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

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

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

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 * accompanied this code).

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package javax.naming.directory;

import java.util.Vector;

import java.util.Enumeration;

import java.util.NoSuchElementException;

import javax.naming.NamingException;

import javax.naming.NamingEnumeration;

import javax.naming.OperationNotSupportedException;

/**

  * This interface represents an attribute associated with a named object.

  *<p>

  * In a directory, named objects can have associated with them

  * attributes.  The {@code Attribute} interface represents an attribute associated

  * with a named object.  An attribute contains 0 or more, possibly null, values.

  * The attribute values can be ordered or unordered (see {@code isOrdered()}).

  * If the values are unordered, no duplicates are allowed.

  * If the values are ordered, duplicates are allowed.

  *<p>

  * The content and representation of an attribute and its values is defined by

  * the attribute's <em>schema</em>. The schema contains information

  * about the attribute's syntax and other properties about the attribute.

  * See {@code getAttributeDefinition()} and

  * {@code getAttributeSyntaxDefinition()}

  * for details regarding how to get schema information about an attribute

  * if the underlying directory service supports schemas.

  *<p>

  * Equality of two attributes is determined by the implementation class.

  * A simple implementation can use {@code Object.equals()} to determine equality

  * of attribute values, while a more sophisticated implementation might

  * make use of schema information to determine equality.

  * Similarly, one implementation might provide a static storage

  * structure which simply returns the values passed to its

  * constructor, while another implementation might define {@code get()} and

  * {@code getAll()}.

  * to get the values dynamically from the directory.

  *<p>

  * Note that updates to {@code Attribute} (such as adding or removing a

  * value) do not affect the corresponding representation of the attribute

  * in the directory.  Updates to the directory can only be effected

  * using operations in the {@code DirContext} interface.

  *

  * @author Rosanna Lee

  * @author Scott Seligman

  *

  * @see BasicAttribute

  * @since 1.3

  */

public interface Attribute extends Cloneable, java.io.Serializable {

    /**

      * Retrieves an enumeration of the attribute's values.

      * The behaviour of this enumeration is unspecified

      * if the attribute's values are added, changed,

      * or removed while the enumeration is in progress.

      * If the attribute values are ordered, the enumeration's items

      * will be ordered.

      *

      * @return A non-null enumeration of the attribute's values.

      * Each element of the enumeration is a possibly null Object. The object's

      * class is the class of the attribute value. The element is null

      * if the attribute's value is null.

      * If the attribute has zero values, an empty enumeration

      * is returned.

      * @exception NamingException

      *         If a naming exception was encountered while retrieving

      *         the values.

      * @see #isOrdered

      */

    NamingEnumeration<?> getAll() throws NamingException;

    /**

      * Retrieves one of this attribute's values.

      * If the attribute has more than one value and is unordered, any one of

      * the values is returned.

      * If the attribute has more than one value and is ordered, the

      * first value is returned.

      *

      * @return A possibly null object representing one of

      *        the attribute's value. It is null if the attribute's value

      *        is null.

      * @exception NamingException

      *         If a naming exception was encountered while retrieving

      *         the value.

      * @exception java.util.NoSuchElementException

      *         If this attribute has no values.

      */

    Object get() throws NamingException;

    /**

      * Retrieves the number of values in this attribute.

      *

      * @return The nonnegative number of values in this attribute.

      */

    int size();

    /**

      * Retrieves the id of this attribute.

      *

      * @return The id of this attribute. It cannot be null.

      */

    String getID();

    /**

      * Determines whether a value is in the attribute.

      * Equality is determined by the implementation, which may use

      * {@code Object.equals()} or schema information to determine equality.

      *

      * @param attrVal The possibly null value to check. If null, check

      *  whether the attribute has an attribute value whose value is null.

      * @return true if attrVal is one of this attribute's values; false otherwise.

      * @see java.lang.Object#equals

      * @see BasicAttribute#equals

      */

    boolean contains(Object attrVal);

    /**

      * Adds a new value to the attribute.

      * If the attribute values are unordered and

      * {@code attrVal} is already in the attribute, this method does nothing.

      * If the attribute values are ordered, {@code attrVal} is added to the end of

      * the list of attribute values.

      *<p>

      * Equality is determined by the implementation, which may use

      * {@code Object.equals()} or schema information to determine equality.

      *

      * @param attrVal The new possibly null value to add. If null, null

      *  is added as an attribute value.

      * @return true if a value was added; false otherwise.

      */

    boolean add(Object attrVal);

    /**

      * Removes a specified value from the attribute.

      * If {@code attrval} is not in the attribute, this method does nothing.

      * If the attribute values are ordered, the first occurrence of

      * {@code attrVal} is removed and attribute values at indices greater

      * than the removed

      * value are shifted up towards the head of the list (and their indices

      * decremented by one).

      *<p>

      * Equality is determined by the implementation, which may use

      * {@code Object.equals()} or schema information to determine equality.

      *

      * @param attrval The possibly null value to remove from this attribute.

      * If null, remove the attribute value that is null.

      * @return true if the value was removed; false otherwise.

      */

    boolean remove(Object attrval);

    /**

      * Removes all values from this attribute.

      */

    void clear();

    /**

      * Retrieves the syntax definition associated with the attribute.

      * An attribute's syntax definition specifies the format

      * of the attribute's value(s). Note that this is different from

      * the attribute value's representation as a Java object. Syntax

      * definition refers to the directory's notion of <em>syntax</em>.

      *<p>

      * For example, even though a value might be

      * a Java String object, its directory syntax might be "Printable String"

      * or "Telephone Number". Or a value might be a byte array, and its

      * directory syntax is "JPEG" or "Certificate".

      * For example, if this attribute's syntax is "JPEG",

      * this method would return the syntax definition for "JPEG".

      * <p>

      * The information that you can retrieve from a syntax definition

      * is directory-dependent.

      *<p>

      * If an implementation does not support schemas, it should throw

      * OperationNotSupportedException. If an implementation does support

      * schemas, it should define this method to return the appropriate

      * information.

      * @return The attribute's syntax definition. Null if the implementation

      *    supports schemas but this particular attribute does not have

      *    any schema information.

      * @exception OperationNotSupportedException If getting the schema

      *         is not supported.

      * @exception NamingException If a naming exception occurs while getting

      *         the schema.

      */

    DirContext getAttributeSyntaxDefinition() throws NamingException;

    /**

      * Retrieves the attribute's schema definition.

      * An attribute's schema definition contains information

      * such as whether the attribute is multivalued or single-valued,

      * the matching rules to use when comparing the attribute's values.

      *

      * The information that you can retrieve from an attribute definition

      * is directory-dependent.

      *

      *<p>

      * If an implementation does not support schemas, it should throw

      * OperationNotSupportedException. If an implementation does support

      * schemas, it should define this method to return the appropriate

      * information.

      * @return This attribute's schema definition. Null if the implementation

      *     supports schemas but this particular attribute does not have

      *     any schema information.

      * @exception OperationNotSupportedException If getting the schema

      *         is not supported.

      * @exception NamingException If a naming exception occurs while getting

      *         the schema.

      */

    DirContext getAttributeDefinition() throws NamingException;

    /**

      * Makes a copy of the attribute.

      * The copy contains the same attribute values as the original attribute:

      * the attribute values are not themselves cloned.

      * Changes to the copy will not affect the original and vice versa.

      *

      * @return A non-null copy of the attribute.

      */

    Object clone();

    //----------- Methods to support ordered multivalued attributes

    /**

      * Determines whether this attribute's values are ordered.

      * If an attribute's values are ordered, duplicate values are allowed.

      * If an attribute's values are unordered, they are presented

      * in any order and there are no duplicate values.

      * @return true if this attribute's values are ordered; false otherwise.

      * @see #get(int)

      * @see #remove(int)

      * @see #add(int, java.lang.Object)

      * @see #set(int, java.lang.Object)

      */

    boolean isOrdered();

    /**

     * Retrieves the attribute value from the ordered list of attribute values.

     * This method returns the value at the {@code ix} index of the list of

     * attribute values.

     * If the attribute values are unordered,

     * this method returns the value that happens to be at that index.

     * @param ix The index of the value in the ordered list of attribute values.

     * {@code 0 <= ix < size()}.

     * @return The possibly null attribute value at index {@code ix};

     *   null if the attribute value is null.

     * @exception NamingException If a naming exception was encountered while

     * retrieving the value.

     * @exception IndexOutOfBoundsException If {@code ix} is outside the specified range.

     */

    Object get(int ix) throws NamingException;

    /**

     * Removes an attribute value from the ordered list of attribute values.

     * This method removes the value at the {@code ix} index of the list of

     * attribute values.

     * If the attribute values are unordered,

     * this method removes the value that happens to be at that index.

     * Values located at indices greater than {@code ix} are shifted up towards

     * the front of the list (and their indices decremented by one).

     *

     * @param ix The index of the value to remove.

     * {@code 0 <= ix < size()}.

     * @return The possibly null attribute value at index {@code ix} that was removed;

     *   null if the attribute value is null.

     * @exception IndexOutOfBoundsException If {@code ix} is outside the specified range.

     */

    Object remove(int ix);

    /**

     * Adds an attribute value to the ordered list of attribute values.

     * This method adds {@code attrVal} to the list of attribute values at

     * index {@code ix}.

     * Values located at indices at or greater than {@code ix} are

     * shifted down towards the end of the list (and their indices incremented

     * by one).

     * If the attribute values are unordered and already have {@code attrVal},

     * {@code IllegalStateException} is thrown.

     *

     * @param ix The index in the ordered list of attribute values to add the new value.

     * {@code 0 <= ix <= size()}.

     * @param attrVal The possibly null attribute value to add; if null, null is

     * the value added.

     * @exception IndexOutOfBoundsException If {@code ix} is outside the specified range.

     * @exception IllegalStateException If the attribute values are unordered and

     * {@code attrVal} is one of those values.

     */

    void add(int ix, Object attrVal);

    /**

     * Sets an attribute value in the ordered list of attribute values.

     * This method sets the value at the {@code ix} index of the list of

     * attribute values to be {@code attrVal}. The old value is removed.

     * If the attribute values are unordered,

     * this method sets the value that happens to be at that index

     * to {@code attrVal}, unless {@code attrVal} is already one of the values.

     * In that case, {@code IllegalStateException} is thrown.

     *

     * @param ix The index of the value in the ordered list of attribute values.

     * {@code 0 <= ix < size()}.

     * @param attrVal The possibly null attribute value to use.

     * If null, 'null' replaces the old value.

     * @return The possibly null attribute value at index ix that was replaced.

     *   Null if the attribute value was null.

     * @exception IndexOutOfBoundsException If {@code ix} is outside the specified range.

     * @exception IllegalStateException If {@code attrVal} already exists and the

     *    attribute values are unordered.

     */

    Object set(int ix, Object attrVal);

    /**

     * Use serialVersionUID from JNDI 1.1.1 for interoperability.

     */

    static final long serialVersionUID = 8707690322213556804L;

}