Add ExifTool examples for batch processing

docs/guides/java-integration.md

@@ -213,8 +213,40 @@ String perlScript = Files.readString(Path.of("legacy.pl"));
 engine.eval(perlScript);
 ```
 
+### Repeated Execution / Batch Processing
+
+For processing multiple items (e.g., files), don't run a CLI script repeatedly.
+Instead, use the Perl module directly and call methods in a loop:
+
+```java
+// Load module once, call methods repeatedly
+String initCode = """
+    use Image::ExifTool;
+    our $exif = Image::ExifTool->new();
+
+    sub process_file {
+        my ($file) = @_;
+        return $exif->ImageInfo($file, qw(Make Model));
+    }
+    1;
+    """;
+
+engine.eval(initCode);
+
+// Now call the subroutine for each file - no recompilation needed
+for (String file : files) {
+    engine.eval("process_file('" + file + "')");
+}
+```
+
+See `examples/ExifToolExample.java` and `examples/ExifToolExample.pl` for a complete
+working example using Image::ExifTool.
+
 ## Examples
 
+- `examples/ExifToolExample.pl` - Batch image processing with Image::ExifTool
+- `examples/ExifToolExample.java` - Java integration example
+
 See also:
 - [Quick Start](../../QUICKSTART.md) - Basic examples
 - [Architecture](../reference/architecture.md) - How it works internally

examples/ExifToolExample.java

@@ -0,0 +1,78 @@
+package examples;
+
+import org.perlonjava.app.cli.CompilerOptions;
+import org.perlonjava.app.scriptengine.PerlLanguageProvider;
+import org.perlonjava.runtime.runtimetypes.*;
+
+/**
+ * Example: Using Image::ExifTool module from Java for batch processing.
+ * 
+ * For repeated execution with different files, using the Image::ExifTool 
+ * Perl module directly is more efficient than running the CLI script 
+ * repeatedly. The module is loaded once, then methods can be called 
+ * for each file.
+ * 
+ * Prerequisites:
+ *   Download and extract ExifTool in the PerlOnJava root directory:
+ *     cd PerlOnJava
+ *     curl -LO https://exiftool.org/Image-ExifTool-13.44.tar.gz
+ *     tar xzf Image-ExifTool-13.44.tar.gz
+ * 
+ * Run the Perl version with:
+ *   ./gradlew run --args='examples/ExifToolExample.pl'
+ * 
+ * Or compile and run the Java version (requires fat jar).
+ */
+public class ExifToolExample {
+
+    public static void main(String[] args) throws Exception {
+        // Initialize PerlOnJava
+        PerlLanguageProvider.resetAll();
+
+        // Add ExifTool lib to @INC
+        RuntimeArray inc = GlobalVariable.getGlobalArray("main::INC");
+        RuntimeArray.push(inc, new RuntimeScalar("Image-ExifTool-13.44/lib"));
+
+        // Load Image::ExifTool and define helper subroutine
+        String initScript = """
+            use strict;
+            use warnings;
+            use Image::ExifTool;
+
+            our $exif = Image::ExifTool->new();
+
+            sub process_image {
+                my ($file) = @_;
+                my $info = $exif->ImageInfo($file, qw(Make Model DateTimeOriginal));
+                print "File: $file\\n";
+                for my $tag (sort keys %$info) {
+                    print "  $tag: $info->{$tag}\\n";
+                }
+                print "\\n";
+            }
+            1;
+            """;
+
+        CompilerOptions options = new CompilerOptions();
+        options.fileName = "<init>";
+        options.code = initScript;
+
+        System.out.println("Loading Image::ExifTool...");
+        PerlLanguageProvider.executePerlCode(options, true);
+        System.out.println("Ready.\n");
+
+        // Process multiple images by calling the Perl subroutine
+        String[] images = {
+            "Image-ExifTool-13.44/t/images/Canon.jpg",
+            "Image-ExifTool-13.44/t/images/Nikon.jpg"
+        };
+
+        RuntimeScalar processImage = GlobalVariable.getGlobalCodeRef("main::process_image");
+
+        for (String image : images) {
+            RuntimeArray callArgs = new RuntimeArray();
+            RuntimeArray.push(callArgs, new RuntimeScalar(image));
+            RuntimeCode.apply(processImage, callArgs, RuntimeContextType.VOID);
+        }
+    }
+}

examples/ExifToolExample.pl

@@ -0,0 +1,38 @@
+#!/usr/bin/env perl
+# Example: Using Image::ExifTool module for batch processing
+#
+# Prerequisites:
+#   Download and extract ExifTool in the PerlOnJava root directory:
+#     cd PerlOnJava
+#     curl -LO https://exiftool.org/Image-ExifTool-13.44.tar.gz
+#     tar xzf Image-ExifTool-13.44.tar.gz
+#
+# Run with:
+#   ./gradlew run --args='examples/ExifToolExample.pl'
+
+use strict;
+use warnings;
+use lib 'Image-ExifTool-13.44/lib';
+use Image::ExifTool;
+
+# Create one ExifTool instance - reusable for multiple files
+my $exif = Image::ExifTool->new();
+
+# Sample images to process
+my @images = (
+    'Image-ExifTool-13.44/t/images/Canon.jpg',
+    'Image-ExifTool-13.44/t/images/Nikon.jpg',
+    'Image-ExifTool-13.44/t/images/Sony.jpg',
+);
+
+print "ExifTool version: ", $exif->GetValue('ExifToolVersion'), "\n\n";
+
+for my $file (@images) {
+    my $info = $exif->ImageInfo($file, qw(Make Model DateTimeOriginal ImageSize));
+
+    print "File: $file\n";
+    for my $tag (sort keys %$info) {
+        print "  $tag: $info->{$tag}\n";
+    }
+    print "\n";
+}