Copyright (c) 2005, 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
    James Blackburn (Broadcom Corp.) - ongoing development
    Lars Vogel  - Bug 473427
/*******************************************************************************
 * Copyright (c) 2005, 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
 *     James Blackburn (Broadcom Corp.) - ongoing development
 *     Lars Vogel <Lars.Vogel@vogella.com> - Bug 473427
 *******************************************************************************/
package org.eclipse.core.resources.mapping;

import java.util.*;
import org.eclipse.core.internal.resources.mapping.ModelProviderManager;
import org.eclipse.core.resources.*;
import org.eclipse.core.runtime.*;

Represents the provider of a logical model. The main purpose of this
API is to support batch operations on sets of ResourceMapping
objects that are part of the same model.

This class may be subclassed by clients.

See Also:
ResourceMapping
Since:
3.2/**
 * Represents the provider of a logical model. The main purpose of this
 * API is to support batch operations on sets of <code>ResourceMapping</code>
 * objects that are part of the same model.
 *
 * <p>
 * This class may be subclassed by clients.
 * </p>
 * @see org.eclipse.core.resources.mapping.ResourceMapping
 * @since 3.2
 */
public abstract class ModelProvider extends PlatformObject {
	
The model provider id of the Resources model.
/**
	 * The model provider id of the Resources model.
	 */
	public static final String RESOURCE_MODEL_PROVIDER_ID = "org.eclipse.core.resources.modelProvider"; //$NON-NLS-1$

	private IModelProviderDescriptor descriptor;

	
Returns the descriptor for the model provider of the given id
or null if the provider has not been registered.
Params:
id – a model provider id.
Returns:
the descriptor for the model provider of the given id
or null if the provider has not been registered/**
	 * Returns the descriptor for the model provider of the given id
	 * or <code>null</code> if the provider has not been registered.
	 * @param id a model provider id.
	 * @return the descriptor for the model provider of the given id
	 * or <code>null</code> if the provider has not been registered
	 */
	public static IModelProviderDescriptor getModelProviderDescriptor(String id) {
		IModelProviderDescriptor[] descs = ModelProviderManager.getDefault().getDescriptors();
		for (IModelProviderDescriptor descriptor : descs) {
			if (descriptor.getId().equals(id)) {
				return descriptor;
			}
		}
		return null;
	}

	
Returns the descriptors for all model providers that are registered.
Returns:
the descriptors for all model providers that are registered./**
	 * Returns the descriptors for all model providers that are registered.
	 *
	 * @return the descriptors for all model providers that are registered.
	 */
	public static IModelProviderDescriptor[] getModelProviderDescriptors() {
		return ModelProviderManager.getDefault().getDescriptors();
	}

	@Override
	public boolean equals(Object obj) {
		if (obj instanceof ModelProvider) {
			ModelProvider other = (ModelProvider) obj;
			return other.getDescriptor().getId().equals(getDescriptor().getId());
		}
		return super.equals(obj);
	}

	
Returns the descriptor of this model provider. The descriptor
is set during initialization so implements cannot call this method
until after the initialize method is invoked.
Returns:
the descriptor of this model provider/**
	 * Returns the descriptor of this model provider. The descriptor
	 * is set during initialization so implements cannot call this method
	 * until after the <code>initialize</code> method is invoked.
	 * @return the descriptor of this model provider
	 */
	public final IModelProviderDescriptor getDescriptor() {
		return descriptor;
	}

	
Returns the unique identifier of this model provider.

The model provider identifier is composed of the model provider's
plug-in id and the simple id of the provider extension. For example, if
plug-in "com.xyz" defines a provider extension with id
"myModelProvider", the unique model provider identifier will be
"com.xyz.myModelProvider".

Returns:
the unique model provider identifier/**
	 * Returns the unique identifier of this model provider.
	 * <p>
	 * The model provider identifier is composed of the model provider's
	 * plug-in id and the simple id of the provider extension. For example, if
	 * plug-in <code>"com.xyz"</code> defines a provider extension with id
	 * <code>"myModelProvider"</code>, the unique model provider identifier will be
	 * <code>"com.xyz.myModelProvider"</code>.
	 * </p>
	 *
	 * @return the unique model provider identifier
	 */
	public final String getId() {
		return descriptor.getId();
	}

	
Returns the resource mappings that cover the given resource. By default, an empty array is returned. Subclass may override this method but should consider overriding either getMappings(IResource[], ResourceMappingContext, IProgressMonitor) or getMappings(ResourceTraversal[], ResourceMappingContext, IProgressMonitor) if more context is needed to determine the proper mappings. 
Params:
resource – the resource
context – a resource mapping context
monitor – a progress monitor, or null if progress
    reporting is not desired
Throws:
CoreException – 
Returns:
the resource mappings that cover the given resource./**
	 * Returns the resource mappings that cover the given resource.
	 * By default, an empty array is returned. Subclass may override
	 * this method but should consider overriding either
	 * {@link #getMappings(IResource[], ResourceMappingContext, IProgressMonitor)}
	 * or {@link #getMappings(ResourceTraversal[], ResourceMappingContext, IProgressMonitor)}
	 * if more context is needed to determine the proper mappings.
	 *
	 * @param resource the resource
	 * @param context a resource mapping context
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *     reporting is not desired
	 * @return the resource mappings that cover the given resource.
	 * @exception CoreException
	 */
	public ResourceMapping[] getMappings(IResource resource, ResourceMappingContext context, IProgressMonitor monitor) throws CoreException {
		return new ResourceMapping[0];
	}

	
Returns the set of mappings that cover the given resources.
This method is used to map operations on resources to
operations on resource mappings. By default, this method
calls getMapping(IResource) for each resource.

Subclasses may override this method.

Params:
resources – the resources
context – a resource mapping context
monitor – a progress monitor, or null if progress
    reporting is not desired
Throws:
CoreException – 
Returns:
the set of mappings that cover the given resources/**
	 * Returns the set of mappings that cover the given resources.
	 * This method is used to map operations on resources to
	 * operations on resource mappings. By default, this method
	 * calls <code>getMapping(IResource)</code> for each resource.
	 * <p>
	 * Subclasses may override this method.
	 * </p>
	 *
	 * @param resources the resources
	 * @param context a resource mapping context
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *     reporting is not desired
	 * @return the set of mappings that cover the given resources
	 * @exception CoreException
	 */
	public ResourceMapping[] getMappings(IResource[] resources, ResourceMappingContext context, IProgressMonitor monitor) throws CoreException {
		Set<ResourceMapping> mappings = new HashSet<>();
		for (IResource resource : resources) {
			ResourceMapping[] resourceMappings = getMappings(resource, context, monitor);
			if (resourceMappings.length > 0)
				mappings.addAll(Arrays.asList(resourceMappings));
		}
		return mappings.toArray(new ResourceMapping[mappings.size()]);
	}

	
Returns the set of mappings that overlap with the given resource traversals. This method is used to map operations on resources to operations on resource mappings. By default, this method calls getMappings(IResource[], ResourceMappingContext, IProgressMonitor) with the resources extracted from each traversal. 

Subclasses may override this method.

Params:
traversals – the traversals
context – a resource mapping context
monitor – a progress monitor, or null if progress
    reporting is not desired
Returns:
the set of mappings that overlap with the given resource traversals/**
	 * Returns the set of mappings that overlap with the given resource traversals.
	 * This method is used to map operations on resources to
	 * operations on resource mappings. By default, this method
	 * calls {@link #getMappings(IResource[], ResourceMappingContext, IProgressMonitor)}
	 * with the resources extracted from each traversal.
	 * <p>
	 * Subclasses may override this method.
	 * </p>
	 *
	 * @param traversals the traversals
	 * @param context a resource mapping context
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *     reporting is not desired
	 * @return the set of mappings that overlap with the given resource traversals
	 */
	public ResourceMapping[] getMappings(ResourceTraversal[] traversals, ResourceMappingContext context, IProgressMonitor monitor) throws CoreException {
		Set<ResourceMapping> result = new HashSet<>();
		for (ResourceTraversal traversal : traversals) {
			ResourceMapping[] mappings = getMappings(traversal.getResources(), context, monitor);
			result.addAll(Arrays.asList(mappings));
		}
		return result.toArray(new ResourceMapping[result.size()]);
	}

	
Returns a set of traversals that cover the given resource mappings. The
provided mappings must be from this provider or one of the providers this
provider extends.

The default implementation accumulates the traversals from the given
mappings. Subclasses can override to provide a more optimal
transformation.

Params:
mappings – the mappings being mapped to resources
context – the context used to determine the set of traversals that
    cover the mappings
monitor – a progress monitor, or null if progress
    reporting is not desired
Throws:
CoreException – 
Returns:
a set of traversals that cover the given mappings/**
	 * Returns a set of traversals that cover the given resource mappings. The
	 * provided mappings must be from this provider or one of the providers this
	 * provider extends.
	 * <p>
	 * The default implementation accumulates the traversals from the given
	 * mappings. Subclasses can override to provide a more optimal
	 * transformation.
	 * </p>
	 *
	 * @param mappings the mappings being mapped to resources
	 * @param context the context used to determine the set of traversals that
	 *     cover the mappings
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *     reporting is not desired
	 * @return a set of traversals that cover the given mappings
	 * @exception CoreException
	 */
	public ResourceTraversal[] getTraversals(ResourceMapping[] mappings, ResourceMappingContext context, IProgressMonitor monitor) throws CoreException {
		SubMonitor subMonitor = SubMonitor.convert(monitor, mappings.length);
		List<ResourceTraversal> traversals = new ArrayList<>();
		for (ResourceMapping mapping : mappings) {
			Collections.addAll(traversals, mapping.getTraversals(context, subMonitor.newChild(1)));
		}
		return traversals.toArray(new ResourceTraversal[traversals.size()]);
	}

	@Override
	public int hashCode() {
		return getDescriptor().getId().hashCode();
	}

	
This method is called by the model provider framework when the model
provider is instantiated. This method should not be called by clients and
cannot be overridden by subclasses. However, it invokes the
initialize method once the descriptor is set so subclasses
can override that method if they need to do additional initialization.
Params:
desc – the description of the provider as it appears in the plugin manifest
@noreference
This method is not intended to be referenced by clients./**
	 * This method is called by the model provider framework when the model
	 * provider is instantiated. This method should not be called by clients and
	 * cannot be overridden by subclasses. However, it invokes the
	 * <code>initialize</code> method once the descriptor is set so subclasses
	 * can override that method if they need to do additional initialization.
	 *
	 * @param desc the description of the provider as it appears in the plugin manifest
	 * @noreference This method is not intended to be referenced by clients.
	 */
	public final void init(IModelProviderDescriptor desc) {
		if (descriptor != null) {
			// prevent subsequent calls from damaging this instance
			return;
		}
		descriptor = desc;
		initialize();
	}

	
Initialization method that is called after the descriptor
of this provider is set. Subclasses may override.
/**
	 * Initialization method that is called after the descriptor
	 * of this provider is set. Subclasses may override.
	 */
	protected void initialize() {
		// Do nothing
	}

	
Validates the proposed changes contained in the given delta.
 This method must return either a ModelStatus, or a MultiStatus whose children are ModelStatus. The severity of the returned status indicates the severity of the possible side-effects of the operation. Any severity other than OK will be shown to the user. The
message should be a human readable message that will allow the user to
make a decision on whether to continue with the operation. The model
provider id should indicate which model is flagging the possible side effects.

This default implementation accepts all changes and returns a status with
severity OK. Subclasses should override to perform
validation specific to their model.

Params:
delta – a delta tree containing the proposed changes
monitor – a progress monitor, or null if progress
    reporting is not desired
Returns:
a status indicating any potential side effects
    on the model that provided this validator./**
	 * Validates the proposed changes contained in the given delta.
	 * <p>
	 * This method must return either a {@link ModelStatus}, or a {@link MultiStatus}
	 * whose children are {@link ModelStatus}. The severity of the returned status
	 * indicates the severity of the possible side-effects of the operation.  Any
	 * severity other than <code>OK</code> will be shown to the user. The
	 * message should be a human readable message that will allow the user to
	 * make a decision on whether to continue with the operation. The model
	 * provider id should indicate which model is flagging the possible side effects.
	 * <p>
	 * This default implementation accepts all changes and returns a status with
	 * severity <code>OK</code>. Subclasses should override to perform
	 * validation specific to their model.
	 * </p>
	 *
	 * @param delta a delta tree containing the proposed changes
	 * @param monitor a progress monitor, or <code>null</code> if progress
	 *     reporting is not desired
	 * @return a status indicating any potential side effects
	 *     on the model that provided this validator.
	 */
	public IStatus validateChange(IResourceDelta delta, IProgressMonitor monitor) {
		return new ModelStatus(IStatus.OK, ResourcesPlugin.PI_RESOURCES, descriptor.getId(), Status.OK_STATUS.getMessage());
	}
}