AttributeSet.java

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packagejavax.swing.text;

importjava.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
 */
publicinterfaceAttributeSet {

/**
 * 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.
 */
publicinterfaceFontAttribute {
 }

/**
 * This interface is the type signature that is expected
 * to be present on any attribute key that contributes to
 * presentation of color.
 */
publicinterfaceColorAttribute {
 }

/**
 * 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.
 */
publicinterfaceCharacterAttribute {
 }

/**
 * This interface is the type signature that is expected
 * to be present on any attribute key that contributes to
 * the paragraph level presentation.
 */
publicinterfaceParagraphAttribute {
 }

/**
 * 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 &gt;= 0
 */
publicintgetAttributeCount();

/**
 * 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
 */
publicbooleanisDefined(ObjectattrName);

/**
 * Determines if the two attribute sets are equivalent.
 *
 * @param attr an attribute set
 * @return true if the sets are equivalent
 */
publicbooleanisEqual(AttributeSetattr);

/**
 * Returns an attribute set that is guaranteed not
 * to change over time.
 *
 * @return a copy of the attribute set
 */
publicAttributeSetcopyAttributes();

/**
 * 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
 */
publicObjectgetAttribute(Objectkey);

/**
 * 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
 */
publicEnumeration<?> 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}
 */
publicbooleancontainsAttribute(Objectname, Objectvalue);

/**
 * 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}
 */
publicbooleancontainsAttributes(AttributeSetattributes);

/**
 * Gets the resolving parent.
 *
 * @return the parent
 */
publicAttributeSetgetResolveParent();

/**
 * Attribute name used to name the collection of
 * attributes.
 */
publicstaticfinalObjectNameAttribute = StyleConstants.NameAttribute;

/**
 * Attribute name used to identify the resolving parent
 * set of attributes, if one is defined.
 */
publicstaticfinalObjectResolveAttribute = StyleConstants.ResolveAttribute;

}