msgunit.java

java开源的企业总线.xmlBlaster

/*------------------------------------------------------------------------------
Name:      MsgUnit.java
Project:   xmlBlaster.org
Copyright: xmlBlaster.org, see xmlBlaster-LICENSE file
------------------------------------------------------------------------------*/
package org.xmlBlaster.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Properties;

import org.xmlBlaster.util.def.MethodName;
import org.xmlBlaster.util.def.ErrorCode;
import org.xmlBlaster.util.qos.QosData;
import org.xmlBlaster.util.key.KeyData;
import org.xmlBlaster.client.key.PublishKey;
import org.xmlBlaster.client.qos.PublishQos;
import org.xmlBlaster.util.def.Constants;

/**
 * Encapsulates the parsed xmlKey and QoS, and the raw content. 
 * <p />
 * The constructor arguments are checked to be not null and corrected
 * to "" or 'new byte[0]' if they are null
 */
public final class MsgUnit implements java.io.Serializable
{
   private static final long serialVersionUID = -4816978454646848077L;
   private transient static final byte[] EMPTY_BYTEARR = new byte[0];
   private transient Global glob;
   private QosData qosData; // never null
   private byte[] content;  // never null
   private KeyData keyData; // can be null

   /**
    * Uses the default global and assumes a PUBLISH. 
    * @see #MsgUnit(Global, String, byte[], String, MethodName)
    */
   public MsgUnit(String key, byte[] content, String qos) throws XmlBlasterException {
      this((Global)null, key, content, qos);
   }

   /**
    * Assumes a PUBLISH. 
    * @see #MsgUnit(Global, String, byte[], String, MethodName)
    */
   public MsgUnit(Global glob, String key, byte[] content, String qos) throws XmlBlasterException {
      this(glob, key, content, qos, MethodName.PUBLISH);
   }

   /**
    * @see #MsgUnit(Global, String, byte[], String, MethodName)
    */
   public MsgUnit(Global glob, MsgUnitRaw msgUnitRaw, MethodName methodName) throws XmlBlasterException {
      this(glob, msgUnitRaw.getKey(), msgUnitRaw.getContent(), msgUnitRaw.getQos(), methodName);
   }

   /**
    * The normal constructor. 
    * @param glob The specific Global handle
    * @param key The XML key
    * @param qos The XML qos
    * @param methodName The method you want to invoked (like PUBLISH or SUBSCRIBE)
    */
   public MsgUnit(Global glob, String key, byte[] content, String qos, MethodName methodName) throws XmlBlasterException {
      this.glob = (glob == null) ? Global.instance() : glob;
      setContent(content);
      if (methodName == MethodName.PUBLISH) {
         // The proper way, but then we need to import package engine.qos
         //PublishQosServer qos = new PublishQosServer(glob, qos); // sets timestamp etc.
         //this.qosData = qos.getData();
         this.qosData = this.glob.getMsgQosFactory().readObject(qos);
         //boolean fromPersistenceStore = false;
         //if (!fromPersistenceStore)
         //   this.qosData.touchRcvTimestamp();
         this.keyData = this.glob.getMsgKeyFactory().readObject(key);
      }
      else if (methodName == MethodName.UPDATE) {
         this.qosData = this.glob.getMsgQosFactory().readObject(qos);
         this.keyData = this.glob.getMsgKeyFactory().readObject(key);
      }
      else if (methodName == MethodName.SUBSCRIBE || methodName == MethodName.UNSUBSCRIBE ||
               methodName == MethodName.GET || methodName == MethodName.ERASE) {
         this.qosData = this.glob.getQueryQosFactory().readObject(qos);
         this.keyData = this.glob.getQueryKeyFactory().readObject(key);
      }
      else if (methodName == MethodName.CONNECT) {
         this.qosData = this.glob.getConnectQosFactory().readObject(qos);
         this.keyData = null;
      }
      else if (methodName == MethodName.DISCONNECT) {
         this.qosData = this.glob.getDisconnectQosFactory().readObject(qos);
         this.keyData = null;
      }
      else {
         throw new XmlBlasterException(this.glob, ErrorCode.INTERNAL_NOTIMPLEMENTED, "MsgUnit", "Sorry method support for '" + methodName.toString() + "' is missing");
      }
   }

   /**
    * Uses the default global and assumes a PUBLISH. 
    * @see #MsgUnit(Global, String, byte[], String, MethodName)
    */
   public MsgUnit(String key, String contentAsString, String qos) throws XmlBlasterException {
      this(null, key, contentAsString, qos);
   }

   /**
    * Assumes a PUBLISH. 
    * @see #MsgUnit(Global, String, byte[], String, MethodName)
    */
   public MsgUnit(Global glob, String key, String contentAsString, String qos) throws XmlBlasterException {
      this(glob, key, contentAsString.getBytes(), qos, MethodName.PUBLISH);
   }

   /**
    * This is a constructor suitable for clients. 
    */
   public MsgUnit(PublishKey key, String contentAsString, PublishQos qos) {
      this(key, contentAsString.getBytes(), qos);
   }

   /**
    * This is a constructor suitable for clients. 
    */
   public MsgUnit(PublishKey key, byte[] content, PublishQos qos) {
      this(key.getData(), content, qos.getData());
   }

   /**
    * Create a MsgUnit with pre-parsed parameters. 
    * @param key can be null
    * @param content can be null
    * @param qos Never null!
    */
   public MsgUnit(KeyData key, byte[] content, QosData qos) {
      if (qos == null) {
         Thread.dumpStack();
         throw new IllegalArgumentException("MsgUnit constructor with qos="+qos+" is invalid");
      }
      this.glob = qos.getGlobal();
      this.keyData = key;
      this.qosData = qos;
      setContent(content);
   }

   /**
    * Clone this message unit (but not the content). 
    * <p>
    *  In order to keep up with performance we don't encapsulate the content in an immutable object.
    *  Keep in mind however that you should never (ever) change the content of a MsgUnit since
    *  such a change would affect the messages to all other reference of this message (e.g. subscribers)
    *  and therefore it might lead to unpredictable (and undesired) results.
    * </p>
    * <p>Example:</p>
    * <pre> 
    * byte[] content = msgUnit.getContent();
    * content[6] = (byte)'A';  // NOT ALLOWED !
    * </pre> 
    * @param old      The MsgUnit to clone
    * @param key      The new key to use, if you pass 'null' the old is shallow cloned
    * @param content  If you pass null note that the byte[] is a reference
    *                     to the original and you should not manipulate it
    * @param qos      The new qos to use, if you pass 'null' the old is shallow cloned
    */
   public MsgUnit(MsgUnit old, KeyData key, byte[] content, QosData qos) {
      glob = old.getGlobal();
      this.qosData = (qos==null) ? (QosData)old.getQosData().clone() : qos;
      this.keyData = (key==null) ? (KeyData)old.getKeyData().clone() : key;
      setContent( (content==null) ? old.getContent() : content);
   }

  /*
   public MsgUnit(MsgUnit old, MsgKeyData key, byte[] content, MsgQosData qos) {
      glob = old.getGlobal();
      this.qosData = (qos==null) ? (QosData)old.getQosData().clone() : qos;
      this.keyData = (key==null) ? (KeyData)old.getKeyData().clone() : key;
      setContent( (content==null) ? old.getContent() : content);
   }
   */

   public Global getGlobal() {
      return glob;
   }

   public void setGlobal(Global glob) {
      this.glob = glob;
      if (this.keyData != null) this.keyData.setGlobal(this.glob);
      this.qosData.setGlobal(this.glob);
   }

   public MethodName getMethodName() {
      return this.qosData.getMethod();
   }

   /**
    * Used internally and my be used by publish mime plugin
    */
   public void setContent(byte[] content) {
      if (content == null)
         this.content = EMPTY_BYTEARR;
      else
         this.content = content;
   }

   /**
    * The key oid, can be null if not a PUBLISH or UPDATE
    */
   public String getKeyOid() {
      if (this.keyData != null) {
         return this.keyData.getOid();
      }
      return null;
   }

   /**
    * The raw XML string for PUBLISH/UPDATE never null, otherwise it may be null
    */
   public String getKey() {
      if (this.keyData != null) {
         return this.keyData.toXml();
      }
      return null;
   }

   /**
    * Get the raw content. 
    * <p>
    * For performance reasons you get a reference to the internal byte[] buffer and no copy.
    * Note that you are not allowed to manipulate the returned byte[].
    * </p>