/*************************************************************************

"FreePastry" Peer-to-Peer Application Development Substrate 

Copyright 2002, Rice University. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.

- Neither  the name  of Rice  University (RICE) nor  the names  of its
contributors may be  used to endorse or promote  products derived from
this software without specific prior written permission.

This software is provided by RICE and the contributors on an "as is"
basis, without any representations or warranties of any kind, express
or implied including, but not limited to, representations or
warranties of non-infringement, merchantability or fitness for a
particular purpose. In no event shall RICE or contributors be liable
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consequential damages (including, but not limited to, procurement of
substitute goods or services; loss of use, data, or profits; or
business interruption) however caused and on any theory of liability,
whether in contract, strict liability, or tort (including negligence
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if advised of the possibility of such damage.

********************************************************************************/

package rice.p2p.util;

import java.io.*;
import java.util.*;

/**
 * @(#) ImmutableSortedMap.java Class which is an implementation of a sorted map
 * which wraps and protects an internal sorted map. Any attempts to modify the
 * underlying map will result in a UnsupportedOperationException.
 *
 * @version $Id: ImmutableSortedMap.java 2302 2005-03-11 00:58:26Z jeffh $
 * @author Alan Mislove
 */
public class ImmutableSortedMap implements SortedMap, Serializable {

  // the internal map
  /**
   * DESCRIBE THE FIELD
   */
  protected SortedMap map;

  /**
   * Constructor which takes an existing map
   *
   * @param map the existing map
   */
  public ImmutableSortedMap(SortedMap map) {
    this.map = map;
  }

  /**
   * Returns <tt>true</tt> if this map contains no key-value mappings.
   *
   * @return <tt>true</tt> if this map contains no key-value mappings.
   */
  public boolean isEmpty() {
    return map.isEmpty();
  }

  /**
   * Returns the value to which this map maps the specified key. Returns <tt>
   * null</tt> if the map contains no mapping for this key.
   *
   * @param key key whose associated value is to be returned.
   * @return the value to which this map maps the specified key, or <tt>null
   *      </tt> if the map contains no mapping for this key.
   */
  public Object get(Object key) {
    return map.get(key);
  }

  /**
   * Returns the comparator associated with this sorted map, or <tt>null</tt> if
   * it uses its keys' natural ordering.
   *
   * @return the comparator associated with this sorted map, or <tt>null</tt> if
   *      it uses its keys' natural ordering.
   */
  public Comparator comparator() {
    return map.comparator();
  }

  /**
   * Returns a view of the portion of this sorted map whose keys range from <tt>
   * fromKey</tt> , inclusive, to <tt>toKey</tt> , exclusive.
   *
   * @param fromKey low endpoint (inclusive) of the subMap.
   * @param toKey high endpoint (exclusive) of the subMap.
   * @return a view of the specified range within this sorted map.
   */
  public SortedMap subMap(Object fromKey, Object toKey) {
    return new ImmutableSortedMap(map.subMap(fromKey, toKey));
  }

  /**
   * Returns a view of the portion of this sorted map whose keys are strictly
   * less than toKey.
   *
   * @param toKey high endpoint (exclusive) of the subMap.
   * @return a view of the specified initial range of this sorted map.
   */
  public SortedMap headMap(Object toKey) {
    return new ImmutableSortedMap(map.headMap(toKey));
  }

  /**
   * Returns a view of the portion of this sorted map whose keys are greater
   * than or equal to <tt>fromKey</tt> .
   *
   * @param fromKey low endpoint (inclusive) of the tailMap.
   * @return a view of the specified final range of this sorted map.
   */
  public SortedMap tailMap(Object fromKey) {
    return new ImmutableSortedMap(map.tailMap(fromKey));
  }

  /**
   * Returns the first (lowest) key currently in this sorted map.
   *
   * @return the first (lowest) key currently in this sorted map.
   * @throws NoSuchElementException if this map is empty.
   */
  public Object firstKey() {
    return map.firstKey();
  }

  /**
   * Returns the last (highest) key currently in this sorted map.
   *
   * @return the last (highest) key currently in this sorted map.
   * @throws NoSuchElementException if this map is empty.
   */
  public Object lastKey() {
    return map.lastKey();
  }

  /**
   * Returns the number of key-value mappings in this map. If the map contains
   * more than <tt>Integer.MAX_VALUE</tt> elements, returns <tt>
   * Integer.MAX_VALUE</tt> .
   *
   * @return the number of key-value mappings in this map.
   */
  public int size() {
    return map.size();
  }

  /**
   * Returns <tt>true</tt> if this map contains a mapping for the specified key.
   *
   * @param key key whose presence in this map is to be tested.
   * @return <tt>true</tt> if this map contains a mapping for the specified
   */
  public boolean containsKey(Object key) {
    return map.containsKey(key);
  }

  /**
   * Returns <tt>true</tt> if this map maps one or more keys to the specified
   * value.
   *
   * @param value value whose presence in this map is to be tested.
   * @return <tt>true</tt> if this map maps one or more keys to the specified
   *      value.
   */
  public boolean containsValue(Object value) {
    return map.containsValue(value);
  }

  // Modification Operations

  /**
   * Associates the specified value with the specified key in this map (optional
   * operation). If the map previously contained a mapping for this key, the old
   * value is replaced by the specified value.
   *
   * @param key key with which the specified value is to be associated.
   * @param value value to be associated with the specified key.
   * @return previous value associated with specified key, or <tt>null</tt> if
   *      there was no mapping for key. A <tt>null</tt> return can also indicate
   *      that the map previously associated <tt>null</tt> with the specified
   *      key, if the implementation supports <tt>null</tt> values.
   * @throws UnsupportedOperationException if the <tt>put</tt> operation is not
   *      supported by this map.
   */
  public Object put(Object key, Object value) {
    throw new UnsupportedOperationException("put not supported by immutablemap");
  }

  /**
   * Removes the mapping for this key from this map if it is present (optional
   * operation). More formally, if this map contains a mapping from key <tt>k
   * </tt> to value <tt>v</tt> such that <code>(key==null ?  k==null : key.equals(k))</code>
   * , that mapping is removed.
   *
   * @param key key whose mapping is to be removed from the map.
   * @return previous value associated with specified key, or <tt>null</tt> if
   *      there was no mapping for key.
   */
  public Object remove(Object key) {
    throw new UnsupportedOperationException("remove not supported by immutablemap");
  }

  /**
   * Copies all of the mappings from the specified map to this map (optional
   * operation).
   *
   * @param t Mappings to be stored in this map.
   */
  public void putAll(Map t) {
    throw new UnsupportedOperationException("putall not supported by immutablemap");
  }

  /**
   * Removes all mappings from this map (optional operation).
   *
   * @throws UnsupportedOperationException clear is not supported by this map.
   */
  public void clear() {
    throw new UnsupportedOperationException("clear not supported by immutablemap");
  }

  /**
   * Returns a set view of the keys contained in this map. The set is backed by
   * the map, so changes to the map are reflected in the set, and vice-versa. If
   * the map is modified while an iteration over the set is in progress, the
   * results of the iteration are undefined. The set supports element removal,
   * which removes the corresponding mapping from the map, via the <tt>
   * Iterator.remove</tt> , <tt>Set.remove</tt> , <tt>removeAll</tt> <tt>
   * retainAll</tt> , and <tt>clear</tt> operations. It does not support the add
   * or <tt>addAll</tt> operations.
   *
   * @return a set view of the keys contained in this map.
   */
  public Set keySet() {
    return map.keySet();
  }

  /**
   * Returns a collection view of the values contained in this map. The
   * collection is backed by the map, so changes to the map are reflected in the
   * collection, and vice-versa. If the map is modified while an iteration over
   * the collection is in progress, the results of the iteration are undefined.
   * The collection supports element removal, which removes the corresponding
   * mapping from the map, via the <tt>Iterator.remove</tt> , <tt>
   * Collection.remove</tt> , <tt>removeAll</tt> , <tt>retainAll</tt> and <tt>
   * clear</tt> operations. It does not support the add or <tt>addAll</tt>
   * operations.
   *
   * @return a collection view of the values contained in this map.
   */
  public Collection values() {
    return map.values();
  }

  /**
   * Returns a set view of the mappings contained in this map. Each element in
   * the returned set is a {@link Map.Entry}. The set is backed by the map, so
   * changes to the map are reflected in the set, and vice-versa. If the map is
   * modified while an iteration over the set is in progress, the results of the
   * iteration are undefined. The set supports element removal, which removes
   * the corresponding mapping from the map, via the <tt>Iterator.remove</tt> ,
   * <tt>Set.remove</tt> , <tt>removeAll</tt> , <tt>retainAll</tt> and <tt>clear
   * </tt> operations. It does not support the <tt>add</tt> or <tt>addAll</tt>
   * operations.
   *
   * @return a set view of the mappings contained in this map.
   */
  public Set entrySet() {
    return map.entrySet();
  }
}

