org.voltdb.messaging.FastDeserializer Maven / Gradle / Ivy
/* This file is part of VoltDB.
* Copyright (C) 2008-2018 VoltDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with VoltDB. If not, see DataInputStream subclass to read objects that implement
* the FastSerializable interface.
*
*/
public class FastDeserializer implements DataInput {
/**
* Interface to monitor metrics and other information about the deserialization process
*
*/
public interface DeserializationMonitor {
public void deserializedBytes(int numBytes);
}
private final ByteBuffer buffer;
/**
* Create a FastDeserializer from an array of bytes.
*
* @param in A byte array to wrap.
*/
public FastDeserializer(final byte[] in) {
buffer = ByteBuffer.wrap(in);
assert(buffer.order() == ByteOrder.BIG_ENDIAN);
}
public FastDeserializer(final byte[] in, ByteOrder order) {
buffer = ByteBuffer.wrap(in);
buffer.order(order);
}
/** Create a FastDeserializer from a ByteBuffer.
* @param in The ByteBuffer that will be part of this FastDeserializer. */
public FastDeserializer(final ByteBuffer in) {
buffer = in;
assert(buffer.order() == ByteOrder.BIG_ENDIAN);
}
/**
* Reset this FastDeserializer and make it ready for more reads. This will set the first 4 bytes to 0
* so that you can differentiate between no results and the last set of results that were placed
* in the buffer used by this FastDeserializer
**/
public void clear() {
//Don't rely on the EE to set the value to 0 when there are no results
buffer.clear();
buffer.putInt(0, 0);
}
/** @return The byte buffer contained in this object. */
public ByteBuffer buffer() { return buffer; }
/** @return the unread bytes from the contained byte buffer. */
public ByteBuffer remainder() { return buffer.slice(); }
/**
* Read an object from its byte array representation. This is a shortcut
* utility method useful when only a single object needs to be deserialized.
*
* @return The byte array representation for object.
*/
public final static T deserialize(
final byte[] data, final Class expectedType) throws IOException {
final FastDeserializer in = new FastDeserializer(data);
return in.readObject(expectedType);
}
/**
* Read an object from a a byte array stream assuming you know the expected type.
*
* @param expectedType The class of the type to be deserialized.
* @return A derserialized object.
* @throws IOException Rethrows any IOExceptions thrown.
*/
public T readObject(final Class expectedType) throws IOException {
assert(expectedType != null);
T obj = null;
try {
obj = expectedType.newInstance();
obj.readExternal(this);
} catch (final InstantiationException e) {
e.printStackTrace();
} catch (final IllegalAccessException e) {
e.printStackTrace();
}
return obj;
}
/**
* Read an object from a a byte array stream into th provied instance. Takes in a
* deserialization monitor which is notified of how many bytes were deserialized.
*
* @param obj Instance of the class of the type to be deserialized.
* @param monitor Monitor that will be notified of how many bytes are deserialized
* @return A deserialized object.
* @throws IOException Rethrows any IOExceptions thrown.
*/
public FastSerializable readObject(final FastSerializable obj, final DeserializationMonitor monitor) throws IOException {
final int startPosition = buffer.position();
obj.readExternal(this);
final int endPosition = buffer.position();
if (monitor != null) {
monitor.deserializedBytes(endPosition - startPosition);
}
return obj;
}
/**
* Read a string in the standard VoltDB way without
* wrapping the byte buffer[
*/
public static String readString(ByteBuffer buffer) throws IOException {
final int NULL_STRING_INDICATOR = -1;
final int len = buffer.getInt();
// check for null string
if (len == NULL_STRING_INDICATOR)
return null;
assert len >= 0;
if (len > VoltType.MAX_VALUE_LENGTH) {
throw new IOException("Serializable strings cannot be longer then "
+ VoltType.MAX_VALUE_LENGTH + " bytes");
}
if (len < NULL_STRING_INDICATOR) {
throw new IOException("String length is negative " + len);
}
// now assume not null
final byte[] strbytes = new byte[len];
buffer.get(strbytes);
String retval = null;
try {
retval = new String(strbytes, "UTF-8");
} catch (final UnsupportedEncodingException e) {
e.printStackTrace();
}
return retval;
}
/**
* Read a string in the standard VoltDB way. That is, four
* bytes of length info followed by the bytes of characters
* encoded in UTF-8.
*
* @return The String value read from the stream.
* @throws IOException Rethrows any IOExceptions.
*/
public String readString() throws IOException {
final int len = readInt();
// check for null string
if (len == VoltType.NULL_STRING_LENGTH) {
return null;
}
if (len < VoltType.NULL_STRING_LENGTH) {
throw new IOException("String length is negative " + len);
}
if (len > buffer.remaining()) {
throw new IOException("String length is bigger than total buffer " + len);
}
// now assume not null
final byte[] strbytes = new byte[len];
readFully(strbytes);
return new String(strbytes, Constants.UTF8ENCODING);
}
/**
* Read a varbinary, serialized the same way VoltDB serializes
* strings, but returned as byte[].
*
* @return The byte[] value read from the stream.
* @throws IOException Rethrows any IOExceptions.
*/
public byte[] readVarbinary() throws IOException {
final int len = readInt();
// check for null string
if (len == VoltType.NULL_STRING_LENGTH) {
return null;
}
assert len >= 0;
if (len < VoltType.NULL_STRING_LENGTH) {
throw new IOException("Varbinary length is negative " + len);
}
if (len > buffer.remaining()) {
throw new IOException("Varbinary length is bigger than total buffer " + len);
}
// now assume not null
final byte[] retval = new byte[len];
readFully(retval);
return retval;
}
/**
* Read the VoltDB BigDecimal serialization.
* @return BigDecimal
* @throws IOException
*/
public BigDecimal readBigDecimal() throws IOException {
return VoltDecimalHelper.deserializeBigDecimal(buffer);
}
/**
* Read the VoltDB BigDecimal serialization.
* @return BigDecimal
* @throws IOException
*/
public BigDecimal readBigDecimalFromString() throws IOException {
return VoltDecimalHelper.deserializeBigDecimalFromString(this.readString());
}
public Object readArray(final Class type) throws IOException {
final int count = type == byte.class ? readInt() : readShort();
if (count < 0) {
throw new IOException("Array length is negative " + count);
}
if (type == byte.class) {
if (count > (VoltType.MAX_VALUE_LENGTH)) {
throw new IOException("Array length is greater then the max of 1 megabyte " + count);
}
}
if (type == byte.class) {
final byte[] retval = new byte[count];
readFully(retval);
return retval;
}
if (type == byte[].class) {
final byte[][] retval = new byte[count][];
for (int i = 0; i < count; i++) {
int size = readInt();
if (size == -1) { // null length prefix
retval[i] = null;
}
else {
retval[i] = new byte[size];
readFully(retval[i]);
}
}
return retval;
}
if (type == short.class) {
final short[] retval = new short[count];
for (int i = 0; i < count; i++) {
retval[i] = readShort();
}
return retval;
}
if (type == int.class) {
final int[] retval = new int[count];
for (int i = 0; i < count; i++)
retval[i] = readInt();
return retval;
}
if (type == long.class) {
final long[] retval = new long[count];
for (int i = 0; i < count; i++)
retval[i] = readLong();
return retval;
}
if (type == Long.class) {
final Long[] retval = new Long[count];
for (int i = 0; i < count; i++)
retval[i] = readLong();
return retval;
}
if (type == String.class) {
final String[] retval = new String[count];
for (int i = 0; i < count; i++)
retval[i] = readString();
return retval;
}
if (type == double.class) {
final double[] retval = new double[count];
for (int i = 0; i < count; i++)
retval[i] = readDouble();
return retval;
}
if (type == Double.class) {
final Double[] retval = new Double[count];
for (int i = 0; i < count; i++)
retval[i] = readDouble();
return retval;
}
if (type == TimestampType.class) {
final TimestampType[] retval = new TimestampType[count];
for (int i = 0; i < count; i++)
retval[i] = new TimestampType(readLong());
return retval;
}
if (type == BigDecimal.class) {
final BigDecimal[] retval = new BigDecimal[count];
for (int i = 0; i < count; ++i) {
retval[i] = readBigDecimal();
}
return retval;
}
// probably throws an exception if type is not fastserializable
@SuppressWarnings("unchecked")
final
Class cls = (Class) type;
final FastSerializable[] retval = (FastSerializable[])Array.newInstance(type, count);
for (int i = 0; i < count; i++)
retval[i] = readObject(cls);
return retval;
}
/**
* Create a copy of the first byteLen bytes of the underlying buffer.
* @param byteLen Number of bytes to copy
* @return ByteBuffer wrapping the copied data
*/
public ByteBuffer readBuffer(final int byteLen) {
final byte[] data = new byte[byteLen];
buffer.get(data);
return ByteBuffer.wrap(data);
}
@Override
public boolean readBoolean() throws IOException {
return buffer.get() > 0;
}
@Override
public byte readByte() throws IOException {
return buffer.get();
}
@Override
public char readChar() throws IOException {
return buffer.getChar();
}
@Override
public double readDouble() throws IOException {
return buffer.getDouble();
}
@Override
public float readFloat() throws IOException {
return buffer.getFloat();
}
@Override
public void readFully(final byte[] b) throws IOException {
buffer.get(b);
}
@Override
public void readFully(final byte[] b, final int off, final int len) throws IOException {
buffer.get(b, off, len);
}
@Override
public int readInt() throws IOException {
return buffer.getInt();
}
@Override
public String readLine() throws IOException {
throw new RuntimeException("FastDeserializer.readLine() not supported.");
}
@Override
public long readLong() throws IOException {
return buffer.getLong();
}
@Override
public short readShort() throws IOException {
return buffer.getShort();
}
@Override
public String readUTF() throws IOException {
throw new RuntimeException("FastDeserializer.readUTF() not supported.");
}
@Override
public int readUnsignedByte() throws IOException {
throw new RuntimeException("FastDeserializer.readUnsignedByte() not supported.");
}
@Override
public int readUnsignedShort() throws IOException {
throw new RuntimeException("FastDeserializer.readUnsignedShort() not supported.");
}
@Override
public int skipBytes(final int n) throws IOException {
for (int i=0; i < n; i++)
readByte();
return n;
}
/**
* return Current position within the underlying buffer, for self-comparison only.
*/
public int getPosition() {
return buffer.position();
}
/**
* Set current position of underlying buffer. Useful only in concert with getPosition()
* @param pos The position to set to.
*/
public void setPosition(int pos) {
buffer.position(pos);
}
}