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/*
* Copyright 2000-2021 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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