Explore the technical principles of Google Collections framework in the Java class library
Google Collection's framework is an open source collection framework for the Java class library. Its technical principles include the following aspects: serial support, tool class, thread security, functional programming and performance optimization.This article will explore these technical principles and provide examples of Java code to illustrate their usage.
1. Serialized support:
Google Collection's framework provides a collection class for serialized support.By implementing Java's Serializable interface, users can easily serialize the concentration instances into byte flow, or the derivative of the byte flow into a collection of instances.This is very useful to store the setting class as a disk or transmit it through the network.
Example code:
import com.google.common.collect.Lists;
import com.google.common.collect.Serialization;
import java.io.IOException;
import java.util.List;
public class SerializationExample {
public static void main(String[] args) throws IOException, ClassNotFoundException {
List<String> list = Lists.newArrayList("foo", "bar", "baz");
// Serialize the list
byte[] serializedBytes = Serialization.toByteArray(list);
// Deserialize the list
List<String> deserializedList = Serialization
.reserialize(serializedBytes)
.to(List.class)
.get();
System.out.println(deserializedList); // Output: [foo, bar, baz]
}
}
Tool category:
The Google Collections framework also provides a series of practical tool classes to simplify the operation and processing of the collection class.These tool classes include collective operations, iterators, comparators, converters, etc.Using these tools can be more convenient to perform common operations, such as filtering, conversion, sorting, etc.
Example code:
import com.google.common.collect.Collections2;
import com.google.common.collect.Lists;
import java.util.Collection;
import java.util.List;
public class CollectionsExample {
public static void main(String[] args) {
List<String> list = Lists.newArrayList("foo", "bar", "baz");
// Filter elements that start with 'b'
Collection<String> filteredCollection = Collections2.filter(list, element -> element.startsWith("b"));
System.out.println(filteredCollection); // Output: [bar, baz]
}
}
Three, thread safety:
Google Collection's framework provides some thread -safe set classes for safe operations in multi -threaded environments.These thread -safe set classes include CONCURRENTMAP, ConcurrentSet, etc., which can ensure that data competition or other thread security issues will not occur during concurrent access.
Example code:
import com.google.common.collect.MapMaker;
import java.util.Map;
import java.util.concurrent.ConcurrentMap;
public class ThreadSafeExample {
public static void main(String[] args) {
ConcurrentMap<String, Integer> map = new MapMaker()
.concurrencyLevel(4)
.makeMap();
// Thread 1
map.put("foo", 1);
// Thread 2
map.put("bar", 2);
// Thread 3
map.put("baz", 3);
System.out.println(map); // Output: {foo=1, bar=2, baz=3}
}
}
Fourth, functional programming:
Google Collection's framework supports functional programming paradigms. By providing some functional interfaces and operations, the operation of the collection class is more concise and flexible.For example, the LAMBDA expressions can be used to transfer functions to mappore and filter the set class.
Example code:
import com.google.common.collect.Lists;
import java.util.List;
public class FunctionalProgrammingExample {
public static void main(String[] args) {
List<Integer> numbers = Lists.newArrayList(1, 2, 3, 4, 5);
// Square each number
numbers.stream()
.map(number -> number * number)
.forEach(System.out::println);
}
}
5. Performance optimization:
Google Collection ’s framework has been optimized by performance to provide more efficient collection classes.It uses some efficient data structures and algorithms to improve the execution speed and memory utilization rate of collective operations.In addition, the Google CollectionS framework also provides some cache mechanisms to reduce the number of access to external resources such as disk or database.
Example code:
import com.google.common.collect.ImmutableList;
import java.util.List;
public class PerformanceOptimizationExample {
public static void main(String[] args) {
List<String> list = ImmutableList.of("foo", "bar", "baz");
// Optimize for reading
list.stream()
.forEach(System.out::println);
}
}
In summary, the technical principles of Google Collections framework in the Java library include serialized support, tool classes, thread security, functional programming and performance optimization.By understanding and applying these technical principles, we can handle and operate a collection class more easily to improve the readability, maintenance and performance of code.
