* In a directory, named objects can have associated with them * attributes. The 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 isOrdered()). * If the values are unordered, no duplicates are allowed. * If the values are ordered, duplicates are allowed. *
* The content and representation of an attribute and its values is defined by * the attribute's schema. The schema contains information * about the attribute's syntax and other properties about the attribute. * See getAttributeDefinition() and * getAttributeSyntaxDefinition() * for details regarding how to get schema information about an attribute * if the underlying directory service supports schemas. *
* Equality of two attributes is determined by the implementation class. * A simple implementation can use 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 get() and * getAll(). * to get the values dynamically from the directory. *
* Note that updates to 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 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 * 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 * attrVal is already in the attribute, this method does nothing. * If the attribute values are ordered, attrVal is added to the end of * the list of attribute values. *
* Equality is determined by the implementation, which may use * 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 attrval is not in the attribute, this method does nothing. * If the attribute values are ordered, the first occurrence of * 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). *
* Equality is determined by the implementation, which may use * 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 syntax. *
* 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". *
* The information that you can retrieve from a syntax definition * is directory-dependent. *
* 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. * *
* 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 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 ix; * null if the attribute value is null. * @exception NamingException If a naming exception was encountered while * retrieving the value. * @exception IndexOutOfBoundsException If 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 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 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 ix that was removed; * null if the attribute value is null. * @exception IndexOutOfBoundsException If ix is outside the specified range. */ Object remove(int ix); /** * Adds an attribute value to the ordered list of attribute values. * This method adds attrVal to the list of attribute values at * index ix. * Values located at indices at or greater than 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 attrVal, * 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 ix is outside the specified range. * @exception IllegalStateException If the attribute values are unordered and * 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 ix index of the list of * attribute values to be 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 attrVal, unless attrVal is already one of the values. * In that case, 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 ix is outside the specified range. * @exception IllegalStateException If 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; }