com.globalmentor.swing.text.Styles Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of globalmentor-swing Show documentation
GlobalMentor Java Swing library.
The newest version!
/*
 * Copyright © 1996-2009 GlobalMentor, 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.globalmentor.swing.text;

import javax.swing.text.AttributeSet;
import javax.swing.text.MutableAttributeSet;

/**
 * A collection of utilities for working with Swing styles in attribute sets.
 * @author Garret Wilson
 */
public class Styles {

	/** The characters to prepend to Swing-specific attribute names. */
	public static final String SWING_ATTRIBUTE_START = "$";

	/** Whether a view for this element should be visible or hidden. */
	public static final String VISIBLE_ATTRIBUTE_NAME = SWING_ATTRIBUTE_START + "visible";

	/**
	 * Returns an attribute in the attribute set only if it is defined; the attribute is not resolved by searching the parent attribute set hierarchy.
	 * @param attributeSet The attribute set, which may be null.
	 * @return The attribute if the attribute is defined, else null.
	 */
	public static Object getDefinedAttribute(final AttributeSet attributeSet, final String attributeName) {
		return attributeSet != null ? //make sure there is an attribute set
		(attributeSet.isDefined(attributeName) ? attributeSet.getAttribute(attributeName) : null)
				: null; //return the attribute if it is defined, or null if it isn't
	}

	/**
	 * Checks whether the element has been specified as visible or hidden, without checking up the element hierarchy.
	 * @param attributeSet The attribute set.
	 * @return true if the visible attribute is true or not set, else false if the visible attribute is set to
	 *         false.
	 * @see #VISIBLE_ATTRIBUTE_NAME
	 */
	public static boolean isVisible(final AttributeSet attributeSet) {
		final Object visibleAttribute = getDefinedAttribute(attributeSet, Styles.VISIBLE_ATTRIBUTE_NAME); //get the visible attribute, if there is one
		return !Boolean.FALSE.equals(visibleAttribute); //the element is visible unless the visible attribute is set to false
	}

	/**
	 * Sets the visibility of the element.
	 * @param attributeSet The attribute set.
	 * @param visible true if the element should be visible, else false if the view created from the element should not be shown.
	 */
	public static void setVisible(final MutableAttributeSet attributeSet, final boolean visible) {
		attributeSet.addAttribute(Styles.VISIBLE_ATTRIBUTE_NAME, Boolean.valueOf(visible)); //set the value of the visible attribute
	}

}