Add StringBuffer::delete

Author: dlunch

java_runtime/src/classes/java/lang/string_buffer.rs

@@ -41,6 +41,7 @@ impl StringBuffer {
                 JavaMethodProto::new("append", "(J)Ljava/lang/StringBuffer;", Self::append_long, Default::default()),
                 JavaMethodProto::new("append", "(C)Ljava/lang/StringBuffer;", Self::append_character, Default::default()),
                 JavaMethodProto::new("append", "([CII)Ljava/lang/StringBuffer;", Self::append_char_array, Default::default()),
+                JavaMethodProto::new("delete", "(II)Ljava/lang/StringBuffer;", Self::delete, Default::default()),
                 JavaMethodProto::new("toString", "()Ljava/lang/String;", Self::to_string, Default::default()),
                 JavaMethodProto::new("setLength", "(I)V", Self::set_length, Default::default()),
                 JavaMethodProto::new("length", "()I", Self::length, Default::default()),
@@ -174,6 +175,28 @@ impl StringBuffer {
         Ok(this)
     }
 
+    async fn delete(jvm: &Jvm, _: &mut RuntimeContext, mut this: ClassInstanceRef<Self>, start: i32, end: i32) -> Result<ClassInstanceRef<Self>> {
+        tracing::debug!("java.lang.StringBuffer::delete({this:?}, {start}, {end})");
+
+        let count: i32 = jvm.get_field(&this, "count", "I").await?;
+
+        let mut java_value: ClassInstanceRef<Array<JavaChar>> = jvm.get_field(&this, "value", "[C").await?;
+        let chars: Vec<JavaChar> = jvm.load_array(&java_value, 0, count as _).await?;
+
+        let new_chars = chars
+            .iter()
+            .take(start as _)
+            .chain(chars.iter().skip(end as _))
+            .cloned()
+            .collect::<Vec<_>>();
+        let new_count = new_chars.len() as i32;
+
+        jvm.store_array(&mut java_value, 0, new_chars).await?;
+        jvm.put_field(&mut this, "count", "I", new_count as i32).await?;
+
+        Ok(this)
+    }
+
     async fn to_string(jvm: &Jvm, _: &mut RuntimeContext, this: ClassInstanceRef<Self>) -> Result<ClassInstanceRef<String>> {
         tracing::debug!("java.lang.StringBuffer::toString({:?})", &this);
 

java_runtime/tests/classes/java/lang/test_string_buffer.rs

@@ -32,5 +32,12 @@ async fn test_string_buffer() -> Result<()> {
 
     assert_eq!("Hello, 42H42", result);
 
+    let _: ClassInstanceRef<StringBuffer> = jvm
+        .invoke_virtual(&string_buffer, "delete", "(II)Ljava/lang/StringBuffer;", (5, 7))
+        .await?;
+    let result = jvm.invoke_virtual(&string_buffer, "toString", "()Ljava/lang/String;", ()).await?;
+    let result = JavaLangString::to_rust_string(&jvm, &result).await?;
+    assert_eq!("Hello42H42", result);
+
     Ok(())
 }