com.credibledoc.iso8583packer.hex.HexBodyPacker Maven / Gradle / Ivy
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package com.credibledoc.iso8583packer.hex;
import com.credibledoc.iso8583packer.body.BodyPacker;
import com.credibledoc.iso8583packer.exception.PackerRuntimeException;
import java.util.Arrays;
/**
* Implements {@link BodyPacker} where hexadecimal chars '0'..'9', 'A'..'F' converted to and from bytes. Thus, "12CD" is
* converted to 2 bytes: 0x12, 0xCD.
*
* More examples
* hex-body-packer.md
*
* @author Kyrylo Semenko
*/
public class HexBodyPacker implements BodyPacker {
/**
* Single instance.
*/
private static HexBodyPacker instance;
/**
* Only one instance is allowed, see the {@link #getInstance()} method.
*/
private HexBodyPacker() {
// empty
}
/**
* @return The {@link #instance} singleton.
*/
public static HexBodyPacker getInstance() {
if (instance == null) {
instance = new HexBodyPacker();
}
return instance;
}
/**
* Expected type of object is String, for example FFFF (hex of two bytes).
* @param object the String data to be packed.
* @param bytes an empty or partially filled bytes.
* @param offset the index of the first unfilled byte in the bytes array from start packing at.
*/
@Override
public void pack(Object object, byte[] bytes, int offset) {
if (object == null) {
return;
}
if (!(object instanceof String)) {
throw new PackerRuntimeException("Expected String but found " + object.getClass().getSimpleName());
}
String data = (String) object;
int packedLength = getPackedLength(data);
int available = bytes.length - offset;
if (available < packedLength) {
throw new PackerRuntimeException("Available bytes number '" + available +
"' is less than required packedLength '" + packedLength + "' of the data object.");
}
byte[] bytesFromHex = HexService.hex2byte(data);
System.arraycopy(bytesFromHex, 0, bytes, offset, bytesFromHex.length);
}
@Override
@SuppressWarnings("unchecked")
public String unpack(byte[] rawData, int offset, int bytesCount) {
int available = rawData.length - offset;
if (available < bytesCount) {
throw new PackerRuntimeException("Available bytes number '" + available +
"' is less than required bytesCount '" + bytesCount + "' from the parameter.");
}
byte[] bytes = Arrays.copyOfRange(rawData, offset, offset + bytesCount);
return HexService.bytesToHex(bytes);
}
@Override
public int getPackedLength(Object object) {
if (object == null) {
return 0;
}
if (!(object instanceof String)) {
throw new PackerRuntimeException("Expected String but found " + object.getClass().getSimpleName());
}
String string = (String) object;
return string.length() / 2;
}
}