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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.ui;
-
- import java.util.Collections;
- import java.util.Iterator;
-
- import com.vaadin.shared.customcomponent.CustomComponentState;
-
- /**
- * Custom component provides a simple implementation of the {@link Component}
- * interface to allow creating new UI components by composition of existing
- * server-side components.
- *
- * <p>
- * The component is used by inheriting the CustomComponent class and setting the
- * composition root component. The composition root must be set with
- * {@link #setCompositionRoot(Component)} before the CustomComponent is used,
- * such as by adding it to a layout, so it is preferable to set it in the
- * constructor.
- * </p>
- *
- * <p>
- * The composition root itself can contain more components. The advantage of
- * wrapping it in a CustomComponent is that its details, such as interfaces, are
- * hidden from the users of the component, thereby contributing to information
- * hiding.
- * </p>
- *
- * <p>
- * The CustomComponent does not display the caption of the composition root, so
- * if you want to have it shown in the layout where the custom component is
- * contained, you need to set it as caption of the CustomComponent.
- * </p>
- *
- * <p>
- * The component expands horizontally and has undefined height by default.
- * </p>
- *
- * @author Vaadin Ltd.
- * @since 3.0
- */
- @SuppressWarnings("serial")
- public class CustomComponent extends AbstractComponent
- implements HasComponents {
-
- /**
- * The root component implementing the custom component.
- */
- private Component root = null;
-
- /**
- * Constructs a new custom component.
- *
- * <p>
- * Note that you must set the composition root before the component can be
- * used, preferably in the constructor.
- * </p>
- */
- public CustomComponent() {
- // Expand horizontally by default
- setWidth(100, Unit.PERCENTAGE);
- }
-
- /**
- * Constructs a new custom component.
- *
- * @param compositionRoot
- * the root of the composition component tree. It must not be
- * null.
- */
- public CustomComponent(Component compositionRoot) {
- this();
- setCompositionRoot(compositionRoot);
- }
-
- /**
- * Returns the composition root.
- *
- * @return the Component Composition root.
- */
- protected Component getCompositionRoot() {
- return root;
- }
-
- /**
- * Sets the composition root for the component.
- *
- * <p>
- * You must set the composition root to a non-null value before the
- * component can be used. You can change it later.
- * </p>
- *
- * @param compositionRoot
- * the root of the composition component tree.
- */
- protected void setCompositionRoot(Component compositionRoot) {
- if (compositionRoot != root) {
- if (root != null && equals(root.getParent())) {
- // remove old component
- root.setParent(null);
- }
- if (compositionRoot != null) {
- // set new component
- if (compositionRoot.getParent() != null) {
- // If the component already has a parent, try to remove it
- AbstractSingleComponentContainer
- .removeFromParent(compositionRoot);
- }
- compositionRoot.setParent(this);
- }
- root = compositionRoot;
- markAsDirty();
- }
- }
-
- /* Basic component features ------------------------------------------ */
-
- @Override
- public Iterator<Component> iterator() {
- if (getCompositionRoot() != null) {
- return Collections.singletonList(getCompositionRoot()).iterator();
- } else {
- return Collections.<Component> emptyList().iterator();
- }
- }
-
- /**
- * Gets the number of contained components.
- *
- * @return the number of contained components (zero or one)
- */
- public int getComponentCount() {
- return (root != null ? 1 : 0);
- }
-
- @Override
- protected CustomComponentState getState() {
- return (CustomComponentState) super.getState();
- }
-
- @Override
- protected CustomComponentState getState(boolean markAsDirty) {
- return (CustomComponentState) super.getState(markAsDirty);
- }
-
- }
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