001 package edu.harvard.deas.hyperenc;
002
003 import java.io.File;
004 import java.io.Serializable;
005 import java.util.ArrayList;
006 import java.util.Iterator;
007 import java.util.List;
008 import java.util.NoSuchElementException;
009
010 import javax.mail.Address;
011
012 /**
013 * A contact list backed by a database on disk. This class uses PersistentMap to
014 * store the Contacts to disk. Because PersistentMap provides an unsorted view
015 * of the data, this class also stores all Contacts in the list in a sorted
016 * collection in memory; all changes to this list are made in the in-memory copy
017 * and also written through to disk via the PersistentMap.
018 * <p>
019 * <code>DBContactList</code> attempts to read in any existing contact list from
020 * disk that has the same owner. If none is found, a new, empty DBContactList is
021 * created. Because entries are stored in the on-disk database in an inherently
022 * unsorted manner, the order of Contacts in a DBContactList may not be
023 * consistent across multiple sessions—the order is subject to change
024 * every time the data is read in from disk.
025 *
026 * @see PersistentMap
027 */
028 public class DBContactList extends ContactList {
029 // ignore values and use a PersistentMap as a set -- kind of lame, but it works
030 private PersistentMap<Contact,Obj> myMap;
031
032 // should always contain the same values as myMap.keySet()
033 private List<Contact> myList;
034
035 // owner of this ContactList -- should be included in getContact calls, but not
036 // in get calls
037 private Contact myOwner;
038
039 // placeholder class for values of the map
040 private static class Obj implements Serializable {
041 private static final long serialVersionUID = 1L;
042 }
043
044 /**
045 * Creates a new DBContactList. Attempts to read in any existing contact list
046 * from disk that has the same owner. If none is found, a new, empty
047 * DBContactList is created. Because entries are stored in the on-disk
048 * database in an inherently unsorted manner, the order of Contacts in a
049 * DBContactList may not be consistent across multiple sessions—the
050 * order of the Contacts in the created list may be different from the order
051 * in which they were written by a previous instance of DBContactList.
052 *
053 * @param owner
054 * the owner of this list (usually the Contact corresponding to the
055 * user of the hyper-encryption application)
056 * @param envPath
057 * The path on disk of the database backing this map.
058 * Must be readable and writable. If it doesn't
059 * exist, it will be created. If <code>null</code>, the default
060 * environment specified by {@link PersistentMap#DEFAULT_HOME} is used.
061 * @see PersistentMap
062 */
063 public DBContactList(Contact owner, File envPath) {
064 myMap = PersistentMap.getInstance(owner.getEmail().toString() + ".Contacts",
065 Contact.class,
066 Obj.class,
067 envPath);
068 myList = new ArrayList<Contact>(myMap.keySet());
069 myOwner = owner;
070 }
071
072 /**
073 * Equivalent to <code>DBContactList(owner, null)</code>.
074 *
075 * @param owner
076 * the owner of this list (usually the Contact corresponding to the
077 * user of the hyper-encryption application)
078 */
079 public DBContactList(Contact owner) {
080 this(owner, null);
081 }
082
083 @Override
084 public Iterator<Contact> iterator() {
085 return myList.iterator();
086 }
087
088 @Override
089 public void addContact(Contact c) {
090 myMap.put(c, new Obj());
091 myList.add(c);
092 }
093
094 @Override
095 public void removeContact(Contact c) {
096 myMap.remove(c);
097 myList.remove(c);
098 }
099
100 @Override
101 public Contact get(int index) {
102 return myList.get(index);
103 }
104
105 @Override
106 public int size() {
107 return myList.size();
108 }
109
110 @Override
111 public boolean isEmpty() {
112 return myList.isEmpty();
113 }
114
115 /**
116 * Returns the Contact in this list with e-mail address <code>a</code>.
117 * @param a e-mail address
118 * @return the Contact with the given e-mail address
119 */
120 @Override
121 public Contact getContact(Address a) {
122 if (a.equals(myOwner.getEmail()))
123 return myOwner;
124 for (Contact c : myList)
125 if (a.equals(c.getEmail()))
126 return c;
127 throw new NoSuchElementException(
128 "Contact list does not contain a Contact with Address " + a);
129 }
130 }