Package org.zkoss.io

Class RepeatableReader

  • All Implemented Interfaces:
    java.io.Closeable, java.io.Serializable, java.lang.AutoCloseable, java.lang.Readable, Repeatable
    public class RepeatableReader
extends java.io.Reader
implements Repeatable, java.io.Serializable
    RepeatableReader adds functionality to another reader, the ability to read repeatedly. By repeatable-read we mean, after close(), the next invocation of read(char[], int, int) will re-open the reader.

    RepeatableInputStream actually creates a temporary space to buffer the content, so it can be re-opened again after closed. Notice that the temporary space (a.k.a., the buffered reader) is never closed until garbage-collected.

    If the content size of the given reader is smaller than the value specified in the system property called "org.zkoss.io.memoryLimitSize", the content will be buffered in the memory. If the size exceeds, the content will be buffered in a temporary file. By default, it is 512KB. Note: the maximal value is Integer.MAX_VALUE

    If the content size of the given reader is larger than the value specified in the system property called "org.zkoss.io.bufferLimitSize", the content won't be buffered, and it means the read is not repeatable. By default, it is 20MB. Note: the maximal value is Integer.MAX_VALUE

    Since:
    3.0.4
    Author:
    tomyeh
    See Also:
    Serialized Form

    • Field Summary

      • Fields inherited from class java.io.Reader

        lock

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void close()
      Closes the current access, and the next call of read(char[], int, int) re-opens the buffered reader.
      protected void finalize()  
      static java.io.Reader getInstance​(java.io.File file)
      Returns a reader to read a file, encoded in UTF-8, that can be read repeatedly.
      static java.io.Reader getInstance​(java.io.File file, java.lang.String charset)
      Returns a reader to read a file that can be read repeatedly.
      static java.io.Reader getInstance​(java.io.Reader rd)
      Returns a reader that can be read repeatedly, or null if the given reader is null.
      static java.io.Reader getInstance​(java.lang.String filename)
      Returns a reader to read a file, encoded in UTF-8, that can be read repeatedly.
      static java.io.Reader getInstance​(java.lang.String filename, java.lang.String charset)
      Returns a reader to read a file that can be read repeatedly.
      static java.io.Reader getInstance​(java.net.URL url)
      Returns a reader to read the resource of the specified URL, encoded in UTF-8.
      static java.io.Reader getInstance​(java.net.URL url, java.lang.String charset)
      Returns a reader to read the resource of the specified URL.
      int read​(char[] cbuf, int off, int len)  

      • Methods inherited from class java.io.Reader

        mark, markSupported, nullReader, read, read, read, ready, reset, skip, transferTo

      • Methods inherited from class java.lang.Object

        clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Method Detail

      • getInstance

        public static java.io.Reader getInstance​(java.io.Reader rd)
        Returns a reader that can be read repeatedly, or null if the given reader is null. Note: the returned reader encapsulates the given reader, rd (a.k.a., the buffered reader) to adds the functionality to re-opens the reader once close() is called.

        By repeatable-read we mean, after close(), the next invocation of read(char[], int, int) will re-open the reader.

        Use this method instead of instantiating RepeatableReader with the constructor.

        See Also:
        getInstance(File)

      • getInstance

        public static java.io.Reader getInstance​(java.io.File file,
                                         java.lang.String charset)
                                  throws java.io.FileNotFoundException
        Returns a reader to read a file that can be read repeatedly. Note: it assumes the file is text (rather than binary).

        By repeatable-read we mean, after close(), the next invocation of read(char[], int, int) will re-open the reader.

        Note: it is efficient since we don't have to buffer the content of the file to make it repeatable-read.

        Parameters:
        charset - the charset. If null, "UTF-8" is assumed.
        Throws:
        java.lang.IllegalArgumentException - if file is null.
        java.io.FileNotFoundException
        Since:
        3.0.8
        See Also:
        getInstance(Reader), getInstance(String, String)

      • getInstance

        public static java.io.Reader getInstance​(java.io.File file)
                                  throws java.io.FileNotFoundException
        Returns a reader to read a file, encoded in UTF-8, that can be read repeatedly. Note: it assumes the file is text (rather than binary).

        By repeatable-read we mean, after close(), the next invocation of read(char[], int, int) will re-open the reader.

        Note: it is efficient since we don't have to buffer the content of the file to make it repeatable-read.

        Throws:
        java.lang.IllegalArgumentException - if file is null.
        java.io.FileNotFoundException
        See Also:
        getInstance(Reader), getInstance(String)

      • getInstance

        public static java.io.Reader getInstance​(java.lang.String filename,
                                         java.lang.String charset)
                                  throws java.io.FileNotFoundException
        Returns a reader to read a file that can be read repeatedly. Note: it assumes the file is text (rather than binary).

        By repeatable-read we mean, after close(), the next invocation of read(char[], int, int) will re-open the reader.

        Note: it is efficient since we don't have to buffer the content of the file to make it repeatable-read.

        Parameters:
        filename - the file name
        charset - the charset. If null, "UTF-8" is assumed.
        Throws:
        java.lang.IllegalArgumentException - if file is null.
        java.io.FileNotFoundException - if file is not found.
        Since:
        3.0.8
        See Also:
        getInstance(Reader), getInstance(File, String)

      • getInstance

        public static java.io.Reader getInstance​(java.lang.String filename)
                                  throws java.io.FileNotFoundException
        Returns a reader to read a file, encoded in UTF-8, that can be read repeatedly. Note: it assumes the file is text (rather than binary).

        By repeatable-read we mean, after close(), the next invocation of read(char[], int, int) will re-open the reader.

        Note: it is efficient since we don't have to buffer the content of the file to make it repeatable-read.

        Parameters:
        filename - the file name
        Throws:
        java.lang.IllegalArgumentException - if file is null.
        java.io.FileNotFoundException - if file is not found.
        See Also:
        getInstance(Reader), getInstance(File)

      • getInstance

        public static java.io.Reader getInstance​(java.net.URL url,
                                         java.lang.String charset)
        Returns a reader to read the resource of the specified URL. The reader can be read repeatedly. Note: it assumes the resource is text (rather than binary).

        By repeatable-read we mean, after close(), the next invocation of read(char[], int, int) will re-open the reader.

        Note: it is efficient since we don't have to buffer the content of the file to make it repeatable-read.

        Parameters:
        charset - the charset. If null, "UTF-8" is assumed.
        Throws:
        java.lang.IllegalArgumentException - if file is null.
        Since:
        3.0.8
        See Also:
        getInstance(Reader), getInstance(String, String)

      • getInstance

        public static java.io.Reader getInstance​(java.net.URL url)
        Returns a reader to read the resource of the specified URL, encoded in UTF-8. The reader can be read repeatedly. Note: it assumes the resource is text (rather than binary).

        By repeatable-read we mean, after close(), the next invocation of read(char[], int, int) will re-open the reader.

        Note: it is efficient since we don't have to buffer the content of the file to make it repeatable-read.

        Throws:
        java.lang.IllegalArgumentException - if file is null.
        See Also:
        getInstance(Reader), getInstance(String)

      • read

        public int read​(char[] cbuf,
                int off,
                int len)
         throws java.io.IOException
        Specified by:
        read in class java.io.Reader
        Throws:
        java.io.IOException

      • close

        public void close()
           throws java.io.IOException
        Closes the current access, and the next call of read(char[], int, int) re-opens the buffered reader.
        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Specified by:
        close in class java.io.Reader
        Throws:
        java.io.IOException

      • finalize

        protected void finalize()
                 throws java.lang.Throwable
        Overrides:
        finalize in class java.lang.Object
        Throws:
        java.lang.Throwable