Java Convert via ByteBuffer toASCIIString(URI u)

Description

Returns the content of this URI as a US-ASCII string.

License

Open Source License

Return

The string form of this URI, encoded as needed so that it only contains characters in the US-ASCII charset

Declaration

public static String toASCIIString(URI u) 

Method Source Code

//package com.java2s;
import sun.nio.cs.ThreadLocalCoders;

import java.net.URI;

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharacterCodingException;

public class Main {
    private final static char[] hexDigits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
            'E', 'F' };

    /**//from www  . ja va  2  s  .  c o m
     * Returns the content of this URI as a US-ASCII string.
     *
     * <p><b>Note:</b> this starts our customized version of URI's toASCIIString.  We differ in only one aspect: we do
     * NOT normalize Unicode characters.  This is because certain Unicode characters may have different compositions
     * and normalization may change the UTF-8 sequence represented by a character.  We must maintain the same UTF-8
     * sequence in and out and therefore we cannot normalize the sequences.</p>
     *
     * <p> If this URI does not contain any characters in the <i>other</i>
     * category then an invocation of this method will return the same value as
     * an invocation of the {@link #toString() toString} method.  Otherwise
     * this method works as if by invoking that method and then
     * <a href="#encode">encoding</a> the result.  </p>
     *
     * @return  The string form of this URI, encoded as needed
     *          so that it only contains characters in the US-ASCII
     *          charset
     */
    public static String toASCIIString(URI u) {
        String s = defineString(u);
        return encode(s);
    }

    /**
     * Defines a URI string.  Provided for our special URI encoder.
     * @param u URI to encode
     * @return String for the URI
     */
    private static String defineString(URI u) {

        StringBuffer sb = new StringBuffer();
        if (u.getScheme() != null) {
            sb.append(u.getScheme());
            sb.append(':');
        }
        if (u.isOpaque()) {
            sb.append(u.getRawSchemeSpecificPart());
        } else {
            if (u.getHost() != null) {
                sb.append("//");
                if (u.getUserInfo() != null) {
                    sb.append(u.getUserInfo());
                    sb.append('@');
                }
                boolean needBrackets = ((u.getHost().indexOf(':') >= 0) && !u.getHost().startsWith("[")
                        && !u.getHost().endsWith("]"));
                if (needBrackets)
                    sb.append('[');
                sb.append(u.getHost());
                if (needBrackets)
                    sb.append(']');
                if (u.getPort() != -1) {
                    sb.append(':');
                    sb.append(u.getPort());
                }
            } else if (u.getRawAuthority() != null) {
                sb.append("//");
                sb.append(u.getRawAuthority());
            }
            if (u.getRawPath() != null)
                sb.append(u.getRawPath());
            if (u.getRawQuery() != null) {
                sb.append('?');
                sb.append(u.getRawQuery());
            }
        }
        if (u.getRawFragment() != null) {
            sb.append('#');
            sb.append(u.getRawFragment());
        }
        return sb.toString();
    }

    /**
     * Encodes all characters >= \u0080 into escaped, <strikethrough>normalized</strikethrough> UTF-8 octets,
     * assuming that s is otherwise legal
     */
    private static String encode(String s) {
        int n = s.length();
        if (n == 0)
            return s;

        // First check whether we actually need to encode
        for (int i = 0;;) {
            if (s.charAt(i) >= '\u0080')
                break;
            if (++i >= n)
                return s;
        }

        ByteBuffer bb = null;
        try {
            bb = ThreadLocalCoders.encoderFor("UTF-8").encode(CharBuffer.wrap(s));
        } catch (CharacterCodingException x) {
            assert false;
        }

        StringBuffer sb = new StringBuffer();
        while (bb.hasRemaining()) {
            int b = bb.get() & 0xff;
            if (b >= 0x80)
                appendEscape(sb, (byte) b);
            else
                sb.append((char) b);
        }
        return sb.toString();
    }

    private static void appendEscape(StringBuffer sb, byte b) {
        sb.append('%');
        sb.append(hexDigits[(b >> 4) & 0x0f]);
        sb.append(hexDigits[(b >> 0) & 0x0f]);
    }
}

Related

1. toArray(int value)
2. toArray(IntBuffer src, int[] dst, int offset)
3. toArray(long length)
4. toASCII(String str)
5. toAsciiBytes(String s)
6. toAttributeValue(Object value)
7. toBigDecimal(byte[] bytes, int scale)
8. toBigInteger(byte[] bytes)
9. toBinaryFloatingPoint(double source)