http://www.eclipse.org/platform: Refactoring Core (Eclipse Foundation) 
Copyright (c) 2000, 2015 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, 2015 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.ltk.core.refactoring.participants;

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

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.NullProgressMonitor;
import org.eclipse.core.runtime.OperationCanceledException;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.SubProgressMonitor;

import org.eclipse.core.resources.IFile;

import org.eclipse.ltk.core.refactoring.IRefactoringCoreStatusCodes;
import org.eclipse.ltk.core.refactoring.RefactoringStatus;
import org.eclipse.ltk.internal.core.refactoring.Messages;
import org.eclipse.ltk.internal.core.refactoring.RefactoringCoreMessages;
import org.eclipse.ltk.internal.core.refactoring.RefactoringCorePlugin;


A context that is shared between the refactoring processor and all its
associated participants during condition checking.

 The context manages a set of IConditionCheckerobjects to collect condition checks that should be perform across all participants and the processor. For example validating if a file can be changed (see IWorkspace.validateEdit(IFile[], Object) should only be called once for all files modified by the processor and all participants. 



Note: this class is not intended to be extended by clients.



Since:3.0
@noextendThis class is not intended to be subclassed by clients.
/**
 * A context that is shared between the refactoring processor and all its
 * associated participants during condition checking.
 * <p>
 * The context manages a set of {@link IConditionChecker}objects to collect
 * condition checks that should be perform across all participants and the
 * processor. For example validating if a file can be changed (see
 * {@link org.eclipse.core.resources.IWorkspace#validateEdit(org.eclipse.core.resources.IFile[], java.lang.Object)}
 * should only be called once for all files modified by the processor and all
 * participants.
 * </p>
 * <p>
 * Note: this class is not intended to be extended by clients.
 * </p>
 *
 * @since 3.0
 *
 * @noextend This class is not intended to be subclassed by clients.
 */
public class CheckConditionsContext {

	private Map<Class<? extends IConditionChecker>, IConditionChecker> fCheckers= new HashMap<>();

	
Returns the condition checker of the given type.

Params:
  • clazz – the type of the condition checker
Returns:the condition checker or null if
 no checker is registered for the given type
/**
	 * Returns the condition checker of the given type.
	 *
	 * @param clazz the type of the condition checker
	 *
	 * @return the condition checker or <code>null</code> if
	 *  no checker is registered for the given type
	 */
	public <T extends IConditionChecker> T getChecker(Class<T> clazz) {
		return clazz.cast(fCheckers.get(clazz));
	}

	
Adds the given condition checker. An exception will be
thrown if a checker of the same type already exists in
this context.

Params:
  • checker – the checker to add
Throws:
/**
	 * Adds the given condition checker. An exception will be
	 * thrown if a checker of the same type already exists in
	 * this context.
	 *
	 * @param checker the checker to add
	 * @throws CoreException if a checker of the same type already
	 *  exists
	 */
	public void add(IConditionChecker checker) throws CoreException {
		IConditionChecker old= fCheckers.put(checker.getClass(), checker);
		if (old != null) {
			fCheckers.put(checker.getClass(), old);
			throw new CoreException(new Status(IStatus.ERROR, RefactoringCorePlugin.getPluginId(),
				IRefactoringCoreStatusCodes.CHECKER_ALREADY_EXISTS_IN_CONTEXT,
				Messages.format(RefactoringCoreMessages.CheckConditionContext_error_checker_exists, checker.getClass().toString()),
				null));
		}
	}

	
Checks the condition of all registered condition checkers and returns a
merge status result.

Params:
  • pm – a progress monitor or null if no progress
 reporting is desired
Throws:
Returns:the combined status result
/**
	 * Checks the condition of all registered condition checkers and returns a
	 * merge status result.
	 *
	 * @param pm a progress monitor or <code>null</code> if no progress
	 *  reporting is desired
	 *
	 * @return the combined status result
	 *
	 * @throws CoreException if an error occurs during condition checking
	 */
	public RefactoringStatus check(IProgressMonitor pm) throws CoreException {
		if (pm == null)
			pm= new NullProgressMonitor();
		RefactoringStatus result= new RefactoringStatus();
		mergeResourceOperationAndValidateEdit();
		List<IConditionChecker> values= new ArrayList<>(fCheckers.values());
		Collections.sort(values, new Comparator<IConditionChecker>() {
			@Override
			public int compare(IConditionChecker o1, IConditionChecker o2) {
				// Note there can only be one ResourceOperationChecker. So it
				// is save to not test the case that both objects are
				// ResourceOperationChecker
				if (o1 instanceof ResourceChangeChecker)
					return -1;
				if (o2 instanceof ResourceChangeChecker)
					return 1;
				return 0;
			}
		});
		pm.beginTask("", values.size()); //$NON-NLS-1$
		for (IConditionChecker checker : values) {
			result.merge(checker.check(new SubProgressMonitor(pm, 1)));
			if (pm.isCanceled())
				throw new OperationCanceledException();
		}
		return result;
	}

	private void mergeResourceOperationAndValidateEdit() throws CoreException {
		ValidateEditChecker validateEditChecker= getChecker(ValidateEditChecker.class);
		if (validateEditChecker == null)
			return;
		ResourceChangeChecker resourceChangeChecker= getChecker(ResourceChangeChecker.class);
		if (resourceChangeChecker == null)
			return;

		IFile[] changedFiles= resourceChangeChecker.getChangedFiles();
		validateEditChecker.addFiles(changedFiles);
	}
}