Java: File IO skill (#1399)

Co-authored-by: Mark Wallace <[email protected]>

java/semantickernel-core-skills/pom.xml

@@ -23,6 +23,17 @@
             <artifactId>junit-jupiter-api</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>io.projectreactor</groupId>
+            <artifactId>reactor-test</artifactId>
+            <scope>test</scope>
+            <version>3.5.6</version>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
 </project>

java/semantickernel-core-skills/src/main/java/com/microsoft/semantickernel/coreskills/FileIOSkill.java

@@ -0,0 +1,82 @@
+// Copyright (c) Microsoft. All rights reserved.
+package com.microsoft.semantickernel.coreskills;
+
+import com.microsoft.semantickernel.skilldefinition.annotations.DefineSKFunction;
+import com.microsoft.semantickernel.skilldefinition.annotations.SKFunctionInputAttribute;
+import com.microsoft.semantickernel.skilldefinition.annotations.SKFunctionParameters;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+/**
+ * Read and write from a file.
+ *
+ * <p>Usage: kernel.ImportSkill("file", new FileIOSkill());
+ *
+ * <p>Examples:
+ *
+ * <pre>{@code
+ * file.readAsync($path) => "hello world"
+ * file.writeAsync()
+ * }</pre>
+ */
+public class FileIOSkill {
+
+    /**
+     * Read a file.
+     *
+     * <p>Example:
+     *
+     * <pre>{@code
+     * file.readAsync($path) => "hello world"
+     * }</pre>
+     *
+     * @param path Source file.
+     * @return File content.
+     */
+    @DefineSKFunction(description = "Read a file", name = "readAsync")
+    public String readFileAsync(
+            @SKFunctionInputAttribute
+                    @SKFunctionParameters(name = "path", description = "Source file")
+                    String path,
+                    @SKFunctionParameters(name = "charset", description = "Character set to use to read the file", defaultValue="UTF-8")
+                    String charset) throws IOException {
+        Path filePath = Paths.get(path);
+        byte[] fileBytes;
+        fileBytes = Files.readAllBytes(filePath);
+        String fileContents = new String(fileBytes, charset);
+        return fileContents;
+    }
+
+    /**
+     * Write a file.
+     *
+     * <p>Example:
+     *
+     * <pre>{@code
+     * file.writeAsync()
+     * }</pre>
+     *
+     * @param path The destination file.
+     * @param content Contains the 'content' to write
+     * @return An awaitable task.
+     */
+    @DefineSKFunction(description = "Write a file", name = "writeAsync")
+    public void writeFileAsync(
+            @SKFunctionInputAttribute
+                    @SKFunctionParameters(name = "path", description = "Destination file")
+                    String path,
+                    @SKFunctionParameters(
+                            name = "content",
+                            description = "File content",
+                            defaultValue = "",
+                            type = String.class)
+                    String content,
+                    @SKFunctionParameters(name = "charset", description = "Character set to use to read the file", defaultValue="UTF-8")
+                    String charset) throws IOException {
+                        Path filePath = Paths.get(path);
+                        Files.write(filePath, content.getBytes(charset));
+    }
+}

java/semantickernel-core-skills/src/test/java/com/microsoft/semantickernel/coreskills/FileIOSkillTest.java

@@ -0,0 +1,61 @@
+// Copyright (c) Microsoft. All rights reserved.
+package com.microsoft.semantickernel.coreskills;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+import com.microsoft.semantickernel.orchestration.ContextVariables;
+import com.microsoft.semantickernel.orchestration.SKContext;
+
+import reactor.test.StepVerifier;
+
+public class FileIOSkillTest {
+
+    @Test
+    public void testReadFileAsync() throws IOException {
+        // Create a temporary file with some content
+        String content = "Hello, World!";
+        Path tempFile = Files.createTempFile("test", ".txt");
+        Files.write(tempFile, content.getBytes());
+
+        // Create an instance of FileIOSkill
+        FileIOSkill fileIOSkill = new FileIOSkill();
+
+        // Call the readFileAsync method with the temporary file path
+        String filePath = tempFile.toAbsolutePath().toString();
+        String outcome = fileIOSkill.readFileAsync(filePath, "UTF-8");
+
+        // Assert content (expected) is the same as the outcome (actual)
+        Assertions.assertEquals(content, outcome);
+
+        // Delete the temporary file
+        Files.delete(tempFile);
+    }
+
+    @Test
+    public void testWriteFileAsync() throws IOException {
+        // Create a temporary file
+        Path tempFile = Files.createTempFile("test", ".txt");
+
+        // Create an instance of FileIOSkill
+        FileIOSkill fileIOSkill = new FileIOSkill();
+
+        // Define the content to write
+        String content = "Hello, World!";
+
+        // Call the writeFileAsync method with the temporary file path and content
+        fileIOSkill.writeFileAsync(tempFile.toAbsolutePath().toString(), content, "UTF-8");
+
+        // Read the written file to verify the content
+        String fileContents = new String(Files.readAllBytes(tempFile));
+        Assertions.assertEquals(content, fileContents);
+
+        // Delete the temporary file
+        Files.delete(tempFile);
+    }
+}