Copyright (c) 2000, 2013 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2000, 2013 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jdt.internal.core;

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

import org.eclipse.core.resources.*;
import org.eclipse.core.runtime.*;
import org.eclipse.core.runtime.jobs.ISchedulingRule;
import org.eclipse.jdt.core.*;
import org.eclipse.jdt.internal.core.util.Messages;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.text.edits.TextEdit;

Defines behavior common to all Java Model operations
/**
 * Defines behavior common to all Java Model operations
 */
@SuppressWarnings({"rawtypes", "unchecked"})
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 = JavaModelManager.TRUE;
	//public static final String FALSE = "false";

	
The elements this operation operates on,
or null if this operation
does not operate on specific elements.
/**
	 * The elements this operation operates on,
	 * or <code>null</code> if this operation
	 * does not operate on specific elements.
	 */
	protected IJavaElement[] elementsToProcess;
	
The parent elements this operation operates with
or null if this operation
does not operate with specific parent elements.
/**
	 * The parent elements this operation operates with
	 * or <code>null</code> if this operation
	 * does not operate with specific parent elements.
	 */
	protected IJavaElement[] parentElements;
	
An empty collection of IJavaElements - the common
empty result if no elements are created, or if this
operation is not actually executed.
/**
	 * 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 final IJavaElement[] NO_ELEMENTS= new IJavaElement[] {};


	
The elements created by this operation - empty
until the operation actually creates elements.
/**
	 * 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
/**
	 * The progress monitor passed into this operation
	 */
	public SubMonitor progressMonitor= SubMonitor.convert(null);
	
A flag indicating whether this operation is nested.
/**
	 * A flag indicating whether this operation is nested.
	 */
	protected boolean isNested = false;
	
Conflict resolution policy - by default do not force (fail on a conflict).
/**
	 * 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 final ThreadLocal OPERATION_STACKS = new ThreadLocal();
	protected JavaModelOperation() {
		// default constructor used in subclasses
	}
	
A common constructor for all Java Model operations.
/**
	 * A common constructor for all Java Model operations.
	 */
	protected JavaModelOperation(IJavaElement[] elements) {
		this.elementsToProcess = elements;
	}
	
Common constructor for all Java Model operations.
/**
	 * Common constructor for all Java Model operations.
	 */
	protected JavaModelOperation(IJavaElement[] elementsToProcess, IJavaElement[] parentElements) {
		this.elementsToProcess = elementsToProcess;
		this.parentElements= parentElements;
	}
	
A common constructor for all Java Model operations.
/**
	 * A common constructor for all Java Model operations.
	 */
	protected JavaModelOperation(IJavaElement[] elementsToProcess, IJavaElement[] parentElements, boolean force) {
		this.elementsToProcess = elementsToProcess;
		this.parentElements= parentElements;
		this.force= force;
	}
	
A common constructor for all Java Model operations.
/**
	 * A common constructor for all Java Model operations.
	 */
	protected JavaModelOperation(IJavaElement[] elements, boolean force) {
		this.elementsToProcess = elements;
		this.force= force;
	}

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

	/*
	 * 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().getDeltaProcessor().registerJavaModelDelta(delta);
	}
	/*
	 * Registers the given reconcile delta with the Java Model Manager.
	 */
	protected void addReconcileDelta(ICompilationUnit workingCopy, IJavaElementDelta delta) {
		Map<ICompilationUnit, IJavaElementDelta> reconcileDeltas = JavaModelManager.getJavaModelManager().getDeltaProcessor().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);
			}
			// note that the last delta's AST always takes precedence over the existing delta's AST
			// since it is the result of the last reconcile operation
			if ((delta.getFlags() & IJavaElementDelta.F_AST_AFFECTED) != 0) {
				previousDelta.changedAST(delta.getCompilationUnitAST());
			}

		} else {
			reconcileDeltas.put(workingCopy, delta);
		}
	}
	/*
	 * Deregister the reconcile delta for the given working copy
	 */
	protected void removeReconcileDelta(ICompilationUnit workingCopy) {
		JavaModelManager.getJavaModelManager().getDeltaProcessor().reconcileDeltas.remove(workingCopy);
	}
	protected void applyTextEdit(ICompilationUnit cu, TextEdit edits) throws JavaModelException {
		try {
			edits.apply(getDocument(cu));
		} catch (BadLocationException e) {
			// content changed under us
			throw new JavaModelException(e, IJavaModelStatusConstants.INVALID_CONTENTS);
		}
	}
	
See Also:
IProgressMonitor/**
	 * @see IProgressMonitor
	 */
	@Override
	public void beginTask(String name, int totalWork) {
		if (this.progressMonitor != null) {
			this.progressMonitor.beginTask(name, totalWork);
		}
	}
	/*
	 * Returns whether this operation can modify the package fragment roots.
	 */
	protected boolean canModifyRoots() {
		return false;
	}
	
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.
Throws:
OperationCanceledException – if cancelling the operation has been requested
See Also:
IProgressMonitor.isCanceled/**
	 * 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(Messages.operation_cancelled);
		}
	}
	
Common code used to verify the elements this operation is processing.
See Also:
verify.verify()/**
	 * Common code used to verify the elements this operation is processing.
	 * @see JavaModelOperation#verify()
	 */
	protected IJavaModelStatus commonVerify() {
		if (this.elementsToProcess == null || this.elementsToProcess.length == 0) {
			return new JavaModelStatus(IJavaModelStatusConstants.NO_ELEMENTS_TO_PROCESS);
		}
		for (int i = 0; i < this.elementsToProcess.length; i++) {
			if (this.elementsToProcess[i] == null) {
				return new JavaModelStatus(IJavaModelStatusConstants.NO_ELEMENTS_TO_PROCESS);
			}
		}
		return JavaModelStatus.VERIFIED_OK;
	}
	
Convenience method to copy resources
/**
	 * Convenience method to copy resources
	 */
	protected void copyResources(IResource[] resources, IPath container) throws JavaModelException {
		IProgressMonitor subProgressMonitor = getSubProgressMonitor(resources.length);
		IWorkspaceRoot root =  ResourcesPlugin.getWorkspace().getRoot();
		try {
			for (int i = 0, length = resources.length; i < length; i++) {
				IResource resource = resources[i];
				IPath destination = container.append(resource.getName());
				if (root.findMember(destination) == null) {
					resource.copy(destination, false, subProgressMonitor);
				}
			}
			setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}
	
Convenience method to create a file
/**
	 * Convenience method to create a file
	 */
	protected void createFile(IContainer folder, String name, InputStream contents, boolean forceFlag) throws JavaModelException {
		IFile file= folder.getFile(new Path(name));
		try {
			file.create(
				contents,
				forceFlag ? IResource.FORCE | IResource.KEEP_HISTORY : IResource.KEEP_HISTORY,
				getSubProgressMonitor(1));
				setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}
	
Convenience method to create a folder
/**
	 * Convenience method to create a folder
	 */
	protected void createFolder(IContainer parentFolder, String name, boolean forceFlag) 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(
				forceFlag ? IResource.FORCE | IResource.KEEP_HISTORY : IResource.KEEP_HISTORY,
				true, // local
				getSubProgressMonitor(1));
			setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}
	
Convenience method to delete an empty package fragment
/**
	 * Convenience method to delete an empty package fragment
	 */
	protected void deleteEmptyPackageFragment(
		IPackageFragment fragment,
		boolean forceFlag,
		IResource rootResource)
		throws JavaModelException {

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

		try {
			resource.delete(
				forceFlag ? IResource.FORCE | IResource.KEEP_HISTORY : IResource.KEEP_HISTORY,
				getSubProgressMonitor(1));
			setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
			while (resource instanceof IFolder) {
				// deleting a package: delete the parent if it is empty (e.g. 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(
						forceFlag ? IResource.FORCE | IResource.KEEP_HISTORY : IResource.KEEP_HISTORY,
						getSubProgressMonitor(1));
					setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
				} else {
					// we didn't delete the package, so its parent packages cannot be empty
					break;
				}
			}
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}
	
Convenience method to delete a resource
/**
	 * Convenience method to delete a resource
	 */
	protected void deleteResource(IResource resource,int flags) throws JavaModelException {
		try {
			resource.delete(flags, getSubProgressMonitor(1));
			setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}
	
Convenience method to delete resources
/**
	 * Convenience method to delete resources
	 */
	protected void deleteResources(IResource[] resources, boolean forceFlag) throws JavaModelException {
		if (resources == null || resources.length == 0) return;
		IProgressMonitor subProgressMonitor = getSubProgressMonitor(resources.length);
		IWorkspace workspace = resources[0].getWorkspace();
		try {
			workspace.delete(
				resources,
				forceFlag ? IResource.FORCE | IResource.KEEP_HISTORY : IResource.KEEP_HISTORY,
				subProgressMonitor);
				setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}
	
See Also:
IProgressMonitor/**
	 * @see IProgressMonitor
	 */
	@Override
	public void done() {
		if (this.progressMonitor != null) {
			this.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;
	}
	
Convenience method to run an operation within this operation
/**
	 * Convenience method to run an operation within this operation
	 */
	public void executeNestedOperation(JavaModelOperation operation, int subWorkAmount) throws JavaModelException {
		IJavaModelStatus status= operation.verify();
		if (!status.isOK()) {
			throw new JavaModelException(status);
		}
		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.
/**
	 * 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 static Object getAttribute(Object key) {
		ArrayList stack = 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 null.
/**
	 * 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 static ArrayList getCurrentOperationStack() {
		ArrayList stack = (ArrayList)OPERATION_STACKS.get();
		if (stack == null) {
			stack = new ArrayList();
			OPERATION_STACKS.set(stack);
		}
		return stack;
	}
	/*
	 * Returns the existing document for the given cu, or a DocumentAdapter if none.
	 */
	protected IDocument getDocument(ICompilationUnit cu) throws JavaModelException {
		IBuffer buffer = cu.getBuffer();
		if (buffer instanceof IDocument)
			return (IDocument) buffer;
		return new DocumentAdapter(buffer);
	}
	
Returns the element to which this operation applies,
or null if not applicable.
/**
	 * Returns the element to which this operation applies,
	 * or <code>null</code> if not applicable.
	 */
	protected IJavaElement getElementToProcess() {
		if (this.elementsToProcess == null || this.elementsToProcess.length == 0) {
			return null;
		}
		return this.elementsToProcess[0];
	}
	
Returns the Java Model this operation is operating in.
/**
	 * Returns the Java Model this operation is operating in.
	 */
	public IJavaModel getJavaModel() {
		return JavaModelManager.getJavaModelManager().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 null if not applicable.
/**
	 * Returns the parent element to which this operation applies,
	 * or <code>null</code> if not applicable.
	 */
	protected IJavaElement getParentElement() {
		if (this.parentElements == null || this.parentElements.length == 0) {
			return null;
		}
		return this.parentElements[0];
	}
	
Returns the parent elements to which this operation applies,
or null if not applicable.
/**
	 * Returns the parent elements to which this operation applies,
	 * or <code>null</code> if not applicable.
	 */
	protected IJavaElement[] getParentElements() {
		return this.parentElements;
	}
	
Returns the elements created by this operation.
/**
	 * Returns the elements created by this operation.
	 */
	public IJavaElement[] getResultElements() {
		return this.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.
/**
	 * Creates and returns a subprogress monitor if appropriate.
	 */
	protected IProgressMonitor getSubProgressMonitor(int workAmount) {
		return this.progressMonitor.split(workAmount);
	}

	
Returns whether this operation has performed any resource modifications.
Returns false if this operation has not been executed yet.
/**
	 * Returns whether this operation has performed any resource modifications.
	 * Returns false if this operation has not been executed yet.
	 */
	public boolean hasModifiedResource() {
		return !isReadOnly() && getAttribute(HAS_MODIFIED_RESOURCE_ATTR) == TRUE;
	}
	@Override
	public void internalWorked(double work) {
		if (this.progressMonitor != null) {
			this.progressMonitor.internalWorked(work);
		}
	}
	
See Also:
IProgressMonitor/**
	 * @see IProgressMonitor
	 */
	@Override
	public boolean isCanceled() {
		if (this.progressMonitor != null) {
			return this.progressMonitor.isCanceled();
		}
		return false;
	}
	
Returns true if this operation performs no resource modifications,
otherwise false. Subclasses must override.
/**
	 * 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 = 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
/**
	 * Convenience method to move resources
	 */
	protected void moveResources(IResource[] resources, IPath container) throws JavaModelException {
		SubMonitor subProgressMonitor = this.progressMonitor.newChild(resources.length);
		IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
		try {
			for (int i = 0, length = resources.length; i < length; i++) {
				IResource resource = resources[i];
				IPath destination = container.append(resource.getName());
				if (root.findMember(destination) == null) {
					resource.move(destination, false, subProgressMonitor.split(1));
				}
			}
			setAttribute(HAS_MODIFIED_RESOURCE_ATTR, TRUE);
		} catch (CoreException e) {
			throw new JavaModelException(e);
		}
	}
	
Creates and returns a new IJavaElementDelta
on the Java Model.
/**
	 * 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
				OPERATION_STACKS.set(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);
	}
	/*
	 * Removes all actions with the given id from the queue of post actions.
	 * Does nothing if no such action is in the queue.
	 */
	protected void removeAllPostAction(String actionID) {
		if (POST_ACTION_VERBOSE) {
			System.out.println("(" + Thread.currentThread() + ") [JavaModelOperation.removeAllPostAction(String)] Removing actions " + actionID); //$NON-NLS-1$ //$NON-NLS-2$
		}

		JavaModelOperation topLevelOp = (JavaModelOperation)getCurrentOperationStack().get(0);
		IPostAction[] postActions = topLevelOp.actions;
		if (postActions == null) return;
		int index = this.actionsStart-1;
		while ((index = topLevelOp.firstActionWithID(actionID, index+1)) >= 0) {
			// remove action[index]
			System.arraycopy(postActions, index+1, postActions, index, topLevelOp.actionsEnd - index);
			postActions[topLevelOp.actionsEnd--] = null;
		}
	}

	
Runs this operation and registers any deltas created.
Throws:
CoreException – if the operation fails
See Also:
IWorkspaceRunnable/**
	 * Runs this operation and registers any deltas created.
	 *
	 * @see IWorkspaceRunnable
	 * @exception CoreException if the operation fails
	 */
	@Override
	public void run(IProgressMonitor monitor) throws CoreException {
		SubMonitor oldMonitor = this.progressMonitor;
		try {
			JavaModelManager manager = JavaModelManager.getJavaModelManager();
			DeltaProcessor deltaProcessor = manager.getDeltaProcessor();
			int previousDeltaCount = deltaProcessor.javaModelDeltas.size();
			try {
				this.progressMonitor = SubMonitor.convert(monitor);
				pushOperation(this);
				try {
					if (canModifyRoots()) {
						// computes the root infos before executing the operation
						// noop if aready initialized
						JavaModelManager.getDeltaState().initializeRoots(false/*not initiAfterLoad*/);
					}

					executeOperation();
				} finally {
					if (isTopLevelOperation()) {
						runPostActions();
					}
				}
			} finally {
				try {
					// reacquire delta processor as it can have been reset during executeOperation()
					deltaProcessor = manager.getDeltaProcessor();

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

					// close the parents of the created elements and reset their project's cache (in case we are in an
					// IWorkspaceRunnable and the clients wants to use the created element's parent)
					// see https://bugs.eclipse.org/bugs/show_bug.cgi?id=83646
					for (int i = 0, length = this.resultElements.length; i < length; i++) {
						IJavaElement element = this.resultElements[i];
						Openable openable = (Openable) element.getOpenable();
						if (!(openable instanceof CompilationUnit) || !((CompilationUnit) openable).isWorkingCopy()) { // a working copy must remain a child of its parent even after a move
							((JavaElement) openable.getParent()).close();
						}
						switch (element.getElementType()) {
							case IJavaElement.PACKAGE_FRAGMENT_ROOT:
							case IJavaElement.PACKAGE_FRAGMENT:
								deltaProcessor.projectCachesToReset.add(element.getJavaProject());
								break;
						}
					}
					deltaProcessor.resetProjectCaches();

					// 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 (isTopLevelOperation()) {
						if ((deltaProcessor.javaModelDeltas.size() > previousDeltaCount || !deltaProcessor.reconcileDeltas.isEmpty())
								&& !hasModifiedResource()) {
							deltaProcessor.fire(null, DeltaProcessor.DEFAULT_CHANGE_EVENT);
						} // else deltas are fired while processing the resource delta
					}
				} finally {
					popOperation();
				}
			}
		} finally {
			if (monitor != null) {
				monitor.done();
			}
			this.progressMonitor = oldMonitor;
		}
	}
	
Main entry point for Java Model operations. Runs a Java Model Operation as an IWorkspaceRunnable
if not read-only.
/**
	 * 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 resource changes are batched
				// 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 static void setAttribute(Object key, Object attribute) {
		ArrayList operationStack = getCurrentOperationStack();
		if (operationStack.size() == 0)
			return;
		JavaModelOperation topLevelOp = (JavaModelOperation) operationStack.get(0);
		if (topLevelOp.attributes == null) {
			topLevelOp.attributes = new HashMap();
		}
		topLevelOp.attributes.put(key, attribute);
	}
	
See Also:
IProgressMonitor/**
	 * @see IProgressMonitor
	 */
	@Override
	public void setCanceled(boolean b) {
		if (this.progressMonitor != null) {
			this.progressMonitor.setCanceled(b);
		}
	}
	
Sets whether this operation is nested or not.
See Also:
checkCanceled.checkCanceled/**
	 * Sets whether this operation is nested or not.
	 * @see CreateElementInCUOperation#checkCanceled
	 */
	protected void setNested(boolean nested) {
		this.isNested = nested;
	}
	
See Also:
IProgressMonitor/**
	 * @see IProgressMonitor
	 */
	@Override
	public void setTaskName(String name) {
		if (this.progressMonitor != null) {
			this.progressMonitor.setTaskName(name);
		}
	}
	
See Also:
IProgressMonitor/**
	 * @see IProgressMonitor
	 */
	@Override
	public void subTask(String name) {
		if (this.progressMonitor != null) {
			this.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 Also:
IJavaModelStatus/**
	 * 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 Also:
IProgressMonitor/**
	 * @see IProgressMonitor
	 */
	@Override
	public void worked(int work) {
		if (this.progressMonitor != null) {
			this.progressMonitor.worked(work);
			checkCanceled();
		}
	}
}