Remove use of try-with-resources. (#388)

Author: vkryachko

transport/transport-backend-cct/src/main/java/com/google/android/datatransport/cct/CctTransportBackend.java

@@ -202,22 +202,31 @@ private BackendResponse doSend(BatchedLogRequest requestBody) throws IOException
     connection.setRequestMethod("POST");
     connection.setRequestProperty(CONTENT_ENCODING_HEADER_KEY, GZIP_CONTENT_ENCODING);
     connection.setRequestProperty(CONTENT_TYPE_HEADER_KEY, PROTOBUF_CONTENT_TYPE);
-    try (WritableByteChannel channel = Channels.newChannel(connection.getOutputStream())) {
+
+    WritableByteChannel channel = Channels.newChannel(connection.getOutputStream());
+    try {
       ByteArrayOutputStream output = new ByteArrayOutputStream();
-      try (GZIPOutputStream gzipOutputStream = new GZIPOutputStream(output)) {
+      GZIPOutputStream gzipOutputStream = new GZIPOutputStream(output);
+
+      try {
         requestBody.writeTo(gzipOutputStream);
+      } finally {
+        gzipOutputStream.close();
       }
       channel.write(ByteBuffer.wrap(output.toByteArray()));
       int responseCode = connection.getResponseCode();
       LOGGER.info("Status Code: " + responseCode);
 
       long nextRequestMillis;
-      try (InputStream inputStream = connection.getInputStream()) {
+      InputStream inputStream = connection.getInputStream();
+      try {
         try {
           nextRequestMillis = LogResponse.parseFrom(inputStream).getNextRequestWaitMillis();
         } catch (InvalidProtocolBufferException e) {
           return BackendResponse.fatalError();
         }
+      } finally {
+        inputStream.close();
       }
       if (responseCode == 200) {
         return BackendResponse.ok(nextRequestMillis);
@@ -226,6 +235,8 @@ private BackendResponse doSend(BatchedLogRequest requestBody) throws IOException
       } else {
         return BackendResponse.fatalError();
       }
+    } finally {
+      channel.close();
     }
   }
 

transport/transport-runtime/src/main/java/com/google/android/datatransport/runtime/scheduling/persistence/SQLiteEventStore.java

@@ -127,20 +127,21 @@ private long ensureTransportContext(SQLiteDatabase db, TransportContext transpor
 
   @Nullable
   private Long getTransportContextId(SQLiteDatabase db, TransportContext transportContext) {
-    try (Cursor cursor =
+    return tryWithCursor(
         db.query(
             "transport_contexts",
             new String[] {"_id"},
             "backend_name = ?",
             new String[] {transportContext.getBackendName()},
             null,
             null,
-            null)) {
-      if (!cursor.moveToNext()) {
-        return null;
-      }
-      return cursor.getLong(0);
-    }
+            null),
+        cursor -> {
+          if (!cursor.moveToNext()) {
+            return null;
+          }
+          return cursor.getLong(0);
+        });
   }
 
   @Override
@@ -184,19 +185,20 @@ private static String toIdList(Iterable<PersistedEvent> events) {
 
   @Override
   public long getNextCallTime(TransportContext transportContext) {
-    try (Cursor cursor =
+    return tryWithCursor(
         getDb()
             .rawQuery(
                 "SELECT next_request_ms FROM transport_contexts WHERE backend_name = ? and priority = ?",
                 new String[] {
                   transportContext.getBackendName(),
                   String.valueOf(transportContext.getPriority().ordinal())
-                })) {
-      if (cursor.moveToNext()) {
-        return cursor.getLong(0);
-      }
-    }
-    return 0;
+                }),
+        cursor -> {
+          if (cursor.moveToNext()) {
+            return cursor.getLong(0);
+          }
+          return 0L;
+        });
   }
 
   @Override
@@ -207,13 +209,12 @@ public boolean hasPendingEventsFor(TransportContext transportContext) {
           if (contextId == null) {
             return false;
           }
-          try (Cursor cursor =
+          return tryWithCursor(
               getDb()
                   .rawQuery(
                       "SELECT 1 FROM events WHERE context_id = ? LIMIT 1",
-                      new String[] {contextId.toString()})) {
-            return cursor.moveToNext();
-          }
+                      new String[] {contextId.toString()}),
+              Cursor::moveToNext);
         });
   }
 
@@ -264,7 +265,7 @@ private List<PersistedEvent> loadEvents(SQLiteDatabase db, TransportContext tran
       return events;
     }
 
-    try (Cursor cursor =
+    tryWithCursor(
         db.query(
             "events",
             new String[] {"_id", "transport_name", "timestamp_ms", "uptime_ms", "payload"},
@@ -273,19 +274,21 @@ private List<PersistedEvent> loadEvents(SQLiteDatabase db, TransportContext tran
             null,
             null,
             null,
-            String.valueOf(config.getLoadBatchSize()))) {
-      while (cursor.moveToNext()) {
-        long id = cursor.getLong(0);
-        EventInternal event =
-            EventInternal.builder()
-                .setTransportName(cursor.getString(1))
-                .setEventMillis(cursor.getLong(2))
-                .setUptimeMillis(cursor.getLong(3))
-                .setPayload(cursor.getBlob(4))
-                .build();
-        events.add(PersistedEvent.create(id, transportContext, event));
-      }
-    }
+            String.valueOf(config.getLoadBatchSize())),
+        cursor -> {
+          while (cursor.moveToNext()) {
+            long id = cursor.getLong(0);
+            EventInternal event =
+                EventInternal.builder()
+                    .setTransportName(cursor.getString(1))
+                    .setEventMillis(cursor.getLong(2))
+                    .setUptimeMillis(cursor.getLong(3))
+                    .setPayload(cursor.getBlob(4))
+                    .build();
+            events.add(PersistedEvent.create(id, transportContext, event));
+          }
+          return null;
+        });
     return events;
   }
 
@@ -301,25 +304,27 @@ private Map<Long, Set<Metadata>> loadMetadata(SQLiteDatabase db, List<PersistedE
     }
     whereClause.append(')');
 
-    try (Cursor cursor =
+    tryWithCursor(
         db.query(
             "event_metadata",
             new String[] {"event_id", "name", "value"},
             whereClause.toString(),
             null,
             null,
             null,
-            null)) {
-      while (cursor.moveToNext()) {
-        long eventId = cursor.getLong(0);
-        Set<Metadata> currentSet = metadataIndex.get(eventId);
-        if (currentSet == null) {
-          currentSet = new HashSet<>();
-          metadataIndex.put(eventId, currentSet);
-        }
-        currentSet.add(new Metadata(cursor.getString(1), cursor.getString(2)));
-      }
-    }
+            null),
+        cursor -> {
+          while (cursor.moveToNext()) {
+            long eventId = cursor.getLong(0);
+            Set<Metadata> currentSet = metadataIndex.get(eventId);
+            if (currentSet == null) {
+              currentSet = new HashSet<>();
+              metadataIndex.put(eventId, currentSet);
+            }
+            currentSet.add(new Metadata(cursor.getString(1), cursor.getString(2)));
+          }
+          return null;
+        });
     return metadataIndex;
   }
 
@@ -436,6 +441,14 @@ private long getPageCount() {
     return getDb().compileStatement("PRAGMA page_count").simpleQueryForLong();
   }
 
+  private static <T> T tryWithCursor(Cursor c, Function<Cursor, T> function) {
+    try {
+      return function.apply(c);
+    } finally {
+      c.close();
+    }
+  }
+
   private static class OpenHelper extends SQLiteOpenHelper {
     // TODO: when we do schema upgrades in the future we need to make sure both downgrades and
     // upgrades work as expected, e.g. `up+down+up` is equivalent to `up`.