Merge pull request #8125 from eugenp/revert-8119-BAEL-3275-2

Revert "BAEL-3275: Using blocking queue for pub-sub"

java-collections-conversions/src/main/java/com/baeldung/convertToMap/Book.java

@@ -0,0 +1,48 @@
+package com.baeldung.convertToMap;
+
+public class Book {
+    private String name;
+    private int releaseYear;
+    private String isbn;
+
+
+    @Override
+    public String toString() {
+        return "Book{" +
+                "name='" + name + '\'' +
+                ", releaseYear=" + releaseYear +
+                ", isbn='" + isbn + '\'' +
+                '}';
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getReleaseYear() {
+        return releaseYear;
+    }
+
+    public void setReleaseYear(int releaseYear) {
+        this.releaseYear = releaseYear;
+    }
+
+    public String getIsbn() {
+        return isbn;
+    }
+
+    public void setIsbn(String isbn) {
+        this.isbn = isbn;
+    }
+
+    public Book(String name, int releaseYear, String isbn) {
+        this.name = name;
+        this.releaseYear = releaseYear;
+        this.isbn = isbn;
+    }
+}
+

java-collections-conversions/src/main/java/com/baeldung/convertToMap/ConvertToMap.java

@@ -0,0 +1,33 @@
+package com.baeldung.convertToMap;
+
+import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public class ConvertToMap {
+    public Map<String, String> listToMap(List<Book> books) {
+        return books.stream().collect(Collectors.toMap(Book::getIsbn, Book::getName));
+    }
+
+    public Map<Integer, Book> listToMapWithDupKeyError(List<Book> books) {
+        return books.stream().collect(Collectors.toMap(Book::getReleaseYear, Function.identity()));
+    }
+
+    public Map<Integer, Book> listToMapWithDupKey(List<Book> books) {
+        return books.stream().collect(Collectors.toMap(Book::getReleaseYear, Function.identity(), (existing, replacement) -> existing));
+    }
+
+    public Map<Integer, Book> listToConcurrentMap(List<Book> books) {
+        return books.stream().collect(Collectors.toMap(Book::getReleaseYear, Function.identity(), (o1, o2) -> o1, ConcurrentHashMap::new));
+    }
+
+    public TreeMap<String, Book> listToSortedMap(List<Book> books) {
+        return books.stream()
+                .sorted(Comparator.comparing(Book::getName))
+                .collect(Collectors.toMap(Book::getName, Function.identity(), (o1, o2) -> o1, TreeMap::new));
+    }
+
+
+}
+

java-collections-conversions/src/main/java/com/baeldung/convertcollectiontoarraylist/Foo.java

@@ -0,0 +1,52 @@
+package com.baeldung.convertcollectiontoarraylist;
+
+/**
+ * This POJO is the element type of our collection. It has a deepCopy() method.
+ *
+ * @author chris
+ */
+public class Foo {
+
+    private int id;
+    private String name;
+    private Foo parent;
+
+    public Foo() {
+    }
+
+    public Foo(int id, String name, Foo parent) {
+        this.id = id;
+        this.name = name;
+        this.parent = parent;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Foo getParent() {
+        return parent;
+    }
+
+    public void setParent(Foo parent) {
+        this.parent = parent;
+    }
+
+    public Foo deepCopy() {
+        return new Foo(
+          this.id, this.name, this.parent != null ? this.parent.deepCopy() : null);
+    }
+
+}

java-collections-conversions/src/main/java/com/baeldung/convertlisttomap/Animal.java

@@ -0,0 +1,27 @@
+package com.baeldung.convertlisttomap;
+
+public class Animal {
+    private int id;
+    private String name;
+
+    public Animal(int id, String name) {
+        this.id = id;
+        this.setName(name);
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

java-collections-conversions/src/main/java/com/baeldung/convertlisttomap/ConvertListToMapService.java

@@ -0,0 +1,42 @@
+package com.baeldung.convertlisttomap;
+
+import com.google.common.collect.Maps;
+import org.apache.commons.collections4.MapUtils;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+public class ConvertListToMapService {
+
+    public Map<Integer, Animal> convertListBeforeJava8(List<Animal> list) {
+
+        Map<Integer, Animal> map = new HashMap<>();
+
+        for (Animal animal : list) {
+            map.put(animal.getId(), animal);
+        }
+        return map;
+    }
+
+    public Map<Integer, Animal> convertListAfterJava8(List<Animal> list) {
+        Map<Integer, Animal> map = list.stream().collect(Collectors.toMap(Animal::getId, animal -> animal));
+        return map;
+    }
+
+    public Map<Integer, Animal> convertListWithGuava(List<Animal> list) {
+
+        Map<Integer, Animal> map = Maps.uniqueIndex(list, Animal::getId);
+        return map;
+    }
+
+    public Map<Integer, Animal> convertListWithApacheCommons(List<Animal> list) {
+
+        Map<Integer, Animal> map = new HashMap<>();
+
+        MapUtils.populateMap(map, list, Animal::getId);
+
+        return map;
+    }
+}