Java example source code file (AttributeSet.java)

This example Java source code file (AttributeSet.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

attributeset, characterattribute, colorattribute, enumeration, fontattribute, nameattribute, object, paragraphattribute, resolveattribute, util

The AttributeSet.java Java example source code

/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
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 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 may be anything and are not constrained to
     * a particular <code>Object 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;

}