databasefilesystem.java

来自「jsr170接口的java实现。是个apache的开源项目。」· Java 代码 · 共 1,559 行 · 第 1/4 页

            ResultSet rs = null;
            try {
                Statement stmt = executeStmt(
                        selectFolderExistSQL, new Object[]{parentDir, name});
                rs = stmt.getResultSet();

                // a folder exists if the result set has at least one entry
                return rs.next();
            } catch (SQLException e) {
                String msg = "failed to check existence of folder: " + path;
                log.error(msg, e);
                throw new FileSystemException(msg, e);
            } finally {
                closeResultSet(rs);
            }
        }
    }

    /**
     * {@inheritDoc}
     */
    public long lastModified(String path) throws FileSystemException {
        if (!initialized) {
            throw new IllegalStateException("not initialized");
        }

        FileSystemPathUtil.checkFormat(path);

        String parentDir = FileSystemPathUtil.getParentDir(path);
        String name = FileSystemPathUtil.getName(path);

        synchronized (selectLastModifiedSQL) {
            ResultSet rs = null;
            try {
                Statement stmt = executeStmt(
                        selectLastModifiedSQL, new Object[]{parentDir, name});
                rs = stmt.getResultSet();
                if (!rs.next()) {
                    throw new FileSystemException("no such file system entry: " + path);
                }
                return rs.getLong(1);
            } catch (SQLException e) {
                String msg = "failed to determine lastModified of file system entry: " + path;
                log.error(msg, e);
                throw new FileSystemException(msg, e);
            } finally {
                closeResultSet(rs);
            }
        }
    }

    /**
     * {@inheritDoc}
     */
    public long length(String filePath) throws FileSystemException {
        if (!initialized) {
            throw new IllegalStateException("not initialized");
        }

        FileSystemPathUtil.checkFormat(filePath);

        String parentDir = FileSystemPathUtil.getParentDir(filePath);
        String name = FileSystemPathUtil.getName(filePath);

        synchronized (selectLengthSQL) {
            ResultSet rs = null;
            try {
                Statement stmt = executeStmt(
                        selectLengthSQL, new Object[]{parentDir, name});
                rs = stmt.getResultSet();
                if (!rs.next()) {
                    throw new FileSystemException("no such file: " + filePath);
                }
                return rs.getLong(1);
            } catch (SQLException e) {
                String msg = "failed to determine length of file: " + filePath;
                log.error(msg, e);
                throw new FileSystemException(msg, e);
            } finally {
                closeResultSet(rs);
            }
        }
    }

    /**
     * {@inheritDoc}
     */
    public boolean hasChildren(String path) throws FileSystemException {
        if (!initialized) {
            throw new IllegalStateException("not initialized");
        }

        FileSystemPathUtil.checkFormat(path);

        if (!exists(path)) {
            throw new FileSystemException("no such file system entry: " + path);
        }

        synchronized (selectChildCountSQL) {
            ResultSet rs = null;
            try {
                Statement stmt = executeStmt(selectChildCountSQL, new Object[]{path});
                rs = stmt.getResultSet();
                if (!rs.next()) {
                    return false;
                }
                int count = rs.getInt(1);
                if (FileSystemPathUtil.denotesRoot(path)) {
                    // ingore file system root entry
                    count--;
                }
                return (count > 0);
            } catch (SQLException e) {
                String msg = "failed to determine child count of file system entry: " + path;
                log.error(msg, e);
                throw new FileSystemException(msg, e);
            } finally {
                closeResultSet(rs);
            }
        }
    }

    /**
     * {@inheritDoc}
     */
    public String[] list(String folderPath) throws FileSystemException {
        if (!initialized) {
            throw new IllegalStateException("not initialized");
        }

        FileSystemPathUtil.checkFormat(folderPath);

        if (!isFolder(folderPath)) {
            throw new FileSystemException("no such folder: " + folderPath);
        }

        synchronized (selectFileAndFolderNamesSQL) {
            ResultSet rs = null;
            try {
                Statement stmt = executeStmt(
                        selectFileAndFolderNamesSQL, new Object[]{folderPath});
                rs = stmt.getResultSet();
                ArrayList names = new ArrayList();
                while (rs.next()) {
                    String name = rs.getString(1);
                    if (name.length() == 0
                            && FileSystemPathUtil.denotesRoot(folderPath)) {
                        // this is the file system root entry, skip...
                        continue;
                    }
                    names.add(name);
                }
                return (String[]) names.toArray(new String[names.size()]);
            } catch (SQLException e) {
                String msg = "failed to list child entries of folder: " + folderPath;
                log.error(msg, e);
                throw new FileSystemException(msg, e);
            } finally {
                closeResultSet(rs);
            }
        }
    }

    /**
     * {@inheritDoc}
     */
    public String[] listFiles(String folderPath) throws FileSystemException {
        if (!initialized) {
            throw new IllegalStateException("not initialized");
        }

        FileSystemPathUtil.checkFormat(folderPath);

        if (!isFolder(folderPath)) {
            throw new FileSystemException("no such folder: " + folderPath);
        }

        synchronized (selectFileNamesSQL) {
            ResultSet rs = null;
            try {
                Statement stmt = executeStmt(
                        selectFileNamesSQL, new Object[]{folderPath});
                rs = stmt.getResultSet();
                ArrayList names = new ArrayList();
                while (rs.next()) {
                    names.add(rs.getString(1));
                }
                return (String[]) names.toArray(new String[names.size()]);
            } catch (SQLException e) {
                String msg = "failed to list file entries of folder: " + folderPath;
                log.error(msg, e);
                throw new FileSystemException(msg, e);
            } finally {
                closeResultSet(rs);
            }
        }
    }

    /**
     * {@inheritDoc}
     */
    public String[] listFolders(String folderPath) throws FileSystemException {
        if (!initialized) {
            throw new IllegalStateException("not initialized");
        }

        FileSystemPathUtil.checkFormat(folderPath);

        if (!isFolder(folderPath)) {
            throw new FileSystemException("no such folder: " + folderPath);
        }

        synchronized (selectFolderNamesSQL) {
            ResultSet rs = null;
            try {
                Statement stmt = executeStmt(
                        selectFolderNamesSQL, new Object[]{folderPath});
                rs = stmt.getResultSet();
                ArrayList names = new ArrayList();
                while (rs.next()) {
                    String name = rs.getString(1);
                    if (name.length() == 0
                            && FileSystemPathUtil.denotesRoot(folderPath)) {
                        // this is the file system root entry, skip...
                        continue;
                    }
                    names.add(name);
                }
                return (String[]) names.toArray(new String[names.size()]);
            } catch (SQLException e) {
                String msg = "failed to list folder entries of folder: " + folderPath;
                log.error(msg, e);
                throw new FileSystemException(msg, e);
            } finally {
                closeResultSet(rs);
            }
        }
    }

    /**
     * {@inheritDoc}
     */
    public void touch(String filePath) throws FileSystemException {
        if (!initialized) {
            throw new IllegalStateException("not initialized");
        }

        FileSystemPathUtil.checkFormat(filePath);

        String parentDir = FileSystemPathUtil.getParentDir(filePath);
        String name = FileSystemPathUtil.getName(filePath);

        int count = 0;
        synchronized (updateLastModifiedSQL) {
            try {
                Statement stmt = executeStmt(updateLastModifiedSQL, new Object[]{
                        new Long(System.currentTimeMillis()),
                        parentDir,
                        name});
                count = stmt.getUpdateCount();
            } catch (SQLException e) {
                String msg = "failed to touch file: " + filePath;
                log.error(msg, e);
                throw new FileSystemException(msg, e);
            }
        }

        if (count == 0) {
            throw new FileSystemException("no such file: " + filePath);
        }
    }

    /**
     * {@inheritDoc}
     */
    public InputStream getInputStream(String filePath) throws FileSystemException {
        if (!initialized) {
            throw new IllegalStateException("not initialized");
        }

        FileSystemPathUtil.checkFormat(filePath);

        String parentDir = FileSystemPathUtil.getParentDir(filePath);
        String name = FileSystemPathUtil.getName(filePath);

        synchronized (selectDataSQL) {
            try {
                Statement stmt = executeStmt(
                        selectDataSQL, new Object[]{parentDir, name});

                final ResultSet rs = stmt.getResultSet();
                if (!rs.next()) {
                    throw new FileSystemException("no such file: " + filePath);
                }
                InputStream in = rs.getBinaryStream(1);
                /**
                 * return an InputStream wrapper in order to
                 * close the ResultSet when the stream is closed
                 */
                return new FilterInputStream(in) {
                    public void close() throws IOException {
                        super.close();
                        // close ResultSet
                        closeResultSet(rs);
                    }
                };
            } catch (SQLException e) {
                String msg = "failed to retrieve data of file: " + filePath;
                log.error(msg, e);
                throw new FileSystemException(msg, e);
            }
        }
    }

    /**
     * {@inheritDoc}
     */
    public OutputStream getOutputStream(final String filePath)
            throws FileSystemException {
        if (!initialized) {
            throw new IllegalStateException("not initialized");
        }

        FileSystemPathUtil.checkFormat(filePath);

        final String parentDir = FileSystemPathUtil.getParentDir(filePath);
        final String name = FileSystemPathUtil.getName(filePath);

        if (!isFolder(parentDir)) {
            throw new FileSystemException("path not found: " + parentDir);
        }

        if (isFolder(filePath)) {
            throw new FileSystemException("path denotes folder: " + filePath);
        }

        try {
            TransientFileFactory fileFactory = TransientFileFactory.getInstance();
            final File tmpFile = fileFactory.createTransientFile("bin", null, null);

            return new FilterOutputStream(new FileOutputStream(tmpFile)) {

                public void close() throws IOException {
                    super.close();

                    InputStream in = null;
                    try {
                        if (isFile(filePath)) {
                            synchronized (updateDataSQL) {
                                long length = tmpFile.length();
                                in = new FileInputStream(tmpFile);
                                executeStmt(updateDataSQL,
                                        new Object[]{
                                            new SizedInputStream(in, length),
                                            new Long(System.currentTimeMillis()),
                                            new Long(length),
                                            parentDir,
                                            name
                                        });
                            }
                        } else {
                            synchronized (insertFileSQL) {
                                long length = tmpFile.length();
                                in = new FileInputStream(tmpFile);
                                executeStmt(insertFileSQL,
                                        new Object[]{
                                            parentDir,
                                            name,
                                            new SizedInputStream(in, length),
                                            new Long(System.currentTimeMillis()),
                                            new Long(length)
                                        });
                            }
                        }

                    } catch (Exception e) {
                        throw new IOException(e.getMessage());
                    } finally {
                        if (in != null) {
                            in.close();
                        }
                        // temp file can now safely be removed
                        tmpFile.delete();
                    }
                }
            };
        } catch (Exception e) {
            String msg = "failed to open output stream to file: " + filePath;
            log.error(msg, e);
            throw new FileSystemException(msg, e);