/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package net.sourceforge.phpdt.internal.core;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;

import net.sourceforge.phpdt.core.ICompilationUnit;
import net.sourceforge.phpdt.core.IJavaElement;
import net.sourceforge.phpdt.core.IJavaElementDelta;
import net.sourceforge.phpdt.core.IJavaModel;
import net.sourceforge.phpdt.core.IJavaModelStatus;
import net.sourceforge.phpdt.core.IJavaModelStatusConstants;
import net.sourceforge.phpdt.core.IPackageFragment;
import net.sourceforge.phpdt.core.IWorkingCopy;
import net.sourceforge.phpdt.core.JavaModelException;
import net.sourceforge.phpdt.internal.core.util.PerThreadObject;
import net.sourceforge.phpdt.internal.core.util.Util;

import org.eclipse.core.resources.IContainer;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IFolder;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceStatus;
import org.eclipse.core.resources.IWorkspace;
import org.eclipse.core.resources.IWorkspaceRunnable;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.OperationCanceledException;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.SubProgressMonitor;
import org.eclipse.core.runtime.jobs.ISchedulingRule;

/**
 * Defines behavior common to all Java Model operations
 */
public abstract class JavaModelOperation implements IWorkspaceRunnable,
		IProgressMonitor {
	protected interface IPostAction {
		/*
		 * Returns the id of this action.
		 * 
		 * @see JavaModelOperation#postAction
		 */
		String getID();

		/*
		 * Run this action.
		 */
		void run() throws JavaModelException;
	}

	/*
	 * Constants controlling the insertion mode of an action.
	 * 
	 * @see JavaModelOperation#postAction
	 */
	protected static final int APPEND = 1; // insert at the end

	protected static final int REMOVEALL_APPEND = 2; // remove all existing
														// ones with same ID,
														// and add new one at
														// the end

	protected static final int KEEP_EXISTING = 3; // do not insert if already
													// existing with same ID

	/*
	 * Whether tracing post actions is enabled.
	 */
	protected static boolean POST_ACTION_VERBOSE;

	/*
	 * A list of IPostActions.
	 */
	protected IPostAction[] actions;

	protected int actionsStart = 0;

	protected int actionsEnd = -1;

	/*
	 * A HashMap of attributes that can be used by operations
	 */
	protected HashMap attributes;

	public static final String HAS_MODIFIED_RESOURCE_ATTR = "hasModifiedResource"; //$NON-NLS-1$

	public static final String TRUE = "true"; //$NON-NLS-1$

	// public static final String FALSE = "false"; //$NON-NLS-1$

	/**
	 * The elements this operation operates on, or <code>null</code> if this
	 * operation does not operate on specific elements.
	 */
	protected IJavaElement[] fElementsToProcess;

	/**
	 * The parent elements this operation operates with or <code>null</code>
	 * if this operation does not operate with specific parent elements.
	 */
	protected IJavaElement[] fParentElements;

	/**
	 * An empty collection of <code>IJavaElement</code> s - the common empty
	 * result if no elements are created, or if this operation is not actually
	 * executed.
	 */
	protected static IJavaElement[] NO_ELEMENTS = new IJavaElement[] {};

	/**
	 * The elements created by this operation - empty until the operation
	 * actually creates elements.
	 */
	protected IJavaElement[] resultElements = NO_ELEMENTS;

	/**
	 * The progress monitor passed into this operation
	 */
	protected IProgressMonitor progressMonitor = null;

	/**
	 * A flag indicating whether this operation is nested.
	 */
	protected boolean isNested = false;

	/**
	 * Conflict resolution policy - by default do not force (fail on a
	 * conflict).
	 */
	protected boolean force = false;

	/*
	 * A per thread stack of java model operations (PerThreadObject of
	 * ArrayList).
	 */
	protected static PerThreadObject operationStacks = new PerThreadObject();

	protected JavaModelOperation() {
	}

	/**
	 * A common constructor for all Java Model operations.
	 */
	protected JavaModelOperation(IJavaElement[] elements) {
		fElementsToProcess = elements;
	}

	/**
	 * Common constructor for all Java Model operations.
	 */
	protected JavaModelOperation(IJavaElement[] elementsToProcess,
			IJavaElement[] parentElements) {
		fElementsToProcess = elementsToProcess;
		fParentElements = parentElements;
	}

	/**
	 * A common constructor for all Java Model operations.
	 */
	protected JavaModelOperation(IJavaElement[] elementsToProcess,
			IJavaElement[] parentElements, boolean force) {
		fElementsToProcess = elementsToProcess;
		fParentElements = parentElements;
		this.force = force;
	}

	/**
	 * A common constructor for all Java Model operations.
	 */
	protected JavaModelOperation(IJavaElement[] elements, boolean force) {
		fElementsToProcess = elements;
		this.force = force;
	}

	/**
	 * Common constructor for all Java Model operations.
	 */
	protected JavaModelOperation(IJavaElement element) {
		fElementsToProcess = new IJavaElement[] { element };
	}

	/**
	 * A common constructor for all Java Model operations.
	 */
	protected JavaModelOperation(IJavaElement element, boolean force) {
		fElementsToProcess = new IJavaElement[] { element };
		this.force = force;
	}

	/*
	 * Registers the given action at the end of the list of actions to run.
	 */
	protected void addAction(IPostAction action) {
		int length = this.actions.length;
		if (length == ++this.actionsEnd) {
			System.arraycopy(this.actions, 0,
					this.actions = new IPostAction[length * 2], 0, length);
		}
		this.actions[this.actionsEnd] = action;
	}

	/*
	 * Registers the given delta with the Java Model Manager.
	 */
	protected void addDelta(IJavaElementDelta delta) {
		JavaModelManager.getJavaModelManager().registerJavaModelDelta(delta);
	}

	/*
	 * Registers the given reconcile delta with the Java Model Manager.
	 */
	protected void addReconcileDelta(IWorkingCopy workingCopy,
			IJavaElementDelta delta) {
		HashMap reconcileDeltas = JavaModelManager.getJavaModelManager().reconcileDeltas;
		JavaElementDelta previousDelta = (JavaElementDelta) reconcileDeltas
				.get(workingCopy);
		if (previousDelta != null) {
			IJavaElementDelta[] children = delta.getAffectedChildren();
			for (int i = 0, length = children.length; i < length; i++) {
				JavaElementDelta child = (JavaElementDelta) children[i];
				previousDelta.insertDeltaTree(child.getElement(), child);
			}
		} else {
			reconcileDeltas.put(workingCopy, delta);
		}
	}

	/*
	 * Deregister the reconcile delta for the given working copy
	 */
	protected void removeReconcileDelta(IWorkingCopy workingCopy) {
		JavaModelManager.getJavaModelManager().reconcileDeltas
				.remove(workingCopy);
	}

	/**
	 * @see IProgressMonitor
	 */
	public void beginTask(String name, int totalWork) {
		if (progressMonitor != null) {
			progressMonitor.beginTask(name, totalWork);
		}
	}

	/**
	 * Checks with the progress monitor to see whether this operation should be
	 * canceled. An operation should regularly call this method during its
	 * operation so that the user can cancel it.
	 * 
	 * @exception OperationCanceledException
	 *                if cancelling the operation has been requested
	 * @see IProgressMonitor#isCanceled
	 */
	protected void checkCanceled() {
		if (isCanceled()) {
			throw new OperationCanceledException(Util
					.bind("operation.cancelled")); //$NON-NLS-1$
		}
	}

	/**
	 * Common code used to verify the elements this operation is processing.
	 * 
	 * @see JavaModelOperation#verify()
	 */
	protected IJavaModelStatus commonVerify() {
		if (fElementsToProcess == null || fElementsToProcess.length == 0) {
			return new JavaModelStatus(
					IJavaModelStatusConstants.NO_ELEMENTS_TO_PROCESS);
		}
		for (int i = 0; i < fElementsToProcess.length; i++) {
			if (fElementsToProcess[i] == null) {
				return new JavaModelStatus(
						IJavaModelStatusConstants.NO_ELEMENTS_TO_PROCESS);
			}
		}
		return JavaModelStatus.VERIFIED_OK;
	}

	/**
	 * Convenience method to copy resources
	 */
	protected void copyResources(IResource[] resources, IPath destinationPath)
			throws JavaModelException {
		IProgressMonitor subProgressMonitor = getSubProgressMonitor(resources.length);
		IWorkspace workspace = resources[0].getWorkspace();
		try {
			workspace.copy(resources, destinationPath, false,
					subProgressMonitor);
			this.setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}

	/**
	 * Convenience method to create a file
	 */
	protected void createFile(IContainer folder, String name,
			InputStream contents, boolean force) throws JavaModelException {
		IFile file = folder.getFile(new Path(name));
		try {
			file.create(contents, force ? IResource.FORCE
					| IResource.KEEP_HISTORY : IResource.KEEP_HISTORY,
					getSubProgressMonitor(1));
			this.setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}

	/**
	 * Convenience method to create a folder
	 */
	protected void createFolder(IContainer parentFolder, String name,
			boolean force) throws JavaModelException {
		IFolder folder = parentFolder.getFolder(new Path(name));
		try {
			// we should use true to create the file locally. Only VCM should
			// use tru/false
			folder.create(force ? IResource.FORCE | IResource.KEEP_HISTORY
					: IResource.KEEP_HISTORY, true, // local
					getSubProgressMonitor(1));
			this.setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}

	/**
	 * Convenience method to delete an empty package fragment
	 */
	protected void deleteEmptyPackageFragment(IPackageFragment fragment,
			boolean force, IResource rootResource) throws JavaModelException {

		IContainer resource = (IContainer) fragment.getResource();

		try {
			resource.delete(force ? IResource.FORCE | IResource.KEEP_HISTORY
					: IResource.KEEP_HISTORY, getSubProgressMonitor(1));
			this.setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
			while (resource instanceof IFolder) {
				// deleting a package: delete the parent if it is empty (eg.
				// deleting x.y where folder x doesn't have resources but y)
				// without deleting the package fragment root
				resource = resource.getParent();
				if (!resource.equals(rootResource)
						&& resource.members().length == 0) {
					resource.delete(force ? IResource.FORCE
							| IResource.KEEP_HISTORY : IResource.KEEP_HISTORY,
							getSubProgressMonitor(1));
					this.setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
				}
			}
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}

	/**
	 * Convenience method to delete a resource
	 */
	protected void deleteResource(IResource resource, int flags)
			throws JavaModelException {
		try {
			resource.delete(flags, getSubProgressMonitor(1));
			this.setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}

	/**
	 * Convenience method to delete resources
	 */
	protected void deleteResources(IResource[] resources, boolean force)
			throws JavaModelException {
		if (resources == null || resources.length == 0)
			return;
		IProgressMonitor subProgressMonitor = getSubProgressMonitor(resources.length);
		IWorkspace workspace = resources[0].getWorkspace();
		try {
			workspace.delete(resources, force ? IResource.FORCE
					| IResource.KEEP_HISTORY : IResource.KEEP_HISTORY,
					subProgressMonitor);
			this.setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}

	/**
	 * @see IProgressMonitor
	 */
	public void done() {
		if (progressMonitor != null) {
			progressMonitor.done();
		}
	}

	/*
	 * Returns whether the given path is equals to one of the given other paths.
	 */
	protected boolean equalsOneOf(IPath path, IPath[] otherPaths) {
		for (int i = 0, length = otherPaths.length; i < length; i++) {
			if (path.equals(otherPaths[i])) {
				return true;
			}
		}
		return false;
	}

	/**
	 * Verifies the operation can proceed and executes the operation. Subclasses
	 * should override <code>#verify</code> and <code>executeOperation</code>
	 * to implement the specific operation behavior.
	 * 
	 * @exception JavaModelException
	 *                The operation has failed.
	 */
	// protected void execute() throws JavaModelException {
	// IJavaModelStatus status= verify();
	// if (status.isOK()) {
	// // if first time here, computes the root infos before executing the
	// operation
	// DeltaProcessor deltaProcessor =
	// JavaModelManager.getJavaModelManager().deltaProcessor;
	// if (deltaProcessor.roots == null) {
	// deltaProcessor.initializeRoots();
	// }
	// executeOperation();
	// } else {
	// throw new JavaModelException(status);
	// }
	// }
	/**
	 * Convenience method to run an operation within this operation
	 */
	public void executeNestedOperation(JavaModelOperation operation,
			int subWorkAmount) throws JavaModelException {
		IProgressMonitor subProgressMonitor = getSubProgressMonitor(subWorkAmount);
		// fix for 1FW7IKC, part (1)
		try {
			operation.setNested(true);
			operation.run(subProgressMonitor);
		} catch (CoreException ce) {
			if (ce instanceof JavaModelException) {
				throw (JavaModelException) ce;
			} else {
				// translate the core exception to a java model exception
				if (ce.getStatus().getCode() == IResourceStatus.OPERATION_FAILED) {
					Throwable e = ce.getStatus().getException();
					if (e instanceof JavaModelException) {
						throw (JavaModelException) e;
					}
				}
				throw new JavaModelException(ce);
			}
		}
	}

	/**
	 * Performs the operation specific behavior. Subclasses must override.
	 */
	protected abstract void executeOperation() throws JavaModelException;

	/*
	 * Returns the attribute registered at the given key with the top level
	 * operation. Returns null if no such attribute is found.
	 */
	protected Object getAttribute(Object key) {
		ArrayList stack = this.getCurrentOperationStack();
		if (stack.size() == 0)
			return null;
		JavaModelOperation topLevelOp = (JavaModelOperation) stack.get(0);
		if (topLevelOp.attributes == null) {
			return null;
		} else {
			return topLevelOp.attributes.get(key);
		}
	}

	/**
	 * Returns the compilation unit the given element is contained in, or the
	 * element itself (if it is a compilation unit), otherwise <code>null</code>.
	 */
	protected ICompilationUnit getCompilationUnitFor(IJavaElement element) {

		return ((JavaElement) element).getCompilationUnit();
	}

	/*
	 * Returns the stack of operations running in the current thread. Returns an
	 * empty stack if no operations are currently running in this thread.
	 */
	protected ArrayList getCurrentOperationStack() {
		ArrayList stack = (ArrayList) operationStacks.getCurrent();
		if (stack == null) {
			stack = new ArrayList();
			operationStacks.setCurrent(stack);
		}
		return stack;
	}

	/**
	 * Returns the elements to which this operation applies, or
	 * <code>null</code> if not applicable.
	 */
	protected IJavaElement[] getElementsToProcess() {
		return fElementsToProcess;
	}

	/**
	 * Returns the element to which this operation applies, or <code>null</code>
	 * if not applicable.
	 */
	protected IJavaElement getElementToProcess() {
		if (fElementsToProcess == null || fElementsToProcess.length == 0) {
			return null;
		}
		return fElementsToProcess[0];
	}

	/**
	 * Returns the Java Model this operation is operating in.
	 */
	public IJavaModel getJavaModel() {
		if (fElementsToProcess == null || fElementsToProcess.length == 0) {
			return getParentElement().getJavaModel();
		} else {
			return fElementsToProcess[0].getJavaModel();
		}
	}

	// protected IPath[] getNestedFolders(IPackageFragmentRoot root) throws
	// JavaModelException {
	// IPath rootPath = root.getPath();
	// IClasspathEntry[] classpath = root.getJavaProject().getRawClasspath();
	// int length = classpath.length;
	// IPath[] result = new IPath[length];
	// int index = 0;
	// for (int i = 0; i < length; i++) {
	// IPath path = classpath[i].getPath();
	// if (rootPath.isPrefixOf(path) && !rootPath.equals(path)) {
	// result[index++] = path;
	// }
	// }
	// if (index < length) {
	// System.arraycopy(result, 0, result = new IPath[index], 0, index);
	// }
	// return result;
	// }
	/**
	 * Returns the parent element to which this operation applies, or
	 * <code>null</code> if not applicable.
	 */
	protected IJavaElement getParentElement() {
		if (fParentElements == null || fParentElements.length == 0) {
			return null;
		}
		return fParentElements[0];
	}

	/**
	 * Returns the parent elements to which this operation applies, or
	 * <code>null</code> if not applicable.
	 */
	protected IJavaElement[] getParentElements() {
		return fParentElements;
	}

	/**
	 * Returns the elements created by this operation.
	 */
	public IJavaElement[] getResultElements() {
		return resultElements;
	}

	/*
	 * Returns the scheduling rule for this operation (i.e. the resource that
	 * needs to be locked while this operation is running. Subclasses can
	 * override.
	 */
	protected ISchedulingRule getSchedulingRule() {
		return ResourcesPlugin.getWorkspace().getRoot();
	}

	/**
	 * Creates and returns a subprogress monitor if appropriate.
	 */
	protected IProgressMonitor getSubProgressMonitor(int workAmount) {
		IProgressMonitor sub = null;
		if (progressMonitor != null) {
			sub = new SubProgressMonitor(progressMonitor, workAmount,
					SubProgressMonitor.PREPEND_MAIN_LABEL_TO_SUBTASK);
		}
		return sub;
	}

	/**
	 * Returns whether this operation has performed any resource modifications.
	 * Returns false if this operation has not been executed yet.
	 */
	public boolean hasModifiedResource() {
		return !this.isReadOnly()
				&& this.getAttribute(HAS_MODIFIED_RESOURCE_ATTR) == TRUE;
	}

	public void internalWorked(double work) {
		if (progressMonitor != null) {
			progressMonitor.internalWorked(work);
		}
	}

	/**
	 * @see IProgressMonitor
	 */
	public boolean isCanceled() {
		if (progressMonitor != null) {
			return progressMonitor.isCanceled();
		}
		return false;
	}

	/**
	 * Returns <code>true</code> if this operation performs no resource
	 * modifications, otherwise <code>false</code>. Subclasses must override.
	 */
	public boolean isReadOnly() {
		return false;
	}

	/*
	 * Returns whether this operation is the first operation to run in the
	 * current thread.
	 */
	protected boolean isTopLevelOperation() {
		ArrayList stack;
		return (stack = this.getCurrentOperationStack()).size() > 0
				&& stack.get(0) == this;
	}

	/*
	 * Returns the index of the first registered action with the given id,
	 * starting from a given position. Returns -1 if not found.
	 */
	protected int firstActionWithID(String id, int start) {
		for (int i = start; i <= this.actionsEnd; i++) {
			if (this.actions[i].getID().equals(id)) {
				return i;
			}
		}
		return -1;
	}

	/**
	 * Convenience method to move resources
	 */
	protected void moveResources(IResource[] resources, IPath destinationPath)
			throws JavaModelException {
		IProgressMonitor subProgressMonitor = null;
		if (progressMonitor != null) {
			subProgressMonitor = new SubProgressMonitor(progressMonitor,
					resources.length,
					SubProgressMonitor.PREPEND_MAIN_LABEL_TO_SUBTASK);
		}
		IWorkspace workspace = resources[0].getWorkspace();
		try {
			workspace.move(resources, destinationPath, false,
					subProgressMonitor);
			this.setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}

	/**
	 * Creates and returns a new <code>IJavaElementDelta</code> on the Java
	 * Model.
	 */
	public JavaElementDelta newJavaElementDelta() {
		return new JavaElementDelta(getJavaModel());
	}

	/*
	 * Removes the last pushed operation from the stack of running operations.
	 * Returns the poped operation or null if the stack was empty.
	 */
	protected JavaModelOperation popOperation() {
		ArrayList stack = getCurrentOperationStack();
		int size = stack.size();
		if (size > 0) {
			if (size == 1) { // top level operation
				operationStacks.setCurrent(null); // release reference (see
													// http://bugs.eclipse.org/bugs/show_bug.cgi?id=33927)
			}
			return (JavaModelOperation) stack.remove(size - 1);
		} else {
			return null;
		}
	}

	/*
	 * Registers the given action to be run when the outer most java model
	 * operation has finished. The insertion mode controls whether: - the action
	 * should discard all existing actions with the same id, and be queued at
	 * the end (REMOVEALL_APPEND), - the action should be ignored if there is
	 * already an action with the same id (KEEP_EXISTING), - the action should
	 * be queued at the end without looking at existing actions (APPEND)
	 */
	protected void postAction(IPostAction action, int insertionMode) {
		if (POST_ACTION_VERBOSE) {
			System.out
					.print("(" + Thread.currentThread() + ") [JavaModelOperation.postAction(IPostAction, int)] Posting action " + action.getID()); //$NON-NLS-1$ //$NON-NLS-2$
			switch (insertionMode) {
			case REMOVEALL_APPEND:
				System.out.println(" (REMOVEALL_APPEND)"); //$NON-NLS-1$
				break;
			case KEEP_EXISTING:
				System.out.println(" (KEEP_EXISTING)"); //$NON-NLS-1$
				break;
			case APPEND:
				System.out.println(" (APPEND)"); //$NON-NLS-1$
				break;
			}
		}

		JavaModelOperation topLevelOp = (JavaModelOperation) getCurrentOperationStack()
				.get(0);
		IPostAction[] postActions = topLevelOp.actions;
		if (postActions == null) {
			topLevelOp.actions = postActions = new IPostAction[1];
			postActions[0] = action;
			topLevelOp.actionsEnd = 0;
		} else {
			String id = action.getID();
			switch (insertionMode) {
			case REMOVEALL_APPEND:
				int index = this.actionsStart - 1;
				while ((index = topLevelOp.firstActionWithID(id, index + 1)) >= 0) {
					// remove action[index]
					System.arraycopy(postActions, index + 1, postActions,
							index, topLevelOp.actionsEnd - index);
					postActions[topLevelOp.actionsEnd--] = null;
				}
				topLevelOp.addAction(action);
				break;
			case KEEP_EXISTING:
				if (topLevelOp.firstActionWithID(id, 0) < 0) {
					topLevelOp.addAction(action);
				}
				break;
			case APPEND:
				topLevelOp.addAction(action);
				break;
			}
		}
	}

	/*
	 * Returns whether the given path is the prefix of one of the given other
	 * paths.
	 */
	protected boolean prefixesOneOf(IPath path, IPath[] otherPaths) {
		for (int i = 0, length = otherPaths.length; i < length; i++) {
			if (path.isPrefixOf(otherPaths[i])) {
				return true;
			}
		}
		return false;
	}

	/*
	 * Pushes the given operation on the stack of operations currently running
	 * in this thread.
	 */
	protected void pushOperation(JavaModelOperation operation) {
		getCurrentOperationStack().add(operation);
	}

	/**
	 * Main entry point for Java Model operations. Executes this operation and
	 * registers any deltas created.
	 * 
	 * @see IWorkspaceRunnable
	 * @exception CoreException
	 *                if the operation fails
	 */
	public void run(IProgressMonitor monitor) throws CoreException {
		JavaModelManager manager = JavaModelManager.getJavaModelManager();
		DeltaProcessor deltaProcessor = manager.getDeltaProcessor();
		int previousDeltaCount = deltaProcessor.javaModelDeltas.size();
		try {
			progressMonitor = monitor;
			pushOperation(this);
			try {
				// computes the root infos before executing the operation
				// noop if aready initialized
				JavaModelManager.getJavaModelManager().deltaState
						.initializeRoots();

				executeOperation();
			} finally {
				if (this.isTopLevelOperation()) {
					this.runPostActions();
				}
			}
		} finally {

			try {
				// update JavaModel using deltas that were recorded during this
				// operation
				for (int i = previousDeltaCount, size = manager.javaModelDeltas
						.size(); i < size; i++) {
					manager
							.updateJavaModel((IJavaElementDelta) manager.javaModelDeltas
									.get(i));
				}

				// fire only iff:
				// - the operation is a top level operation
				// - the operation did produce some delta(s)
				// - but the operation has not modified any resource
				if (this.isTopLevelOperation()) {
					if ((manager.javaModelDeltas.size() > previousDeltaCount || !manager.reconcileDeltas
							.isEmpty())
							&& !this.hasModifiedResource()) {
						manager.fire(null,
								JavaModelManager.DEFAULT_CHANGE_EVENT);
					} // else deltas are fired while processing the resource
						// delta
				}
			} finally {
				popOperation();
			}
		}
	}

	/**
	 * Main entry point for Java Model operations. Runs a Java Model Operation
	 * as an IWorkspaceRunnable if not read-only.
	 */
	public void runOperation(IProgressMonitor monitor)
			throws JavaModelException {
		IJavaModelStatus status = verify();
		if (!status.isOK()) {
			throw new JavaModelException(status);
		}
		try {
			if (isReadOnly()) {
				run(monitor);
			} else {
				// Use IWorkspace.run(...) to ensure that a build will be done
				// in autobuild mode.
				// Note that if the tree is locked, this will throw a
				// CoreException, but this is ok
				// as this operation is modifying the tree (not read-only) and a
				// CoreException will be thrown anyway.
				ResourcesPlugin.getWorkspace().run(this, getSchedulingRule(),
						IWorkspace.AVOID_UPDATE, monitor);
			}
		} catch (CoreException ce) {
			if (ce instanceof JavaModelException) {
				throw (JavaModelException) ce;
			} else {
				if (ce.getStatus().getCode() == IResourceStatus.OPERATION_FAILED) {
					Throwable e = ce.getStatus().getException();
					if (e instanceof JavaModelException) {
						throw (JavaModelException) e;
					}
				}
				throw new JavaModelException(ce);
			}
		}
	}

	protected void runPostActions() throws JavaModelException {
		while (this.actionsStart <= this.actionsEnd) {
			IPostAction postAction = this.actions[this.actionsStart++];
			if (POST_ACTION_VERBOSE) {
				System.out
						.println("(" + Thread.currentThread() + ") [JavaModelOperation.runPostActions()] Running action " + postAction.getID()); //$NON-NLS-1$ //$NON-NLS-2$
			}
			postAction.run();
		}
	}

	/*
	 * Registers the given attribute at the given key with the top level
	 * operation.
	 */
	protected void setAttribute(Object key, Object attribute) {
		JavaModelOperation topLevelOp = (JavaModelOperation) this
				.getCurrentOperationStack().get(0);
		if (topLevelOp.attributes == null) {
			topLevelOp.attributes = new HashMap();
		}
		topLevelOp.attributes.put(key, attribute);
	}

	/**
	 * @see IProgressMonitor
	 */
	public void setCanceled(boolean b) {
		if (progressMonitor != null) {
			progressMonitor.setCanceled(b);
		}
	}

	/**
	 * Sets whether this operation is nested or not.
	 * 
	 * @see CreateElementInCUOperation#checkCanceled
	 */
	protected void setNested(boolean nested) {
		isNested = nested;
	}

	/**
	 * @see IProgressMonitor
	 */
	public void setTaskName(String name) {
		if (progressMonitor != null) {
			progressMonitor.setTaskName(name);
		}
	}

	/**
	 * @see IProgressMonitor
	 */
	public void subTask(String name) {
		if (progressMonitor != null) {
			progressMonitor.subTask(name);
		}
	}

	/**
	 * Returns a status indicating if there is any known reason this operation
	 * will fail. Operations are verified before they are run.
	 * 
	 * Subclasses must override if they have any conditions to verify before
	 * this operation executes.
	 * 
	 * @see IJavaModelStatus
	 */
	protected IJavaModelStatus verify() {
		return commonVerify();
	}

	/**
	 * @see IProgressMonitor
	 */
	public void worked(int work) {
		if (progressMonitor != null) {
			progressMonitor.worked(work);
			checkCanceled();
		}
	}
}