ABCL Armed Bear Common Lisp: How to integrate an external library in the Java class library

ABCL Armed Bear Common Lisp: How to integrate an external library in the Java class library ABCL armed bear COMmon Lisp is a LISP dialect that runs on the Java virtual machine. It provides rich Java interoperability and can directly use the Java class library in the Common Lisp environment.In this article, we will introduce how to integrate external libraries in the Java class library and provide some Java code examples. Integrated external libraries are often encountered in the development process. Sometimes we want to use the existing Java class libraries in our LISP applications, but the Java class library is not intuitive in ABCL.To solve this problem, ABCL provides a simple and powerful mechanism called Java interoperability, which allows us to call Java code directly in the Lisp code. To use the Java class library in ABCL, we must first ensure that the Java class library has been compiled into .jar files.Add this .jar file to the class path of ABCL, you can use `(JVM: add-classpath" path/to/you/library.jar ") to add. Once your Java library is added to the class path, you can use it in the Lisp code.The general method of calling the Java code in the Lisp code is to use `(Java: Import 'your-java-package.yourjavaclass)` to import the Java class.For example, suppose you have a Java class `com.example.utils`, it has a static method called` add` to perform additional operations. lisp (java:import 'com.example.Utils) (defun add-numbers (a b) (java:call-static-method "com.example.Utils" "add" '(java:int java:int) a b)) In the above example, we first introduced the `com.example.utils` class.Then, we defined a LISP function `add-numbers`, which received two parameters` A` and `B`, and use the` (java: call-static-med) `to call the` ADD` method to execute the additional operation. In addition to calling the static method, we can also use the method of Java objects using JNEW 'YOUR-JAVA-PACKAGE.Yourjavaclass) `and use the Java object.For example, suppose you have a java class `com.example.person`, which has an instance method called` Sayhello` to print personalized greetings. lisp (java:import 'com.example.Person) (let ((person (jnew 'com.example.Person))) (java:call-nonvirtual person "sayHello" '())) In the above example, we first introduced the `com.example.person` class.Then, we used `(JNEW)` to create an `Person` object and assign it to the variable` person`.Finally, we use `(java: call-nonvirtual)` to call the `Sayhello` method to print the greetings. To sum up, the Java interoperability of the ABCL armed bear COMMON LISP allows us to directly call the Java code in the Lisp code.By importing the Java class and using the corresponding call method, we can easily integrate the external Java class library in LISP applications. It is hoped that this article will be helpful for integrating external libraries in ABCL.The complete Java code examples and more details can be found in the official documentation of ABCL armed bear community.I wish you use ABCL to develop a stronger application!