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/*
* Copyright 2000-2016 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.ui.renderers;
import com.vaadin.shared.ui.grid.renderers.ComponentRendererState;
import com.vaadin.ui.Component;
import com.vaadin.ui.Grid;
import com.vaadin.ui.Label;
import elemental.json.Json;
import elemental.json.JsonValue;
/**
* A renderer for presenting Components.
* <p>
* <strong>Note:</strong> The use of ComponentRenderer causes the Grid to
* generate components for all items currently available in the client-side.
* This means that a number of components is always generated and sent to the
* client. Using complex structures of many nested components might be heavy to
* generate and store, which will lead to performance problems.
* <p>
* <strong>Note:</strong> Components will occasionally be generated again during
* runtime e.g. when selection changes. If your component has an internal state
* that is not stored into the object, you should reuse the same component
* instances.
* <p>
* Example of how to add a {@link Label} component to {@link Grid}:
*
* <pre>
* Grid<Person> grid;
* grid.addColumn(person -> new Label(person.getFullName()),
* new ComponentRenderer()).setCaption("Full Name");
* </pre>
*
* @author Vaadin Ltd
* @since 8.1
*/
@SuppressWarnings("serial")
public class ComponentRenderer extends AbstractRenderer<Object, Component> {
/**
* Constructor for ComponentRenderer.
*/
public ComponentRenderer() {
super(Component.class);
}
@Override
public JsonValue encode(Component value) {
return value != null ? Json.create(value.getConnectorId()) : null;
}
@Override
protected ComponentRendererState getState(boolean markAsDirty) {
return (ComponentRendererState) super.getState(markAsDirty);
}
@Override
protected ComponentRendererState getState() {
return (ComponentRendererState) super.getState();
}
}
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