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omp-ha-2019
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improvements 7

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generic-observer 7
Lisa 7 years ago
parent a5f57c0d4e
commit 67280ac2cd
3 changed files with 128 additions and 126 deletions
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21
src/main/java/_7/_1/LambdaTest.java
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@ -3,27 +3,26 @@ package _7._1;
public class LambdaTest { public class LambdaTest {
public static void main(String[] args) { public static void main(String[] args) {
Function<Double,Double> id = (x) -> x; Function<Double, Double> id = (x) -> x;
Function<Double,Double> inverse = (x) -> x*-1; Function<Double, Double> inverse = (x) -> -x;
Function<Double,Double> timesTen = (x) -> x*10; Function<Double, Double> timesTen = (x) -> 10*x;
Function<Double,Double> divideByPi = (x) -> x/Math.PI; Function<Double, Double> divideByPi = (x) -> x/Math.PI;
Function<Double,Long> round = Math::round;
Function<Double, Long> round = Math::round;
@SuppressWarnings("unchecked") @SuppressWarnings("unchecked")
Function<Double, Double> chain = makeChain(new Function[] {inverse, id, timesTen, divideByPi}); Function<Double, Double> chain = makeChain(new Function[]{ inverse, id, timesTen, divideByPi });
System.out.println(round.calculate((chain.calculate(5.5)))); System.out.println(round.calculate(chain.calculate(5.5)));
} }
private static Function<Double, Double> makeChain(final Function<Double, Double>[] functions) { private static Function<Double, Double> makeChain(final Function<Double, Double>[] functions) {
return (x) -> { return (x) -> {
for (Function<Double, Double> i : functions) { for (Function<Double, Double> f : functions) {
x = i.calculate(x); x = f.calculate(x);
} }
return x; return x;
}; };

13
src/main/java/_7/_2/StreamTest.java
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@ -5,16 +5,7 @@ import java.util.stream.Stream;
public class StreamTest { public class StreamTest {
public static void main(String[] args) { public static void main(String[] args) {
Stream<Integer> naturals = Stream.iterate(1, i -> i + 1); Stream<Integer> naturals = Stream.iterate(1, i -> i + 1);
Stream<Integer> integers = Stream.iterate(0, i -> i > 0 ? -i : -i + 1);
Stream<Integer> integers = Stream.iterate(0, i -> {
int next;
if (i>0) {
next = i*(-1);
} else {
next = i*(-1)+1;
}
return next;
});
System.out.println(filterAndSum(naturals)); System.out.println(filterAndSum(naturals));
System.out.println(filterAndSum(integers)); System.out.println(filterAndSum(integers));
@ -23,7 +14,7 @@ public class StreamTest {
private static Integer filterAndSum(Stream<Integer> stream) { private static Integer filterAndSum(Stream<Integer> stream) {
return stream.filter((i) -> i % 2 == 0) return stream.filter((i) -> i % 2 == 0)
.limit(10) .limit(10)
.reduce((a,b) -> a+b) .reduce(Integer::sum)
.orElse(0); .orElse(0);
} }
} }

220
src/main/java/_7/_3/PersonTest.java
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@ -1,117 +1,129 @@
package _7._3; package _7._3;
import java.io.*; import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList; import java.util.ArrayList;
import java.util.List; import java.util.List;
class Person implements Serializable { class Person implements Serializable {
private String firstname; private String firstname;
private String lastname; private String lastname;
private transient String sortname; private transient String sortname;
public Person() { } public Person() {
public Person(String firstname, String lastname) { }
this.firstname = firstname;
this.lastname = lastname; public Person(String firstname, String lastname) {
updateSortname(); this.firstname = firstname;
} this.lastname = lastname;
public String getFirstname() { updateSortname();
return firstname; }
}
public void setFirstname(String firstname) { public String getFirstname() {
this.firstname = firstname; return firstname;
updateSortname(); }
}
public String getLastname() { public void setFirstname(String firstname) {
return lastname; this.firstname = firstname;
} updateSortname();
public void setLastname(String lastname) { }
this.lastname = lastname;
updateSortname(); public String getLastname() {
} return lastname;
public String getSortname() { }
return sortname;
} public void setLastname(String lastname) {
public void updateSortname() { this.lastname = lastname;
sortname = lastname + firstname; updateSortname();
} }
@Override public String getSortname() {
public String toString() { return sortname;
return firstname + " " + lastname + " (" + sortname + ")"; }
}
public void updateSortname() {
sortname = lastname + firstname;
public static List<Person> load(String filename) throws IOException { }
List<Person> people = new ArrayList<>();
try (DataInputStream in = new DataInputStream(new BufferedInputStream( @Override
new FileInputStream(filename)))) { public String toString() {
boolean nextExists = in.readBoolean(); return firstname + " " + lastname + " (" + sortname + ")";
while (nextExists) { }
people.add(load(in));
nextExists = in.readBoolean();
} public static List<Person> load(String filename) throws IOException {
} try(DataInputStream in = new DataInputStream(new BufferedInputStream(new FileInputStream(filename)))) {
return people; return loadAll(in);
} }
}
public static Person load(DataInputStream in) throws IOException {
return new Person(in.readUTF(),in.readUTF()); public static List<Person> loadAll(DataInputStream in) throws IOException {
} int size = in.readInt();
List<Person> persons = new ArrayList<>();
for (int i = 0; i < size; i++) {
public static void save(String filename, List<Person> list) throws IOException { persons.add(load(in));
try (DataOutputStream out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(filename)))) { }
for (Person p : list) { return persons;
out.writeBoolean(true); }
save(out, p);
} public static Person load(DataInputStream in) throws IOException {
out.writeBoolean(false); return new Person(in.readUTF(), in.readUTF());
} }
}
public static void save(String filename, List<Person> list) throws IOException {
public static void save(DataOutputStream out, Person person) throws IOException { try(DataOutputStream out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(filename)))) {
out.writeUTF(person.getFirstname()); saveAll(out, list);
out.writeUTF(person.getLastname()); }
} }
public static void saveAll(DataOutputStream out, List<Person> persons) throws IOException {
@SuppressWarnings("unchecked") out.writeInt(persons.size());
public static List<Person> unserialize(String filename) throws IOException, ClassNotFoundException { for (Person person : persons) {
List<Person> people; save(out, person);
try (ObjectInputStream in = new ObjectInputStream( }
new BufferedInputStream(new FileInputStream(filename)))) { }
people = (List<Person>) in.readObject();
for (Person p : people) { public static void save(DataOutputStream out, Person person) throws IOException {
p.updateSortname(); out.writeUTF(person.getFirstname());
} out.writeUTF(person.getLastname());
} }
return people;
}
@SuppressWarnings("unchecked")
public static void serialize(String filename, List<Person> persons) throws IOException { public static List<Person> unserialize(String filename) throws IOException, ClassNotFoundException {
try (ObjectOutputStream out = new ObjectOutputStream( try (ObjectInputStream in = new ObjectInputStream(
new BufferedOutputStream(new FileOutputStream(filename)))) { new BufferedInputStream(new FileInputStream(filename)))) {
out.writeObject(persons); List<Person> people = (List<Person>) in.readObject();
} people.forEach(Person::updateSortname);
} return people;
}
}
public static void serialize(String filename, List<Person> persons) throws IOException {
try (ObjectOutputStream out = new ObjectOutputStream(
new BufferedOutputStream(new FileOutputStream(filename)))) {
out.writeObject(persons);
}
}
} }
public class PersonTest { public class PersonTest {
public static void main(String[] args) throws IOException, ClassNotFoundException { public static void main(String[] args) throws IOException, ClassNotFoundException {
List<Person> persons = new ArrayList<>(); List<Person> persons = new ArrayList<>();
persons.add(new Person("Willy", "Wonka")); persons.add(new Person("Willy", "Wonka"));
persons.add(new Person("Charlie", "Bucket")); persons.add(new Person("Charlie", "Bucket"));
persons.add(new Person("Grandpa", "Joe")); persons.add(new Person("Grandpa", "Joe"));
System.out.println(persons); System.out.println(persons);
Person.save("persons.sav", persons); Person.save("persons.sav", persons);
persons = Person.load("persons.sav"); persons = Person.load("persons.sav");
System.out.println(persons); System.out.println(persons);
Person.serialize("persons.ser", persons); Person.serialize("persons.ser", persons);
persons = Person.unserialize("persons.ser"); persons = Person.unserialize("persons.ser");
System.out.println(persons); System.out.println(persons);
} }
} }

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