com.google.gwt.user.client.ui.Hidden.java Source code

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Here is the source code for com.google.gwt.user.client.ui.Hidden.java

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/*
 * Copyright 2008 Google Inc.
 * 
 * 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.google.gwt.user.client.ui;

import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.InputElement;
import com.google.gwt.editor.client.IsEditor;
import com.google.gwt.editor.client.LeafValueEditor;
import com.google.gwt.editor.client.adapters.TakesValueEditor;
import com.google.gwt.user.client.TakesValue;

/**
 * Represents a hidden field in an HTML form.
 */
public class Hidden extends Widget implements HasName, TakesValue<String>, IsEditor<LeafValueEditor<String>> {

    /**
     * Creates a Hidden widget that wraps an existing &lt;input type='hidden'&gt;
     * element.
     * 
     * This element must already be attached to the document. If the element is
     * removed from the document, you must call
     * {@link RootPanel#detachNow(Widget)}.
     * 
     * @param element the element to be wrapped
     */
    public static Hidden wrap(Element element) {
        // Assert that the element is attached.
        assert Document.get().getBody().isOrHasChild(element);

        Hidden hidden = new Hidden(element);

        // Mark it attached and remember it for cleanup.
        hidden.onAttach();
        RootPanel.detachOnWindowClose(hidden);

        return hidden;
    }

    private LeafValueEditor<String> editor;

    /**
     * Constructor for <code>Hidden</code>.
     */
    public Hidden() {
        setElement(Document.get().createHiddenInputElement());
    }

    /**
     * Constructor for <code>Hidden</code>.
     * 
     * @param name name of the hidden field
     */
    public Hidden(String name) {
        this();
        setName(name);
    }

    /**
     * Constructor for <code>Hidden</code>.
     * 
     * @param name name of the hidden field
     * @param value value of the hidden field
     */
    public Hidden(String name, String value) {
        this(name);
        setValue(value);
    }

    /**
     * This constructor may be used by subclasses to explicitly use an existing
     * element. This element must be an &lt;input&gt; element whose type is
     * 'hidden'.
     * 
     * @param element the element to be used
     */
    protected Hidden(Element element) {
        assert InputElement.as(element).getType().equalsIgnoreCase("hidden");
        setElement(element);
    }

    public LeafValueEditor<String> asEditor() {
        if (editor == null) {
            editor = TakesValueEditor.of(this);
        }
        return editor;
    }

    /**
     * Gets the default value of the hidden field.
     * 
     * @return the default value
     */
    public String getDefaultValue() {
        return getInputElement().getDefaultValue();
    }

    /**
     * Gets the id of the hidden field.
     * 
     * @return the id
     */
    public String getID() {
        return getElement().getId();
    }

    /**
     * Gets the name of the hidden field.
     * 
     * @return the name
     */

    public String getName() {
        return getInputElement().getName();
    }

    /**
     * Gets the value of the hidden field.
     * 
     * @return the value
     */
    public String getValue() {
        return getInputElement().getValue();
    }

    /**
     * Sets the default value of the hidden field.
     * 
     * @param defaultValue default value to set
     */
    public void setDefaultValue(String defaultValue) {
        getInputElement().setDefaultValue(defaultValue);
    }

    /**
     * Sets the id of the hidden field.
     * 
     * @param id id to set
     */
    public void setID(String id) {
        getElement().setId(id);
    }

    /**
     * Sets the name of the hidden field.
     * 
     * @param name name of the field
     */
    public void setName(String name) {
        if (name == null) {
            throw new NullPointerException("Name cannot be null");
        } else if (name.equals("")) {
            throw new IllegalArgumentException("Name cannot be an empty string.");
        }

        getInputElement().setName(name);
    }

    /**
     * Sets the value of the hidden field.
     * 
     * @param value value to set
     */
    public void setValue(String value) {
        getInputElement().setValue(value);
    }

    private InputElement getInputElement() {
        return getElement().cast();
    }
}