On the technical principles and design ideas of Google Collection's framework in the Java library

Google Collections (now renamed GUAVA) is a set of excellent class libraries provided by Google for Java developers. It expands based on the standard class library of Java and provides many convenient, efficient and powerful tool categories and data structures.This article will introduce the technical principles and design ideas of the Google Collections framework, and provide some Java code examples. 1. Technical principle: 1. Use powerful generic types: Google Collections framework widely uses Java generic technology to provide types of safe sets and algorithms. 2. Control the Equals and HashCode methods: The collection classes in the Google Collections framework such as HashSet and HashMap are used to determine the equal and hash values using the Equals and HashCode methods of the element itself when storing and finding elements. 3. Use memory optimization algorithm: In order to reduce memory occupation, some data structures in the Google Collections framework such as ImmutableList, ImmutableSet, and ImmutableMap use some special internal representations and the strategies of reused some objects. 4. JDK -based concurrent framework: The concurrent tool classes and thread safety sets in the Google Collection frame are based on JDK -based concurrent frameworks, such as ConcurrenThashmap and ThreadPoolexecutor, which provides an efficient concurrent operating mechanism. 2. Design ideas: 1. Uncharacteria: Google Collections framework provides rich uncharacteristic collection classes, such as ImmutableList, ImmutableSet, and ImmutableMap. They are characterized by not being modified once they are created, which can improve thread security and performance. ImmutableList<String> immutableList = ImmutableList.of("apple", "orange", "banana"); 2. Functional programming support: Functional interfaces and tool classes in the Google CollectionS framework make functional programming easier, such as Function, Predicate, and Streams.This can simplify code, improve readability and maintainability. List<String> fruits = Arrays.asList("apple", "orange", "banana"); List<String> filteredFruits = Collections2.filter(fruits, (fruit) -> fruit.length() > 5); 3. High -efficiency collection operation: Google Collection ’s framework provides some efficient collection operations, such as the intersection of the collection, collection and differences.These operations can simplify the code and improve operational efficiency. Set<Integer> set1 = ImmutableSet.of(1, 2, 3); Set<Integer> set2 = ImmutableSet.of(2, 3, 4); Set<Integer> intersect = Sets.intersection(set1, set2); // 交集 4. Convenient class library extension: Google Collection ’s framework expands the Java standard class library, providing some convenient tool category and data structures, such as the new collection class Table and Range.These extensions help developers to handle various scenes more conveniently. Table<Integer, Integer, String> table = HashBasedTable.create(); table.put(1, 1, "one"); table.put(1, 2, "two"); In short, the Google CollectionS framework is used to use powerful generics such as genetics, memory optimization algorithms and JDK -based concurrent framework, as well as design ideas for providing uncharacteristic collection, functional programming support, efficient collection operations and convenient expansion of libraries.Java developers provide more convenient, efficient and powerful tools and data structures.It has become one of the important dependencies of many Java projects, providing developers with a better development experience.