Functional Programming in Java, Second Edition (Pragmatic Bookshelf)
Latest Threads About This Book
@venkats
Appears to be a broken link in Appendix 3 a(Web Resources) on Page 234, for article to “Tell, Don’t Ask”.
Link goes to: https:...
New
@venkats
In the section “Iterating a String” found in chapter 3 “Strings, Comparators, and Filters” there seems to be a typo:
“But we w...
New
Nothing surprising here, just adapting the form to the other examples.
Ah yes, compute() now returns an immutable list in all cases.
pa...
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As usual, but the original code to be refactored was just too evil and had to be fixed.
package chapter11;
import org.junit.jupiter.api...
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In this code:
We actually create the (temporary) file we want to read and delete it again at the end.
Default charsets for reading text...
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The usual changes but:
The “FirstRepeatedLetter.findIn()” has been improved out of the box. In particular returning ‘\0’ is too C-like ...
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Nothing special here, same changes as formerly, but we are using people.isEmpty() instead of people.size() == 0 for even better legibilit...
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The same remarks apply as for “Refactoring the Traditional for Loop”
No init()
Negative tests which apply for input less than 1900, res...
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The same remarks apply as for “Refactoring the Traditional for Loop”
No init()
Classes under test implement a common interface that is...
New
Suggestions for some JUnit test improvements in Refactoring the Traditional “for” loop p 181 ff
Below code for testing the original/cla...
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Although now aged by 34 years:
“The Conception, Evolution, and Application of Functional Programming Languages”
by Paul Hudak (1989-09-...
New
On page 15, we read:
In this example we’re sending a function, price -> price * 0.9, as an argument to mapToDouble The function bein...
New
In Chapter 9, p.164 the stream is parallelized in 1 step.
This inspired my to write some test some code to call a task “in parallel”:
...
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On page 179:
First, imperative style was the way of life in Java and most programmers are very familiar with that style, since that was...
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As traditional , the “impure” code of page 207 in the form of a pretend test.
(Doesn’t “impure” refer to performing uncontrolled side ef...
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A question to highlight is:
Is there a way to make sure that a stream is NOT parallel, and make this evident in the code?
As in:
strea...
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I have been thinking about how to collect “two adjacent elements” in a stream, for example transform a stream of Long into a stream of Pa...
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On page 200, the code can use boxed() instead of the (somewhat mysterious) maptoObject(e -> e)
One should also reveal to the reader t...
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One should refer the user to the official java.util.stream package (Stream API) documentation.
First appearance of the API in Java 8 (Ma...
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Joe asks: Are stream pipelines the same as ‘RxJava’
Not quite. Although Java 8 Streams and RxJava (“Reactive Extensions in Java”) are bo...
New
On page 174:
StreamAPI
Should probably be
Stream API
Also on page 174:
blow up with an exception
Suggesting to change this wh...
New
It turns out that Try<T> can be ameliorated by judicious application of subclassing: no need to distinguish by actual type in the s...
New
As for FinanceData on page 91, the code for AirportInfo uses the suspect and soon-to-be-deprecated java.net.URL. Let’s use java.net.URI i...
New
Just some thoughts on being hard on exceptions in functional languages.
On p. 167 we read:
Functional style code is amazing, concise, ...
New
We read:
We are using the amazing feature of the switch expression of Java [Java 12]. If you’re using an older version of Java, you may...
New
All the code for Chapter 8, Using Tail-Call Optimization, in one class. But without the part where we later need to “fix the arithmetic o...
New
On p.27, after “Found 2 names”, we read:
The filter() method returns an iterator just like the map() method does,
But it really return...
New
The filter stream operation appears on several places in Chapter 2 and Chapter 3, so it’s difficult to say where to put this, but there s...
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SimpleTimer.java
package chapter7;
import java.util.function.Supplier;
public abstract class SimpleTimer {
public record Result<...
New
Nothing special:
package chapter7;
import org.junit.jupiter.api.Test;
import java.util.List;
import java.util.function.Supplier;
impor...
New
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@venkats
Appears to be a broken link in Appendix 3 a(Web Resources) on Page 234, for article to “Tell, Don’t Ask”.
Link goes to: https:...
New
Most Active Over Three Years
Learn and apply the powerful streams API and lambda expressions to create highly expressive, concise, and maintainable functional style c...
New
@venkats
On page 21:
For each price from the prices list that passes through the filter(), the mapToInt() method invokes the provided ...
New
On p.27, after “Found 2 names”, we read:
The filter() method returns an iterator just like the map() method does,
But it really return...
New
On page 91, we use a short method to request a stock ticker, class FinanceData
However, this method is based on java.net.URL which has a...
New
We read:
Recursion is a powerful and charming way to solve problems. It’s highly expressive—using recursion we can provide a solution t...
New
In several places, the method
String.toUpperCase()
is misspelled as
String.toUppercase()
sometimes via the :: method reference,
Stri...
New
We find this code on page 61, for ListSelectFiles.java
final String[] files =
new File("fpij").list(new java.io.FilenameFilter()...
New
Just some thoughts on being hard on exceptions in functional languages.
On p. 167 we read:
Functional style code is amazing, concise, ...
New
@venkats
At 2/3rd of the page, we read;
Within the computeMaxProfit() method, we perform our task, and when it’s time to recurse we ro...
New
On page 148, “An optimization problem” we read:
We’ll employ a solution for a company that buys rods at wholesale and sells them at reta...
New
As previously, the code uses
List<String> names = Arrays.asList(...);
which yields an “array-backed list”, rather than
List<S...
New
As for FinanceData on page 91, the code for AirportInfo uses the suspect and soon-to-be-deprecated java.net.URL. Let’s use java.net.URI i...
New
On page 174:
StreamAPI
Should probably be
Stream API
Also on page 174:
blow up with an exception
Suggesting to change this wh...
New
On page 90, CalculateNAVTest.java:
public class CalculateNAVTest {
@Test
public void computeStockWorth() {
final CalculateN...
New
It turns out that Try<T> can be ameliorated by judicious application of subclassing: no need to distinguish by actual type in the s...
New
Publisher:
Pragmatic Bookshelf
Latest in Functional Programming in Java, Second Edition
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