001: /*
002: *
003: *
004: * Copyright 1990-2007 Sun Microsystems, Inc. All Rights Reserved.
005: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
006: *
007: * This program is free software; you can redistribute it and/or
008: * modify it under the terms of the GNU General Public License version
009: * 2 only, as published by the Free Software Foundation.
010: *
011: * This program is distributed in the hope that it will be useful, but
012: * WITHOUT ANY WARRANTY; without even the implied warranty of
013: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014: * General Public License version 2 for more details (a copy is
015: * included at /legal/license.txt).
016: *
017: * You should have received a copy of the GNU General Public License
018: * version 2 along with this work; if not, write to the Free Software
019: * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
020: * 02110-1301 USA
021: *
022: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
023: * Clara, CA 95054 or visit www.sun.com if you need additional
024: * information or have any questions.
025: */
026:
027: package javax.wireless.messaging;
028:
029: /**
030: * This is the base interface for derived interfaces
031: * that represent various types of messages. This package is
032: * designed to work with <code>Message</code> objects that
033: * may contain different elements depending on the underlying
034: * messaging protocol. This is different from <code>Datagram</code>s that
035: * are assumed always to be just blocks of binary data.
036: * An adapter specification for a given messaging protocol
037: * may define further interfaces derived from the <code>Message</code>
038: * interfaces included in this generic specification.
039: *
040: * <p>
041: * The wireless messaging protocols that are accessed
042: * via this API are typically of store-and-forward nature,
043: * unlike network layer datagrams. Thus, the messages will
044: * usually reach the recipient, even if the recipient is not
045: * connected at the time of sending the message. This may
046: * happen significantly later if the recipient is
047: * disconnected for a long time. Sending, and possibly also
048: * receiving, these wireless messages typically involves
049: * a financial cost to the end user that cannot be neglected. Therefore,
050: * applications should not send many messages unnecessarily.
051: * </p>
052: * <p>This interface contains the functionality common
053: * to all messages. Concrete object instances representing
054: * a message will typically implement other (sub)interfaces
055: * providing access to the content and other information in
056: * the message which is dependent on the type of the message.
057: * </p>
058: * <p>Object instances implementing this interface are just
059: * containers for the data that is passed in. The <code>setAddress()</code>
060: * method just sets the value of the address in the
061: * data container without any checking whether the value
062: * is valid in any way.
063: * </p>
064: */
065:
066: public interface Message {
067:
068: /**
069: * Returns the address associated with this message.
070: *
071: * <p>If this is a message to be sent, then this address
072: * is the recipient's address.
073: * </p>
074: * <p>If this is a message that has been received, then
075: * this address is the sender's address.
076: * </p>
077: * <p>Returns <code>null</code>, if the address for the message
078: * is not set.
079: * </p>
080: * <p><strong>Note</strong>: This design allows responses to be
081: * sent to a received message by reusing the
082: * same <code>Message</code> object and just replacing the
083: * payload. The address field can normally be
084: * kept untouched (unless the messaging protocol
085: * requires some special handling of the address).
086: * </p>
087: * <p>The returned address uses the same URL string
088: * syntax that <code>Connector.open()</code> uses to
089: * obtain this <code>MessageConnection</code>.</p>
090: * @return the address of this message, or <code>null</code>
091: * if the address is not set
092: * @see #setAddress(String)
093: */
094: public String getAddress();
095:
096: /**
097: * Sets the address associated with this message,
098: * that is, the address returned by the <code>getAddress</code> method.
099: * The address may be set to <code>null</code>.
100: * <p> The address MUST use the same URL string
101: * syntax that <code>Connector.open()</code> uses to obtain
102: * this <code>MessageConnection</code>. </p>
103: * @param addr address for the message
104: * @see #getAddress()
105: */
106: public void setAddress(String addr);
107:
108: /**
109: * Returns the timestamp indicating when this message has been
110: * sent.
111: * @return <code>Date</code> indicating the timestamp in the message or
112: * <code>null</code> if the timestamp is not set or
113: * if the time information is not available in the underlying
114: * protocol message
115: */
116: public java.util.Date getTimestamp();
117:
118: }
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