/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE
 * or https://OpenDS.dev.java.net/OpenDS.LICENSE.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at
 * trunk/opends/resource/legal-notices/OpenDS.LICENSE.  If applicable,
 * add the following below this CDDL HEADER, with the fields enclosed
 * by brackets "[]" replaced with your own identifying information:
 *      Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 *
 *      Copyright 2009 Sun Microsystems, Inc.
 */

package org.opends.sdk;



import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Set;



/**
 * An attribute, comprising of an attribute description and zero or more
 * attribute values.
 * <p>
 * Any methods which perform comparisons between attribute values use the
 * equality matching rule associated with the attribute description.
 * <p>
 * Any methods which accept {@code Object} based attribute values convert the
 * attribute values to instances of {@code ByteString} as follows:
 *
 * <pre>
 * Object object = ...;
 * ByteString value = null;
 * if (object instanceof ByteSequence)
 * {
 *   value = ((ByteSequence)object).toByteString();
 * }
 * else
 * {
 *   value = ByteString.valueOf(object.toString());
 * }
 * </pre>
 * <p>
 * TODO: matching against attribute value assertions.
 */
public interface Attribute extends Set<ByteString>
{
  /**
   * Adds {@code value} to this attribute if it is not already present (optional
   * operation). If this attribute already contains {@code value}, the call
   * leaves the attribute unchanged and returns {@code false}.
   *
   * @param value
   *          The attribute value to be added to this attribute.
   * @return {@code true} if this attribute changed as a result of this call.
   * @throws UnsupportedOperationException
   *           If this attribute does not support addition of attribute values.
   * @throws NullPointerException
   *           If {@code value} was {@code null}.
   */
  boolean add(ByteString value) throws UnsupportedOperationException,
      NullPointerException;



  /**
   * Adds all of the provided attribute values to this attribute if they are not
   * already present (optional operation).
   * <p>
   * Any attribute values which are not instances of {@code ByteString} will be
   * converted using the {@link ByteString#valueOf(Object)} method.
   *
   * @param firstValue
   *          The first attribute value to be added to this attribute.
   * @param remainingValues
   *          The remaining attribute values to be added to this attribute.
   * @return {@code true} if this attribute changed as a result of this call.
   * @throws UnsupportedOperationException
   *           If this attribute does not support addition of attribute values.
   * @throws NullPointerException
   *           If {@code firstValue} was {@code null}.
   */
  boolean add(Object firstValue, Object... remainingValues)
      throws UnsupportedOperationException, NullPointerException;



  /**
   * Adds all of the attribute values contained in {@code values} to this
   * attribute if they are not already present (optional operation).
   * <p>
   * An invocation of this method is equivalent to:
   *
   * <pre>
   * attribute.addAll(values, null);
   * </pre>
   *
   * @param values
   *          The attribute values to be added to this attribute.
   * @return {@code true} if this attribute changed as a result of this call.
   * @throws UnsupportedOperationException
   *           If this attribute does not support addition of attribute values.
   * @throws NullPointerException
   *           If {@code values} was {@code null}.
   */
  boolean addAll(Collection<? extends ByteString> values)
      throws UnsupportedOperationException, NullPointerException;



  /**
   * Adds all of the attribute values contained in {@code values} to this
   * attribute if they are not already present (optional operation). Any
   * attribute values which are already present will be added to {@code
   * duplicateValues} if specified.
   *
   * @param values
   *          The attribute values to be added to this attribute.
   * @param duplicateValues
   *          A collection into which duplicate values will be added, or {@code
   *          null} if duplicate values should not be saved.
   * @return {@code true} if this attribute changed as a result of this call.
   * @throws UnsupportedOperationException
   *           If this attribute does not support addition of attribute values.
   * @throws NullPointerException
   *           If {@code values} was {@code null}.
   */
  boolean addAll(Collection<? extends ByteString> values,
      Collection<? super ByteString> duplicateValues)
      throws UnsupportedOperationException, NullPointerException;



  /**
   * Removes all of the attribute values from this attribute (optional
   * operation). This attribute will be empty after this call returns.
   *
   * @throws UnsupportedOperationException
   *           If this attribute does not support removal of attribute values.
   */
  void clear() throws UnsupportedOperationException;



  /**
   * Returns {@code true} if this attribute contains {@code value}.
   * <p>
   * If {@code value} is not an instance of {@code ByteString} then it will be
   * converted using the {@link ByteString#valueOf(Object)} method.
   *
   * @param value
   *          The attribute value whose presence in this attribute is to be
   *          tested.
   * @return {@code true} if this attribute contains {@code value}, or {@code
   *         false} if not.
   * @throws NullPointerException
   *           If {@code value} was {@code null}.
   */
  boolean contains(Object value) throws NullPointerException;



  /**
   * Returns {@code true} if this attribute contains all of the attribute values
   * contained in {@code values}.
   * <p>
   * Any attribute values which are not instances of {@code ByteString} will be
   * converted using the {@link ByteString#valueOf(Object)} method.
   *
   * @param values
   *          The attribute values whose presence in this attribute is to be
   *          tested.
   * @return {@code true} if this attribute contains all of the attribute values
   *         contained in {@code values}, or {@code false} if not.
   * @throws NullPointerException
   *           If {@code values} was {@code null}.
   */
  boolean containsAll(Collection<?> values) throws NullPointerException;



  /**
   * Returns {@code true} if {@code object} is an attribute which is equal to
   * this attribute. Two attributes are considered equal if their attribute
   * descriptions are equal, they both have the same number of attribute values,
   * and every attribute value contained in the first attribute is also
   * contained in the second attribute.
   *
   * @param object
   *          The object to be tested for equality with this attribute.
   * @return {@code true} if {@code object} is an attribute which is equal to
   *         this attribute, or {@code false} if not.
   */
  boolean equals(Object object);



  /**
   * Returns the first attribute value in this attribute.
   *
   * @return The first attribute value in this attribute.
   * @throws NoSuchElementException
   *           If this attribute is empty.
   */
  ByteString firstValue() throws NoSuchElementException;



  /**
   * Returns the first attribute value in this attribute decoded as a UTF-8
   * string.
   *
   * @return The first attribute value in this attribute decoded as a UTF-8
   *         string.
   * @throws NoSuchElementException
   *           If this attribute is empty.
   */
  String firstValueAsString() throws NoSuchElementException;



  /**
   * Returns the attribute description of this attribute, which includes its
   * attribute type and any options.
   *
   * @return The attribute description.
   */
  AttributeDescription getAttributeDescription();



  /**
   * Returns the string representation of the attribute description of this
   * attribute, which includes its attribute type and any options.
   *
   * @return The string representation of the attribute description.
   */
  String getAttributeDescriptionAsString();



  /**
   * Returns the hash code for this attribute. It will be calculated as the sum
   * of the hash codes of the attribute description and all of the attribute
   * values.
   *
   * @return The hash code for this attribute.
   */
  int hashCode();



  /**
   * Returns {@code true} if this attribute contains no attribute values.
   *
   * @return {@code true} if this attribute contains no attribute values.
   */
  boolean isEmpty();



  /**
   * Returns an iterator over the attribute values in this attribute. The
   * attribute values are returned in no particular order, unless the
   * implementation of this attribute provides such a guarantee.
   *
   * @return An iterator over the attribute values in this attribute.
   */
  Iterator<ByteString> iterator();



  /**
   * Removes {@code value} from this attribute if it is present (optional
   * operation). If this attribute does not contain {@code value}, the call
   * leaves the attribute unchanged and returns {@code false}.
   * <p>
   * If {@code value} is not an instance of {@code ByteString} then it will be
   * converted using the {@link ByteString#valueOf(Object)} method.
   *
   * @param value
   *          The attribute value to be removed from this attribute.
   * @return {@code true} if this attribute changed as a result of this call.
   * @throws UnsupportedOperationException
   *           If this attribute does not support removal of attribute values.
   * @throws NullPointerException
   *           If {@code value} was {@code null}.
   */
  boolean remove(Object value) throws UnsupportedOperationException,
      NullPointerException;



  /**
   * Removes all of the attribute values contained in {@code values} from this
   * attribute if they are present (optional operation).
   * <p>
   * Any attribute values which are not instances of {@code ByteString} will be
   * converted using the {@link ByteString#valueOf(Object)} method.
   * <p>
   * An invocation of this method is equivalent to:
   *
   * <pre>
   * attribute.removeAll(values, null);
   * </pre>
   *
   * @param values
   *          The attribute values to be removed from this attribute.
   * @return {@code true} if this attribute changed as a result of this call.
   * @throws UnsupportedOperationException
   *           If this attribute does not support removal of attribute values.
   * @throws NullPointerException
   *           If {@code values} was {@code null}.
   */
  boolean removeAll(Collection<?> values) throws UnsupportedOperationException,
      NullPointerException;



  /**
   * Removes all of the attribute values contained in {@code values} from this
   * attribute if they are present (optional operation). Any attribute values
   * which are not already present will be added to {@code missingValues} if
   * specified.
   * <p>
   * Any attribute values which are not instances of {@code ByteString} will be
   * converted using the {@link ByteString#valueOf(Object)} method.
   *
   * @param <T>
   *          The type of the attribute value objects being removed.
   * @param values
   *          The attribute values to be removed from this attribute.
   * @param missingValues
   *          A collection into which missing values will be added, or {@code
   *          null} if missing values should not be saved.
   * @return {@code true} if this attribute changed as a result of this call.
   * @throws UnsupportedOperationException
   *           If this attribute does not support removal of attribute values.
   * @throws NullPointerException
   *           If {@code values} was {@code null}.
   */
  <T> boolean removeAll(Collection<T> values,
      Collection<? super T> missingValues)
      throws UnsupportedOperationException, NullPointerException;



  /**
   * Retains only the attribute values in this attribute which are contained in
   * {@code values} (optional operation).
   * <p>
   * Any attribute values which are not instances of {@code ByteString} will be
   * converted using the {@link ByteString#valueOf(Object)} method.
   * <p>
   * An invocation of this method is equivalent to:
   *
   * <pre>
   * attribute.retainAll(values, null);
   * </pre>
   *
   * @param values
   *          The attribute values to be retained in this attribute.
   * @return {@code true} if this attribute changed as a result of this call.
   * @throws UnsupportedOperationException
   *           If this attribute does not support removal of attribute values.
   * @throws NullPointerException
   *           If {@code values} was {@code null}.
   */
  boolean retainAll(Collection<?> values) throws UnsupportedOperationException,
      NullPointerException;



  /**
   * Retains only the attribute values in this attribute which are contained in
   * {@code values} (optional operation). Any attribute values which are not
   * already present will be added to {@code missingValues} if specified.
   * <p>
   * Any attribute values which are not instances of {@code ByteString} will be
   * converted using the {@link ByteString#valueOf(Object)} method.
   *
   * @param <T>
   *          The type of the attribute value objects being retained.
   * @param values
   *          The attribute values to be retained in this attribute.
   * @param missingValues
   *          A collection into which missing values will be added, or {@code
   *          null} if missing values should not be saved.
   * @return {@code true} if this attribute changed as a result of this call.
   * @throws UnsupportedOperationException
   *           If this attribute does not support removal of attribute values.
   * @throws NullPointerException
   *           If {@code values} was {@code null}.
   */
  <T> boolean retainAll(Collection<T> values,
      Collection<? super T> missingValues)
      throws UnsupportedOperationException, NullPointerException;



  /**
   * Returns the number of attribute values in this attribute.
   *
   * @return The number of attribute values in this attribute.
   */
  int size();



  /**
   * Returns an array containing all of the attribute values contained in this
   * attribute.
   * <p>
   * If this attribute makes any guarantees as to what order its attribute
   * values are returned by its iterator, this method must return the attribute
   * values in the same order.
   * <p>
   * The returned array will be "safe" in that no references to it are
   * maintained by this attribute. The caller is thus free to modify the
   * returned array.
   *
   * @return An array containing all of the attribute values contained in this
   *         attribute.
   */
  ByteString[] toArray();



  /**
   * Returns an array containing all of the attribute values in this attribute;
   * the runtime type of the returned array is that of the specified array.
   * <p>
   * If the set fits in the specified array, it is returned therein. Otherwise,
   * a new array is allocated with the runtime type of the specified array and
   * the size of this attribute. If this attribute fits in the specified array
   * with room to spare (i.e., the array has more elements than this attribute),
   * the elements in the array immediately following the end of the set is set
   * to {@code null}.
   * <p>
   * If this attribute makes any guarantees as to what order its attribute
   * values are returned by its iterator, this method must return the attribute
   * values in the same order.
   *
   * @param <T>
   *          The type of elements contained in {@code array}.
   * @param array
   *          An array into which the elements of this attribute should be put.
   * @return An array containing all of the attribute values contained in this
   *         attribute.
   * @throws ArrayStoreException
   *           If the runtime type of {@code array} is not a supertype of
   *           {@code ByteString}.
   * @throws NullPointerException
   *           If {@code array} was {@code null}.
   */
  <T> T[] toArray(T[] array) throws ArrayStoreException, NullPointerException;



  /**
   * Returns a string representation of this attribute.
   *
   * @return The string representation of this attribute.
   */
  String toString();
}