org.eclipse.compare.structuremergeviewer.ICompareInput Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2000, 2011 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.compare.structuremergeviewer;
import org.eclipse.compare.ITypedElement;
import org.eclipse.swt.graphics.Image;
/**
* Interface for objects used as input to a two-way or three-way compare viewer.
* It defines API for accessing the three sides for the compare,
* and a name and image which is used when displaying the three way input
* in the UI, for example, in a title bar.
*
* Note: at most two sides of an {@code ICompareInput} can be {@code null},
* (as it is normal for additions or deletions) but not all three.
*
* {@code ICompareInput} provides methods for registering
* {@link ICompareInputChangeListener}s
* that get informed if one (or more)
* of the three sides of an {@code ICompareInput} object changes its value.
*
* For example when accepting an incoming addition
* the (non-{@code null}) left side of an {@code ICompareInput}
* is copied to the right side by means of method {@code copy}.
* This should trigger a call to {@link ICompareInputChangeListener#compareInputChanged} of registered
* {@link ICompareInputChangeListener}s.
*
* Clients can implement this interface, or use the convenience implementation
* {@link DiffNode}.
*
* @see StructureDiffViewer
* @see org.eclipse.compare.contentmergeviewer.ContentMergeViewer
* @see DiffNode
*/
public interface ICompareInput {
/**
* Returns name of input.
* This name is displayed when this input is shown in a viewer.
* In many cases this name is the name of one of the non-{@code null} sides or a combination
* thereof.
*
* @return name of input
*/
String getName();
/**
* Returns an image representing this input.
* This image is typically displayed when this input is shown in a viewer.
* In many cases this image is the image of one of the non-{@code null} sides.
*
* @return image representing this input, or {@code null} if no icon should be shown
*/
Image getImage();
/**
* Returns the kind of difference between the three sides ancestor, left and right.
* This field is only meaningful if the {@code ICompareInput} is the result of another
* compare. In this case it is used together with {@link #getImage()} to compose an icon
* which reflects the kind of difference between the two or three elements.
*
* @return kind of difference (see {@link Differencer})
*/
int getKind();
/**
* Returns the ancestor side of this input.
* Returns {@code null} if this input has no ancestor
* or in the two-way compare case.
*
* @return the ancestor of this input, or {@code null}
*/
ITypedElement getAncestor();
/**
* Returns the left side of this input.
* Returns {@code null} if there is no left side (deletion or addition).
*
* @return the left side of this input, or {@code null}
*/
ITypedElement getLeft();
/**
* Returns the right side of this input.
* Returns {@code null} if there is no right side (deletion or addition).
*
* @return the right side of this input, or {@code null}
*/
ITypedElement getRight();
/**
* Registers the given listener for notification.
* If the identical listener is already registered the method has no effect.
*
* @param listener the listener to register for changes of this input
*/
void addCompareInputChangeListener(ICompareInputChangeListener listener);
/**
* Unregisters the given listener.
* If the identical listener is not registered the method has no effect.
*
* @param listener the listener to unregister
*/
void removeCompareInputChangeListener(ICompareInputChangeListener listener);
/**
* Copy one side (source) to the other side (destination) depending on the
* value of {@code leftToRight}. This method is called from
* a merge viewer if a corresponding action ("take left" or "take right")
* has been pressed.
*
* The implementation should handle the following cases:
*
* -
* if the source side is {@code null} the destination must be deleted,
*
-
* if the destination is {@code null} the destination must be created
* and filled with the contents from the source,
*
-
* if both sides are non-{@code null} the contents of source must be copied to destination.
*
* In addition the implementation should send out notification to the registered
* {@link ICompareInputChangeListener}.
*
* @param leftToRight if {@code true} the left side is copied to the right side.
* If {@code false} the right side is copied to the left side
*/
void copy(boolean leftToRight);
}