abstractiobuffer.java

mina是以Java实现的一个开源的网络程序框架

                out.flip();
                o.put(out);
                out = o;
                continue;
            }

            if (cr.isError()) {
                // Revert the buffer back to the previous state.
                limit(oldLimit);
                position(oldPos);
                cr.throwException();
            }
        }

        limit(oldLimit);
        position(end);
        return out.flip().toString();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public IoBuffer putString(CharSequence val, CharsetEncoder encoder)
            throws CharacterCodingException {
        if (val.length() == 0) {
            return this;
        }

        CharBuffer in = CharBuffer.wrap(val);
        encoder.reset();

        int expandedState = 0;

        for (;;) {
            CoderResult cr;
            if (in.hasRemaining()) {
                cr = encoder.encode(in, buf(), true);
            } else {
                cr = encoder.flush(buf());
            }

            if (cr.isUnderflow()) {
                break;
            }
            if (cr.isOverflow()) {
                if (isAutoExpand()) {
                    switch (expandedState) {
                    case 0:
                        autoExpand((int) Math.ceil(in.remaining()
                                * encoder.averageBytesPerChar()));
                        expandedState++;
                        break;
                    case 1:
                        autoExpand((int) Math.ceil(in.remaining()
                                * encoder.maxBytesPerChar()));
                        expandedState++;
                        break;
                    default:
                        throw new RuntimeException("Expanded by "
                                + (int) Math.ceil(in.remaining()
                                        * encoder.maxBytesPerChar())
                                + " but that wasn't enough for '" + val + "'");
                    }
                    continue;
                }
            } else {
                expandedState = 0;
            }
            cr.throwException();
        }
        return this;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public IoBuffer putString(CharSequence val, int fieldSize,
            CharsetEncoder encoder) throws CharacterCodingException {
        checkFieldSize(fieldSize);

        if (fieldSize == 0) {
            return this;
        }

        autoExpand(fieldSize);

        boolean utf16 = encoder.charset().name().startsWith("UTF-16");

        if (utf16 && (fieldSize & 1) != 0) {
            throw new IllegalArgumentException("fieldSize is not even.");
        }

        int oldLimit = limit();
        int end = position() + fieldSize;

        if (oldLimit < end) {
            throw new BufferOverflowException();
        }

        if (val.length() == 0) {
            if (!utf16) {
                put((byte) 0x00);
            } else {
                put((byte) 0x00);
                put((byte) 0x00);
            }
            position(end);
            return this;
        }

        CharBuffer in = CharBuffer.wrap(val);
        limit(end);
        encoder.reset();

        for (;;) {
            CoderResult cr;
            if (in.hasRemaining()) {
                cr = encoder.encode(in, buf(), true);
            } else {
                cr = encoder.flush(buf());
            }

            if (cr.isUnderflow() || cr.isOverflow()) {
                break;
            }
            cr.throwException();
        }

        limit(oldLimit);

        if (position() < end) {
            if (!utf16) {
                put((byte) 0x00);
            } else {
                put((byte) 0x00);
                put((byte) 0x00);
            }
        }

        position(end);
        return this;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String getPrefixedString(CharsetDecoder decoder)
            throws CharacterCodingException {
        return getPrefixedString(2, decoder);
    }

    /**
     * Reads a string which has a length field before the actual
     * encoded string, using the specified <code>decoder</code> and returns it.
     *
     * @param prefixLength the length of the length field (1, 2, or 4)
     * @param decoder the decoder to use for decoding the string
     * @return the prefixed string
     * @throws CharacterCodingException when decoding fails
     * @throws BufferUnderflowException when there is not enough data available
     */
    @Override
    public String getPrefixedString(int prefixLength, CharsetDecoder decoder)
            throws CharacterCodingException {
        if (!prefixedDataAvailable(prefixLength)) {
            throw new BufferUnderflowException();
        }

        int fieldSize = 0;

        switch (prefixLength) {
        case 1:
            fieldSize = getUnsigned();
            break;
        case 2:
            fieldSize = getUnsignedShort();
            break;
        case 4:
            fieldSize = getInt();
            break;
        }

        if (fieldSize == 0) {
            return "";
        }

        boolean utf16 = decoder.charset().name().startsWith("UTF-16");

        if (utf16 && (fieldSize & 1) != 0) {
            throw new BufferDataException(
                    "fieldSize is not even for a UTF-16 string.");
        }

        int oldLimit = limit();
        int end = position() + fieldSize;

        if (oldLimit < end) {
            throw new BufferUnderflowException();
        }

        limit(end);
        decoder.reset();

        int expectedLength = (int) (remaining() * decoder.averageCharsPerByte()) + 1;
        CharBuffer out = CharBuffer.allocate(expectedLength);
        for (;;) {
            CoderResult cr;
            if (hasRemaining()) {
                cr = decoder.decode(buf(), out, true);
            } else {
                cr = decoder.flush(out);
            }

            if (cr.isUnderflow()) {
                break;
            }

            if (cr.isOverflow()) {
                CharBuffer o = CharBuffer.allocate(out.capacity()
                        + expectedLength);
                out.flip();
                o.put(out);
                out = o;
                continue;
            }

            cr.throwException();
        }

        limit(oldLimit);
        position(end);
        return out.flip().toString();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public IoBuffer putPrefixedString(CharSequence in, CharsetEncoder encoder)
            throws CharacterCodingException {
        return putPrefixedString(in, 2, 0, encoder);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public IoBuffer putPrefixedString(CharSequence in, int prefixLength,
            CharsetEncoder encoder) throws CharacterCodingException {
        return putPrefixedString(in, prefixLength, 0, encoder);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public IoBuffer putPrefixedString(CharSequence in, int prefixLength,
            int padding, CharsetEncoder encoder)
            throws CharacterCodingException {
        return putPrefixedString(in, prefixLength, padding, (byte) 0, encoder);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public IoBuffer putPrefixedString(CharSequence val, int prefixLength,
            int padding, byte padValue, CharsetEncoder encoder)
            throws CharacterCodingException {
        int maxLength;
        switch (prefixLength) {
        case 1:
            maxLength = 255;
            break;
        case 2:
            maxLength = 65535;
            break;
        case 4:
            maxLength = Integer.MAX_VALUE;
            break;
        default:
            throw new IllegalArgumentException("prefixLength: " + prefixLength);
        }

        if (val.length() > maxLength) {
            throw new IllegalArgumentException(
                    "The specified string is too long.");
        }
        if (val.length() == 0) {
            switch (prefixLength) {
            case 1:
                put((byte) 0);
                break;
            case 2:
                putShort((short) 0);
                break;
            case 4:
                putInt(0);
                break;
            }
            return this;
        }

        int padMask;
        switch (padding) {
        case 0:
        case 1:
            padMask = 0;
            break;
        case 2:
            padMask = 1;
            break;
        case 4:
            padMask = 3;
            break;
        default:
            throw new IllegalArgumentException("padding: " + padding);
        }

        CharBuffer in = CharBuffer.wrap(val);
        skip(prefixLength); // make a room for the length field
        int oldPos = position();
        encoder.reset();

        int expandedState = 0;

        for (;;) {
            CoderResult cr;
            if (in.hasRemaining()) {
                cr = encoder.encode(in, buf(), true);
            } else {
                cr = encoder.flush(buf());
            }

            if (position() - oldPos > maxLength) {
                throw new IllegalArgumentException(
                        "The specified string is too long.");
            }

            if (cr.isUnderflow()) {
                break;
            }
            if (cr.isOverflow()) {
                if (isAutoExpand()) {
                    switch (expandedState) {
                    case 0:
                        autoExpand((int) Math.ceil(in.remaining()
                                * encoder.averageBytesPerChar()));
                        expandedState++;
                        break;
                    case 1:
                        autoExpand((int) Math.ceil(in.remaining()
                                * encoder.maxBytesPerChar()));
                        expandedState++;
                        break;
                    default:
                        throw new RuntimeException("Expanded by "
                                + (int) Math.ceil(in.remaining()
                                        * encoder.maxBytesPerChar())
                                + " but that wasn't enough for '" + val + "'");
                    }
                    continue;
                }
            } else {
                expandedState = 0;
            }
            cr.throwException();
        }

        // Write the length field
        fill(padValue, padding - (position() - oldPos & padMask));
        int length = position() - oldPos;
        switch (prefixLength) {
        case 1:
            put(oldPos - 1, (byte) length);
            break;
        case 2:
            putShort(oldPos - 2, (short) length);
            break;
        case 4:
            putInt(oldPos - 4, length);
            break;
        }
        return this;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public Object getObject() throws ClassNotFoundException {
        return getObject(Thread.currentThread().getContextClassLoader());
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public Object getObject(final ClassLoader classLoader)
            throws ClassNotFoundException {
        if (!prefixedDataAvailable(4)) {
            throw new BufferUnderflowException();
        }

        int length = getInt();
        if (length <= 4) {
            throw new BufferDataException(
                    "Object length should be greater than 4: " + length);
        }

        int oldLimit = limit();
        limit(position() + length);
        try {
            ObjectInputStream in = new ObjectInputStream(asInputStream()) {
                @Override
                protected ObjectStreamClass readClassDescriptor()
                        throws IOException, ClassNotFoundException {
                    int type = read();
                    if (type < 0) {
                        throw new EOFException();
                    }
                    switch (type) {
                    case 0: // Primitive types
                        return super.readClassDescriptor();
                    case 1: // Non-primitive types
                        String className = readUTF();
                        Class<?> clazz = Class.forName(className, true,
                                classLoader);
                        return ObjectStreamClass.lookup(clazz);
                    default:
                        throw new StreamCorruptedException(
                                "Unexpected class descriptor type: " + type);
                    }
                }

                @Override
                protected Class<?> resolveClass(ObjectStreamClass desc)
                        throws IOException, ClassNotFoundException {
                    String name = desc.getName();
                    try {
                        return Class.forName(name, false, classLoader);
                    } catch (ClassNotFoundException ex) {
                        return super.resolveClass(desc);
                    }
                }
            };
            return in.readObject();
        } catch (IOException e) {
            throw new BufferDataException(e);
        } finally {
            limit(oldLimit);
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public IoBuffer putObject(Object o) {
        int oldPos = position();
        skip(4); // Make a room for the length field.
        try {
            ObjectOutputStream out = new ObjectOutputStream(asOutputStream()) {
                @Override
                protected void writeClassDescriptor(ObjectStreamClass desc)
                        throws IOException {
                    if (desc.forClass().isPrimitive()) {
                        write(0);
                        super.writeClassDescriptor(desc);
                    } else {
                        write(1);
                        writeUTF(desc.getName());
                    }
                }
            };
            out.writeObject(o);
            out.flush();
        } catch (IOException e) {
            throw new BufferDataException(e);
        }

        // Fill the length field
        int newPos = position();
        position(oldPos);
        putInt(newPos - oldPos - 4);
        position(newPos);
        return this;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean prefixedDataAvailable(int prefixLength) {
        return prefixedDataAvailable(prefixLength, Integer.MAX_VALUE);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean prefixedDataAvailable(int prefixLength, int maxDataLength) {
        if (remaining() < prefixLength) {
            return false;
        }

        int dataLength;
        switch (prefixLength) {