src/traversing/var/rneedsContext.js

/*
 * Copyright 2000-2014 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;

/**
 * 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 must 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. Consistent with the iterator
     * returned by {@link #getComponentIterator()}.
     * 
     * @return the number of contained components (zero or one)
     */
    public int getComponentCount() {
        return (root != null ? 1 : 0);
    }

}
	Commit message (Collapse)	Author	Age	Files	Lines
*	Core: Use named exports in `src/`	Michał Gołębiowski-Owczarek	2023-09-12	1	-2/+2
\| \| \| \| \| \| \| \| \|	The `default` export is treated differently across tooling when transpiled to CommonJS - tools differ on whether `module.exports` represents the full module object or just its default export. Switch `src/` modules to named exports for tooling consistency. Fixes gh-5262 Closes gh-5292
*	Core: Migrate from AMD to ES modules 🎉	Michał Gołębiowski-Owczarek	2019-11-18	1	-7/+4
\| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \|	Migrate all source AMD modules to ECMAScript modules. The final bundle is compiled by a custom build process that uses Rollup under the hood. Test files themselves are still loaded via RequireJS as that has to work in IE 11. Tests can now be run in "Load as modules" mode which replaces the previous "Load with AMD" option. That option of running tests doesn't work in IE and Edge as it requires support for dynamic imports. Some of the changes required by the migration: * check `typeof` of `noGlobal` instead of using the variable directly as it's not available when modules are used * change the nonce module to be an object as ECMASscript module exports are immutable * remove some unused exports * import `./core/parseHTML.js` directly in `jquery.js` so that it's not being cut out when the `ajax` module is excluded in a custom compilation Closes gh-4541
*	Build: Put all AMD modules in "src/" in strict mode	Michał Gołębiowski	2016-04-25	1	-0/+2
\| \| \| \|	Fixes gh-3073
*	Build: Update jscs and lint files	Oleg Gaidarenko	2015-09-07	1	-2/+2
\| \| \| \|	Fixes gh-2056
*	Separate jQuery.fn.init into its own module (for lighter core dependencies ↵	Timmy Willison	2013-09-09	1	-0/+6
	across all modules)