Praktikum 3: Streams vllt
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@ -1,19 +1,21 @@
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package de.joethei.hs.java2.praktikum.praktikum3;
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import java.io.*;
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import java.io.BufferedReader;
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import java.io.FileReader;
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import java.io.IOException;
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import java.util.*;
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import java.util.stream.Collectors;
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public class Vorlesungsverzeichnis {
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public class Vorlesungsverzeichnis implements Comparator<Vorlesung>{
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private Set<Vorlesung> vorlesungen = new HashSet<>();
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public Vorlesungsverzeichnis(String filename) throws IOException {
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List<List<String>> datenbasis;
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datenbasis = load(filename);
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for(List<String> a : datenbasis) {
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if(a.size() != 4) throw new TextFileFormatException("unexpected number of Strings in line");
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for(String s : a) if(s.isEmpty()) throw new TextFileFormatException("empty attribute");
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for (List<String> a : datenbasis) {
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if (a.size() != 4) throw new TextFileFormatException("unexpected number of Strings in line");
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for (String s : a) if (s.isEmpty()) throw new TextFileFormatException("empty attribute");
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vorlesungen.add(new Vorlesung(a));
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}
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@ -22,22 +24,30 @@ public class Vorlesungsverzeichnis {
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private List<List<String>> load(String filename) throws IOException {
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List<List<String>> result = new ArrayList<>();
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BufferedReader br = new BufferedReader(new FileReader(filename));
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for (String line=br.readLine(); line!=null; line=br.readLine())
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for (String line = br.readLine(); line != null; line = br.readLine())
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result.add(Arrays.asList(line.split(":")));
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br.close();
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return result;
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}
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public List<String> titles() {
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/*
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List<String> list = new ArrayList<>();
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for(Vorlesung v: this.vorlesungen) {
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list.add(v.getTitle());
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}
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Collections.sort(list);
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return list;
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*/
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List<String> list = new ArrayList<>();
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vorlesungen.forEach(vorlesung -> list.add(vorlesung.getTitle()));
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Collections.sort(list);
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return list;
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}
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public Set<String> workaholics() {
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/*
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Set<String> s = new HashSet<>();
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List<String> list = new ArrayList<>();
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for(Vorlesung v:vorlesungen) {
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@ -49,18 +59,28 @@ public class Vorlesungsverzeichnis {
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}
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Collections.sort(list);
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return new HashSet<>(list);
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*/
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Map<String, Set<String>> map = vorlesungen.stream().collect(Collectors.groupingBy(Vorlesung::getDozent, Collectors.mapping(Vorlesung::getTitle, Collectors.toSet())));
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Set<String> set = new HashSet<>();
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map.forEach((s, strings) -> {
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if(strings.size() >= 2) set.add(s);
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});
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return set;
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}
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public Map<String, List<String>> groupToTitles() {
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/*
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Map<String, List<String>> map = new HashMap<>();
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List<String> list = new ArrayList<>();
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Set<String> s = new HashSet<>();
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for(Vorlesung v:vorlesungen) {
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for (Vorlesung v : vorlesungen) {
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s.add(v.getStudiengruppe());
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}
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for(String gruppe : s) {
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for(Vorlesung v : vorlesungen) {
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if(gruppe.equals(v.getStudiengruppe())) {
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for (String gruppe : s) {
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for (Vorlesung v : vorlesungen) {
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if (gruppe.equals(v.getStudiengruppe())) {
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list.add(v.getTitle());
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}
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}
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@ -69,18 +89,23 @@ public class Vorlesungsverzeichnis {
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list = new ArrayList<>();
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}
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return map;
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*/
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Map<String, List<String>> map = vorlesungen.stream().collect(Collectors.groupingBy(Vorlesung::getStudiengruppe, Collectors.mapping(Vorlesung::getTitle, Collectors.toList())));
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map.forEach((s, strings) -> Collections.sort(strings));
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return map;
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}
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public Map<String, List<String>> multipleTitles() {
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/*
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Map<String, List<String>> map = new HashMap<>();
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List<String> list = new ArrayList<>();
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Set<String> s = new HashSet<>();
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for(Vorlesung v:vorlesungen) {
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for (Vorlesung v : vorlesungen) {
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s.add(v.getTitle());
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}
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for(String title : s) {
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for(Vorlesung v:vorlesungen) {
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if(title.equals(v.getTitle())) {
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for (String title : s) {
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for (Vorlesung v : vorlesungen) {
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if (title.equals(v.getTitle())) {
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list.add(v.getDozent());
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}
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}
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@ -89,13 +114,21 @@ public class Vorlesungsverzeichnis {
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list = new ArrayList<>();
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}
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List<String> l = new ArrayList<>(map.keySet());
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for(String title:l) {
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if(map.get(title).size() < 2) map.remove(title);
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for (String title : l) {
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if (map.get(title).size() < 2) map.remove(title);
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}
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return map;
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*/
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Map<String, List<String>> map = vorlesungen.stream().collect(Collectors.groupingBy(Vorlesung::getTitle, Collectors.mapping(Vorlesung::getDozent, Collectors.toList())));
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map.forEach((s, strings) -> Collections.sort(strings));
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return map;
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}
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public List<String> descendingTitles() {
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/*
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List<String> l = new ArrayList<>();
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List<Vorlesung> vl = new ArrayList<>(vorlesungen);
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int most=0, index=0;
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@ -111,5 +144,19 @@ public class Vorlesungsverzeichnis {
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vl.remove(index);
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}
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return l;
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*/
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SortedSet<Vorlesung> set = new TreeSet<>(this.reversed());
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set.addAll(vorlesungen);
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List<String> list = new ArrayList<>();
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set.forEach(vorlesung -> list.add(vorlesung.getTitle()));
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return list;
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}
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@Override
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public int compare(Vorlesung o1, Vorlesung o2) {
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return Integer.compare(o1.getTeilnehmerzahl(), o2.getTeilnehmerzahl());
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}
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}
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@ -81,8 +81,8 @@ public class VorlesungsverzeichnisTest {
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Map<String, List<String>> map = vorlesungsverzeichnis.multipleTitles();
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List<String> math = new ArrayList<>();
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math.add("von Coelln");
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math.add("Rabe");
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math.add("von Coelln");
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Collections.sort(math);
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assertEquals(map.get("Mathematik 2"), math);
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