public RolloverDescription rollover()

in log4j-core/src/main/java/org/apache/logging/log4j/core/appender/rolling/DefaultRolloverStrategy.java [559:638]
70 lines of code
12 McCabe index (conditional complexity)

    public RolloverDescription rollover(final RollingFileManager manager) throws SecurityException {
        int fileIndex;
        final StringBuilder buf = new StringBuilder(255);
        if (minIndex == Integer.MIN_VALUE) {
            final SortedMap<Integer, Path> eligibleFiles = getEligibleFiles(manager);
            fileIndex = eligibleFiles.size() > 0 ? eligibleFiles.lastKey() + 1 : 1;
            manager.getPatternProcessor().formatFileName(strSubstitutor, buf, fileIndex);
        } else {
            if (maxIndex < 0) {
                return null;
            }
            final long startNanos = System.nanoTime();
            fileIndex = purge(minIndex, maxIndex, manager);
            if (fileIndex < 0) {
                return null;
            }
            manager.getPatternProcessor().formatFileName(strSubstitutor, buf, fileIndex);
            if (LOGGER.isTraceEnabled()) {
                final double durationMillis = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNanos);
                LOGGER.trace("DefaultRolloverStrategy.purge() took {} milliseconds", durationMillis);
            }
        }

        final String currentFileName = manager.getFileName();

        String renameTo = buf.toString();
        final String compressedName = renameTo;
        Action compressAction = null;

        final FileExtension fileExtension = manager.getFileExtension();
        if (fileExtension != null) {
            final File renameToFile = new File(renameTo);
            renameTo = renameTo.substring(0, renameTo.length() - fileExtension.length());
            if (tempCompressedFilePattern != null) {
                buf.delete(0, buf.length());
                tempCompressedFilePattern.formatFileName(strSubstitutor, buf, fileIndex);
                final String tmpCompressedName = buf.toString();
                final File tmpCompressedNameFile = new File(tmpCompressedName);
                final File parentFile = tmpCompressedNameFile.getParentFile();
                if (parentFile != null) {
                    parentFile.mkdirs();
                }
                compressAction = new CompositeAction(
                        Arrays.asList(
                                fileExtension.createCompressAction(renameTo, tmpCompressedName, true, compressionLevel),
                                new FileRenameAction(tmpCompressedNameFile, renameToFile, true)),
                        true);
            } else {
                compressAction = fileExtension.createCompressAction(renameTo, compressedName, true, compressionLevel);
            }
        }

        if (currentFileName.equals(renameTo)) {
            LOGGER.warn("Attempt to rename file {} to itself will be ignored", currentFileName);
            return new RolloverDescriptionImpl(currentFileName, false, null, null);
        }

        if (compressAction != null && manager.isAttributeViewEnabled()) {
            // Propagate POSIX attribute view to compressed file
            // @formatter:off
            final Action posixAttributeViewAction = PosixViewAttributeAction.newBuilder()
                    .withBasePath(compressedName)
                    .withFollowLinks(false)
                    .withMaxDepth(1)
                    .withPathConditions(PathCondition.EMPTY_ARRAY)
                    .withSubst(getStrSubstitutor())
                    .withFilePermissions(manager.getFilePermissions())
                    .withFileOwner(manager.getFileOwner())
                    .withFileGroup(manager.getFileGroup())
                    .build();
            // @formatter:on
            compressAction = new CompositeAction(Arrays.asList(compressAction, posixAttributeViewAction), false);
        }

        final FileRenameAction renameAction =
                new FileRenameAction(new File(currentFileName), new File(renameTo), manager.isRenameEmptyFiles());

        final Action asyncAction = merge(compressAction, customActions, stopCustomActionsOnError);
        return new RolloverDescriptionImpl(currentFileName, false, renameAction, asyncAction);
    }