Apache HashBag Guava HashMultiset 和 Eclipse HashBag

Created: November-22, 2018

Bag / ultiset 將每個物件與出現次數一起儲存在集合中。介面上的額外方法允許一次新增或刪除物件的多個副本。JDK analog 是 HashMap <T，Integer>，當值是此鍵的副本數時。

型別	番石榴	Apache Commons Collections	GS 系列	JDK
排序未定義	HashMultiset	HashBag	HashBag	HashMap 中
排序	TreeMultiset	TreeBag	TreeBag	TreeMap 的
插入順序	LinkedHashMultiset	-	-	LinkedHashMap 的
併發變體	ConcurrentHashMultiset	SynchronizedBag	SynchronizedBag	`Collections.synchronizedMap(HashMap<String, Integer>)`
併發和排序	-	SynchronizedSortedBag	SynchronizedSortedBag	`Collections.synchronizedSortedMap(TreeMap<String,Integer>)`
永恆的收藏	ImmutableMultiset	UnmodifiableBag	UnmodifiableBag	`Collections.unmodifiableMap(HashMap<String, Integer)]`
不可變和分類	ImmutableSortedMultiset	UnmodifiableSortedBag	UnmodifiableSortedBag	`Collections.unmodifiableSortedMap(TreeMap<String, Integer>`）

示例：

1. 使用 Apache 的 SynchronizedSortedBag ：

    // Parse text to separate words
    String INPUT_TEXT = "Hello World! Hello All! Hi World!";
    // Create Multiset
    Bag bag = SynchronizedSortedBag.synchronizedBag(new TreeBag(Arrays.asList(INPUT_TEXT.split(" "))));

    // Print count words
    System.out.println(bag); // print [1:All!,2:Hello,1:Hi,2:World!]- in natural (alphabet) order
    // Print all unique words
    System.out.println(bag.uniqueSet());    // print [All!, Hello, Hi, World!]- in natural (alphabet) order

    // Print count occurrences of words
    System.out.println("Hello = " + bag.getCount("Hello"));    // print 2
    System.out.println("World = " + bag.getCount("World!"));    // print 2
    System.out.println("All = " + bag.getCount("All!"));    // print 1
    System.out.println("Hi = " + bag.getCount("Hi"));    // print 1
    System.out.println("Empty = " + bag.getCount("Empty"));    // print 0

    // Print count all words
    System.out.println(bag.size());    //print 6

    // Print count unique words
    System.out.println(bag.uniqueSet().size());    //print 4

2.使用 Eclipse 中的 `TreeBag(GC)` ：

    // Parse text to separate words
    String INPUT_TEXT = "Hello World! Hello All! Hi World!";
    // Create Multiset
    MutableSortedBag<String> bag =  TreeBag.newBag(Arrays.asList(INPUT_TEXT.split(" ")));

    // Print count words
    System.out.println(bag); // print [All!, Hello, Hello, Hi, World!, World!]- in natural order
    // Print all unique words
    System.out.println(bag.toSortedSet());    // print [All!, Hello, Hi, World!]- in natural order

    // Print count occurrences of words
    System.out.println("Hello = " + bag.occurrencesOf("Hello"));    // print 2
    System.out.println("World = " + bag.occurrencesOf("World!"));    // print 2
    System.out.println("All = " + bag.occurrencesOf("All!"));    // print 1
    System.out.println("Hi = " + bag.occurrencesOf("Hi"));    // print 1
    System.out.println("Empty = " + bag.occurrencesOf("Empty"));    // print 0

    // Print count all words
    System.out.println(bag.size());    //print 6

    // Print count unique words
    System.out.println(bag.toSet().size());    //print 4

3. 使用 Guava 的 LinkedHashMultiset ：

    // Parse text to separate words
    String INPUT_TEXT = "Hello World! Hello All! Hi World!";
    // Create Multiset
    Multiset<String> multiset = LinkedHashMultiset.create(Arrays.asList(INPUT_TEXT.split(" ")));

    // Print count words
    System.out.println(multiset); // print [Hello x 2, World! x 2, All!, Hi]- in predictable iteration order
    // Print all unique words
    System.out.println(multiset.elementSet());    // print [Hello, World!, All!, Hi] - in predictable iteration order

    // Print count occurrences of words
    System.out.println("Hello = " + multiset.count("Hello"));    // print 2
    System.out.println("World = " + multiset.count("World!"));    // print 2
    System.out.println("All = " + multiset.count("All!"));    // print 1
    System.out.println("Hi = " + multiset.count("Hi"));    // print 1
    System.out.println("Empty = " + multiset.count("Empty"));    // print 0

    // Print count all words
    System.out.println(multiset.size());    //print 6

    // Print count unique words
    System.out.println(multiset.elementSet().size());    //print 4

1. 使用 Apache 的 SynchronizedSortedBag ：

2.使用 Eclipse 中的 TreeBag(GC) ：

3. 使用 Guava 的 LinkedHashMultiset ：

更多例子：

2.使用 Eclipse 中的 `TreeBag(GC)` ：