svn commit: r1678281 [2/2] - in /nutch/trunk: ./ src/java/org/apache/nutch/fetcher/

[le...@apache.org]

Added: nutch/trunk/src/java/org/apache/nutch/fetcher/QueueFeeder.java
URL: http://svn.apache.org/viewvc/nutch/trunk/src/java/org/apache/nutch/fetcher/QueueFeeder.java?rev=1678281&view=auto
==============================================================================
--- nutch/trunk/src/java/org/apache/nutch/fetcher/QueueFeeder.java (added)
+++ nutch/trunk/src/java/org/apache/nutch/fetcher/QueueFeeder.java Fri May  8 04:25:05 2015
@@ -0,0 +1,104 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nutch.fetcher;
+
+import java.io.IOException;
+
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapred.RecordReader;
+import org.apache.nutch.crawl.CrawlDatum;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This class feeds the queues with input items, and re-fills them as items
+ * are consumed by FetcherThread-s.
+ */
+public class QueueFeeder extends Thread {
+  
+  private static final Logger LOG = LoggerFactory.getLogger(QueueFeeder.class);
+
+  
+  private RecordReader<Text, CrawlDatum> reader;
+  private FetchItemQueues queues;
+  private int size;
+  private long timelimit = -1;
+
+  public QueueFeeder(RecordReader<Text, CrawlDatum> reader,
+      FetchItemQueues queues, int size) {
+    this.reader = reader;
+    this.queues = queues;
+    this.size = size;
+    this.setDaemon(true);
+    this.setName("QueueFeeder");
+  }
+
+  public void setTimeLimit(long tl) {
+    timelimit = tl;
+  }
+
+  public void run() {
+    boolean hasMore = true;
+    int cnt = 0;
+    int timelimitcount = 0;
+    while (hasMore) {
+      if (System.currentTimeMillis() >= timelimit && timelimit != -1) {
+        // enough .. lets' simply
+        // read all the entries from the input without processing them
+        try {
+          Text url = new Text();
+          CrawlDatum datum = new CrawlDatum();
+          hasMore = reader.next(url, datum);
+          timelimitcount++;
+        } catch (IOException e) {
+          LOG.error("QueueFeeder error reading input, record " + cnt, e);
+          return;
+        }
+        continue;
+      }
+      int feed = size - queues.getTotalSize();
+      if (feed <= 0) {
+        // queues are full - spin-wait until they have some free space
+        try {
+          Thread.sleep(1000);
+        } catch (Exception e) {
+        }
+        ;
+        continue;
+      } else {
+        LOG.debug("-feeding " + feed + " input urls ...");
+        while (feed > 0 && hasMore) {
+          try {
+            Text url = new Text();
+            CrawlDatum datum = new CrawlDatum();
+            hasMore = reader.next(url, datum);
+            if (hasMore) {
+              queues.addFetchItem(url, datum);
+              cnt++;
+              feed--;
+            }
+          } catch (IOException e) {
+            LOG.error("QueueFeeder error reading input, record " + cnt, e);
+            return;
+          }
+        }
+      }
+    }
+    LOG.info("QueueFeeder finished: total " + cnt
+        + " records + hit by time limit :" + timelimitcount);
+  }
+}