org.sventon.util.RepositoryEntryComparator.java Source code

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Here is the source code for org.sventon.util.RepositoryEntryComparator.java

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/*
 * ====================================================================
 * Copyright (c) 2005-2010 sventon project. All rights reserved.
 *
 * This software is licensed as described in the file LICENSE, which
 * you should have received as part of this distribution. The terms
 * are also available at http://www.sventon.org.
 * If newer versions of this license are posted there, you may use a
 * newer version instead, at your option.
 * ====================================================================
 */
package org.sventon.util;

import org.apache.commons.lang.Validate;
import org.sventon.model.RepositoryEntry;

import java.io.Serializable;
import java.util.Comparator;
import java.util.Date;

/**
 * <code>java.util.Comparator&lt;T&gt;</code> implementation to support
 * ordering of <code>RepositoryEntry</code> objects.
 * <p/>
 * The comparator can be configured during construction to tweak sorting behavior.
 *
 * @author patrik@sventon.org
 * @author jesper@sventon.org
 */
public final class RepositoryEntryComparator implements Comparator<RepositoryEntry>, Serializable {

    private static final long serialVersionUID = -823291078109887289L;

    public enum SortType {
        NAME, AUTHOR, REVISION, DATE, FULL_NAME, SIZE
    }

    private boolean groupDirs = false;

    private final SortType sortType;

    /**
     * Create a new comparator for comparing <code>RepositoryEntry</code> objects.
     *
     * @param sortType  Entry type property to perform the comparisons on. See enum constants
     *                  defined in this class.
     * @param groupDirs <code>true</code> to group directories, this will sort an entry
     *                  of kind <code>SVNNodeKind.DIR</code> before an entries of other
     *                  kinds.
     */
    public RepositoryEntryComparator(final SortType sortType, final boolean groupDirs) {
        Validate.notNull(sortType, "sortType cannot be null");
        this.groupDirs = groupDirs;
        this.sortType = sortType;
    }

    /**
     * {@inheritDoc}
     */
    public int compare(final RepositoryEntry entry1, final RepositoryEntry entry2) {
        if (groupDirs) {
            final RepositoryEntry.Kind kind1 = entry1.getKind();
            final RepositoryEntry.Kind kind2 = entry2.getKind();
            if (kind1 != kind2) {
                // Not equal kinds, have to inspect.
                if (RepositoryEntry.Kind.DIR == kind1) {
                    return -1;
                } else if (RepositoryEntry.Kind.DIR == kind2) {
                    return 1;
                }
            } // not equal kind, but neither is DIR
        }

        final String entryName1 = entry1.getName();
        final String entryName2 = entry2.getName();

        // Natural ordering of strings as used below may not always be desirable?
        switch (sortType) {
        case NAME:
            final int nameCompare = nullSafeCompare(entryName1, entryName2);
            if (nameCompare == 0) {
                final long revision1 = entry1.getRevision();
                final long revision2 = entry2.getRevision();
                return revision1 == revision2 ? 0 : revision1 < revision2 ? -1 : 1;
            } else {
                return nameCompare;
            }
        case AUTHOR:
            final String author1 = entry1.getAuthor();
            final String author2 = entry2.getAuthor();
            final int authCompare = nullSafeCompare(author1, author2);
            return authCompare == 0 ? nullSafeCompare(entryName1, entryName2) : authCompare;
        case REVISION:
            final long revision1 = entry1.getRevision();
            final long revision2 = entry2.getRevision();
            if (revision1 == revision2) {
                return nullSafeCompare(entryName1, entryName2);
            } else {
                return revision1 < revision2 ? -1 : 1;
            }
        case SIZE:
            final long size1 = entry1.getSize();
            final long size2 = entry2.getSize();
            if (size1 == size2) {
                return nullSafeCompare(entryName1, entryName2);
            } else {
                return size1 < size2 ? -1 : 1;
            }
        case DATE:
            final Date date1 = entry1.getDate();
            final Date date2 = entry2.getDate();
            final int dateCompare = nullSafeCompare(date1, date2);
            return dateCompare == 0 ? nullSafeCompare(entryName1, entryName2) : dateCompare;
        case FULL_NAME:
            return nullSafeCompare(entry1.getFullEntryName(), entry2.getFullEntryName());
        default:
            throw new IllegalStateException("Illegal sort type: " + sortType);
        }
    }

    private <T> int nullSafeCompare(final Comparable<T> o1, final T o2) {
        if (o1 != null && o2 != null) {
            return o1.compareTo(o2);
        } else if (o1 == null && o2 == null) {
            return 0;
        } else {
            return o1 == null ? -1 : 1;
        }

    }
}