DomGarguilo commented on code in PR #334:
URL: https://github.com/apache/accumulo-website/pull/334#discussion_r960013687
##########
tour/batch-scanner-code.md:
##########
@@ -4,44 +4,52 @@ title: Batch Scanner Code
Below is a solution to the exercise.
-```java
- static void exercise(AccumuloClient client) throws Exception {
- // Create a table called "GothamPD".
- client.tableOperations().create("GothamPD");
-
- // Generate 10,000 rows of henchman data
- try (BatchWriter writer = client.createBatchWriter("GothamPD")) {
- for (int i = 0; i < 10_000; i++) {
- Mutation m = new Mutation(String.format("id%04d", i));
- m.put("villain", "alias", "henchman" + i);
- m.put("villain", "yearsOfService", "" + (new Random().nextInt(50)));
- m.put("villain", "wearsCape?", "false");
- writer.addMutation(m);
- }
- }
- // 1. Create a BatchScanner with 5 query threads
- try (BatchScanner batchScanner = client.createBatchScanner("GothamPD",
Authorizations.EMPTY, 5)) {
-
- // 2. Create a collection of 2 sample ranges and set it to the
batchScanner
- List<Range>ranges = new ArrayList<Range>();
- ranges.add(new Range("id1000", "id1999"));
- ranges.add(new Range("id9000", "id9999"));
- batchScanner.setRanges(ranges);
-
- // 3. Fetch just the columns we want
- batchScanner.fetchColumn(new Text("villain"), new
Text("yearsOfService"));
-
- // 4. Calculate average years of service
- Long totalYears = 0L;
- Long entriesRead = 0L;
- for (Map.Entry<Key, Value> entry : batchScanner) {
- totalYears += Long.valueOf(entry.getValue().toString());
- entriesRead++;
- }
- System.out.println("The average years of service of " + entriesRead + "
villains is " + totalYears / entriesRead);
- }
- }
+Create a table called "GothamBatch".
+
+```commandline
+jshell> client.tableOperations().create("GothamBatch");
+```
+
+Generate 10,000 rows of villain data
+
+```commandline
+jshell> try (BatchWriter writer = client.createBatchWriter("GothamBatch")) {
+ ...> for (int i = 0; i < 10_000; i++) {
+ ...> Mutation m = new Mutation(String.format("id%04d", i));
+ ...> m.put("villain", "alias", "henchman" + i);
+ ...> m.put("villain", "yearsOfService", "" + (new
Random().nextInt(50)));
+ ...> m.put("villain", "wearsCape?", "false");
+ ...> writer.addMutation(m);
+ ...> }
+ ...> }
```
+
+Create a BatchScanner with 5 query threads
+```commandline
+jshell> try (BatchScanner batchScanner =
client.createBatchScanner("GothamBatch", Authorizations.EMPTY, 5)) {
+ ...>
+ ...> // Create a collection of 2 sample ranges and set it to the
batchScanner
+ ...> List<Range> ranges = new ArrayList<Range>();
+ ...>
+ ...> // Create a collection of 2 sample ranges and set it to the
batchScanner
+ ...> ranges.add(new Range("id1000", "id1999"));
+ ...> ranges.add(new Range("id9000", "id9999"));
+ ...> batchScanner.setRanges(ranges);
+ ...>
+ ...> // Fetch just the columns we want
+ ...> batchScanner.fetchColumn(new Text("villain"), new
Text("yearsOfService"));
+ ...>
+ ...> // Calculate average years of service
+ ...> Long totalYears = 0L;
+ ...> Long entriesRead = 0L;
+ ...> for (Map.Entry<Key, Value> entry : batchScanner) {
+ ...> totalYears += Long.valueOf(entry.getValue().toString());
+ ...> entriesRead++;
+ ...> }
+ ...> System.out.println("The average years of service of " + entriesRead
+ " villains is " + totalYears / entriesRead);
Review Comment:
It could be cool to show off how BatchScanner.stream could be used here or
somewhere else.
For example, could be used to find the average like this:
```
Double average =
scanner.stream().map(Map.Entry::getValue).map(Value::toString).mapToLong(Long::valueOf).average().getAsDouble();
```
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