Checks whether or not a file is a text file or a binary one. - Java File Path IO

Java examples for File Path IO:Binary File

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Description

Checks whether or not a file is a text file or a binary one.

Demo Code


import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;

public class Main{
    /**/*from  w  w w.jav a 2 s. co m*/
     * Checks whether or not a file is a text file or a binary one.
     * 
     * @param file - The file to check.
     * @return <tt>true</tt> if the File is a text file, <tt>false</tt> otherwise.
     * @throws IOException I/O error.
     * @throws IllegalArgumentException If the file is <code>null</code> or is not a file.
     */
    // CHECKSTYLE:OFF
    public static boolean isText(final File file) throws IOException,
            IllegalArgumentException {

        if (file == null || !file.isFile())
            throw new IllegalArgumentException(
                    "Must not be null & must be a file.");
        RandomAccessFile raf = null;

        try {
            raf = new RandomAccessFile(file, "r");
            int numberOfNonTextChars = 0;
            while (raf.getFilePointer() < raf.length()) {
                final int b = raf.readUnsignedByte();
                // http://www.table-ascii.com/
                if (b == 0x09 || // horizontal tabulation
                        b == 0x0A || // line feed
                        b == 0x0C || // form feed
                        b == 0x0D || // carriage return
                        (b >= 0x20 && b <= 0x7E) || // "normal" characters
                        (b >= 0x80 && b <= 0x9F) || // latin-1 symbols
                        (b >= 0xA0 && b <= 0xFF)) // latin-1 symbols
                {
                    // OK
                } else {
                    numberOfNonTextChars++;
                }
            }
            return numberOfNonTextChars <= 2
                    && (raf.length() - numberOfNonTextChars / raf.length()) >= 0.99;

        } finally {
            IOUtil.closeQuietly(raf);
        }
    }
}

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