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Diffstat (limited to 'xmerge/source/xmerge/java/org/openoffice/xmerge/merger/Difference.java')
| -rw-r--r-- | xmerge/source/xmerge/java/org/openoffice/xmerge/merger/Difference.java | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/xmerge/source/xmerge/java/org/openoffice/xmerge/merger/Difference.java b/xmerge/source/xmerge/java/org/openoffice/xmerge/merger/Difference.java new file mode 100644 index 000000000000..31977b36f377 --- /dev/null +++ b/xmerge/source/xmerge/java/org/openoffice/xmerge/merger/Difference.java @@ -0,0 +1,242 @@ +/************************************************************************* + * + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * Copyright 2000, 2010 Oracle and/or its affiliates. + * + * OpenOffice.org - a multi-platform office productivity suite + * + * This file is part of OpenOffice.org. + * + * OpenOffice.org is free software: you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License version 3 + * only, as published by the Free Software Foundation. + * + * OpenOffice.org is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License version 3 for more details + * (a copy is included in the LICENSE file that accompanied this code). + * + * You should have received a copy of the GNU Lesser General Public License + * version 3 along with OpenOffice.org. If not, see + * <http://www.openoffice.org/license.html> + * for a copy of the LGPLv3 License. + * + ************************************************************************/ + +package org.openoffice.xmerge.merger; + + +/** + * This is the <code>Difference</code> basic unit. Used by the + * <code>DiffAlgorithm</code> as a set of difference between two + * <code>Iterators</code> (the original and modified + * <code>Iterators</code>). + * + * @author smak + */ +public final class Difference { + + /** + * Add operation. + */ + public static final int ADD = 1; + + /** + * Delete operation. + */ + public static final int DELETE = 2; + + /** + * Change operation. + */ + public static final int CHANGE = 3; + + /** + * Unchange operation (i.e. no change). + */ + public static final int UNCHANGE = 4; + + /** + * The action of the diff - either {@link #ADD} or {@link #DELETE}. + */ + private int operation; + + /** + * <p>The position of the content that should be operated on (original + * iterator).</p> + * + * <p>For ADD, the orgPosition is the position of the original sequence + * where the diff will insert (the element count is starting from 0, and + * always insert before the element). The modPosition is the position + * of the diff in the modified sequence (also starting from 0).</p> + * + * <blockquote><pre> + * example: + * + * diff - <B D>and <A B C D E F> + * note: <B D>is original sequence and <A B C D E F> + * is the modified one. + * + * and here is the position of those sequence: + * <B D> <A B C D E F> + * 0 1 0 1 2 3 4 5 + * + * result: + * <diff orgPos=0 modPos=0 operation=ADD> <-- element A + * <diff orgPos=1 modPos=2 operation=ADD> <-- element C + * <diff orgPos=2 modPos=4 operation=ADD> <-- element E + * <diff orgPos=2 modPos=5 operation=ADD> <-- element F + * + * </pre> </blockquote> + * <p>One can notice the add operation is inserted before the position. + * Hence, in order to append an element, we will have a position of + * original sequence length + 1 to denote an append.</p> + * + * <p>For DELETE, orgPosition is the position that the element + * will be deleted (starting from 0) and modPosition is the position + * where the deleted element should be (consider as an ADD).</p> + * + * <p>The modPosition is less useful and it is difficult to understand + * how the position is calculated. One can just skip this piece of + * information. It is useful if one wants to reverse the role + * of original sequence and modified sequence and find out the diff + * easily (just change add to delete and delete to add for operation + * and swap the orgPosition and modPosition).</p> + * + * <blockquote><pre> + * example: + * + * diff - <A B C D E F> and < B D> + * note: <A B C D E F> is original sequence and <B D> + * is the modified one. + * + * and here is the position of those sequence: + * <A B C D E F> <B D> + * 0 1 2 3 4 5 0 1 + * + * result: + * <diff orgPos=0 modPos=0 operation=DELETE> <-- element A + * <diff orgPos=2 modPos=1 operation=DELETE> <-- element C + * <diff orgPos=4 modPos=2 operation=DELETE> <-- element E + * <diff orgPos=5 modPos=2 operation=DELETE> <-- element F + * </pre></blockquote> + */ + private int orgPosition; + + /** + * The position of the content that should be operated (modified iterator). + * For explanation and examples, see {@link #orgPosition}. + */ + private int modPosition; + + + /** + * Constructor. This is the standard way to create a + * <code>Difference</code> object. + * + * @param operation Either {@link #ADD} or {@link #DELETE}. + * @param orgPosition The position in the original (first) + * <code>Iterator</code>. + * @param modPosition The position in the modified (second) + * <code>Iterator</code>. + */ + public Difference(int operation, int orgPosition, + int modPosition) { + this.operation = operation; + this.orgPosition = orgPosition; + this.modPosition = modPosition; + } + + + /** + * Get the operation of the <code>Difference</code>. + * + * @return the operation of the <code>Difference</code>, + * either {@link #ADD} or {@link #DELETE} + */ + public int getOperation() { + return operation; + } + + /** + * Get the original <code>Iterator</code> position. + * + * @return The position in the original (first) <code>Iterator</code> + */ + public int getOrgPosition() { + return orgPosition; + } + + /** + * Get the modified <code>Iterator</code> position. + * + * @return The position in the modified (second) <code>Iterator</code> + */ + public int getModPosition() { + return modPosition; + } + + + /** + * Two <code>Difference</code> objects will equal if and only if + * all operation, orgPosition, modPosition and content are equal. + * + * @param obj Object to compare. + * + * @return true if equal, false otherwise. + */ + public boolean equals(Object obj) { + if (obj instanceof Difference) { + Difference diff = (Difference) obj; + if ((operation == diff.operation) && + (orgPosition == diff.orgPosition) && + (modPosition == diff.modPosition)) { + return true; + } + } + + return false; + } + + /** + * Display debug information. + * + * @return Debug string. + */ + public String debug() { + + String opStr = ""; + + switch (operation) { + case ADD: + opStr = "add"; + break; + case DELETE: + opStr = "del"; + break; + case CHANGE: + opStr = "chg"; + break; + case UNCHANGE: + opStr = "uch"; + break; + default: + break; + } + return "<diff orgPos=" + orgPosition + " modPos=" + modPosition + + " op=" + opStr + ">"; + } + + /** + * Returns position and operation values as a single string. + * + * @return orgPosition, modPosition and operation as a single string. + */ + public String toString() { + + return orgPosition + " " + modPosition + " " + operation; + } +} + |