Analysis of the technical principles of Google Collections framework in the Java library

Google Collections is a Java class library developed by Google for the development of Java language. It aims to provide a set of expansion and enhanced set frameworks to simplify common tasks in Java development.Below we will analyze the technical principles of the Google Collections framework and provide some Java code examples. 1. Analysis of the core component of Google Collection's framework The core components of the Google Collections framework include: Immutable Collections, BIMAP (two -way mapping), Multiset, Multimap (multiple mapping), etc.These components do not exist in the Java standard library, but they are very useful in actual development. 2. Immutable Collections Uncharacteristic set is an important feature of Google Collection's framework. It provides a thread -safe and non -modified set type.This is very useful for sharing data in the multi -threaded environment.Unchanged collection cannot be changed after creation, which means that they are safe threads and do not require additional synchronous expenses. Example code: List<String> list = ImmutableList.of("apple", "banana", "orange"); Set<Integer> set = ImmutableSet.of(1, 2, 3, 4); Map<String, Integer> map = ImmutableMap.of("apple", 1, "banana", 2, "orange", 3); 3. BIMAP (two -way mapping) BIMAP is a special mapping that provides a two -way mapping relationship with key value pairs.That is, you can quickly find the value through the key, or you can quickly find the corresponding key through the value.BIMAP can ensure the uniqueness of the key and value. If you try to add the existing keys or values to Bimap, it will throw an exception. Example code: BiMap<String, Integer> biMap = HashBiMap.create(); biMap.put("apple", 1); biMap.put("banana", 2); biMap.put("orange", 3); Integer value = bimap.get ("Apple"); // Return 1 1 String key = bimap.inverse (). Get (3); // Return "Orange" 4. Multiset (multiple collection) Multiset is a collection of repetitive elements, similar to SET, but allows elements to repeat.Multiset provides a convenient way to count the number of elements. Example code: Multiset<String> multiset = HashMultiset.create(); multiset.add("apple"); multiset.add("banana"); multiset.add("orange"); multiset.add("apple"); int count = multiset.count ("Apple"); // Return 2 5. Multimap (Multi -mapping) Multimap is a mapping structure that can mappore multiple values.Multimap can simplify the data structure design in the application and provide a convenient way to process the collection of key -value pairs. Example code: Multimap<String, String> multimap = HashMultimap.create(); multimap.put("fruits", "apple"); multimap.put("fruits", "banana"); multimap.put("fruits", "orange"); Collection<String> fruits = multimap.get("fruits"); // 返回["apple", "banana", "orange"] Summarize: The Google Collections framework expands and enhances the functions of the Java collection framework by introducing non -variable collection, two -way mapping, multiple sets, and multiple mapping.It provides a more convenient and more efficient collection operation method for Java developers, making the development process more simplified and efficient.Through the analysis of the technical principles of the Google Collections framework, it is believed that readers have a deeper understanding of the framework.