Allow deleting multiple records of a model at once

jack-core/src/com/rapleaf/jack/AbstractDatabaseModel.java

@@ -23,6 +23,7 @@
 import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Date;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -786,13 +787,18 @@ public String getTableName() {
 
   @Override
   public boolean delete(long id) throws IOException {
+    return delete(Collections.singleton(id));
+  }
+
+  @Override
+  public boolean delete(Collection<Long> ids) throws IOException {
     PreparedStatement stmt = conn.getPreparedStatement(String.format(
-        "DELETE FROM %s WHERE id=%d", tableName, id));
+        "DELETE FROM %s WHERE id IN (%s)", tableName, ids.stream().map(Object::toString).collect(Collectors.joining(","))));
     try {
-      boolean success = stmt.executeUpdate() == 1;
+      boolean success = stmt.executeUpdate() == ids.size();
       stmt.close();
       if (success) {
-        cachedById.remove(id);
+        ids.forEach(cachedById::remove);
       }
       clearForeignKeyCache();
       return success;

jack-core/src/com/rapleaf/jack/IModelPersistence.java

@@ -101,6 +101,11 @@ interface RecordSelector<T extends ModelWithId> {
    */
   boolean delete(long id) throws IOException;
 
+  /**
+   * @return true if all records deleted, false otherwise
+   */
+  boolean delete(Collection<Long> ids) throws IOException;
+
   /**
    * Delete all records in this persistence.
    *

jack-test/test/java/com/rapleaf/jack/BaseDatabaseModelTestCase.java

@@ -501,14 +501,24 @@ public void testNullTreatment() throws Exception {
   }
 
   @Test
-  public void testDelete() throws Exception {
+  public void testDeleteSingle() throws Exception {
     IPostPersistence posts = dbs.getDatabase1().posts();
     Post post = posts.create(null, 10L, 1, 0l);
     long id = post.getId();
     posts.delete(id);
     assertNull(posts.find(id));
   }
 
+  @Test
+  public void testDeleteMultiple() throws Exception {
+    IPostPersistence posts = dbs.getDatabase1().posts();
+    long post1 = posts.create(null, 10L, 1, 0l).getId();
+    long post2 = posts.create(null, 10L, 1, 0l).getId();
+    posts.delete(Arrays.asList(post1, post2));
+    assertTrue(posts.find(Arrays.asList(post1, post2)).isEmpty());
+  }
+
+
   @Test
   public void testSave() throws Exception {
     IPostPersistence posts = dbs.getDatabase1().posts();