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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.

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 Also:
MutableAttributeSet/**
 * 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.
/**
     * 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.
/**
     * 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 run of
style.
/**
     * 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.
/**
     * 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.
Returns:
the number of attributes >= 0/**
     * 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
     */
    public int getAttributeCount();

    
Checks whether the named attribute has a value specified in
the set without resolving through another attribute
set.
Params:
attrName – the attribute name
Returns:
true if the attribute has a value specified/**
     * 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.
Params:
attr – an attribute set
Returns:
true if the sets are equivalent/**
     * 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.
Returns:
a copy of the attribute set/**
     * 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.
Params:
key – the non-null key of the attribute binding
Returns:
the value of the attribute, or null if not found/**
     * 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
Enumeration may be anything and are not constrained to
a particular Object type.
 This method never returns null. For a set with no attributes, it returns an empty Enumeration. 
Returns:
the names/**
     * 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 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. 
Params:
name – the non-null attribute name
value – the value
Throws:
NullPointerException – if either name or value is null
Returns:
true if the set defines the attribute with an equal value, either locally or through its resolving parent/**
     * 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 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. 
Params:
attributes – the set of attributes to check against
Throws:
NullPointerException – if attributes is null
Returns:
true if this set defines all the attributes with equal values, either locally or through its resolving parent/**
     * 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.
Returns:
the parent/**
     * Gets the resolving parent.
     *
     * @return the parent
     */
    public AttributeSet getResolveParent();

    
Attribute name used to name the collection of
attributes.
/**
     * 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.
/**
     * Attribute name used to identify the resolving parent
     * set of attributes, if one is defined.
     */
    public static final Object ResolveAttribute = StyleConstants.ResolveAttribute;

}