[BAEL-4204] JNA (#10113)

* [BAEL-4203] JNA

* [BAEL-4203] JNA

java-native/pom.xml

@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>java-native</artifactId>
+    <name>java-native</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <properties>
+        <jna.version>5.6.0</jna.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>net.java.dev.jna</groupId>
+            <artifactId>jna-platform</artifactId>
+            <version>${jna.version}</version>
+        </dependency>
+    </dependencies>
+    
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <!-- we don't want to reuse JVMs here ! -->
+                    <reuseForks>false</reuseForks>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>

java-native/src/main/java/com/baeldung/jna/CMath.java

@@ -0,0 +1,10 @@
+package com.baeldung.jna;
+
+import com.sun.jna.Library;
+import com.sun.jna.Native;
+import com.sun.jna.Platform;
+
+public interface CMath extends Library {
+    CMath INSTANCE = Native.load(Platform.isWindows() ? "msvcrt" : "c", CMath.class);
+    double cosh(double value);
+}

java-native/src/main/java/com/baeldung/jna/Main.java

@@ -0,0 +1,8 @@
+package com.baeldung.jna;
+
+public class Main {
+	
+	public static void main(String[] args) {
+		
+	}
+}

java-native/src/main/java/com/baeldung/jna/NativeFS.java

@@ -0,0 +1,46 @@
+package com.baeldung.jna;
+
+import java.util.Collections;
+import java.util.Map;
+
+import com.sun.jna.FunctionMapper;
+import com.sun.jna.LastErrorException;
+import com.sun.jna.Library;
+import com.sun.jna.Native;
+import com.sun.jna.NativeLong;
+import com.sun.jna.Platform;
+import com.sun.jna.Structure;
+import com.sun.jna.Structure.FieldOrder;
+
+public interface NativeFS extends Library {
+    
+    FunctionMapper mapper = (library,method) -> {
+        if (Platform.isWindows()) {
+            return "_" + method.getName();
+        }
+        else {
+            return "__x" + method.getName(); // On Linux, stat is actually _xstat
+        }
+    };
+    
+    public NativeFS INSTANCE = Native.load(Platform.isWindows() ? "msvcrt" : "c",
+      NativeFS.class,
+      Collections.singletonMap(Library.OPTION_FUNCTION_MAPPER, mapper));
+
+    int stat(String path, Stat stat) throws LastErrorException;
+
+    @FieldOrder({"st_dev","st_ino","st_mode","st_nlink","st_uid","st_gid","st_rdev","st_size","st_atime","st_mtime","st_ctime"})
+    public class Stat extends Structure {
+        public int st_dev;
+        public int st_ino;
+        public short st_mode;
+        public short st_nlink;
+        public short st_uid;
+        public short st_gid;
+        public int st_rdev;
+        public NativeLong st_size;
+        public NativeLong st_atime;
+        public NativeLong st_mtime;
+        public NativeLong st_ctime;
+    }
+}

java-native/src/main/java/com/baeldung/jna/StdC.java

@@ -0,0 +1,17 @@
+package com.baeldung.jna;
+
+import com.sun.jna.LastErrorException;
+import com.sun.jna.Library;
+import com.sun.jna.Native;
+import com.sun.jna.Platform;
+import com.sun.jna.Pointer;
+
+public interface StdC extends Library {
+    StdC INSTANCE = Native.load(Platform.isWindows() ? "msvcrt" : "c", StdC.class );
+    Pointer malloc(long n);
+    void free(Pointer p);
+    Pointer memset(Pointer p, int c, long n);
+    int open(String path, int flags) throws LastErrorException;
+    int close(int fd) throws LastErrorException;
+}
+

java-native/src/test/java/com/baeldung/jna/CMathUnitTest.java

@@ -0,0 +1,18 @@
+package com.baeldung.jna;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+import com.sun.jna.Native;
+import com.sun.jna.Platform;
+
+class CMathUnitTest {
+    @Test
+    void whenCallNative_thenSuccess() {
+        CMath lib = Native.load(Platform.isWindows() ? "msvcrt" : "c", CMath.class);
+        double result = lib.cosh(0);
+        assertEquals(1.0,result);
+    }
+
+}

java-native/src/test/java/com/baeldung/jna/NativeFSUnitTest.java

@@ -0,0 +1,38 @@
+package com.baeldung.jna;
+
+import static org.junit.Assert.fail;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.jna.NativeFS.Stat;
+import com.sun.jna.LastErrorException;
+import com.sun.jna.Platform;
+
+public class NativeFSUnitTest {
+    
+
+    @Test
+    public void whenCallNative_thenSuccess() throws IOException {
+        NativeFS lib = NativeFS.INSTANCE;
+        
+        File f = Files.createTempFile("junit", ".bin").toFile(); 
+        f.deleteOnExit();
+        Stat stat = new Stat();
+        try {
+            if (Platform.isWindows()) {
+                int rc = lib.stat(f.getAbsolutePath(), stat);
+                assertEquals(0, rc);
+                assertEquals(0,stat.st_size.longValue());
+            }
+        }
+        catch(LastErrorException error) {
+            fail("stat failed: error code=" + error.getErrorCode());
+        }
+        
+    }
+}

java-native/src/test/java/com/baeldung/jna/StdCUnitTest.java

@@ -0,0 +1,47 @@
+package com.baeldung.jna;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.BeforeClass;
+import org.junit.jupiter.api.Test;
+
+import com.sun.jna.Native;
+import com.sun.jna.Platform;
+import com.sun.jna.Pointer;
+
+class StdCUnitTest {
+    
+    @BeforeClass
+    public static void setupProtectedMode() {
+        Native.setProtected(true);
+    }
+
+    @Test
+    public void whenMalloc_thenSuccess() {
+        StdC lib = StdC.INSTANCE;
+        Pointer p = lib.malloc(1024);
+        p.setMemory(0l, 1024l, (byte) 0);
+        lib.free(p);
+    }
+    
+    @Test
+    public void whenAccessViolation_thenShouldThrowError() {
+        // Running this test on Linux requires additional setup using libjsig.so
+        // Details here: http://java-native-access.github.io/jna/5.6.0/javadoc/overview-summary.html#crash-protection
+        // IMPORTANT NOTICE: Code for illustration purposes only. DON'T DO THIS IN YOUR OWN CODE
+        if ( Platform.isWindows()) {
+            Error e = null;
+            Pointer p = new Pointer(0l);
+            
+            try {
+                p.setMemory(0, 100*1024, (byte) 0);
+            }
+            catch(Error err) {
+                e = err;
+            }
+            
+            assertNotNull(e, "Should throw Error");
+        }
+    }
+
+}

jni/pom.xml

@@ -1,14 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-    <artifactId>jni</artifactId>
-    <name>jni</name>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-    </parent>
-
-</project>

pom.xml

@@ -465,7 +465,7 @@
                 <module>jjwt</module>
                 <module>jmeter</module>
                 <module>jmh</module>
-                <module>jni</module>
+                <module>java-native</module>
                 <module>jooby</module>
                 <module>jsf</module>
                 <module>json</module>