</code> |
| <div class="block">Returns the next batch of events in the stream, waiting indefinitely if |
| a new batch is not immediately available.</div> |
| </td> |
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| <h4>LOG</h4> |
| <pre>public static final org.slf4j.Logger LOG</pre> |
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| <a name="poll--"> |
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| <h4>poll</h4> |
| <pre>public <a href="../../../../org/apache/hadoop/hdfs/inotify/EventBatch.html" title="class in org.apache.hadoop.hdfs.inotify">EventBatch</a> poll() |
| throws <a href="https://docs.oracle.com/javase/8/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</a>, |
| <a href="../../../../org/apache/hadoop/hdfs/inotify/MissingEventsException.html" title="class in org.apache.hadoop.hdfs.inotify">MissingEventsException</a></pre> |
| <div class="block">Returns the next batch of events in the stream or null if no new |
| batches are currently available.</div> |
| <dl> |
| <dt><span class="throwsLabel">Throws:</span></dt> |
| <dd><code><a href="https://docs.oracle.com/javase/8/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</a></code> - because of network error or edit log |
| corruption. Also possible if JournalNodes are unresponsive in the |
| QJM setting (even one unresponsive JournalNode is enough in rare cases), |
| so catching this exception and retrying at least a few times is |
| recommended.</dd> |
| <dd><code><a href="../../../../org/apache/hadoop/hdfs/inotify/MissingEventsException.html" title="class in org.apache.hadoop.hdfs.inotify">MissingEventsException</a></code> - if we cannot return the next batch in the |
| stream because the data for the events (and possibly some subsequent |
| events) has been deleted (generally because this stream is a very large |
| number of transactions behind the current state of the NameNode). It is |
| safe to continue reading from the stream after this exception is thrown |
| The next available batch of events will be returned.</dd> |
| </dl> |
| </li> |
| </ul> |
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| <h4>getTxidsBehindEstimate</h4> |
| <pre>public long getTxidsBehindEstimate()</pre> |
| <div class="block">Return a estimate of how many transaction IDs behind the NameNode's |
| current state this stream is. Clients should periodically call this method |
| and check if its result is steadily increasing, which indicates that they |
| are falling behind (i.e. transaction are being generated faster than the |
| client is reading them). If a client falls too far behind events may be |
| deleted before the client can read them. |
| <p> |
| A return value of -1 indicates that an estimate could not be produced, and |
| should be ignored. The value returned by this method is really only useful |
| when compared to previous or subsequent returned values.</div> |
| </li> |
| </ul> |
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| <h4>poll</h4> |
| <pre>public <a href="../../../../org/apache/hadoop/hdfs/inotify/EventBatch.html" title="class in org.apache.hadoop.hdfs.inotify">EventBatch</a> poll(long time, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/TimeUnit.html?is-external=true" title="class or interface in java.util.concurrent">TimeUnit</a> tu) |
| throws <a href="https://docs.oracle.com/javase/8/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</a>, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/InterruptedException.html?is-external=true" title="class or interface in java.lang">InterruptedException</a>, |
| <a href="../../../../org/apache/hadoop/hdfs/inotify/MissingEventsException.html" title="class in org.apache.hadoop.hdfs.inotify">MissingEventsException</a></pre> |
| <div class="block">Returns the next event batch in the stream, waiting up to the specified |
| amount of time for a new batch. Returns null if one is not available at the |
| end of the specified amount of time. The time before the method returns may |
| exceed the specified amount of time by up to the time required for an RPC |
| to the NameNode.</div> |
| <dl> |
| <dt><span class="paramLabel">Parameters:</span></dt> |
| <dd><code>time</code> - number of units of the given TimeUnit to wait</dd> |
| <dd><code>tu</code> - the desired TimeUnit</dd> |
| <dt><span class="throwsLabel">Throws:</span></dt> |
| <dd><code><a href="https://docs.oracle.com/javase/8/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</a></code> - see <a href="../../../../org/apache/hadoop/hdfs/DFSInotifyEventInputStream.html#poll--"><code>poll()</code></a></dd> |
| <dd><code><a href="../../../../org/apache/hadoop/hdfs/inotify/MissingEventsException.html" title="class in org.apache.hadoop.hdfs.inotify">MissingEventsException</a></code> - see <a href="../../../../org/apache/hadoop/hdfs/DFSInotifyEventInputStream.html#poll--"><code>poll()</code></a></dd> |
| <dd><code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/InterruptedException.html?is-external=true" title="class or interface in java.lang">InterruptedException</a></code> - if the calling thread is interrupted</dd> |
| </dl> |
| </li> |
| </ul> |
| <a name="take--"> |
| <!-- --> |
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| <h4>take</h4> |
| <pre>public <a href="../../../../org/apache/hadoop/hdfs/inotify/EventBatch.html" title="class in org.apache.hadoop.hdfs.inotify">EventBatch</a> take() |
| throws <a href="https://docs.oracle.com/javase/8/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</a>, |
| <a href="https://docs.oracle.com/javase/8/docs/api/java/lang/InterruptedException.html?is-external=true" title="class or interface in java.lang">InterruptedException</a>, |
| <a href="../../../../org/apache/hadoop/hdfs/inotify/MissingEventsException.html" title="class in org.apache.hadoop.hdfs.inotify">MissingEventsException</a></pre> |
| <div class="block">Returns the next batch of events in the stream, waiting indefinitely if |
| a new batch is not immediately available.</div> |
| <dl> |
| <dt><span class="throwsLabel">Throws:</span></dt> |
| <dd><code><a href="https://docs.oracle.com/javase/8/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</a></code> - see <a href="../../../../org/apache/hadoop/hdfs/DFSInotifyEventInputStream.html#poll--"><code>poll()</code></a></dd> |
| <dd><code><a href="../../../../org/apache/hadoop/hdfs/inotify/MissingEventsException.html" title="class in org.apache.hadoop.hdfs.inotify">MissingEventsException</a></code> - see |
| <a href="../../../../org/apache/hadoop/hdfs/DFSInotifyEventInputStream.html#poll--"><code>poll()</code></a></dd> |
| <dd><code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/InterruptedException.html?is-external=true" title="class or interface in java.lang">InterruptedException</a></code> - if the calling thread is interrupted</dd> |
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