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- /*
- * Copyright 2000-2018 Vaadin Ltd.
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not
- * use this file except in compliance with the License. You may obtain a copy of
- * the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations under
- * the License.
- */
- package com.vaadin.client.data;
-
- import java.util.function.Consumer;
-
- import com.google.gwt.core.client.Scheduler;
- import com.vaadin.shared.Range;
-
- /**
- * Helper class for creating a {@link DataChangeHandler} for a Widget that does
- * not support lazy loading.
- *
- * @author Vaadin Ltd
- * @since 8.0
- */
- public class SimpleDataChangeHandler implements DataChangeHandler {
-
- /**
- * Class to request the data source to get the full data set.
- */
- private static class DelayedResetScheduler {
-
- private final DataSource<?> dataSource;
- private boolean scheduled = false;
-
- public DelayedResetScheduler(DataSource<?> dataSource) {
- this.dataSource = dataSource;
- }
-
- public void schedule() {
- if (scheduled) {
- return;
- }
- Scheduler.get().scheduleFinally(() -> {
- dataSource.ensureAvailability(0, dataSource.size());
- scheduled = false;
- });
- scheduled = true;
- }
-
- public int getExpectedSize() {
- return dataSource.size();
- }
-
- public boolean isScheduled() {
- return scheduled;
- }
- }
-
- private final DelayedResetScheduler scheduler;
- private final Consumer<Range> refreshMethod;
-
- SimpleDataChangeHandler(DataSource<?> dataSource,
- Consumer<Range> refreshMethod) {
- scheduler = new DelayedResetScheduler(dataSource);
- this.refreshMethod = refreshMethod;
- }
-
- @Override
- public void dataUpdated(int firstRowIndex, int numberOfRows) {
- scheduler.schedule();
- }
-
- @Override
- public void dataRemoved(int firstRowIndex, int numberOfRows) {
- scheduler.schedule();
- }
-
- @Override
- public void dataAdded(int firstRowIndex, int numberOfRows) {
- scheduler.schedule();
- }
-
- @Override
- public void dataAvailable(int firstRowIndex, int numberOfRows) {
- if (!scheduler.isScheduled() && firstRowIndex == 0
- && numberOfRows == scheduler.getExpectedSize()) {
- // All data should now be available.
- refreshMethod.accept(Range.withLength(firstRowIndex, numberOfRows));
- } else {
- scheduler.schedule();
- }
- }
-
- @Override
- public void resetDataAndSize(int newSize) {
- scheduler.schedule();
- }
- }
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