/*******************************************************************************
* Copyright (c) 2006, 2015 IBM Corporation 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:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.ui.navigator;
import java.util.Set;
/**
*
* To correctly implement pipelining you should implement
* {@link IPipelinedTreeContentProvider2} which provides the
* additional
* {@link IPipelinedTreeContentProvider2#hasChildren(Object)} method.
* This allows the calculation of hasChildren to match what will be provided in
* calculating the children. If you don't implement the hasChildren, you may get
* "false positive" hasChildrens which will result in a "+" indication in the
* tree in the event that the pipelined children calculation.
*
* The only reason these are two separate interfaces is historical.
*
* @since 3.2
*
*/
public interface IPipelinedTreeContentProvider extends ICommonContentProvider {
/**
* Intercept the children that would be contributed to the viewer and
* determine how to change the shape of those children. The set of children
* should be modified to contain the correct children to return to the
* viewer.
*
* @param aParent
* A parent from the viewer
* @param theCurrentChildren
* The set of children contributed thus far from upstream content
* providers.
*/
void getPipelinedChildren(Object aParent, Set theCurrentChildren);
/**
* Intercept the elements that would be contributed to the root of the
* viewer and determine how to change the shape of those children. The given
* set of elements should be modified to contain the correct elements to
* return to the viewer.
*
* @param anInput
* An input from the viewer
* @param theCurrentElements
* The set of children contributed thus far from upstream content
* providers.
*/
void getPipelinedElements(Object anInput, Set theCurrentElements);
/**
* Intercept requests for a parent of the given object.
*
* @param anObject
* The object being queried for a parent.
* @param aSuggestedParent
* The parent already suggested from upstream extensions.
* @return The intended parent from this pipelined content provider. If you
* wish to not influence the parent, then return the
* aSuggestedParent value.
*/
Object getPipelinedParent(Object anObject, Object aSuggestedParent);
/**
* Intercept attempts to add elements directly to the viewer.
*
* <p>
* For content extensions that reshape the structure of children in a
* viewer, their overridden extensions may sometimes use optimized refreshes
* to add elements to the tree. These attempts must be intercepted and
* mapped to the correct set of model elements in the overriding extension.
* Clients may add, remove, or modify elements in the given set of added
* children. Clients should return a set for downstream extensions to
* massage further.
* </p>
* <p>
* Clients may change what parent the reshaped elements are added to, so
* long as that parent is not the root of the viewer.
* </p>
* <p>
* Clients should never create their own pipeline shape modifications, but
* instead return the shape modification that was passed in with appropriate
* changes.
* </p>
* <p>
* <b>Clients should not call any of the add, remove, refresh, or update
* methods on the viewer from this method or any code invoked by the
* implementation of this method.</b>
* </p>
*
* @param anAddModification
* The shape modification which contains the current suggested
* parent and children. Clients may modify this parameter
* directly and return it as the new shape modification.
* @return The new shape modification to use. Clients should <b>never</b>
* return <b>null</b> from this method.
*/
PipelinedShapeModification interceptAdd(PipelinedShapeModification anAddModification);
/**
* Intercept attempts to remove elements directly from the viewer.
*
* <p>
* For content extensions that reshape the structure of children in a
* viewer, their overridden extensions may sometimes use optimized refreshes
* to remove elements to the tree. These attempts must be intercepted and
* mapped to the correct set of model elements in the overriding extension.
* Clients may add, remove, or modify elements in the given set of removed
* children. Clients should return a set for downstream extensions to
* massage further.
* </p>
* <p>
* The parent will be <b>null</b> for remove modifications.
* <p>
* Clients should never create their own pipeline shape modifications, but
* instead return the shape modification that was passed in with appropriate
* changes.
* </p>
* <p>
* <b>Clients should not call any of the add, remove, refresh, or update
* methods on the viewer from this method or any code invoked by the
* implementation of this method.</b>
* </p>
*
* @param aRemoveModification
* The shape modification which contains the current suggested
* parent and children. Clients may modify this parameter
* directly and return it as the new shape modification.
* @return The new shape modification to use. Clients should <b>never</b>
* return <b>null</b> from this method.
*/
PipelinedShapeModification interceptRemove(PipelinedShapeModification aRemoveModification);
/**
* Intercept calls to viewer <code>refresh()</code> methods.
*
* <p>
* Clients may modify the given update to add or remove the elements to be
* refreshed. Clients may return the same instance that was passed in for
* the next downstream extension.
* </p>
*
* <p>
* <b>Clients should not call any of the add, remove, refresh, or update
* methods on the viewer from this method or any code invoked by the
* implementation of this method.</b>
* </p>
*
* @param aRefreshSynchronization
* The (current) refresh update to execute against the viewer.
* @return True if the viewer update was modified.
*/
boolean interceptRefresh(PipelinedViewerUpdate aRefreshSynchronization);
/**
* Intercept calls to viewer <code>update()</code> methods.
*
* <p>
* Clients may modify the given update to add or remove the elements to be
* updated. Clients may also add or remove properties for the given targets
* to optimize the refresh. Clients may return the same instance that was
* passed in for the next downstream extension.
* </p>
*
* <p>
* <b>Clients should not call any of the add, remove, refresh, or update
* methods on the viewer from this method or any code invoked by the
* implementation of this method.</b>
* </p>
*
* @param anUpdateSynchronization
* The (current) update to execute against the viewer.
* @return True if the viewer update was modified.
*/
boolean interceptUpdate(PipelinedViewerUpdate anUpdateSynchronization);
}