image files

source files

1 files changed, 453 insertions, 0 deletions

diff --git a/java/src/MessageBlock.java b/java/src/MessageBlock.java
new file mode 100644
index 00000000000..6f81f279291
--- /dev/null
+++ b/java/src/MessageBlock.java
@@ -0,0 +1,453 @@
+/*************************************************
+ *
+ * = PACKAGE
+ *    ACE.ASX
+ *
+ * = FILENAME
+ *    MessageBlock.java
+ *
+ *@author Prashant Jain
+ *
+ *************************************************/
+package ACE.ASX;
+
+import ACE.OS.*;
+
+/**
+ * <hr>
+ * <h2>SYNOPSIS</h2>
+ *<blockquote>
+ *     Object used to store messages in the ASX framework.
+ *</blockquote>
+ *
+ * <h2>DESCRIPTION</h2>
+ *<blockquote>
+ *     <tt>MessageBlock</tt> is modeled after the message data structures
+ *     used in System V STREAMS. A <tt>MessageBlock</tt> is composed of
+ *     one or more <tt>MessageBlock</tt>s that are linked together by <em>PREV</em>
+ *     and <em>NEXT</em> pointers. In addition, a <tt>MessageBlock</tt> may also be
+ *     linked to a chain of other <tt>MessageBlock</tt>s. This structure
+ *     enables efficient manipulation of arbitrarily-large messages
+ *     <em>without</em> incurring memory copying overhead.
+ *</blockquote>
+ *
+ *@see MessageQueue
+ */
+public class MessageBlock
+{
+  /**
+   * Create an empty Message Block
+   */
+  public MessageBlock ()
+    {
+      this (0);
+    }
+
+  /**
+   * Create an empty Message Block.
+   * Note that this assumes that type of MessageBlock is MB_DATA.
+   *@param size size of the Message Block to create.
+   */
+  public MessageBlock (int size)
+    {
+      // Note the explicit cast toString() is needed. For some strange
+      // reason, it fails otherwise if size == 0.
+      this ((new StringBuffer (size)).toString ());
+    }
+
+  /**
+   * Create a Message Block. Note that this assumes that type of
+   * MessageBlock is MB_DATA. 
+   *@param data initial data to create a Message Block with.
+   */
+  public MessageBlock (String data)
+    {
+      this (MessageType.MB_DATA,
+	    null,
+	    data);
+    }
+
+  /**
+   * Create a Message Block.
+   *@param type type of the Message Block (must be one of those
+   * specified in class Message Type)
+   *@param cont next block of data 
+   *@param data initial data to create Message Block with
+   */
+  public MessageBlock (int type,
+		       MessageBlock cont,
+		       String data)
+    {
+      this.flags_ = 0;
+      this.priority_ = 0;
+      this.next_ = null;
+      this.prev_ = null;
+
+      this.init (type, cont, data);
+    }
+
+  /**
+   * Create a Message Block. Note that this assumes that type of
+   * MessageBlock is MB_OBJECT.
+   *@param obj initial object to create a Message Block with.
+   */
+  public MessageBlock (Object obj)
+  {
+    this (MessageType.MB_OBJECT,
+	  null,
+	  obj);
+  }
+
+  /**
+   * Create a Message Block.
+   *@param type type of the Message Block (must be one of those
+   * specified in class Message Type)
+   *@param cont next block of data 
+   *@param obj initial object to create Message Block with
+   */
+  public MessageBlock (int type,
+		       MessageBlock cont,
+		       Object obj)
+  {
+    this.init (type, cont, obj);
+  }
+
+  /* Initialize the Message Block
+   *@param data data to initialize Message Block with
+   */
+  public void init (String data)
+    {
+      this.base_ = new StringBuffer (data);
+    }
+
+  /**
+   * Initialize a Message Block.
+   *@param type type of the Message Block (must be one of those
+   * specified in class Message Type)
+   *@param cont next block of data 
+   *@param data data to initialize Message Block with
+   */
+  public void init (int msgType,
+		   MessageBlock msgCont,
+		   String data)
+    {
+      if (data.length () == 0)
+	this.base_ = new StringBuffer (0);
+      else
+	this.base_ = new StringBuffer (data);
+      this.type_ = msgType;
+      this.cont_ = msgCont;
+    }
+
+  /**
+   * Initialize a Message Block. Note that this assumes that type of
+   * MessageBlock is MB_OBJECT.
+   *@param obj initial object to initialize a Message Block with.
+   */
+  public void init (Object obj)
+    {
+      this.init (MessageType.MB_OBJECT, null, obj);
+    }
+
+  /**
+   * Initialize a Message Block.
+   *@param type type of the Message Block (must be one of those
+   * specified in class Message Type)
+   *@param cont next block of data 
+   *@param obj object to initialize Message Block with
+   */
+  public void init (int msgType,
+		   MessageBlock msgCont,
+		   Object obj)
+    {
+      this.obj_ = obj;
+      this.type_ = msgType;
+      this.cont_ = msgCont;
+      this.flags_ = 0;
+      this.priority_ = 0;
+      this.next_ = null;
+      this.prev_ = null;
+    }
+
+  /**
+   * Set message flags. Note that the flags will be set on top of
+   * already set flags.
+   *@param moreFlags flags to set for the Message Block.
+   */
+  public long setFlags (long moreFlags)
+    {
+      // Later we might mask more_flags so that user can't change
+      // internal ones: more_flags &= ~(USER_FLAGS -1).
+      this.flags_ = ACE.SET_BITS (this.flags_, moreFlags);
+      return this.flags_;
+    }
+
+  /**
+   * Unset message flags.
+   *@param lessFlags flags to unset for the Message Block.
+   */
+  public long clrFlags (long lessFlags)
+    {
+      // Later we might mask more_flags so that user can't change
+      // internal ones: less_flags &= ~(USER_FLAGS -1).
+      this.flags_ = ACE.CLR_BITS (this.flags_, lessFlags);
+      return this.flags_;
+    }
+
+  /**
+   * Get the message flags.
+   *@return Message flags
+   */
+  public long flags ()
+    {
+      return this.flags_;
+    }
+
+  /**
+   * Get the type of the message.
+   *@return message type
+   */
+  public int msgType ()
+    {
+      return this.type_;
+    }
+
+  /**
+   * Set the type of the message.
+   *@param t type of the message
+   */
+  public void msgType (int t)
+    {
+      this.type_ = t;
+    }
+
+  /**
+   * Get the class of the message. Note there are two classes,
+   * <normal> messages and <high-priority> messages.
+   *@return message class
+   */
+  public int msgClass ()
+    {
+      return this.msgType () >= MessageType.MB_PRIORITY
+	? MessageType.MB_PRIORITY : MessageType.MB_NORMAL;
+    }
+
+  /**
+   * Find out if the message is a data message.
+   *@return true if message is a data message, false otherwise
+   */
+  public boolean isDataMsg ()
+    {
+      int mt = this.msgType ();
+      return mt == MessageType.MB_DATA
+	|| mt == MessageType.MB_PROTO
+	  || mt == MessageType.MB_PCPROTO;
+    }
+
+  /**
+   * Find out if the message is an object message.
+   *@return true if message is an object message, false otherwise
+   */
+  public boolean isObjMsg ()
+    {
+      int mt = this.msgType ();
+      return mt == MessageType.MB_OBJECT
+	|| mt == MessageType.MB_PROTO
+	  || mt == MessageType.MB_PCPROTO;
+    }
+
+  /**
+   * Get the priority of the message.
+   *@return message priority
+   */
+  public long msgPriority ()
+    {
+      return this.priority_;
+    }
+
+  /**
+   * Set the priority of the message.
+   *@param pri priority of the message
+   */
+  public void msgPriority (long pri)
+    {
+      this.priority_ = pri;
+    }
+
+  /**
+   * Get message data. This assumes that msgType is MB_DATA.
+   *@return message data
+   */
+  public String base () 
+    {
+      // Create a String object to return
+      char temp[] = new char [this.base_.length ()];
+      this.base_.getChars (0, this.base_.length (), temp, 0);
+      return new String (temp);
+    }
+
+  /**
+   * Set the message data. This assumes that msgType is MB_DATA.
+   *@param data message data
+   *@param msgFlags message flags
+   */
+  public void base (String data,
+		    long msgFlags)
+    {
+      this.base_ = new StringBuffer (data);
+      this.flags_ = msgFlags;
+    }
+
+  /**
+   * Get message object. This assumes that msgType is MB_OBJECT.
+   *@return message object
+   */
+  public Object obj () 
+    {
+      return this.obj_;
+    }
+
+  /**
+   * Set the message object. This assumes that msgType is MB_OBJECT.
+   *@param object message object
+   *@param msgFlags message flags
+   */
+  public void obj (Object obj,
+		   long msgFlags)
+    {
+      this.obj_ = obj;
+      this.flags_ = msgFlags;
+    }
+
+  // = The following four methods only make sense if the Message_Block
+  // is of type MB_DATA and not MB_OBJECT.
+
+  /**
+   * Get length of the message. This method only makes sense if the
+   * MessageBlock is of type MB_DATA and not MB_OBJECT.
+   *@return length of the message.
+   */
+  public int length ()
+    {
+      return this.base_.length ();
+    }
+
+  /**
+   * Set the length of the message. This method only makes sense if the
+   * MessageBlock is of type MB_DATA and not MB_OBJECT.
+   *@param n message length
+   */
+  public void length (int n)
+    {
+      this.base_.setLength (n);
+    }
+
+  /**
+   * Get size of the allocated buffer for the message. This method
+   * only makes sense if the MessageBlock is of type MB_DATA and not
+   * MB_OBJECT. 
+   *@return size of the message buffer
+   */
+  public int size ()
+    {
+      return this.base_.capacity ();
+    }
+
+  /**
+   * Set the total size of the buffer. This method will grow the
+   * buffer if need be. Also, this method only makes sense if the
+   * MessageBlock is of type MB_DATA and not MB_OBJECT.
+   *@param n size of message buffer
+   */
+  public void size (int n)
+    {
+      this.base_.ensureCapacity (n);
+    }
+
+
+  /**
+   * Get the continuation field. The coninuation field is used to
+   * chain together composite messages.
+   *@return the continuation field
+   */
+  public MessageBlock cont ()
+    {
+      return this.cont_;
+    }
+
+  /**
+   * Set the continuation field. The coninuation field is used to
+   * chain together composite messages.
+   *@param msgCont continuation field
+   */
+  void cont (MessageBlock msgCont)
+    {
+      this.cont_ = msgCont;
+    }
+
+  /**
+   * Get link to next message. The next message points to the
+   * <MessageBlock> directly ahead in the MessageQueue.
+   *@return next message block
+   */
+  MessageBlock next ()
+    {
+      return this.next_;
+    }
+
+  /**
+   * Set link to next message. The next message points to the
+   * <MessageBlock> directly ahead in the MessageQueue.
+   *@param msgBlock next message block
+   */
+  void next (MessageBlock msgBlock)
+    {
+      this.next_ = msgBlock;
+    }
+
+  /**
+   * Get link to previous message. The previous message points to the
+   * <MessageBlock> directly before in the MessageQueue.
+   *@return previous message block
+   */
+  MessageBlock prev ()
+    {
+      return this.prev_;
+    }
+
+  /**
+   * Set link to previous message. The previous message points to the
+   * <MessageBlock> directly before in the MessageQueue.
+   *@param msgBlock previous message block
+   */
+  void prev (MessageBlock msgBlock)
+    {
+      this.prev_ = msgBlock;
+    }
+
+  private int type_;		
+  // Type of message.
+
+  private long flags_;
+  // Misc flags.
+
+  private long priority_;
+  // Priority of message.
+
+  private StringBuffer base_;
+  // String data of message block (initialized to null).
+
+  private Object obj_;
+  // Object data of message block (initialized to null).
+
+  private MessageBlock cont_;
+  // Next message block in the chain.
+
+  private MessageBlock next_;	
+  // Next message in the list.
+
+  private MessageBlock prev_;	
+  // Previous message in the list.
+
+}
+