target_explorer/plugins/org.eclipse.tcf.te.tcf.processes.core/src/org/eclipse/tcf/te/tcf/processes/core/model/runtime/services/RuntimeModelRefreshService.java

/*******************************************************************************
 * Copyright (c) 2013, 2014 Wind River Systems, Inc. and others. All rights reserved.
 * This program and the accompanying materials are made available under the terms
 * of the Eclipse Public License v1.0 which accompanies this distribution, and is
 * available at http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * Wind River Systems - initial API and implementation
 *******************************************************************************/
package org.eclipse.tcf.te.tcf.processes.core.model.runtime.services;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.tcf.protocol.IChannel;
import org.eclipse.tcf.protocol.IToken;
import org.eclipse.tcf.protocol.Protocol;
import org.eclipse.tcf.services.IProcesses;
import org.eclipse.tcf.services.ISysMonitor;
import org.eclipse.tcf.services.ISysMonitor.SysMonitorContext;
import org.eclipse.tcf.te.runtime.callback.AsyncCallbackCollector;
import org.eclipse.tcf.te.runtime.callback.Callback;
import org.eclipse.tcf.te.runtime.interfaces.callback.ICallback;
import org.eclipse.tcf.te.runtime.model.interfaces.IContainerModelNode;
import org.eclipse.tcf.te.runtime.model.interfaces.IModelNode;
import org.eclipse.tcf.te.runtime.model.interfaces.contexts.IAsyncRefreshableCtx;
import org.eclipse.tcf.te.runtime.model.interfaces.contexts.IAsyncRefreshableCtx.QueryState;
import org.eclipse.tcf.te.runtime.model.interfaces.contexts.IAsyncRefreshableCtx.QueryType;
import org.eclipse.tcf.te.runtime.services.ServiceUtils;
import org.eclipse.tcf.te.runtime.utils.StatusHelper;
import org.eclipse.tcf.te.tcf.core.async.CallbackInvocationDelegate;
import org.eclipse.tcf.te.tcf.core.model.interfaces.services.IModelChannelService;
import org.eclipse.tcf.te.tcf.core.model.services.AbstractModelService;
import org.eclipse.tcf.te.tcf.processes.core.activator.CoreBundleActivator;
import org.eclipse.tcf.te.tcf.processes.core.model.interfaces.IProcessContextNode;
import org.eclipse.tcf.te.tcf.processes.core.model.interfaces.IProcessContextNode.TYPE;
import org.eclipse.tcf.te.tcf.processes.core.model.interfaces.IProcessContextNodeProperties;
import org.eclipse.tcf.te.tcf.processes.core.model.interfaces.runtime.IRuntimeModel;
import org.eclipse.tcf.te.tcf.processes.core.model.interfaces.runtime.IRuntimeModelRefreshService;
import org.eclipse.tcf.te.tcf.processes.core.model.interfaces.runtime.IRuntimeModelUpdateService;
import org.eclipse.tcf.te.tcf.processes.core.nls.Messages;

/**
 * Runtime model refresh service implementation.
 * <p>
 * <b>Service implementation assumptions</b>
 * <ul>
 * <li>Refresh operations do not update the model or the existing process context model nodes directly. Any
 *     refresh operation is creating a parallel tree of nodes which is merged into the model <i>at the end</i>
 *     of the refresh operation.</li>
 * <li>Refresh operations do not modify the status of asynchronous refreshable context of the refresh operation
 *     root. The caller of the refresh service is responsible for handling the asynchronous refreshable context
 *     state of the refresh operation root.</li>
 * <li>Refresh operations requested for the same root while still running are queued and the callbacks are fired
 *     all at once when the first refresh operation completes.</li>
 * <li>Auto-refresh operations are walking the whole process context model node tree, starting from the model root,
 *     and triggers an refresh of all process context model nodes found where the child list query marker is set to done.</li>
 * </ul>
 */
public class RuntimeModelRefreshService extends AbstractModelService<IRuntimeModel> implements IRuntimeModelRefreshService {
	// For each root context to refresh, remember the callbacks to invoke.
	private final Map<IModelNode, List<ICallback>> ctx2cb = new HashMap<IModelNode, List<ICallback>>();
	// The default processes runtime model refresh service delegate
	/* default */ final IRuntimeModelRefreshService.IDelegate defaultDelegate = new DefaultDelegate();

	/**
	 * Default processes runtime model refresh service delegate implementation.
	 */
	/* default */ final class DefaultDelegate implements IRuntimeModelRefreshService.IDelegate {
		private final String[] managedPropertyNames = new String[] { IProcessContextNodeProperties.PROPERTY_CMD_LINE };

		/* (non-Javadoc)
		 * @see org.eclipse.tcf.te.tcf.processes.core.model.interfaces.runtime.IRuntimeModelRefreshService.IDelegate#setNodeType(java.lang.String, org.eclipse.tcf.te.tcf.processes.core.model.interfaces.IProcessContextNode)
		 */
		@Override
		public void setNodeType(String parentContextId, IProcessContextNode node) {
    		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$
    		Assert.isNotNull(node);

			node.setType(parentContextId == null ? TYPE.Process : TYPE.Thread);
		}

		/* (non-Javadoc)
		 * @see org.eclipse.tcf.te.tcf.processes.core.model.interfaces.runtime.IRuntimeModelRefreshService.IDelegate#postRefreshContext(org.eclipse.tcf.protocol.IChannel, org.eclipse.tcf.te.tcf.processes.core.model.interfaces.IProcessContextNode, org.eclipse.tcf.te.runtime.interfaces.callback.ICallback)
		 */
        @Override
        public void postRefreshContext(final IChannel channel, final IProcessContextNode node, final ICallback callback) {
    		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$
    		Assert.isNotNull(channel);
    		Assert.isNotNull(node);
    		Assert.isNotNull(callback);

    		// The channel must be opened, otherwise the query cannot run
    		if (channel.getState() != IChannel.STATE_OPEN) {
    			IStatus status = new Status(IStatus.ERROR, CoreBundleActivator.getUniqueIdentifier(), Messages.RuntimeModelRefreshService_error_channelClosed);
    			callback.done(RuntimeModelRefreshService.this, status);
    			return;
    		}

    		// Get the required services
    		final ISysMonitor sysMonService = channel.getRemoteService(ISysMonitor.class);

    		// The system monitor service must be available
    		if (sysMonService == null) {
    			callback.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
    			return;
    		}

    		// The context id must be set
    		String contextId = node.getStringProperty(IProcessContextNodeProperties.PROPERTY_ID);
    		if (contextId == null) {
    			callback.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
    			return;
    		}

			// Get the command line of the context
			sysMonService.getCommandLine(contextId, new ISysMonitor.DoneGetCommandLine() {
				@Override
				public void doneGetCommandLine(IToken token, Exception error, String[] cmd_line) {
					node.setProperty(IProcessContextNodeProperties.PROPERTY_CMD_LINE, error == null ? cmd_line : null);
	    			callback.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
				}
			});
        }

		/* (non-Javadoc)
		 * @see org.eclipse.tcf.te.tcf.processes.core.model.interfaces.runtime.IRuntimeModelRefreshService.IDelegate#getManagedPropertyNames()
		 */
        @Override
        public String[] getManagedPropertyNames() {
	        return managedPropertyNames;
        }
	}

	/**
	 * Constructor
	 *
	 * @param model The parent model. Must not be <code>null</code>.
	 */
	public RuntimeModelRefreshService(IRuntimeModel model) {
		super(model);
	}

	/* (non-Javadoc)
	 * @see org.eclipse.tcf.te.tcf.core.model.interfaces.services.IModelRefreshService#refresh(org.eclipse.tcf.te.runtime.interfaces.callback.ICallback)
	 */
	@Override
	public void refresh(final ICallback callback) {
		refresh(callback, 2);
	}

	/* (non-Javadoc)
	 * @see org.eclipse.tcf.te.tcf.processes.core.model.interfaces.runtime.IRuntimeModelRefreshService#refresh(org.eclipse.tcf.te.runtime.interfaces.callback.ICallback, int)
	 */
	@Override
	public void refresh(ICallback callback, int depth) {
		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$

		// Get the parent model
		final IRuntimeModel model = getModel();
		Assert.isNotNull(model);

		// If the parent model is already disposed, the service will drop out immediately
		if (model.isDisposed()) {
			if (callback != null) callback.done(this, Status.OK_STATUS);
			return;
		}

		// A refresh for the passed in node is already running if the model
		// is associated with a callback list in 'ctx2cb'.
		final boolean isRefreshAlreadyRunning = ctx2cb.containsKey(model);

		// Queue the callback to invoke once the refresh is done
		List<ICallback> callbacks = ctx2cb.get(model);
		if (callbacks == null) {
			callbacks = new ArrayList<ICallback>();
			ctx2cb.put(model, callbacks);
		}
		Assert.isNotNull(callbacks);
		if (callback != null) callbacks.add(callback);

		// If a refresh is already running, drop out. The callback is already
		// queued and will be invoked once the refresh operation is done.
		if (isRefreshAlreadyRunning) return;

		// The refresh operation is building up a parallel data tree. Pass in an empty container
		// to receive the fetched children.
		final IProcessContextNode container = model.getFactory().newInstance(IProcessContextNode.class);
		// Mark the container as refresh in progress
		final IAsyncRefreshableCtx containerRefreshable = (IAsyncRefreshableCtx)container.getAdapter(IAsyncRefreshableCtx.class);
		Assert.isNotNull(containerRefreshable);
		containerRefreshable.setQueryState(QueryType.CHILD_LIST, QueryState.IN_PROGRESS);
		// Initiate the refresh of the level 1 children
		refreshChildrenLevel1(null, depth, container, new Callback() {
			@Override
			protected void internalDone(Object caller, IStatus status) {
				// Mark the container refresh as done
				containerRefreshable.setQueryState(QueryType.CHILD_LIST, QueryState.DONE);

				// If the refresh succeeded, update the tree
				if (status.isOK()) {
					// Process the new child list and merge it with the model
					model.getService(IRuntimeModelUpdateService.class).updateChildren(model, container);

					// Walk the tree on check the children at level 2 to determine if there are
					// nodes which got expanded by the user and must be refreshed therefore too.
					final List<IProcessContextNode> children = new ArrayList<IProcessContextNode>();
					// Get the first level children from the model
					List<IProcessContextNode> candidates = model.getChildren(IProcessContextNode.class);
					for (IProcessContextNode candidate : candidates) {
						// If the child list got not queried for the candidate, skip it
						IAsyncRefreshableCtx refreshable = (IAsyncRefreshableCtx)candidate.getAdapter(IAsyncRefreshableCtx.class);
						Assert.isNotNull(refreshable);
						if (refreshable.getQueryState(QueryType.CHILD_LIST) != QueryState.DONE) continue;
						// Get the second level children and find those candidates where
						// the child list query is marked done. Add those candidates to
						// the list of children to refresh too.
						List<IProcessContextNode> candidates2 = candidate.getChildren(IProcessContextNode.class);
						for (IProcessContextNode candidate2 : candidates2) {
							// Get the asynchronous refreshable for the candidate
							refreshable = (IAsyncRefreshableCtx)candidate2.getAdapter(IAsyncRefreshableCtx.class);
							Assert.isNotNull(refreshable);
							if (refreshable.getQueryState(QueryType.CHILD_LIST) != QueryState.DONE) continue;
							// This child needs an additional refresh
							children.add(candidate2);
						}
					}

					// Run the auto-refresh logic for all children we have found
					final ICallback callback = new Callback() {
						@Override
						protected void internalDone(Object caller, IStatus status) {
							// Invoke the callbacks
							invokeCallbacks(model, RuntimeModelRefreshService.this, status);
						}
					};

					// Create the callback collector to fire once all refresh operations are completed
					final AsyncCallbackCollector collector = new AsyncCallbackCollector(callback, new CallbackInvocationDelegate());

					// Get the first level of children and check if they are need to be refreshed
					if (children.size() > 0) {
						// Initiate the refresh of the children
						doAutoRefresh(model, children.toArray(new IProcessContextNode[children.size()]), 0, collector);
					}

					// Mark the collector initialization done
					collector.initDone();
				} else {
					// Invoke the callbacks
					invokeCallbacks(model, RuntimeModelRefreshService.this, status);
				}
			}
		});
	}

	/* (non-Javadoc)
	 * @see org.eclipse.tcf.te.tcf.core.model.interfaces.services.IModelRefreshService#refresh(org.eclipse.tcf.te.runtime.model.interfaces.IModelNode, org.eclipse.tcf.te.runtime.interfaces.callback.ICallback)
	 */
	@Override
	public void refresh(final IModelNode node, final ICallback callback) {
		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$
		Assert.isNotNull(node);

		// Get the parent model
		final IRuntimeModel model = getModel();
		Assert.isNotNull(model);
		// If the model is already disposed, drop out immediately
		if (model.isDisposed() || !(node instanceof IProcessContextNode)) {
			if (callback != null) callback.done(this, Status.OK_STATUS);
			return;
		}

		// Get the context id
		final String contextId = node.getStringProperty(IProcessContextNodeProperties.PROPERTY_ID);
		if (contextId == null) {
			if (callback != null) callback.done(this, Status.OK_STATUS);
			return;
		}

		// A refresh for the passed in node is already running if the node
		// is associated with a callback list in 'ctx2cb'.
		final boolean isRefreshAlreadyRunning = ctx2cb.containsKey(node);

		// Queue the callback to invoke once the refresh is done
		List<ICallback> callbacks = ctx2cb.get(node);
		if (callbacks == null) {
			callbacks = new ArrayList<ICallback>();
			ctx2cb.put(node, callbacks);
		}
		Assert.isNotNull(callbacks);
		// Add the current callback to the list of callbacks
		if (callback != null) callbacks.add(callback);

		// If a refresh is already running, drop out. The callback is already
		// queued and will be invoked once the refresh operation is done.
		if (isRefreshAlreadyRunning) return;

		// The refresh operation is building up a parallel data tree. Pass in an empty container
		// to receive the fetched context properties and context children.
		final IProcessContextNode container = model.getFactory().newInstance(IProcessContextNode.class);
		// Mark the container as refresh in progress
		final IAsyncRefreshableCtx containerRefreshable = (IAsyncRefreshableCtx)container.getAdapter(IAsyncRefreshableCtx.class);
		Assert.isNotNull(containerRefreshable);
		containerRefreshable.setQueryState(QueryType.CHILD_LIST, QueryState.IN_PROGRESS);
		// The context id must be set to the container (asserted by the update service)
		container.setProperty(IProcessContextNodeProperties.PROPERTY_ID, contextId);
		// The container has the same type as the original node
		container.setType(((IProcessContextNode)node).getType());
		// Initiate the refresh of context
		refreshContextLevel1(contextId, 2, container, new Callback() {
			@Override
			protected void internalDone(Object caller, IStatus status) {
				// Mark the container refresh as done
				containerRefreshable.setQueryState(QueryType.CHILD_LIST, QueryState.DONE);

				// If the refresh succeeded, update the original node
				if (status.isOK()) {
					// Process the new context node and merge it with the original context node
					model.getService(IRuntimeModelUpdateService.class).update(node, container);

					// Walk the tree on check the children at level 2 to determine if there are
					// nodes which got expanded by the user and must be refreshed therefore too.
					final List<IProcessContextNode> children = new ArrayList<IProcessContextNode>();
					// Get the first level children from the model
					List<IProcessContextNode> candidates = ((IProcessContextNode)node).getChildren(IProcessContextNode.class);
					for (IProcessContextNode candidate : candidates) {
						// If the child list got not queried for the candidate, skip it
						IAsyncRefreshableCtx refreshable = (IAsyncRefreshableCtx)candidate.getAdapter(IAsyncRefreshableCtx.class);
						Assert.isNotNull(refreshable);
						if (refreshable.getQueryState(QueryType.CHILD_LIST) != QueryState.DONE) continue;
						// Get the second level children and find those candidates where
						// the child list query is marked done. Add those candidates to
						// the list of children to refresh too.
						List<IProcessContextNode> candidates2 = candidate.getChildren(IProcessContextNode.class);
						for (IProcessContextNode candidate2 : candidates2) {
							// Get the asynchronous refreshable for the candidate
							refreshable = (IAsyncRefreshableCtx)candidate2.getAdapter(IAsyncRefreshableCtx.class);
							Assert.isNotNull(refreshable);
							if (refreshable.getQueryState(QueryType.CHILD_LIST) != QueryState.DONE) continue;
							// This child needs an additional refresh
							children.add(candidate2);
						}
					}

					// Run the auto-refresh logic for all children we have found
					final ICallback callback = new Callback() {
						@Override
						protected void internalDone(Object caller, IStatus status) {
							// Invoke the callbacks
							invokeCallbacks(node, RuntimeModelRefreshService.this, status);
						}
					};

					// Create the callback collector to fire once all refresh operations are completed
					final AsyncCallbackCollector collector = new AsyncCallbackCollector(callback, new CallbackInvocationDelegate());

					// Get the first level of children and check if they are need to be refreshed
					if (children.size() > 0) {
						// Initiate the refresh of the children
						doAutoRefresh(model, children.toArray(new IProcessContextNode[children.size()]), 0, collector);
					}

					// Mark the collector initialization done
					collector.initDone();
				} else {
					// Invoke the callbacks
					invokeCallbacks(node, RuntimeModelRefreshService.this, status);
				}
			}
		});
	}

	/* (non-Javadoc)
	 * @see org.eclipse.tcf.te.tcf.processes.core.model.interfaces.runtime.IRuntimeModelRefreshService#autoRefresh(org.eclipse.tcf.te.runtime.interfaces.callback.ICallback)
	 */
	@Override
	public void autoRefresh(ICallback callback) {
		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$

		// Get the parent model
		final IRuntimeModel model = getModel();

		// If the parent model is already disposed, the service will drop out immediately
		if (model.isDisposed()) {
			if (callback != null) callback.done(this, Status.OK_STATUS);
			return;
		}

		// Determine if there is already a model refresh running.
		// A model refresh can be initiated via refresh(...) or autoRefresh(...).
		final boolean isRefreshAlreadyRunning = ctx2cb.containsKey(model);

		// Queue the callback to invoke once the refresh is done
		List<ICallback> callbacks = ctx2cb.get(model);
		if (callbacks == null) {
			callbacks = new ArrayList<ICallback>();
			ctx2cb.put(model, callbacks);
		}
		Assert.isNotNull(callbacks);
		// Add the current callback to the list of callbacks
		if (callback != null) callbacks.add(callback);

		// If a refresh is already running, drop out. The callback is already
		// queued and will be invoked once the refresh operation is done.
		if (isRefreshAlreadyRunning) return;

		// Create the inner callback which will invoke all queued callbacks
		final ICallback innerCallback = new Callback() {
			@Override
			protected void internalDone(Object caller, IStatus status) {
				// Invoke the callbacks
				invokeCallbacks(model, RuntimeModelRefreshService.this, status);
			}
		};

		// Create the callback collector to fire once all refresh operations are completed
		final AsyncCallbackCollector collector = new AsyncCallbackCollector(innerCallback, new CallbackInvocationDelegate());

		// Get the first level of children and check if they are need to be refreshed
		List<IProcessContextNode> children = model.getChildren(IProcessContextNode.class);
		if (children.size() > 0) {
			// Initiate the refresh of the children
			doAutoRefresh(model, children.toArray(new IProcessContextNode[children.size()]), 0, collector);
		}

		// Mark the collector initialization done
		collector.initDone();
	}

	// ----- Non-API refresh methods -----

	/**
	 * Performs the auto refresh of the given nodes.
	 *
	 * @param model The runtime model. Must not be <code>null</code>.
	 * @param nodes The nodes. Must not be <code>null</code>.
	 * @param index The index of the node to refresh within the nodes array. Must be greater or equal than 0 and less than the array length.
	 * @param collector The callback collector. Must not be <code>null</code>.
	 */
	/* default */ void doAutoRefresh(final IRuntimeModel model, final IProcessContextNode[] nodes, final int index, final AsyncCallbackCollector collector) {
		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$
		Assert.isNotNull(model);
		Assert.isNotNull(nodes);
		Assert.isTrue(index >= 0 && index < nodes.length);
		Assert.isNotNull(collector);

		final IProcessContextNode node = nodes[index];

		// Get the asynchronous refresh context adapter
		final IAsyncRefreshableCtx refreshable = (IAsyncRefreshableCtx)node.getAdapter(IAsyncRefreshableCtx.class);
		if (refreshable != null) {
			// Schedule a refresh if the node got refreshed before
			if (refreshable.getQueryState(QueryType.CHILD_LIST).equals(QueryState.DONE)) {
				// Create a new callback for the collector to wait for
				final ICallback callback = new Callback() {
					@Override
                    protected void internalDone(Object caller, IStatus status) {
						// We need a reference to the outer callback (== this)
						final ICallback outerCallback = this;
						// Create the inner callback
						final ICallback innerCallback = new Callback() {
							@Override
							protected void internalDone(Object caller, IStatus status) {
								// More nodes to process?
								int newIndex = index + 1;
								if (newIndex < nodes.length) {
									doAutoRefresh(model, nodes, newIndex, collector);
								}
								// Remove the outer callback from the collector
								collector.removeCallback(outerCallback);
							}
						};

						// If the node has children, process them first
						List<IProcessContextNode> children = node.getChildren(IProcessContextNode.class);
						if (children.size() > 0) {
							// Create a new callback collector for processing the children
							final AsyncCallbackCollector childCollector = new AsyncCallbackCollector(innerCallback, new CallbackInvocationDelegate());
							// Initiate the refresh of the children
							doAutoRefresh(model, children.toArray(new IProcessContextNode[children.size()]), 0, childCollector);
							// Mark the collector initialization done
							childCollector.initDone();
						} else {
							// Invoke the inner callback right away
							innerCallback.done(this, Status.OK_STATUS);
						}
					}
				};
				collector.addCallback(callback);

				// Get the context id
				final String contextId = node.getStringProperty(IProcessContextNodeProperties.PROPERTY_ID);
				if (contextId == null) {
					callback.done(this, Status.OK_STATUS);
					return;
				}

				// The refresh operation is building up a parallel data tree. Pass in an empty container
				// to receive the fetched context properties and context children.
				final IProcessContextNode container = model.getFactory().newInstance(IProcessContextNode.class);
				// Mark the container as refresh in progress
				final IAsyncRefreshableCtx containerRefreshable = (IAsyncRefreshableCtx)container.getAdapter(IAsyncRefreshableCtx.class);
				Assert.isNotNull(containerRefreshable);
				containerRefreshable.setQueryState(QueryType.CHILD_LIST, QueryState.IN_PROGRESS);
				// The context id must be set to the container (asserted by the update service)
				container.setProperty(IProcessContextNodeProperties.PROPERTY_ID, contextId);
				// The container has the same type as the original node
				container.setType(node.getType());
				// Initiate the refresh of context (only node and the direct children)
				refreshContextLevel1(contextId, 1, container, new Callback() {
					@Override
					protected void internalDone(Object caller, IStatus status) {
						// Mark the container refresh as done
						containerRefreshable.setQueryState(QueryType.CHILD_LIST, QueryState.DONE);

						// If the refresh succeeded, update the original node
						if (status.isOK()) {
							// Auto refresh requires to update the children of any new child found for
							// the node refreshed. Collect all child nodes not being children of the original node.
							List<IProcessContextNode> oldChildren = node.getChildren(IProcessContextNode.class);
							List<IProcessContextNode> newChildren = container.getChildren(IProcessContextNode.class);
							for (IProcessContextNode child : oldChildren) {
								// Get the context id of the exiting child
								String id = child.getStringProperty(IProcessContextNodeProperties.PROPERTY_ID);
								if (id == null) continue;
								// Find the context id in the new children list
								IProcessContextNode node = null;
								for (IProcessContextNode candidate : newChildren) {
									if (id.equals(candidate.getStringProperty(IProcessContextNodeProperties.PROPERTY_ID))) {
										node = candidate;
										break;
									}
								}
								// If found in the new children list, remove it
								if (node != null) newChildren.remove(node);
							}

							// Process the new context node and merge it with the original context node
							model.getService(IRuntimeModelUpdateService.class).update(node, container);

							// If there are any new children detected, update the child list of those new children
							if (newChildren.size() > 0) {
								// Create the collector firing the final callback at the end
								final AsyncCallbackCollector collector = new AsyncCallbackCollector(callback, new CallbackInvocationDelegate());
								// Get the real children list
								oldChildren = node.getChildren(IProcessContextNode.class);

								for (IProcessContextNode child : newChildren) {
									// Get the context id of the child
									String id = child.getStringProperty(IProcessContextNodeProperties.PROPERTY_ID);
									if (id == null) continue;

									// Find the real child node
									IProcessContextNode realChild = null;
									for (IProcessContextNode candidate : oldChildren) {
										if (id.equals(candidate.getStringProperty(IProcessContextNodeProperties.PROPERTY_ID))) {
											realChild = candidate;
											break;
										}
									}
									if (realChild == null) continue;

									// The refresh operation is building up a parallel data tree. Pass in an empty container
									// to receive the fetched context properties and context children.
									final IProcessContextNode container = model.getFactory().newInstance(IProcessContextNode.class);
									// Mark the container as refresh in progress
									final IAsyncRefreshableCtx containerRefreshable = (IAsyncRefreshableCtx)container.getAdapter(IAsyncRefreshableCtx.class);
									Assert.isNotNull(containerRefreshable);
									containerRefreshable.setQueryState(QueryType.CHILD_LIST, QueryState.IN_PROGRESS);
									// The context id must be set to the container (asserted by the update service)
									container.setProperty(IProcessContextNodeProperties.PROPERTY_ID, contextId);
									// The container has the same type as the original node
									container.setType(node.getType());

									// Create the callback to invoke
									final IProcessContextNode finRealChild = realChild;
									final ICallback cb = new Callback() {
										@Override
                                        protected void internalDone(Object caller, IStatus status) {
											// Mark the container refresh as done
											containerRefreshable.setQueryState(QueryType.CHILD_LIST, QueryState.DONE);

											// If the refresh succeeded, update the original child node
											if (status.isOK()) {
												model.getService(IRuntimeModelUpdateService.class).updateChildren(finRealChild, container);
											}

											// Remove the callback from the collector
											if (status.getException() != null) {
												collector.handleError(status.getException());
											} else {
												collector.removeCallback(this);
											}
										}
									};
									collector.addCallback(cb);

									// Refresh the children of the new child
									refreshChildrenLevel1(id, 1, container, cb);
								}

								collector.initDone();
							} else {
								// Invoke the callback
								callback.done(RuntimeModelRefreshService.this, status);
							}
						} else {
							// Invoke the callback
							callback.done(RuntimeModelRefreshService.this, status);
						}
					}
				});
			}
		}
	}

	/**
	 * Refresh the context properties for the given context id.
	 * <p>
	 * The method fetches the children of the given context id and generates a new set of process
	 * context nodes to represent the children until the max depth is reached.
	 * <p>
	 * The fetched properties are added to the given container.
	 *
	 * @param contextId The context id. Must not be <code>null</code>.
	 * @param maxDepth The max depth of the tree to refresh. Must be greater than 0.
	 * @param container The container. Must not be <code>null</code>.
	 * @param callback The callback to invoke once the operation is completed. Must not be <code>null</code>.
	 */
	protected void refreshContextLevel1(final String contextId, final int maxDepth, final IProcessContextNode container, final ICallback callback) {
		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$
		Assert.isNotNull(contextId);
		Assert.isNotNull(container);
		Assert.isNotNull(callback);

		// Make sure that the callback is invoked even for unexpected cases
		try {
			// Get an open channel
			IModelChannelService channelService = getModel().getService(IModelChannelService.class);
			channelService.openChannel(new IModelChannelService.DoneOpenChannel() {
				@Override
				public void doneOpenChannel(Throwable error, final IChannel channel) {
					if (error == null) {
						// Query the context properties
						refreshContext(channel, contextId, container, new Callback() {
							@Override
                            protected void internalDone(Object caller, IStatus status) {
								if (status.isOK()) {
									// Query the first level child contexts
									refreshChildContexts(channel, contextId, container, new Callback() {
										@Override
			                            protected void internalDone(Object caller, IStatus status) {
											// Refresh the next level if the depth is still larger than 0
											if (maxDepth < 0 || maxDepth - 1 > 0) {
												List<IProcessContextNode> children = container.getChildren(IProcessContextNode.class);
												Assert.isNotNull(children);
												refreshChildrenLevelN(channel, children.toArray(new IProcessContextNode[children.size()]), maxDepth - 1, callback);
											} else {
												// Refresh completed, invoke the callback
												callback.done(RuntimeModelRefreshService.this, status);
											}
										}
									});
								} else {
									callback.done(RuntimeModelRefreshService.this, status);
								}
							}
						});
					} else {
						callback.done(RuntimeModelRefreshService.this, new Status(IStatus.ERROR, CoreBundleActivator.getUniqueIdentifier(), error.getLocalizedMessage(), error));
					}
				}
			});
		} catch (Throwable e) {
			callback.done(RuntimeModelRefreshService.this, new Status(IStatus.ERROR, CoreBundleActivator.getUniqueIdentifier(), e.getLocalizedMessage(), e));
		}
	}

	/**
	 * Fetches the first level of children for the given parent context id.
	 * <p>
	 * The method fetches the first level of children and generates a new set of process
	 * context nodes to represent the children. Each child is refresh itself until the max
	 * depth is reached.
	 * <p>
	 * The fetched first level children are added to the given container.
	 *
	 * @param parentContextId The parent context id or <code>null</code> for the root context.
	 * @param maxDepth The max depth of the tree to refresh. Must be greater than 0.
	 * @param container The container. Must not be <code>null</code>.
	 * @param callback The callback to invoke once the operation is completed. Must not be <code>null</code>.
	 */
	/* default */ void refreshChildrenLevel1(final String parentContextId, final int maxDepth, final IProcessContextNode container, final ICallback callback) {
		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$
		Assert.isNotNull(container);
		Assert.isNotNull(callback);

		// Make sure that the callback is invoked even for unexpected cases
		try {
			// Get an open channel
			IModelChannelService channelService = getModel().getService(IModelChannelService.class);
			channelService.openChannel(new IModelChannelService.DoneOpenChannel() {
				@Override
				public void doneOpenChannel(Throwable error, final IChannel channel) {
					if (error == null) {
						// Query the first level child contexts
						refreshChildContexts(channel, parentContextId, container, new Callback() {
							@Override
                            protected void internalDone(Object caller, IStatus status) {
								// Refresh the next level if the depth is still larger than 0
								if (maxDepth < 0 || maxDepth - 1 > 0) {
									List<IProcessContextNode> children = container.getChildren(IProcessContextNode.class);
									Assert.isNotNull(children);
									refreshChildrenLevelN(channel, children.toArray(new IProcessContextNode[children.size()]), maxDepth - 1, callback);
								} else {
									// Refresh completed, invoke the callback
									callback.done(RuntimeModelRefreshService.this, status);
								}
							}
						});
					} else {
						callback.done(RuntimeModelRefreshService.this, new Status(IStatus.ERROR, CoreBundleActivator.getUniqueIdentifier(), error.getLocalizedMessage(), error));
					}
				}
			});
		} catch (Throwable e) {
			callback.done(RuntimeModelRefreshService.this, new Status(IStatus.ERROR, CoreBundleActivator.getUniqueIdentifier(), e.getLocalizedMessage(), e));
		}
	}

	/**
	 * Fetches the children of the given parent context nodes.
	 * <p>
	 * The method calls itself recursively until <code>maxDepth - 1 == 0</code> is true.
	 *
	 * @param channel An open channel. Must not be <code>null</code>.
	 * @param parents The parent contexts. Must not be <code>null</code>.
	 * @param maxDepth The max depth of the tree to refresh. Must be greater than 0.
	 * @param callback The callback to invoke once the operation is completed. Must not be <code>null</code>.
	 */
	/* default */ void refreshChildrenLevelN(final IChannel channel, final IProcessContextNode[] parents, final int maxDepth, final ICallback callback) {
		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$
		Assert.isNotNull(channel);
		Assert.isNotNull(parents);
		Assert.isNotNull(callback);

		// The channel must be opened, otherwise the query cannot run
		if (channel.getState() != IChannel.STATE_OPEN) {
			IStatus status = new Status(IStatus.ERROR, CoreBundleActivator.getUniqueIdentifier(), Messages.RuntimeModelRefreshService_error_channelClosed);
			callback.done(RuntimeModelRefreshService.this, status);
			return;
		}

		// If the parents list is empty, there is nothing to refresh
		if (parents.length == 0) {
			callback.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
			return;
		}

		// The callback collector to be fired if the children of all parents got fully refreshed
		final AsyncCallbackCollector collector = new AsyncCallbackCollector(new Callback() {
			@Override
			protected void internalDone(Object caller, IStatus status) {
				// Refresh the next level if the depth is still larger than 0
				if (maxDepth < 0 || maxDepth - 1 > 0) {
					// The callback collector to be fired if the children of all children of all parent contexts got fully refreshed
					final AsyncCallbackCollector collector2 = new AsyncCallbackCollector(callback, new CallbackInvocationDelegate());

					for (IProcessContextNode parent : parents) {
						List<IProcessContextNode> children = parent.getChildren(IProcessContextNode.class);
						Assert.isNotNull(children);
						refreshChildrenLevelN(channel, children.toArray(new IProcessContextNode[children.size()]), maxDepth - 1, new AsyncCallbackCollector.SimpleCollectorCallback(collector2));
					}

					collector2.initDone();
				} else {
					// Refresh completed, invoke the callback
					callback.done(RuntimeModelRefreshService.this, status);
				}
			}
		}, new CallbackInvocationDelegate());

		// Loop the parent contexts and refresh the children of each one.
		for (final IProcessContextNode parent : parents) {
			// Get the context id of the parent. Must be not null here.
			String parentContextId = parent.getStringProperty(IProcessContextNodeProperties.PROPERTY_ID);
			if (parentContextId == null) continue;
			// Create the callback
			final ICallback cb = new AsyncCallbackCollector.SimpleCollectorCallback(collector);
			// Get the asynchronous refresh context adapter
			final IAsyncRefreshableCtx refreshable = (IAsyncRefreshableCtx)parent.getAdapter(IAsyncRefreshableCtx.class);
			Assert.isNotNull(refreshable);
			// If not IN_PROGRESS, initiate the refresh
			if (!refreshable.getQueryState(QueryType.CHILD_LIST).equals(QueryState.IN_PROGRESS)) {
				// Mark the refresh as in progress
				refreshable.setQueryState(QueryType.CHILD_LIST, QueryState.IN_PROGRESS);
				// Don't send change events while refreshing
				final boolean changed = parent.setChangeEventsEnabled(false);
				// Refresh the children of the parent context
				refreshChildContexts(channel, parentContextId, parent, new Callback() {
					@Override
					protected void internalDone(Object caller, IStatus status) {
						// Mark the refresh as done
						refreshable.setQueryState(QueryType.CHILD_LIST, QueryState.DONE);
						// Re-enable the change events if they had been enabled before
						if (changed) parent.setChangeEventsEnabled(true);
						// Invoke the callback
						cb.done(RuntimeModelRefreshService.this, status);
					}
				});
			} else {
				// Invoke the callback
				cb.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
			}
		}

		collector.initDone();
	}

	/**
	 * Refresh the properties of the given context id using the given channel.
	 * All context properties are <i>added</i> to the passed in node.
	 *
	 * @param channel An open channel. Must not be <code>null</code>.
	 * @param contextId The context id. Must not be <code>null</code>.
	 * @param node The node. Must not be <code>null</code>.
	 * @param callback The callback to invoke once the operation is completed. Must not be <code>null</code>.
	 */
	/* default */ void refreshContext(final IChannel channel, final String contextId, final IProcessContextNode node, final ICallback callback) {
		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$
		Assert.isNotNull(channel);
		Assert.isNotNull(contextId);
		Assert.isNotNull(node);
		Assert.isNotNull(callback);

		// The channel must be opened, otherwise the query cannot run
		if (channel.getState() != IChannel.STATE_OPEN) {
			IStatus status = new Status(IStatus.ERROR, CoreBundleActivator.getUniqueIdentifier(), Messages.RuntimeModelRefreshService_error_channelClosed);
			callback.done(RuntimeModelRefreshService.this, status);
			return;
		}

		// Get the required services
		final IProcesses service = channel.getRemoteService(IProcesses.class);
		final ISysMonitor sysMonService = channel.getRemoteService(ISysMonitor.class);

		// At least the processes and the system monitor service must be available
		if (service == null || sysMonService == null) {
			callback.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
			return;
		}

		// Callback collector to fire once the system monitor and process context queries completed
		final AsyncCallbackCollector collector = new AsyncCallbackCollector(new Callback() {
			@Override
            protected void internalDone(Object caller, IStatus status) {
				// Determine if a delegate is registered
				IRuntimeModelRefreshService.IDelegate delegate = ServiceUtils.getDelegateServiceDelegate(channel.getRemotePeer(), channel.getRemotePeer(), IRuntimeModelRefreshService.IDelegate.class);
				// Run the post refresh context delegate
				if (delegate == null) delegate = defaultDelegate;
				Assert.isNotNull(delegate);
				delegate.postRefreshContext(channel, node, callback);
			}
		}, new CallbackInvocationDelegate());

		// Query the system monitor context object
		final ICallback cb1 = new AsyncCallbackCollector.SimpleCollectorCallback(collector);
		sysMonService.getContext(contextId, new ISysMonitor.DoneGetContext() {
			@Override
			public void doneGetContext(IToken token, Exception error, SysMonitorContext context) {
				// Ignore errors. Some of the context might be OS context we do not have
				// permissions to read the properties from.
				node.setSysMonitorContext(context);
				// Invoke the callback
				cb1.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
			}
		});

		// Query the process context object
		final ICallback cb2 = new AsyncCallbackCollector.SimpleCollectorCallback(collector);
		service.getContext(contextId, new IProcesses.DoneGetContext() {
			@Override
			public void doneGetContext(IToken token, Exception error, IProcesses.ProcessContext context) {
				// Errors are ignored
				node.setProcessContext(context);
				// Set the context name from the process context if available
				if (context != null) node.setProperty(IProcessContextNodeProperties.PROPERTY_NAME, context.getName());
				// Invoke the callback
				cb2.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
			}
		});

		collector.initDone();
	}

	/**
	 * Refresh the child contexts of the given parent context id using the given channel.
	 * All child contexts are <i>added</i> to the passed in container.
	 *
	 * @param channel An open channel. Must not be <code>null</code>.
	 * @param parentContextId The parent context id or <code>null</code> for the root context.
	 * @param container The container. Must not be <code>null</code>.
	 * @param callback The callback to invoke once the operation is completed. Must not be <code>null</code>.
	 */
	/* default */ void refreshChildContexts(final IChannel channel, final String parentContextId, final IContainerModelNode container, final ICallback callback) {
		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$
		Assert.isNotNull(channel);
		Assert.isNotNull(container);
		Assert.isNotNull(callback);

		// The channel must be opened, otherwise the query cannot run
		if (channel.getState() != IChannel.STATE_OPEN) {
			IStatus status = new Status(IStatus.ERROR, CoreBundleActivator.getUniqueIdentifier(), Messages.RuntimeModelRefreshService_error_channelClosed);
			callback.done(RuntimeModelRefreshService.this, status);
			return;
		}

		// Get the required services
		final IProcesses service = channel.getRemoteService(IProcesses.class);
		final ISysMonitor sysMonService = channel.getRemoteService(ISysMonitor.class);

		// At least the processes and the system monitor service must be available
		if (service == null || sysMonService == null) {
			callback.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
			return;
		}

		// Get the child context id's of the given parent context id
		sysMonService.getChildren(parentContextId, new ISysMonitor.DoneGetChildren() {
			@Override
			public void doneGetChildren(IToken token, Exception error, String[] context_ids) {
				if (error == null) {
					if (context_ids != null && context_ids.length > 0) {
						// Callback collector to fire the passed in callback once all child contexts got fully refreshed
						final AsyncCallbackCollector collector = new AsyncCallbackCollector(callback, new CallbackInvocationDelegate());

						// Loop the returned context id's and query the context data
						for (String id : context_ids) {
							final String contextId = id;

							// Create the context node for the current context id
							final IProcessContextNode node = createContextNodeFrom(contextId);
							Assert.isNotNull(node);
							// Add the node to the container
							container.add(node);

							// Callback collector to fire once the system monitor and process context queries completed
							final ICallback innerCallback = new AsyncCallbackCollector.SimpleCollectorCallback(collector);
							final AsyncCallbackCollector innerCollector = new AsyncCallbackCollector(new Callback() {
								@Override
                                protected void internalDone(Object caller, IStatus status) {
									// Determine if a delegate is registered
									IRuntimeModelRefreshService.IDelegate delegate = ServiceUtils.getDelegateServiceDelegate(channel.getRemotePeer(), channel.getRemotePeer(), IRuntimeModelRefreshService.IDelegate.class);
									// Determine the node type
									if (delegate != null) delegate.setNodeType(parentContextId, node);
									// Fallback to the default delegate if node type is not set by delegate
									if (node.getType() == TYPE.Unknown) defaultDelegate.setNodeType(parentContextId, node);

									// Run the post refresh context delegate
									if (delegate == null) delegate = defaultDelegate;
									Assert.isNotNull(delegate);
									delegate.postRefreshContext(channel, node, innerCallback);
								}
							}, new CallbackInvocationDelegate());

							// Query the system monitor context object
							final ICallback cb1 = new AsyncCallbackCollector.SimpleCollectorCallback(innerCollector);
							sysMonService.getContext(contextId, new ISysMonitor.DoneGetContext() {
								@Override
								public void doneGetContext(IToken token, Exception error, SysMonitorContext context) {
									// Ignore errors. Some of the context might be OS context we do not have
									// permissions to read the properties from.
									node.setSysMonitorContext(context);
									// Invoke the callback
									cb1.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
								}
							});

							// Query the process context object
							final ICallback cb2 = new AsyncCallbackCollector.SimpleCollectorCallback(innerCollector);
							service.getContext(contextId, new IProcesses.DoneGetContext() {
								@Override
								public void doneGetContext(IToken token, Exception error, IProcesses.ProcessContext context) {
									// Errors are ignored
									node.setProcessContext(context);
									// Set the context name from the process context if available
									if (context != null) node.setProperty(IProcessContextNodeProperties.PROPERTY_NAME, context.getName());
									// Invoke the callback
									cb2.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
								}
							});

							innerCollector.initDone();
						}

						collector.initDone();
					} else {
						callback.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
					}
				} else {
					if (StatusHelper.unwrapErrorReport(error.getLocalizedMessage()).equals("Invalid context")) { //$NON-NLS-1$
						// OK, the context got invalid during the query. Mark the
						// context as invalid and return with OK to keep the refresh going
						container.setProperty(IProcessContextNodeProperties.PROPERTY_INVALID_CTX, true);
						callback.done(RuntimeModelRefreshService.this, Status.OK_STATUS);
					} else {
						callback.done(RuntimeModelRefreshService.this, new Status(IStatus.ERROR, CoreBundleActivator.getUniqueIdentifier(), error.getLocalizedMessage(), error));
					}
				}
			}
		});
	}

	/**
	 * Create a process context node instance for the given context id.
	 *
	 * @param contextId The context id. Must not be <code>null</code>.
	 * @return The process context node instance.
	 */
	/* default */ IProcessContextNode createContextNodeFrom(String contextId) {
		Assert.isNotNull(contextId);

		// Create a context node and associate the given context
		IProcessContextNode node = getModel().getFactory().newInstance(IProcessContextNode.class);

		// Set the context id
		node.setProperty(IProcessContextNodeProperties.PROPERTY_ID, contextId);

		return node;
	}

	// ----- Utility methods ------

	/**
	 * Invoke all pending callbacks for the given context.
	 * <p>
	 * Each callback is invoked as single runnable dispatched to the
	 * TCF event dispatch thread.
	 *
	 * @param context The context. Must not be <code>null</code>.
	 * @param caller The caller of the callback or <code>null</code>.
	 * @param status The status. Must not be <code>null</code>.
	 */
	protected void invokeCallbacks(final IModelNode context, final Object caller, final IStatus status) {
		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$
		Assert.isNotNull(context);
		Assert.isNotNull(status);

		List<ICallback> callbacks = ctx2cb.remove(context);
		if (callbacks != null) {
			for (final ICallback callback : callbacks) {
				Protocol.invokeLater(new Runnable() {
					@Override
					public void run() {
						callback.done(caller, status);
					}
				});
			}
		}
	}
}