feat: add load_by_class function to catalog

01.workspace/heave/src/fun/sqlite_load_by_class.rs

@@ -1,10 +1,22 @@
 use crate::*;
+use rusqlite::*;
 
-pub fn run() {
-    todo!("sqlite_load_by_class: missing implementation");
+const SELECT_ENTITY_BY_CLASS: &str = r#"
+    SELECT * FROM entity
+    WHERE class = ?1;
+"#;
+
+pub fn run(path: &path::Path, entity_class: &str) -> Vec<Entity> {
+    let mut entities = Vec::<Entity>::new();
+    let connection = Connection::open(path).unwrap();
+    let mut statement = connection.prepare(SELECT_ENTITY_BY_CLASS).unwrap();
+    let result = statement
+        .query_map([entity_class], sqlite::map::row_to_entity)
+        .unwrap();
+    for entity in result {
+        let mut entity = entity.unwrap();
+        sqlite::load::attributes(&connection, &mut entity);
+        entities.push(entity);
+    }
+    entities
 }
-
-// #[cfg(test)]
-// mod unit_tests {
-// use super::*;
-// }

01.workspace/heave/src/str/catalog.rs

@@ -46,15 +46,11 @@ impl O {
             Some(entity) => self.insert(entity),
         }
     }
+    pub fn load_by_class(&mut self, class: &str) {
+        let path = path::Path::new(&self.path);
+        let entities = sqlite::load::by_class(path, class);
+        for entity in entities {
+            self.insert(entity);
+        }
+    }
 }
-
-// impl std::fmt::Display for O {
-// fn fmt(&self, _f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
-// todo!();
-// }
-// }
-
-// #[cfg(test)]
-// mod unit_tests {
-// use super::*;
-// }

01.workspace/heave/src/tst/intended_use.rs

@@ -190,4 +190,32 @@ mod tests {
             )
         );
     }
+    #[test]
+    fn check_011() {
+        // demonstrate load by class
+        let tempfile = tempfile::NamedTempFile::new().unwrap();
+        let path = tempfile.path();
+        let mut catalog = Catalog::new(path.to_str().unwrap());
+        catalog.init();
+        let product_01 = Product {
+            id: short_uuid::short!().to_string(),
+            name: "laptop".to_string(),
+            price: 200000u64,
+        };
+        let product_02 = Product {
+            id: short_uuid::short!().to_string(),
+            name: "desktop".to_string(),
+            price: 300000u64,
+        };
+        let expected_value_01 = product_01.clone();
+        catalog.insert(product_01);
+        catalog.insert(product_02);
+        catalog.persist();
+        // new empty catalog
+        let mut catalog = Catalog::new(path.to_str().unwrap());
+        catalog.load_by_class("product");
+        assert_eq!(catalog.items.len(), 2);
+        let loaded_value_01: Product = catalog.get(&expected_value_01.id).unwrap();
+        assert_eq!(loaded_value_01, expected_value_01);
+    }
 }