contextnode.java

java开源的企业总线.xmlBlaster

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

import org.xmlBlaster.util.Global;
import org.xmlBlaster.util.StringPairTokenizer;
import org.xmlBlaster.util.def.Constants;

import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.logging.Logger;

import javax.management.ObjectName;

/**
 * This represents one node in the administrative hierarchy, and is a linked
 * list to its parent and its childs. 
 *
 * @author [e-mail]
 * @see <a href="http://www.xmlBlaster.org/xmlBlaster/doc/requirements/admin.commands.html">The admin.commands requirement</a>
 */
public final class ContextNode
{
   private static Logger log = Logger.getLogger(ContextNode.class.getName());
   /** Name for logging output */
   public final static String SEP = "/";
   public final static String ROOT_MARKER_TAG = SEP+"xmlBlaster";
   /** Use to mark a cluster node name */
   public final static String CLUSTER_MARKER_TAG = "node";
   /** Use to mark a client */
   public final static String SUBJECT_MARKER_TAG = "client";
   /** Use to mark a contrib */
   public final static String CONTRIB_MARKER_TAG = "contrib";
   /** Use to mark a login session */
   public final static String SESSION_MARKER_TAG = "session";
   /** Use for client side XmlBlasterAccess */
   public final static String CONNECTION_MARKER_TAG = "connection";
   /** Use to mark a queue */
   public final static String QUEUE_MARKER_TAG = "queue";
   /** Use to mark a service */
   public final static String SERVICE_MARKER_TAG = "service";
   /** Use to mark a plugin inside the RunlevelManager (xmlBlasterPlugins.xml) */
   public final static String RUNLEVEL_PLUGIN_MARKER_TAG = "plugin";
   /** Use to mark a protocol plugin like XMLRPC or email */
   public final static String PROTOCOL_MARKER_TAG = "protocol";
   /** Use to mark a message store map */
   public final static String MAP_MARKER_TAG = "map";
   /** Use to mark a topic */
   public final static String TOPIC_MARKER_TAG = "topic";
   /** Use to mark a subscription */
   public final static String SUBSCRIPTION_MARKER_TAG = "subscription";
   /** Use to mark event methods */
   public final static String EVENT_MARKER_TAG = "event";
   /** Use to mark a system and configuration properties and command line arguments */
   public final static String SYSPROP_MARKER_TAG = "sysprop";
   /** Use to mark logging settings */
   public final static String LOGGING_MARKER_TAG = "logging";

   /** For XPath conforming query */
   public final static String SCHEMA_XPATH = "xpath";
   /** For JMX conforming ObjectName string */
   public final static String SCHEMA_JMX = "jmx";
   /** For JMX conforming ObjectName string, "org.xmlBlaster:" is our JMX domain */
   public final static String SCHEMA_JMX_DOMAIN = "org.xmlBlaster";
   /** For URL conforming string */
   public final static String SCHEMA_URL = "url";

   private String className; // e.g. "node"
   private String instanceName; // e.g. "heron"
   private ContextNode parent;
   private Map childs; // key=absoluteName, value contains 'new WeakReference(ContextNode)'
   
   public static char QUOTE = '\"';

   //Placeholder for top level node
   public final static ContextNode ROOT_NODE = null; // new ContextNode(null, "/xmlBlaster", "", (ContextNode)null);

   /**
    * @deprecated Use constructor without global
    */
   public ContextNode(Global glob, String className, String instanceName, ContextNode parent) {
      this(className, instanceName, parent);
   }

   /**
    * @param className The tag name like 'node' (ContextNode.CLUSTER_MARKER_TAG) or 'client' (ContextNode.SUBJECT_MARKER_TAG)
    * @param instanceName The instance like 'heron' or 'joe', can be null
    * @param parent The parent node or null if root ContextNode ('node/heron' etc)
    */
   public ContextNode(String className, String instanceName, ContextNode parent) {
      if (className == null) {
         throw new IllegalArgumentException("ContextNode: Missing className argument");
      }
      this.className = className;
      setInstanceName(instanceName);
      this.parent = parent;
      if (this.parent != null) this.parent.addChild(this);
   }

   /*
   public Global getGlobal() {
      return this.glob;
   }
   */

   /**
    * @return The tag name like 'node' (ContextNode.CLUSTER_MARKER_TAG) or 'client' (ContextNode.SUBJECT_MARKER_TAG)
    */
   public String getClassName() {
      return this.className;
   }
   
   /**
    * @param className The tag name like 'node' (ContextNode.CLUSTER_MARKER_TAG) or 'client' (ContextNode.SUBJECT_MARKER_TAG)
    */
   public boolean isOfClass(String className) {
      if (this.className == null) return false;
      return this.className.equals(className);
   }

   public void setInstanceName(String instanceName) {
      /** TODO: Needs some testing
      //Escape offending '/' in the name with quotes "joe/the/great"
      if (instanceName != null 
            && instanceName.indexOf("/") != -1
            && instanceName.charAt(0) != QUOTE) {
         instanceName = QUOTE + instanceName + QUOTE;
      }
      
      //For the time being we suppress '/' in JmxWrapper.validateJmxValue()
      */
      this.instanceName = instanceName;
   }

   /**
    * @return Can be null
    */
   public String getInstanceName() {
      return this.instanceName;
   }

   /**
    * @return Is never null
    */
   public String getInstanceNameNotNull() {
      return (this.instanceName==null) ? "" : this.instanceName;
   }

   /**
    * @return The parent node or null
    */
   public ContextNode getParent() {
      return this.parent;
   }

   /**
    * Walk up the hierarchy and return the matching ContextNode. 
    * @param className The context node to retrieve
    * @return The parent node or null
    */
   public ContextNode getParent(String className) {
      if (className == null) {
         return null;
      }
      if (className.equals(this.getClassName())) {
         return this;
      }
      if (this.parent != null ) {
         return this.parent.getParent(className);
      }
      return null;
   }

   /**
    * Walk up the hierarchy until we find the given className and rename the instance name. 
    *
    * For example rename
    *  "org.xmlBlaster:nodeClass=node,node=clientSUB1,clientClass=connection,connection=jack"
    * to
    *  "org.xmlBlaster:nodeClass=node,node=heron,clientClass=connection,connection=jack"
    *
    * Checks the current node as well.
    * 
    * @param className The class to change, e.g. "node"
    * @param instanceName The new name to use, e.g. "heron"
    */
   public void changeParentName(String className, String instanceName) {
      if (className == null) {
         return;
      }
      ContextNode found = getParent(className);
      if (found != null) {
         found.setInstanceName(instanceName);
      }
   }

   /**
    * Walk up the hierarchy until we find the given className and rename the instance name. 
    *
    * For example rename
    *  "org.xmlBlaster:nodeClass=node,node=clientSUB1,clientClass=connection,connection=jack"
    * to
    *  "org.xmlBlaster:nodeClass=node,node=heron,clientClass=connection,connection=jack"
    *
    * Checks the current node as well.
    * 
    * @param newParentNode The new parent name to use, e.g. "heron"
    */
   public void changeParentName(final ContextNode newParentNode) {
      if (newParentNode == null) {
         return;
      }
      ContextNode found = getParent(newParentNode.getClassName());
      if (found != null) {
         found.setInstanceName(newParentNode.getInstanceName());
      }
   }

   /**
    * Add the given child, it exists already nothing happens. 
    * The child is hold as a weak reference, so you don't need to cleanup. 
    * @param child The child to add
    * @return true if the child was added, the parent of your child is modified!
    *          false if it existed already or if you given child is null
    */
   public boolean addChild(ContextNode child) {
      return addChild(child, false);
   }
   
   /**
    * Add the given child, it exists already nothing happens. 
    * The child is hold as a weak reference, so you don't need to cleanup. 
    * @param child The child to add
    * @param doClone If true the given child is not modified
    *                 if false the given child is changed to have us as a new parent 
    * @return true if the child was added,
    *          false if it existed already or if you given child is null
    */
   public boolean addChild(ContextNode child, boolean doClone) {
      if (child == null) return false;
      if (this.childs != null && this.childs.get(child.getAbsoluteName()) != null) {
            return false; // Child is already here
      }
      synchronized (this) {
         if (this.childs == null) {
            this.childs = new HashMap();
         }
         if (doClone) {
            ContextNode clone = child.getClone();
            clone.parent = this;
            this.childs.put(clone.getAbsoluteName(), new WeakReference(clone));
         }
         else {
            if (child.parent != null && this != child.parent) {
               // If child had another parent already remove it
               child.parent.removeChild(child);
            }
            child.parent = this;
            this.childs.put(child.getAbsoluteName(), new WeakReference(child));
         }
      }
      return true;
   }
   
   public ContextNode getClone() {
      return ContextNode.valueOf(getAbsoluteName());
   }

   /**
    * Merges the given child, it exists already nothing happens. 
    * <p />
    * <pre>
    * this = "/node/heron/client/joe"
    * child = "/node/xyz/client/joe/session/1"
    * results to "/node/heron/client/joe/session/1"
    * </pre>
    * <pre>
    * this = "/node/heron/client/joe/session/1"
    * child = "/node/xyz/service/Pop3Driver"
    * results to "/xmlBlaster/node/heron/client/joe/session/1/service/Pop3Driver"
    * </pre>
    * @param child The child to add, it is not touched as we take a clone
    * @return The new leave or null if failed
    */
   public ContextNode mergeChildTree(final ContextNode child) {
      if (child == null) return null;
      ContextNode childClone = child.getClone();
      ContextNode childParent = childClone;
      while (true) {
         ContextNode thisParent = this.getParent(childParent.getClassName());
         if (thisParent != null) {
            //System.out.println("thisParent=" + thisParent.getAbsoluteName() + " - childParent=" + childParent.getAbsoluteName());
            if (thisParent.getInstanceNameNotNull().equals(childParent.getInstanceNameNotNull())) {
               ContextNode childs[] = childParent.getChildren();
               for (int i=0; i<childs.length; i++) {
                  thisParent.addChild(childs[i]); // suppresses duplicates
               }
               return thisParent.getChild(child.getClassName(), child.getInstanceName());
            }
            ContextNode pp = thisParent.getParent();
            if (pp != null) {
               // Found a node to merge, attach it here
               pp.addChild(childParent);
               return thisParent.getChild(child.getClassName(), child.getInstanceName());
            }
            break; // nothing found to merge with
         }
         childParent = childParent.getParent();
         if (childParent==null) break;
      }
      // Append if not merged:
      this.addChild(childClone);
      return getChild(child.getClassName(), child.getInstanceName());
   }

   /**
    * @return All children, never null (but empty array)
    */
   public synchronized ContextNode[] getChildren() {
      if (this.childs == null || this.childs.size() == 0) {
         return new ContextNode[0];
      }
      WeakReference[] refs = (WeakReference[])this.childs.values().toArray(new WeakReference[this.childs.size()]);
      ArrayList list = new ArrayList(refs.length);
      for (int i=0; i<refs.length; i++) {
         Object referent = refs[i].get();
         if (referent != null) {
            list.add(referent);
         }
         else {
            this.childs.remove(refs[i]); // Cleanup the obsolete WeakReference
            // TODO: ReferenceQueue
         }
      }