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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package javax.swing.text;

import java.util.Enumeration;

/**

 * A collection of unique attributes.  This is a read-only,

 * immutable interface.  An attribute is basically a key and

 * a value assigned to the key.  The collection may represent

 * something like a style run, a logical style, etc.  These

 * are generally used to describe features that will contribute

 * to some graphical representation such as a font.  The

 * set of possible keys is unbounded and can be anything.

 * Typically View implementations will respond to attribute

 * definitions and render something to represent the attributes.

 * <p>

 * Attributes can potentially resolve in a hierarchy.  If a

 * key doesn't resolve locally, and a resolving parent

 * exists, the key will be resolved through the parent.

 *

 * @author  Timothy Prinzing

 * @see MutableAttributeSet

 */

public interface AttributeSet {

    /**

     * This interface is the type signature that is expected

     * to be present on any attribute key that contributes to

     * the determination of what font to use to render some

     * text.  This is not considered to be a closed set, the

     * definition can change across version of the platform and can

     * be amended by additional user added entries that

     * correspond to logical settings that are specific to

     * some type of content.

     */

    public interface FontAttribute {

    }

    /**

     * This interface is the type signature that is expected

     * to be present on any attribute key that contributes to

     * presentation of color.

     */

    public interface ColorAttribute {

    }

    /**

     * This interface is the type signature that is expected

     * to be present on any attribute key that contributes to

     * character level presentation.  This would be any attribute

     * that applies to a so-called <i>run</i> of

     * style.

     */

    public interface CharacterAttribute {

    }

    /**

     * This interface is the type signature that is expected

     * to be present on any attribute key that contributes to

     * the paragraph level presentation.

     */

    public interface ParagraphAttribute {

    }

    /**

     * Returns the number of attributes that are defined locally in this set.

     * Attributes that are defined in the parent set are not included.

     *

     * @return the number of attributes >= 0

     */

    public int getAttributeCount();

    /**

     * Checks whether the named attribute has a value specified in

     * the set without resolving through another attribute

     * set.

     *

     * @param attrName the attribute name

     * @return true if the attribute has a value specified

     */

    public boolean isDefined(Object attrName);

    /**

     * Determines if the two attribute sets are equivalent.

     *

     * @param attr an attribute set

     * @return true if the sets are equivalent

     */

    public boolean isEqual(AttributeSet attr);

    /**

     * Returns an attribute set that is guaranteed not

     * to change over time.

     *

     * @return a copy of the attribute set

     */

    public AttributeSet copyAttributes();

    /**

     * Fetches the value of the given attribute. If the value is not found

     * locally, the search is continued upward through the resolving

     * parent (if one exists) until the value is either

     * found or there are no more parents.  If the value is not found,

     * null is returned.

     *

     * @param key the non-null key of the attribute binding

     * @return the value of the attribute, or {@code null} if not found

     */

    public Object getAttribute(Object key);

    /**

     * Returns an enumeration over the names of the attributes that are

     * defined locally in the set. Names of attributes defined in the

     * resolving parent, if any, are not included. The values of the

     * <code>Enumeration</code> may be anything and are not constrained to

     * a particular <code>Object</code> type.

     * <p>

     * This method never returns {@code null}. For a set with no attributes, it

     * returns an empty {@code Enumeration}.

     *

     * @return the names

     */

    public Enumeration<?> getAttributeNames();

    /**

     * Returns {@code true} if this set defines an attribute with the same

     * name and an equal value. If such an attribute is not found locally,

     * it is searched through in the resolving parent hierarchy.

     *

     * @param name the non-null attribute name

     * @param value the value

     * @return {@code true} if the set defines the attribute with an

     *     equal value, either locally or through its resolving parent

     * @throws NullPointerException if either {@code name} or

     *      {@code value} is {@code null}

     */

    public boolean containsAttribute(Object name, Object value);

    /**

     * Returns {@code true} if this set defines all the attributes from the

     * given set with equal values. If an attribute is not found locally,

     * it is searched through in the resolving parent hierarchy.

     *

     * @param attributes the set of attributes to check against

     * @return {@code true} if this set defines all the attributes with equal

     *              values, either locally or through its resolving parent

     * @throws NullPointerException if {@code attributes} is {@code null}

     */

    public boolean containsAttributes(AttributeSet attributes);

    /**

     * Gets the resolving parent.

     *

     * @return the parent

     */

    public AttributeSet getResolveParent();

    /**

     * Attribute name used to name the collection of

     * attributes.

     */

    public static final Object NameAttribute = StyleConstants.NameAttribute;

    /**

     * Attribute name used to identify the resolving parent

     * set of attributes, if one is defined.

     */

    public static final Object ResolveAttribute = StyleConstants.ResolveAttribute;

}