Class ShpFiles


  • public class ShpFiles
    extends Object
    The collection of all the files that are the shapefile and its metadata and indices.

    This class has methods for performing actions on the files. Currently mainly for obtaining read and write channels and streams. But in the future a move method may be introduced.

    Note: The method that require locks (such as getInputStream()) will automatically acquire locks and the javadocs should document how to release the lock. Therefore the methods acquireRead(ShpFileType, FileReader) and acquireWrite(ShpFileType, FileWriter) svn

    Author:
    jesse
    • Method Detail

      • finalize

        protected void finalize()
                         throws Throwable
        This verifies that this class has been closed correctly (nothing locking)
        Overrides:
        finalize in class Object
        Throws:
        Throwable
      • dispose

        public void dispose()
      • logCurrentLockers

        public void logCurrentLockers​(Level logLevel)
        Writes to the log all the lockers and when they were constructed.
        Parameters:
        logLevel - the level at which to log.
      • getFileNames

        public Map<ShpFileType,​String> getFileNames()
        Returns the URLs (in string form) of all the files for the shapefile datastore.
        Returns:
        the URLs (in string form) of all the files for the shapefile datastore.
      • get

        public String get​(ShpFileType type)
        Returns the string form of the url that identifies the file indicated by the type parameter or null if it is known that the file does not exist.

        Note: a URL should NOT be constructed from the string instead the URL should be obtained through calling one of the aquireLock methods.

        Parameters:
        type - indicates the type of file the caller is interested in.
        Returns:
        the string form of the url that identifies the file indicated by the type parameter or null if it is known that the file does not exist.
      • numberOfLocks

        public int numberOfLocks()
        Returns the number of locks on the current set of shapefile files. This is not thread safe so do not count on it to have a completely accurate picture but it can be useful debugging
        Returns:
        the number of locks on the current set of shapefile files.
      • acquireReadFile

        public File acquireReadFile​(ShpFileType type,
                                    FileReader requestor)
        Acquire a File for read only purposes. It is recommended that get*Stream or get*Channel methods are used when reading or writing to the file is desired.
        Parameters:
        type - the type of the file desired.
        requestor - the object that is requesting the File. The same object must release the lock and is also used for debugging.
        Returns:
        the File type requested
        See Also:
        getInputStream(ShpFileType, FileReader), getReadChannel(ShpFileType, FileReader), #getWriteChannel(ShpFileType, FileReader)
      • acquireRead

        public URL acquireRead​(ShpFileType type,
                               FileReader requestor)
        Acquire a URL for read only purposes. It is recommended that get*Stream or get*Channel methods are used when reading or writing to the file is desired.
        Parameters:
        type - the type of the file desired.
        requestor - the object that is requesting the URL. The same object must release the lock and is also used for debugging.
        Returns:
        the URL to the file of the type requested
        See Also:
        getInputStream(ShpFileType, FileReader), getReadChannel(ShpFileType, FileReader), #getWriteChannel(ShpFileType, FileReader)
      • tryAcquireRead

        public Result<URL,​ShpFiles.State> tryAcquireRead​(ShpFileType type,
                                                               FileReader requestor)
        Tries to acquire a URL for read only purposes. Returns null if the acquire failed or if the file does not.

        It is recommended that get*Stream or get*Channel methods are used when reading or writing to the file is desired.

        Parameters:
        type - the type of the file desired.
        requestor - the object that is requesting the URL. The same object must release the lock and is also used for debugging.
        Returns:
        A result object containing the URL or the reason for the failure.
        See Also:
        getInputStream(ShpFileType, FileReader), getReadChannel(ShpFileType, FileReader), #getWriteChannel(ShpFileType, FileReader)
      • unlockRead

        public void unlockRead​(File file,
                               FileReader requestor)
        Unlocks a read lock. The file and requestor must be the the same as the one of the lockers.
        Parameters:
        file - file that was locked
        requestor - the class that requested the file
      • unlockRead

        public void unlockRead​(URL url,
                               FileReader requestor)
        Unlocks a read lock. The url and requestor must be the the same as the one of the lockers.
        Parameters:
        url - url that was locked
        requestor - the class that requested the url
      • acquireWriteFile

        public File acquireWriteFile​(ShpFileType type,
                                     FileWriter requestor)
        Acquire a File for read and write purposes.

        It is recommended that get*Stream or get*Channel methods are used when reading or writing to the file is desired.

        Parameters:
        type - the type of the file desired.
        requestor - the object that is requesting the File. The same object must release the lock and is also used for debugging.
        Returns:
        the File to the file of the type requested
        See Also:
        getInputStream(ShpFileType, FileReader), getReadChannel(ShpFileType, FileReader), #getWriteChannel(ShpFileType, FileReader)
      • acquireWrite

        public URL acquireWrite​(ShpFileType type,
                                FileWriter requestor)
        Acquire a URL for read and write purposes.

        It is recommended that get*Stream or get*Channel methods are used when reading or writing to the file is desired.

        Parameters:
        type - the type of the file desired.
        requestor - the object that is requesting the URL. The same object must release the lock and is also used for debugging.
        Returns:
        the URL to the file of the type requested
        See Also:
        getInputStream(ShpFileType, FileReader), getReadChannel(ShpFileType, FileReader), #getWriteChannel(ShpFileType, FileReader)
      • tryAcquireWrite

        public Result<URL,​ShpFiles.State> tryAcquireWrite​(ShpFileType type,
                                                                FileWriter requestor)
        Tries to acquire a URL for read/write purposes. Returns null if the acquire failed or if the file does not exist

        It is recommended that get*Stream or get*Channel methods are used when reading or writing to the file is desired.

        Parameters:
        type - the type of the file desired.
        requestor - the object that is requesting the URL. The same object must release the lock and is also used for debugging.
        Returns:
        A result object containing the URL or the reason for the failure.
        See Also:
        getInputStream(ShpFileType, FileReader), getReadChannel(ShpFileType, FileReader), #getWriteChannel(ShpFileType, FileReader)
      • unlockWrite

        public void unlockWrite​(File file,
                                FileWriter requestor)
        Unlocks a write lock. The file and requestor must be the the same as the one of the lockers.
        Parameters:
        file - file that was locked
        requestor - the class that requested the file
      • unlockWrite

        public void unlockWrite​(URL url,
                                FileWriter requestor)
        Unlocks a write lock. The requestor must be have previously obtained a lock for the url.
        Parameters:
        url - url that was locked
        requestor - the class that requested the url
      • isLocal

        public boolean isLocal()
        Determine if the location of this shapefile is local or remote.
        Returns:
        true if local, false if remote
      • isGz

        public boolean isGz()
        Returns:
        whether the files are gzip-ped.
      • isWritable

        public boolean isWritable()
        Returns true if the files are writable
      • delete

        public boolean delete()
        Delete all the shapefile files. If the files are not local or the one files cannot be deleted return false.
      • getInputStream

        public InputStream getInputStream​(ShpFileType type,
                                          FileReader requestor)
                                   throws IOException
        Opens a input stream for the indicated file. A read lock is requested at the method call and released on close.
        Parameters:
        type - the type of file to open the stream to.
        requestor - the object requesting the stream
        Returns:
        an input stream
        Throws:
        IOException - if a problem occurred opening the stream.
      • getOutputStream

        public OutputStream getOutputStream​(ShpFileType type,
                                            FileWriter requestor)
                                     throws IOException
        Opens a output stream for the indicated file. A write lock is requested at the method call and released on close.
        Parameters:
        type - the type of file to open the stream to.
        requestor - the object requesting the stream
        Returns:
        an output stream
        Throws:
        IOException - if a problem occurred opening the stream.
      • getReadChannel

        public ReadableByteChannel getReadChannel​(ShpFileType type,
                                                  FileReader requestor)
                                           throws IOException
        Obtain a ReadableByteChannel from the given URL. If the url protocol is file, a FileChannel will be returned. Otherwise a generic channel will be obtained from the urls input stream.

        A read lock is obtained when this method is called and released when the channel is closed.

        Parameters:
        type - the type of file to open the channel to.
        requestor - the object requesting the channel
        Throws:
        IOException
      • getWriteChannel

        public WritableByteChannel getWriteChannel​(ShpFileType type,
                                                   FileWriter requestor)
                                            throws IOException
        Obtain a WritableByteChannel from the given URL. If the url protocol is file, a FileChannel will be returned. Currently, this method will return a generic channel for remote urls, however both shape and dbf writing can only occur with a local FileChannel channel.

        A write lock is obtained when this method is called and released when the channel is closed.

        Parameters:
        type - the type of file to open the stream to.
        requestor - the object requesting the stream
        Returns:
        a WritableByteChannel for the provided file type
        Throws:
        IOException - if there is an error opening the stream
      • getStorageFile

        public StorageFile getStorageFile​(ShpFileType type)
                                   throws IOException
        Obtains a Storage file for the type indicated. An id is provided so that the same file can be obtained at a later time with just the id
        Parameters:
        type - the type of file to create and return
        Returns:
        StorageFile
        Throws:
        IOException - if temporary files cannot be created
      • getTypeName

        public String getTypeName()
      • isMemoryMapCacheEnabled

        public boolean isMemoryMapCacheEnabled()
        Returns the status of the memory map cache. When enabled the memory mapped portions of the files are cached and shared (giving each thread a clone of it)
      • setMemoryMapCacheEnabled

        public void setMemoryMapCacheEnabled​(boolean memoryMapCacheEnabled)
        Enables the memory map cache. When enabled the memory mapped portions of the files are cached and shared (giving each thread a clone of it)
      • exists

        public boolean exists​(ShpFileType fileType)
                       throws IllegalArgumentException
        Returns true if the file exists. Throws an exception if the file is not local.
        Parameters:
        fileType - the type of file to check existance for.
        Returns:
        true if the file exists.
        Throws:
        IllegalArgumentException - if the files are not local.