Tutorial by Examples: al

Names of male members

// Java: List<String> namesOfMaleMembersCollect = roster .stream() .filter(p -> p.getGender() == Person.Sex.MALE) .map(p -> p.getName()) .collect(Collectors.toList()); // Kotlin: val namesOfMaleMembers = roster.filter { it.gender == Person.Sex.MALE }.map { it.nam...

Kotlin • Java 8 Stream Equivalents

Filter a list to another list

// Java: List<String> filtered = items.stream() .filter( item -> item.startsWith("o") ) .collect(Collectors.toList()); // Kotlin: val filtered = items.filter { item.startsWith('o') }

Kotlin • Java 8 Stream Equivalents

Finding shortest string a list

// Java: String shortest = items.stream() .min(Comparator.comparing(item -> item.length())) .get(); // Kotlin: val shortest = items.minBy { it.length }

Kotlin • Java 8 Stream Equivalents

Different Kinds of Streams #4 - iterate an array, map the values, calculate the average

// Java: Arrays.stream(new int[] {1, 2, 3}) .map(n -> 2 * n + 1) .average() .ifPresent(System.out::println); // 5.0 // Kotlin: arrayOf(1,2,3).map { 2 * it + 1}.average().apply(::println)

Kotlin • Java 8 Stream Equivalents

Different Kinds of Streams #5 - lazily iterate a list of strings, map the values, convert to Int, find max

// Java: Stream.of("a1", "a2", "a3") .map(s -> s.substring(1)) .mapToInt(Integer::parseInt) .max() .ifPresent(System.out::println); // 3 // Kotlin: sequenceOf("a1", "a2", "a3") .map { it.substring(1) } ...

Kotlin • Java 8 Stream Equivalents

Different Kinds of Streams #6 - lazily iterate a stream of Ints, map the values, print results

// Java: IntStream.range(1, 4) .mapToObj(i -> "a" + i) .forEach(System.out::println); // a1 // a2 // a3 // Kotlin: (inclusive range) (1..3).map { "a$it" }.forEach(::println)

Kotlin • Java 8 Stream Equivalents

Counting items in a list after filter is applied

// Java: long count = items.stream().filter( item -> item.startsWith("t")).count(); // Kotlin: val count = items.filter { it.startsWith('t') }.size // but better to not filter, but count with a predicate val count = items.count { it.startsWith('t') }

Kotlin • Java 8 Stream Equivalents

How streams work - filter, upper case, then sort a list

// Java: List<String> myList = Arrays.asList("a1", "a2", "b1", "c2", "c1"); myList.stream() .filter(s -> s.startsWith("c")) .map(String::toUpperCase) .sorted() .forEach(System.out::println); // C1 ...

Kotlin • Java 8 Stream Equivalents

Collect example #5 - find people of legal age, output formatted string

// Java: String phrase = persons .stream() .filter(p -> p.age >= 18) .map(p -> p.name) .collect(Collectors.joining(" and ", "In Germany ", " are of legal age.")); System.out.println(phrase); // In Germany Max and Peter a...

Kotlin • Java 8 Stream Equivalents

External CSS Stylesheet

HTML • Linking Resources

Bold + Italic

Creating ***bold italic*** text is simply a matter of using both **bold** (two asterisks) and *italic* (one asterisk) at the same time, for a total of three asterisks on either side of the text you want to format at once. Creating bold italic text is simply a matter of using both bold (two a...

Markdown • Text Formatting

Accumulate a list of trap work to run at exit.

Have you ever forgotten to add a trap to clean up a temporary file or do other work at exit? Have you ever set one trap which canceled another? This code makes it easy to add things to be done on exit one item at a time, rather than having one large trap statement somewhere in your code, which may...

Bash • Using "trap" to react to signals and system events

Linux Bonding Health

Template Definition template linux.bonding { subject = {{.Last.Status}}: {{.Eval .Alert.Vars.by_host}} bad bond(s) on {{.Group.host}} body = `{{template "header" .}} <h2>Bond Status</h2> <table> <tr><th>Bond</th><th>Slave&...

Bosun • Complete Examples

Low Memory Alert and Template

Templates can be previewed and edited using the Rule Editor tab in Bosun. Use the Jump to links to select the alert you want to edit, then you can use the template button next to macro to switch between the alert an template sections of the configuration. If an alert has multiple instances you can u...

Bosun • Templates: Overview

Generic Template with optional Graphs

It often is faster to use a generic template when first creating a new alert and only specialize the template when you need to display more information. The following template will display a subject with a numerical value, custom formatting, and description string and then a body with up to two grap...

Bosun • Templates: Overview

Graph using Alert Variable

Using .Graph will filter the results to only include those that match the tagset for the alert. For instance an alert for os.low.memory{host=ny-web01} would only include series with the host=ny-web01 tags. If multiple series match then only the first matching result will be used. template graph.tem...

Bosun • Templates: Graph and GraphAll

GraphAll using Alert Variable

Using .GraphAll will include all the results in the graph. template graph.template { subject = ... body = `{{template "header" .}} <strong>GraphAll</strong> <div>{{.GraphAll .Alert.Vars.graph}}</div> <strong>GraphAll With Y Axis...

Bosun • Templates: Graph and GraphAll

Graph or GraphAll using inline or dynamic query

Graph queries can be defined inline if you don't want to use an Alert variable. template graph.template { subject = ... body = `{{template "header" .}} <strong>Graph With Inline Query</strong> <div>{{.Graph "q(\"avg:300s-avg:os.mem.perce...

Bosun • Templates: Graph and GraphAll

Creating a shared link for a file using the Dropbox Java library

This uses the Dropbox Java SDK to create a shared link for a file at the Dropbox path /test.txt: try { SharedLinkMetadata sharedLinkMetadata = client.sharing().createSharedLinkWithSettings("/test.txt"); System.out.println(sharedLinkMetadata.getUrl()); } catch (CreateSharedLinkW...

Dropbox API • Getting a shared link for a file or folder

Advanced Aliases

Git lets you use non-git commands and full sh shell syntax in your aliases if you prefix them with !. In your ~/.gitconfig file: [alias] temp = !git add -A && git commit -m "Temp" The fact that full shell syntax is available in these prefixed aliases also means you can us...

Git • Aliases