001 /*
002 * Copyright (c) 2003, The Regents of the University of California, through
003 * Lawrence Berkeley National Laboratory (subject to receipt of any required
004 * approvals from the U.S. Dept. of Energy). All rights reserved.
005 */
006 package gov.lbl.dsd.sea.nio.event;
007
008 import gov.lbl.dsd.sea.Stage;
009 import gov.lbl.dsd.sea.event.GenericCallbackEvent;
010
011 import java.nio.ByteBuffer;
012 import java.nio.channels.SelectableChannel;
013
014 /**
015 * Requests an agent to perform some action on a given channel.
016 *
017 * @author whoschek@lbl.gov
018 * @author $Author: hoschek3 $
019 * @version $Revision: 1.18 $, $Date: 2004/07/28 19:49:20 $
020 */
021 public abstract class ChannelRequest {
022
023 private ChannelRequest() {} // not instantiable
024
025 /**
026 * Requests an agent to register the given
027 * {@link java.nio.channels.SelectionKey}interest ops with the given
028 * channel; The agent will enqueue future responses to the channel onto the
029 * given observer stage; If an attachment is given the agent will attach it to the channel's key.
030 */
031 public static class Register extends GenericCallbackEvent {
032
033 protected Object attachment;
034
035 protected static final Object NO_ATTACHMENT = new Object(); // indicates agent should not modify current attachment
036
037 public Register(Stage observer, SelectableChannel channel, int interestOps) {
038 this(observer, channel, interestOps, NO_ATTACHMENT);
039 }
040
041 public Register(Stage observer, SelectableChannel channel, int interestOps, Object attachment) {
042 super(observer, channel, new Integer(interestOps));
043 this.attachment = attachment;
044 }
045
046 public int getInterestOps() {
047 return ((Integer) this.getInfo()).intValue();
048 }
049
050 public SelectableChannel getChannel() {
051 return (SelectableChannel) this.getMessage();
052 }
053
054 /**
055 * Returns the attachment the agent should attach to the channel's key.
056 *
057 * @throws IllegalStateException if <code>hasAttachment() == false</code>.
058 */
059 public Object getAttachment() {
060 if (!hasAttachment()) throw new IllegalStateException("no attachment available");
061 return this.attachment;
062 }
063
064 /**
065 * Returns whether or not the request contains an attachment.
066 */
067 public boolean hasAttachment() {
068 return this.attachment != NO_ATTACHMENT;
069 }
070 }
071
072 /**
073 * Requests an agent to close the given channel.
074 */
075 public static class Close extends GenericCallbackEvent {
076
077 public Close(SelectableChannel channel) {
078 super(null, channel);
079 }
080
081 public SelectableChannel getChannel() {
082 return (SelectableChannel) this.getMessage();
083 }
084 }
085
086 /**
087 * Requests an agent to completely write ALL of the bytes in the given buffer
088 * to the given channel; As usual with NIO, the data is contained between
089 * indexes <code>buffer.position()</code> and <code>buffer.limit()</code>,
090 * and <code>buffer.remaining()</code> bytes will be written;
091 */
092 public static class WriteData extends GenericCallbackEvent {
093
094 public WriteData(SelectableChannel channel, ByteBuffer buffer) {
095 super(null, channel, buffer);
096 }
097
098 public SelectableChannel getChannel() {
099 return (SelectableChannel) this.getMessage();
100 }
101
102 public ByteBuffer getBuffer() {
103 return (ByteBuffer) this.getInfo();
104 }
105
106 }
107
108 // /**
109 // * Requests an agent to add the given {@link java.nio.channels.SelectionKey}
110 // * interest ops to the ops registered with the given channel; The agent will
111 // * enqueue future responses to the channel onto the given observer stage; If
112 // * an attachment is given the agent will attach it to the channel's key.
113 // */
114 // public static class RegisterAdd extends Register {
115 //
116 // public RegisterAdd(Stage observer, SelectableChannel channel, int interestOps) {
117 // this(observer, channel, interestOps, NO_ATTACHMENT);
118 // }
119 //
120 // public RegisterAdd(Stage observer, SelectableChannel channel, int interestOps, Object attachment) {
121 // super(observer, channel, interestOps);
122 // this.attachment = attachment;
123 // }
124 //
125 // }
126 //
127 // /**
128 // * Requests an agent to remove the given {@link java.nio.channels.SelectionKey}
129 // * interest ops from the ops registered with the given channel; The agent will
130 // * enqueue future responses to the channel onto the given observer stage; If
131 // * an attachment is given the agent will attach it to the channel's key.
132 // */
133 // public static class RegisterRemove extends Register {
134 //
135 // public RegisterRemove(Stage observer, SelectableChannel channel, int interestOps) {
136 // this(observer, channel, interestOps, NO_ATTACHMENT);
137 // }
138 //
139 // public RegisterRemove(Stage observer, SelectableChannel channel, int interestOps, Object attachment) {
140 // super(observer, channel, interestOps);
141 // this.attachment = attachment;
142 // }
143 //
144 // }
145 //
146 // /**
147 // * Requests an agent to assign the given {@link java.nio.channels.SelectionKey}
148 // * interest ops to the ops registered with the given channel; The agent will
149 // * enqueue future responses to the channel onto the given observer stage; If
150 // * an attachment is given the agent will attach it to the channel's key.
151 // */
152 // public static class RegisterSet extends Register {
153 //
154 // public RegisterSet(Stage observer, SelectableChannel channel, int interestOps) {
155 // this(observer, channel, interestOps, NO_ATTACHMENT);
156 // }
157 //
158 // public RegisterSet(Stage observer, SelectableChannel channel, int interestOps, Object attachment) {
159 // super(observer, channel, interestOps);
160 // this.attachment = attachment;
161 // }
162 //
163 // }
164 }