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Receiving an exception "BufferOverflowException" while running sikuli script via threads. The same script works properly without thread object. I have no clue what causes the bufferoverflowexception. Please guide.
Sample Code:-
import org.sikuli.script.*; // Library import
public class Sikuli {
private Screen screen = new Screen();
private Pattern getPattern(String imagePath) {
return new Pattern(imagePath);
}
public void click(String imagePath) throws FindFailed, InterruptedException {
screen.click(getPattern(imagePath));
}
public void sendKeys(String value) {
screen.type(value);
}
import Sukuli // Custom sikuli class import
public class foo {
Sikuli sk = new Sikuli();
public void test() {
Thread t1 = new Thread(() -> {
sk.click(new Pattern("imagePath"));
sk.type("fooboo");
});
t1.start();
}
}
From Sikuli Library Methods which are being referred by my class methods:-
public int type(String text) {
try {
return this.keyin((Object)null, text, 0);
} catch (FindFailed var3) {
return 0;
}
}
private <PFRML> int keyin(PFRML target, String text, int modifiers) throws FindFailed {
if (target != null && 0 == this.click(target, 0)) {
return 0;
} else {
Debug profiler = Debug.startTimer("Region.type", new Object[0]);
if (text != null && !"".equals(text)) {
String showText = "";
for(int i = 0; i < text.length(); ++i) {
showText = showText + Key.toJavaKeyCodeText(text.charAt(i));
}
String modText = "";
String modWindows = null;
if ((modifiers & 4) != 0) {
modifiers -= 4;
modifiers |= 4;
log(3, "Key.WIN as modifier", new Object[0]);
modWindows = "Windows";
}
if (modifiers != 0) {
modText = String.format("( %s ) ", KeyEvent.getKeyModifiersText(modifiers));
if (modWindows != null) {
modText = modText.replace("Meta", modWindows);
}
}
Debug.action("%s TYPE \"%s\"", new Object[]{modText, showText});
log(3, "%s TYPE \"%s\"", new Object[]{modText, showText});
profiler.lap("before getting Robot");
IRobot r = this.getRobotForRegion();
int pause = 20 + (Settings.TypeDelay > 1.0 ? 1000 : (int)(Settings.TypeDelay * 1000.0));
Settings.TypeDelay = 0.0;
profiler.lap("before typing");
r.typeStarts();
for(int i = 0; i < text.length(); ++i) {
r.pressModifiers(modifiers);
r.typeChar(text.charAt(i), KeyMode.PRESS_RELEASE);
r.releaseModifiers(modifiers);
r.delay(pause);
}
r.typeEnds();
profiler.lap("after typing, before waitForIdle");
r.waitForIdle();
profiler.end();
return 1;
} else {
return 0;
}
}
}
Trace logs:-
[log] CLICK on L[1517,53]#S(0) (555 msec)[log] TYPE "fooboo"Exception in thread "Thread-4" java.nio.BufferOverflowException
at java.nio.Buffer.nextPutIndex(Buffer.java:521)
at java.nio.HeapByteBuffer.put(HeapByteBuffer.java:169)
at org.apache.maven.surefire.api.stream.AbstractStreamEncoder.encodeString(AbstractStreamEncoder.java:127)
at org.apache.maven.surefire.api.stream.AbstractStreamEncoder.encodeStringData(AbstractStreamEncoder.java:171)
at org.apache.maven.surefire.api.stream.AbstractStreamEncoder.encode(AbstractStreamEncoder.java:157)
at org.apache.maven.surefire.booter.spi.EventChannelEncoder.encodeMessage(EventChannelEncoder.java:398)
at org.apache.maven.surefire.booter.spi.EventChannelEncoder.setOutErr(EventChannelEncoder.java:188)
at org.apache.maven.surefire.booter.spi.EventChannelEncoder.testOutput(EventChannelEncoder.java:183)
at org.apache.maven.surefire.api.booter.ForkingRunListener.writeTestOutput(ForkingRunListener.java:113)
at org.apache.maven.surefire.api.booter.ForkingRunListener.writeTestOutput(ForkingRunListener.java:44)
at org.apache.maven.surefire.common.junit4.JUnit4RunListener.writeTestOutput(JUnit4RunListener.java:235)
at org.apache.maven.surefire.api.report.ConsoleOutputCapture$ForwardingPrintStream.println(ConsoleOutputCapture.java:144)
at org.sikuli.basics.Debug.log(Debug.java:881)
at org.sikuli.basics.Debug.action(Debug.java:645)
at org.sikuli.script.Region.keyin(Region.java:4613)
at org.sikuli.script.Region.type(Region.java:4493)
at Sikuli.sendKeys(Sikuli.java:87)
I have Escrypt Smart Card to sign data bytes and get signature and certificate for it.
I have java tool to do it and everything was fine until Java 8. Now application migrated to Java 11. And problem start from here.
SunPKCS11.jar/ library is not a part of Java 11, hence application breaks.
I tried with different solution available over internet and oracle release notes, it suggest to use java.security package for cryptographic operation.
I am not able to switch from Java 8 to java 11, any support would be really useful.
Edit-1: Minimum usable code
Signature calculator is used to parse signature
It is written with Java 8 & SunPKCS11.jar want to migrate it to Java 11
'''
import java.io.IOException;
import java.util.Scanner;
import javax.xml.bind.annotation.adapters.HexBinaryAdapter;
import sun.security.pkcs11.wrapper.CK_ATTRIBUTE;
import sun.security.pkcs11.wrapper.CK_MECHANISM;
import sun.security.pkcs11.wrapper.CK_RSA_PKCS_PSS_PARAMS;
import sun.security.pkcs11.wrapper.PKCS11;
import sun.security.pkcs11.wrapper.PKCS11Constants;
import sun.security.pkcs11.wrapper.PKCS11Exception;
public class Application {
public static void main(String[] args) {
try {
// PKCS11 middleware (UBK PKI) path
String libraryPath = "";
OpenScPkcs11 openScPkcs11 = new OpenScPkcs11(libraryPath);
openScPkcs11.login("", "");
byte[] hash = null;
String keypath = null;
String oid = null;
String authbits = null;
openScPkcs11.calcSign(hash, keypath, oid, authbits);
}
catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
class OpenScPkcs11 {
private static HexBinaryAdapter hexBinaryAdapter = new HexBinaryAdapter();
private int slotId = 0x3;
private String libraryPath;
private PKCS11 pkcs11Instance;
private String signatureAlgo = "RSA";
private long session = -1;
private boolean isLoginDone = false;
private SignatureMechanism.Algorithms algorithm = SignatureMechanism.Algorithms.SHA256;
public OpenScPkcs11(String libraryPath) throws IOException, PKCS11Exception {
this.libraryPath = libraryPath;
initializeMiddleware();
}
public void calcSign(byte[] hash, String keyPath, String userOid, String authbits) throws Exception {
byte[] signature = new byte[512];
if (this.pkcs11Instance != null) {
if (this.session < 0) {
this.openSession();
}
if (!this.isLoginDone) {
this.login("", "");
}
Mechanism mechanism = SignatureMechanism.getMechanism(this.algorithm);
CK_ATTRIBUTE[] pTemplate = new CK_ATTRIBUTE[3];
pTemplate[0] = new CK_ATTRIBUTE(PKCS11Constants.CKA_CLASS, PKCS11Constants.CKO_PRIVATE_KEY);
pTemplate[1] = new CK_ATTRIBUTE(PKCS11Constants.CKA_VENDOR_DEFINED + 1, keyPath);
pTemplate[2] = new CK_ATTRIBUTE(PKCS11Constants.CKA_VENDOR_DEFINED + 2, authbits);
// define the attibutes for certificate
CK_ATTRIBUTE[] certAttribute = new CK_ATTRIBUTE[1];
certAttribute[0] = new CK_ATTRIBUTE(PKCS11Constants.CKA_VENDOR_DEFINED + 3);
long[] c_FindObjects = null;
this.pkcs11Instance.C_FindObjectsInit(this.session, pTemplate);
c_FindObjects = this.pkcs11Instance.C_FindObjects(this.session, 32);
this.pkcs11Instance.C_FindObjectsFinal(this.session);
CK_MECHANISM pMechanism = null;
// RSA Algorithm
String signatureAlgorithmType = this.getSignatureAlgorithmType();
if (signatureAlgorithmType.equalsIgnoreCase("RSA")) {
pMechanism = new CK_MECHANISM(mechanism.getId());
CK_RSA_PKCS_PSS_PARAMS ck_RSA_PKCS_PSS_PARAMS =
new CK_RSA_PKCS_PSS_PARAMS(this.algorithm.name(), "MGF1", this.algorithm.name(), (int) mechanism.getsLen());
pMechanism.pParameter = ck_RSA_PKCS_PSS_PARAMS;
}
else if (signatureAlgorithmType.equalsIgnoreCase("ECDSA")) { // ECDSA Algorithm
pMechanism = new CK_MECHANISM(PKCS11Constants.CKM_ECDSA);
}
else {
throw new Exception("Signature algorithm " + signatureAlgorithmType + " is not supported");
}
if ((c_FindObjects != null) && (c_FindObjects.length > 0)) {
long c_FindObjectFound = c_FindObjects[0];
boolean objFound = false;
for (long c_FindObject : c_FindObjects) {
this.pkcs11Instance.C_GetAttributeValue(this.session, c_FindObject, certAttribute);
// Binary certificate as byte array
byte[] certificateBytes = certAttribute[0].getByteArray();
if ((userOid != null) && !userOid.isEmpty()) {
// Match certificate with userOid, if matches (Certificate parser used)
if (parseOidInfo(certificateBytes, userOid)) {
c_FindObjectFound = c_FindObject;
objFound = true;
break;
}
}
}
if (objFound) {
System.out.println("Signature found for given OID configuration.");
}
else {
this.pkcs11Instance.C_GetAttributeValue(this.session, c_FindObjectFound, certAttribute);
CertificateParser certificateParser = new CertificateParser(certAttribute[0].getByteArray());
}
this.pkcs11Instance.C_SignInit(this.session, pMechanism, c_FindObjectFound);
this.pkcs11Instance.C_SignUpdate(this.session, 0, hash, 0, (int) mechanism.getsLen());
signature = this.pkcs11Instance.C_SignFinal(this.session, mechanism.getSignFinalArgument());
}
else {
String errorMessage = "Unable to find keys.";
throw new Exception(errorMessage);
}
}
else {
throw new Exception("Initialize middleware first.");
}
}
/**
* #return
*/
private String getSignatureAlgorithmType() {
return this.signatureAlgo;
}
public void login(String userName, String password) throws Exception {
if (this.pkcs11Instance != null) {
openSession();
String pwd = password;
if (pwd == null || pwd.trim().isEmpty()) {
Scanner sc = new Scanner(System.in);
pwd = sc.next();
sc.close();
}
this.pkcs11Instance.C_Login(this.session, PKCS11Constants.CKU_USER, pwd.toCharArray());
this.isLoginDone = true;
}
else {
throw new Exception("Initialize middleware first.");
}
}
public void logout() throws PKCS11Exception {
if (this.pkcs11Instance != null) {
this.pkcs11Instance.C_Logout(this.session);
}
}
public void openSession() throws Exception {
if (this.pkcs11Instance != null) {
if (this.session < 0) {
long[] c_GetSlotList = this.pkcs11Instance.C_GetSlotList(true);
if ((c_GetSlotList != null) && (c_GetSlotList.length > 0)) {
for (long element : c_GetSlotList) {
if (element == this.slotId) {
this.session =
this.pkcs11Instance.C_OpenSession(this.slotId, PKCS11Constants.CKF_SERIAL_SESSION, null, null);
break;
}
}
}
}
}
else {
throw new Exception("Initialize middleware first.");
}
}
public void closeSession() throws PKCS11Exception {
if ((this.pkcs11Instance != null) && (this.session >= 0)) {
this.pkcs11Instance.C_CloseSession(this.session);
this.session = -1;
}
}
public void initializeMiddleware(String libraryPath1) throws IOException, PKCS11Exception {
this.pkcs11Instance = PKCS11.getInstance(libraryPath1, "C_GetFunctionList", null, false);
this.libraryPath = libraryPath1;
}
public void initializeMiddleware() throws IOException, PKCS11Exception {
this.pkcs11Instance = PKCS11.getInstance(this.libraryPath, "C_GetFunctionList", null, false);
}
public static String getString(final byte[] data) {
if ((data != null) && (data.length > 0)) {
return hexBinaryAdapter.marshal(data);
}
return null;
}
}
class SignatureMechanism {
public static enum Algorithms {
SHA256(0x250),
/**
* Hash calculation Algorithm
*/
RIPEMD160(0x240),
/**
* Hash calculation Algorithm
*/
RIPEMD160_1(0x0),
/**
* Secure Hash Algorithm 512 for hash Calculation
*/
SHA512(0x251);
private int value = 0;
private Algorithms(final int algorithmValue) {
this.value = algorithmValue;
}
/**
* #return the hash value
*/
public int getValue() {
return this.value;
}
}
/**
* #param algorithm : Algorithm used for hash calculation
* #return signature mechanism
*/
public static Mechanism getMechanism(final Algorithms algorithm) {
Mechanism mechanism = new Mechanism();
if (algorithm == Algorithms.SHA256) {
mechanism.setHashAlg(PKCS11Constants.CKM_SHA256);
mechanism.setMgf(PKCS11Constants.CKG_MGF1_SHA1 + 1);
mechanism.setsLen(32);
mechanism.setSignFinalArgument(512);
} // TODO Verify with ETAS Middleware team
else if (algorithm == Algorithms.SHA512) {
mechanism.setHashAlg(PKCS11Constants.CKM_SHA512);
mechanism.setMgf(PKCS11Constants.CKG_MGF1_SHA1 + 1);
mechanism.setsLen(64);
mechanism.setSignFinalArgument(1024);
}
else if (algorithm == Algorithms.RIPEMD160) {
mechanism.setHashAlg(PKCS11Constants.CKM_RIPEMD160);
mechanism.setMgf(0x80000001); // hard coded becuase it is defined by escrypt and not present in PKCS11
mechanism.setsLen(20);
}
else if (algorithm == Algorithms.RIPEMD160_1) {
mechanism.setId(PKCS11Constants.CKM_RIPEMD160_RSA_PKCS);
}
return mechanism;
}
}
class Mechanism{
private long hashAlg;
private long mgf;
private long sLen;
private long ulMaxObjectCount = 32;
private int signFinalArgument = 128;
private long id = PKCS11Constants.CKM_RSA_PKCS_PSS;
/**
* #return the hashAlg
*/
public long getHashAlg() {
return hashAlg;
}
/**
* #param hashAlg the hashAlg to set
*/
public void setHashAlg(long hashAlg) {
this.hashAlg = hashAlg;
}
/**
* #return the mgf
*/
public long getMgf() {
return mgf;
}
/**
* #param mgf the mgf to set
*/
public void setMgf(long mgf) {
this.mgf = mgf;
}
/**
* #return the sLen
*/
public long getsLen() {
return sLen;
}
/**
* #param sLen the sLen to set
*/
public void setsLen(long sLen) {
this.sLen = sLen;
}
/**
* #return the ulMaxObjectCount
*/
public long getUlMaxObjectCount() {
return ulMaxObjectCount;
}
/**
* #param ulMaxObjectCount the ulMaxObjectCount to set
*/
public void setUlMaxObjectCount(long ulMaxObjectCount) {
this.ulMaxObjectCount = ulMaxObjectCount;
}
/**
* #return the signFinalArgument
*/
public int getSignFinalArgument() {
return signFinalArgument;
}
/**
* #param signFinalArgument the signFinalArgument to set
*/
public void setSignFinalArgument(int signFinalArgument) {
this.signFinalArgument = signFinalArgument;
}
/**
* #return the id
*/
public long getId() {
return id;
}
/**
* #param id the id to set
*/
public void setId(long id) {
this.id = id;
}
}
'''
Thank You!
Java 9 up no longer puts the standard-library in jar files (rt.jar, etc) but they are still there. Your problem is probably (though I didn't read through all the code and certainly can't test without your hardware) that Java 9 up also introduces modules. Much as in Java forever your code can reference another class or interface (or static member therof) by its simple name only if you import it or it is in the same package as your code (if any) or the special package java.lang, now in 9 up you can only access a package if it is in the same module as your code or the special java.base module or your module and/or the other module explicitly allow the access; the explicit specification closet to older Java is an 'open'.
Thus the quick solution is to add to your java command (explicitly or via _JAVA_OPTS or equivalent) --add-opens jdk.crypto.cryptoki/sun.security.pkcs11.*=ALL-UNNAMED -- this should produce substantially the same result as running on 8 (or lower).
The official solution is to put your code in a module -- either by itself or with other related code -- that requires the (or each) needed module, given it exports the needed parts, which I haven't checked for yours. However, since your code apparently isn't even in a package yet, putting it in a module will be some work.
When I run my code for a method calculating the height of a binary search tree, it results in a Stack Overflow error, but only for trees with more than one node (BSTElements in my program). I have read that this is due to a faulty recursive call, but cannot identify the problem in my code.
public int getHeight() {
return getHeight(this.getRoot());
}
private int getHeight(BSTElement<String,MorseCharacter> element) {
int height=0;
if (element == null) {
return -1;
}
int leftHeight = getHeight(element.getLeft());
int rightHeight = getHeight(element.getRight());
if (leftHeight > rightHeight) {
height = leftHeight;
} else {
height = rightHeight;
}
return height +1;
}
Here is full code:
public class MorseCodeTree {
private static BSTElement<String, MorseCharacter> rootElement;
public BSTElement<String, MorseCharacter> getRoot() {
return rootElement;
}
public static void setRoot(BSTElement<String, MorseCharacter> newRoot) {
rootElement = newRoot;
}
public MorseCodeTree(BSTElement<String,MorseCharacter> element) {
rootElement = element;
}
public MorseCodeTree() {
rootElement = new BSTElement("Root", "", new MorseCharacter('\0', null));
}
public int getHeight() {
return getHeight(this.getRoot());
}
private int getHeight(BSTElement<String,MorseCharacter> element) {
if (element == null) {
return -1;
} else {
int leftHeight = getHeight(element.getLeft());
int rightHeight = getHeight(element.getRight());
if (leftHeight < rightHeight) {
return rightHeight + 1;
} else {
return leftHeight + 1;
}
}
}
public static boolean isEmpty() {
return (rootElement == null);
}
public void clear() {
rootElement = null;
}
public static void add(BSTElement<String,MorseCharacter> newElement) {
BSTElement<String, MorseCharacter> target = rootElement;
String path = "";
String code = newElement.getKey();
for (int i=0; i<code.length(); i++) {
if (code.charAt(i)== '.') {
if (target.getLeft()!=null) {
target=target.getLeft();
} else {
target.setLeft(newElement);
target=target.getLeft();
}
} else {
if (target.getRight()!=null) {
target=target.getRight();
} else {
target.setRight(newElement);
target=target.getRight();
}
}
}
MorseCharacter newMorseChar = newElement.getValue();
newElement.setLabel(Character.toString(newMorseChar.getLetter()));
newElement.setKey(Character.toString(newMorseChar.getLetter()));
newElement.setValue(newMorseChar);
}
public static void main(String[] args) {
MorseCodeTree tree = new MorseCodeTree();
BufferedReader reader;
try {
reader = new BufferedReader(new FileReader(file));
String line = reader.readLine();
while (line != null) {
String[] output = line.split(" ");
String letter = output[0];
MorseCharacter morseCharacter = new MorseCharacter(letter.charAt(0), output[1]);
BSTElement<String, MorseCharacter> bstElement = new BSTElement(letter, output[1], morseCharacter);
tree.add(bstElement);
line = reader.readLine();
System.out.println(tree.getHeight());
}
reader.close();
} catch (IOException e) {
System.out.println("Exception" + e);
}
There doesn't appear to be anything significantly wrong1 with the code that you have shown us.
If this code is giving a StackOverflowException for a small tree, that most likely means that your tree has been created incorrectly and has a cycle (loop) in it. If your recursive algorithm encounters a cycle in the "tree" it will loop until the stack overflows2.
To be sure of this diagnosis, we need to see an MVCE which includes all code needed to construct an example tree that exhibits thie behavior.
1 - There is possibly an "off by one" error in the height calculation, but that won't cause a stack overflow.
2 - Current Java implementations do not do tail-call optimization.
I have a class which represents an ArrayList stored in a file, because I need an ArrayList with multiple gigabytes of data in it which is obviously too large to be stored in memory. The data is represented by a class called Field and the function Field.parse() is just for converting the Field into a String and the other way.
The Field class stores a list of (strange) chess pieces and their coordinates.
My class is working fine, but it takes a long time to add an element to the file and I need my program to run as fast as possible. Does anyone know a more efficient/faster way of doing things?
Also, I am not allowed to use external libraries/apis. Please keep that in mind.
This is the class which is responsible for storing Field objects in a temp file:
private File file;
private BufferedReader reader;
private BufferedWriter writer;
public FieldSaver() {
try {
file = File.createTempFile("chess-moves-", ".temp");
System.out.println(file.getAbsolutePath());
} catch (IOException e) {
e.printStackTrace();
}
}
public void add(Field field) {
try {
File temp = File.createTempFile("chess-moves-", ".temp");
writer = new BufferedWriter(new FileWriter(temp));
reader = new BufferedReader(new FileReader(file));
String line;
while((line = reader.readLine()) != null ) {
writer.write(line);
writer.newLine();
}
reader.close();
writer.write(field.parse());
writer.close();
file.delete();
file = new File(temp.getAbsolutePath());
} catch (IOException e) {
e.printStackTrace();
}
}
public Field get(int n) {
try {
reader = new BufferedReader(new FileReader(file));
for (int i = 0; i < n; i++) {
reader.readLine();
}
String line = reader.readLine();
reader.close();
return Field.parse(line);
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
And this is the Field class:
private WildBoar wildBoar;
private HuntingDog[] huntingDogs;
private Hunter hunter;
private int size;
#Override
public String toString() {
String result = "Wildschwein: " + wildBoar.toString();
for (HuntingDog dog : huntingDogs) {
result += "; Hund: " + dog.toString();
}
return result + "; Jäger: " + hunter.toString();
}
#Override
public boolean equals(Object obj) {
if (obj instanceof Field) {
Field field = (Field) obj;
HuntingDog[] dogs = field.getHuntingDogs();
return wildBoar.equals(field.getWildBoar()) && hunter.equals(field.getHunter()) && huntingDogs[0].equals(dogs[0]) && huntingDogs[1].equals(dogs[1]) && huntingDogs[2].equals(dogs[2]);
}
return false;
}
public Field(int size, WildBoar wildBoar, HuntingDog[] huntingDogs, Hunter hunter) {
this.size = size;
this.wildBoar = wildBoar;
this.huntingDogs = huntingDogs;
this.hunter = hunter;
}
public WildBoar getWildBoar() {
return wildBoar;
}
public HuntingDog[] getHuntingDogs() {
return huntingDogs;
}
public Hunter getHunter() {
return hunter;
}
public int getSize() {
return size;
}
public static Field parse(String s) {
String[] arr = s.split(",");
WildBoar boar = WildBoar.parse(arr[0]);
Hunter hunter = Hunter.parse(arr[1]);
HuntingDog[] dogs = new HuntingDog[arr.length - 2];
for(int i = 2; i < arr.length; i++) {
dogs[i - 2] = HuntingDog.parse(arr[i]);
}
return new Field(8, boar, dogs, hunter);
}
public String parse() {
String result = wildBoar.parse() + "," + hunter.parse();
for(HuntingDog dog : huntingDogs) {
result += "," + dog.parse();
}
return result;
}
Here's an MCVE to do what you want, based on the information you provided.
You can run it and see that it can save a Field to the file and get a Field by index very quickly.
The Fields are constant length, so you can get a Field by index by going to byte offset of index times field length in bytes. This would be significantly more difficult if the field were not constant length.
import java.io.Closeable;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
public class FieldSaver implements Closeable {
public static void main(String[] args) throws IOException {
File f = File.createTempFile("chess-moves-", ".temp");
try (FieldSaver test = new FieldSaver(f);) {
for (byte i = 0; i < 100; i++) {
test.add(new Field(8, new WildBoar(i, i), new Hunter(i, i), new HuntingDog[] {
new HuntingDog(i, i),
new HuntingDog(i, i),
new HuntingDog(i, i) }));
}
// Get a few Fields by index
System.out.println(test.get(0));
System.out.println(test.get(50));
System.out.println(test.get(99));
// EOF exception, there is no Field 100
// System.out.println(test.get(100));
}
}
private final RandomAccessFile data;
public FieldSaver(File f) throws FileNotFoundException {
data = new RandomAccessFile(f, "rw");
}
public void add(Field field) throws IOException {
data.seek(data.length());
field.write(data);
}
public Field get(int index) throws IOException {
data.seek(index * Field.STORAGE_LENGTH_BYTES);
return Field.read(data);
}
public void close() throws IOException { data.close(); }
static abstract class Piece {
protected byte xPos;
protected byte yPos;
public Piece(DataInput data) throws IOException {
xPos = data.readByte();
yPos = data.readByte();
}
public Piece(byte xPos, byte yPos) {
this.xPos = xPos;
this.yPos = yPos;
}
public void write(DataOutput data) throws IOException {
data.writeByte(xPos);
data.writeByte(yPos);
}
public String toString() { return "[" + xPos + ", " + yPos + "]"; }
}
static class Hunter extends Piece {
public Hunter(byte xPos, byte yPos) { super(xPos, yPos); }
public Hunter(DataInput data) throws IOException { super(data); }
}
static class HuntingDog extends Piece {
public HuntingDog(byte xPos, byte yPos) { super(xPos, yPos); }
public HuntingDog(DataInput data) throws IOException { super(data); }
}
static class WildBoar extends Piece {
public WildBoar(byte xPos, byte yPos) { super(xPos, yPos); }
public WildBoar(DataInput data) throws IOException { super(data); }
}
static class Field {
// size of boar + hunter + 3 dogs
public static final int STORAGE_LENGTH_BYTES = 2 + 2 + (3 * 2);
private int size;
private WildBoar boar;
private Hunter hunter;
private final HuntingDog[] dogs;
public Field(int size, WildBoar wildBoar, Hunter hunter, HuntingDog[] huntingDogs) {
this.size = size;
this.boar = wildBoar;
this.hunter = hunter;
this.dogs = huntingDogs;
}
public String toString() {
String result = "Wildschwein: " + boar.toString();
for (HuntingDog dog : dogs) {
result += "; Hund: " + dog.toString();
}
return result + "; Jäger: " + hunter.toString();
}
public static Field read(DataInput data) throws IOException {
WildBoar boar = new WildBoar(data);
Hunter hunter = new Hunter(data);
HuntingDog[] dogs = new HuntingDog[3];
for (int i = 0; i < 3; i++) {
dogs[i] = new HuntingDog(data);
}
return new Field(8, boar, hunter, dogs);
}
public void write(DataOutput data) throws IOException {
boar.write(data);
hunter.write(data);
for (HuntingDog dog : dogs) {
dog.write(data);
}
}
}
}
Use a Map implementation like Cache from ehcache. This library will optimize for you so you don't have to handle writing and reading to disk and manage when to keep it in memory or on disk. You can just use it as a normal map. You probably want a map instead of a list for faster lookup so the library can optimize even more for you.
http://www.ehcache.org/
CacheManager cacheManager = CacheManagerBuilder.newCacheManagerBuilder()
.withCache("preConfigured",
CacheConfigurationBuilder.newCacheConfigurationBuilder(Long.class, String.class,
ResourcePoolsBuilder.heap(100))
.build())
.build(true);
Cache<Long, String> preConfigured
= cacheManager.getCache("preConfigured", Long.class, String.class);
I'm doing a simple MessageRenderer.
It's specification:
Render message based on an Context (it's a map that's contains all key/value pair parameters)
Supports simple render such as: Your username is << username >>. Assume username in the context is barcelona and the result will be Your username is Barcelona.
Supported function-like object. Example: Current time is << now() >>, now(): is an object that will returns a string of current date time. And result will be: Current time is 2011-05-30
Each parameter of function can also be templated: Current time is << now( << date_format >> ) >> . This template returns a string of current date time with format is the value of key 'date_format' retrieved from the Context. Assume date_format in Context is dd/MM/yyyy and the result will be: Current time is 30/05/2011
Each parameter of function can also be templated with a different method call: Time is << now_locale ( << getLocale() >> ). Assume that getLocale() is an function object that will be return a locale is en_US and the result will be: Time is 2011/05/30 11:20:34 PM
Template can be nested. Example: Your user name is << << username >> >>. It means, Key username has value param1, Key param1 has value is barcelona so the final result will be: Your user name is Barcelona.
My classes and interfaces:
RenderContext.java
public interface RenderContext {
public String getParameter(String key);
}
MessageRenderer.java
public interface MessageRenderer {
public String render(String s, RenderContext... context);
}
MethodExpressionEvaluator.java
// Using this class to implements the method evaluation, such as now(), now_locale()
public interface MethodExpressionEvaluator {
public String evaluate(String[] methodParams, RenderContext... context);
}
AbstractMessageRenderer.java
public abstract class AbstractMessageRenderer implements MessageRenderer {
public static final String DEFAULT_NULL = "###";
public static final String PLACEHOLDER_START_TOKEN = "<<";
public static final String PLACEHOLDER_END_TOKEN = ">>";
protected int lenPlaceholderStartToken = 0;
protected int lenPlaceholderEndToken = 0;
protected String nullToken;
protected String placeholderStartToken;
protected String placeholderEndToken;
protected boolean escape = true;
public AbstractMessageRenderer() {
placeholderStartToken = PLACEHOLDER_START_TOKEN;
placeholderEndToken = PLACEHOLDER_END_TOKEN;
lenPlaceholderStartToken = placeholderStartToken.length();
lenPlaceholderEndToken = placeholderEndToken.length();
nullToken = DEFAULT_NULL;
}
public String getNullToken() {
return nullToken;
}
public void setNullToken(String defaultNull) {
this.nullToken = defaultNull;
}
public String getPlaceholderStartToken() {
return placeholderStartToken;
}
public void setPlaceholderStartToken(String placeholderStartToken) {
this.placeholderStartToken = placeholderStartToken;
lenPlaceholderStartToken = placeholderStartToken.length();
}
public String getPlaceholderEndToken() {
return placeholderEndToken;
}
public void setPlaceholderEndToken(String placeholderEndToken) {
this.placeholderEndToken = placeholderEndToken;
lenPlaceholderEndToken = placeholderEndToken.length();
}
public boolean isEscape() {
return escape;
}
public boolean getEscape() {
return escape;
}
public void setEscape(boolean escape) {
this.escape = escape;
}
public String getParam(String key, RenderContext... context) {
if(context != null)
{
for(RenderContext param:context)
{
if(param != null)
{
String value = param.getParameter(key);
if(!StringUtil.isEmpty(value))
{
return value;
}
}
}
}
return nullToken;
}
public String render(String s, RenderContext... context) {
// handle trivial cases of empty template or no placeholders
if (s == null)
{
Log4j.app.debug("Message is null in template. Cannot render null message.");
return nullToken;
}
if (context == null)
{
Log4j.app.debug("RenderContext is null. Cannot render message with null RenderContext.");
return nullToken;
}
if (s.indexOf(placeholderStartToken) < 0)
{
return s;
}
String msg = nullToken;
try
{
// private int renderTemplate(Renderable r, String src, StringBuffer dst, String nil, int i, String[] marks, StringBuffer end,boolean escapes)
msg = doRender(s, context);
}
catch (Exception e)
{
Log4j.app.error("Exception in rendering template: " + e.getMessage(), e);
return nullToken;
}
return msg;
}
protected abstract String doRender(String s, RenderContext... context);
}
MethodExpressionRenderer.java
public class MethodExpressionRenderer extends AbstractMessageRenderer {
private boolean inSingleQuote = false;
private boolean inDoubleQuote=false;
private int placeholders;
private Stack<String> methodStack;
private String[] endTokens;
private String marker;
private List<String> methodParams;
private String prefix = "&";
public MethodExpressionRenderer() {
super();
methodStack = new Stack<String>();
marker = ",";
endTokens = new String[] { placeholderEndToken, marker, "(", ")" };
methodParams = new ArrayList<String>();
}
public String getPrefix() {
return prefix;
}
public void setPrefix(String prefix) {
this.prefix = prefix;
}
public String getMarker() {
return marker;
}
public void setMarker(String marker) {
this.marker = marker;
endTokens = new String[] { placeholderEndToken, marker };
}
#Override
public void setPlaceholderEndToken(String placeholderEndToken) {
super.setPlaceholderEndToken(placeholderEndToken);
endTokens = new String[] { placeholderEndToken, marker };
}
protected String doRender(String s, RenderContext... context) {
StringBuffer sb = new StringBuffer();
try
{
renderTemplate(s, sb, nullToken, 0, endTokens, null, context);
}
catch (Exception e)
{
Log4j.app.error("Exception in rendering method expression message emplate: " + e.getMessage(), e);
return nullToken;
}
return sb.toString();
}
private int renderTemplate(String src, StringBuffer dst, String nil, int i, String[] marks, StringBuffer end, RenderContext... context) {
int len = src.length();
while (i < len)
{
char c = src.charAt(i);
if (escape)
{
if (c=='\\')
{
i++;
char ch = src.charAt(i);
if(inSingleQuote)
{
if(ch=='\'')
{
inSingleQuote=false;
}
}
else if(inDoubleQuote)
{
if(ch=='"')
{
inDoubleQuote=false;
}
}
else
{
if(ch=='\'')
{
inSingleQuote=true;
}
else if(ch=='"')
{
inDoubleQuote=true;
}
}
dst.append(ch);
i++;
continue;
}
}
if(inSingleQuote)
{
if(c=='\'')
{
inSingleQuote=false;
}
}
else if(inDoubleQuote)
{
if(c=='"')
{
inDoubleQuote=false;
}
}
else
{
if(c=='\'')
{
inSingleQuote=true;
}
else if(c=='"')
{
inDoubleQuote=true;
}
}
// check for end marker
if (marks != null && !inSingleQuote && !inDoubleQuote)
{
for (int m = 0; m < marks.length; m++)
{
// If one of markers found
if (src.regionMatches(i, marks[m], 0, marks[m].length()))
{
// return marker if required
if (end != null)
{
end.append(marks[m]);
}
return i+marks[m].length();
}
}
}
// check for start of placeholder
if (src.regionMatches(i, placeholderStartToken, i, lenPlaceholderStartToken))
{
synchronized(this)
{
++placeholders;
}
i = renderPlaceholder(src, dst, nil, i, new ArrayList<String>(), context);
continue;
}
// just add plain character
if(c != '\'' && c!= '"')
{
dst.append(c);
}
i++;
}
return i;
}
private int renderPlaceholder(String src, StringBuffer dst, String nil, int i, List<String> params, RenderContext... context){
StringBuffer token = new StringBuffer(); // placeholder token
StringBuffer end = new StringBuffer(); // placeholder end marker
String value;
i = renderTemplate(src, token, nil, i+lenPlaceholderStartToken, endTokens, end);
String sToken = token.toString().trim();
String sEnd = end.toString().trim();
boolean isFunction = sEnd.equals("(");
// This is method name
if(isFunction && placeholders > methodStack.size())
{ // Method
synchronized(this)
{
methodStack.push(sToken); // put method into stack
}
}
else if(!isFunction && (methodStack.size()==0) && sEnd.equals(placeholderEndToken)) // Single template param such as <<param>>
{
value = getParam(sToken, context);
if(value != null)
{
if(value.trim().startsWith(placeholderStartToken))
{
value = render(src, context);
}
dst.append(value);
return i;
}
}
// TODO: Process method parameters to invoke
//.... ?????????
// Found end method token ')'
// Pop method out of stack to invoke
if ( (methodStack.size() >0) && (sEnd.length() == 0 || sEnd.equals(")")))
{
String method = null;
synchronized(this)
{
// Pop method out of stack to invoke
method = methodStack.pop();
--placeholders;
dst.append(invokeMethodEvaluator(method, methodParams.toArray(new String[0]), context));
methodParams.clear();
}
}
return i;
}
// Currently this method just implement to test so it just printout the method name
// and its parameter
// We can register MethodExpressionEvaluator to process
protected String invokeMethodEvaluator(String method, String[] params, RenderContext... context){
StringBuffer result = new StringBuffer();
result.append("[ ")
.append(method)
.append(" ( ");
if(params != null)
{
for(int i=0; i<params.length; i++)
{
result.append(params[i]);
if(i != params.length-1)
{
result.append(" , ");
}
}
}
result.append(" ) ")
.append(" ] ");
return result.toString();
}
}
We can easily register more method to the renderer to invoke. Each method will be an object and can be reused. But I'm in trouble how to resolve the nested method parameter. Can anyone give me an advice how we can process nested template of method parameter to invoke??? The line has TODO. Will my code in on the right way???
When you evaluate something like << count( << getTransId() >> ) >> you can either:
perform direct-evaluation as you parse, and push each function onto a stack, so that once you've evaluated getTransId() you pop the stack and use the return value (from the stack) as an argument for count(), or
you can build a parse tree to represent all the function calls that will be made, and then evaluate your parse tree after building it. (Building a tree probably doesn't buy you anything; since you're writing a template engine there is probably no high-level tree operation 'optimizations' that you could perform.)
An excellent little book I really enjoyed was Language Implementation Patterns by Parr. He walks through building simple to complex languages, and covers decisions like this in some depth. (Yes, he uses the ANTLR parser generator throughout, but your code looks like you're familiar enough with hand-generated parsers that different tools won't be a distraction for you.)
I found the bug and fixed it.
This is my new source:
// AbstractMethodExpressionRenderer.java
public class AbstractMethodExpressionRenderer extends AbstractMessageRenderer {
private boolean inSingleQuote = false;
private boolean inDoubleQuote=false;
private Stack<MethodExpressionDescriptor> functionStack;
private String[] endTokens;
private String marker;
private String prefix = "~";
public AbstractMethodExpressionRenderer() {
super();
functionStack = new Stack<MethodExpressionDescriptor>();
marker = ",";
endTokens = new String[] { placeholderEndToken, "(", ")", };
}
private class MethodExpressionDescriptor {
public List<String> params;
public String function;
public MethodExpressionDescriptor() {
params = new ArrayList<String>();
}
public MethodExpressionDescriptor(String name) {
this();
this.function = name;
}
}
public String getPrefix() {
return prefix;
}
public void setPrefix(String prefix) {
this.prefix = prefix;
}
public String getMarker() {
return marker;
}
public void setMarker(String marker) {
this.marker = marker;
endTokens = new String[] { placeholderEndToken, marker };
}
#Override
public void setPlaceholderEndToken(String placeholderEndToken) {
super.setPlaceholderEndToken(placeholderEndToken);
endTokens = new String[] { placeholderEndToken, marker };
}
protected String doRender(String s, RenderContext... context) {
StringBuffer sb = new StringBuffer();
try
{
renderTemplate(s, sb, nullToken, 0, endTokens, null, context);
}
catch (Exception e)
{
Log4j.app.error("Exception in rendering method expression message emplate: " + e.getMessage(), e);
return nullToken;
}
return sb.toString();
}
private int renderTemplate(String src, StringBuffer dst, String nil, int i, String[] marks, StringBuffer end, RenderContext... context) {
int len = src.length();
while (i < len)
{
char c = src.charAt(i);
if (escape)
{
if (c=='\\')
{
i++;
char ch = src.charAt(i);
if(inSingleQuote)
{
if(ch=='\'')
{
inSingleQuote=false;
}
}
else if(inDoubleQuote)
{
if(ch=='"')
{
inDoubleQuote=false;
}
}
else
{
if(ch=='\'')
{
inSingleQuote=true;
}
else if(ch=='"')
{
inDoubleQuote=true;
}
}
dst.append(ch);
i++;
continue;
}
}
if(inSingleQuote)
{
if(c=='\'')
{
inSingleQuote=false;
}
}
else if(inDoubleQuote)
{
if(c=='"')
{
inDoubleQuote=false;
}
}
else
{
if(c=='\'')
{
inSingleQuote=true;
}
else if(c=='"')
{
inDoubleQuote=true;
}
}
// check for end marker
if (marks != null && !inSingleQuote && !inDoubleQuote)
{
for (int m = 0; m < marks.length; m++)
{
// If one of markers found
if (src.regionMatches(i, marks[m], 0, marks[m].length()))
{
// return marker if required
if (end != null)
{
end.append(marks[m]);
}
return i+marks[m].length();
}
}
}
// check for start of placeholder
if (src.regionMatches(i, placeholderStartToken, 0, lenPlaceholderStartToken))
{
i = renderPlaceholder(src, dst, nil, i, new ArrayList<String>(), context);
continue;
}
// just add plain character
if(c != '\'' && c!= '"')
{
dst.append(c);
}
i++;
}
return i;
}
/**
* Render a placeholder as follows:
*
* <<key>>: Simple render, key value map
* <<function(<<param1>>, <<param2>>)>> : Function object render
*
* #param src
* #param dst
* #param nil
* #param i
* #param params
* #param context
* #return
*/
private int renderPlaceholder(String src, StringBuffer dst, String nil, int i, List<String> params, RenderContext... context){
StringBuffer token = new StringBuffer(); // placeholder token
StringBuffer end = new StringBuffer(); // placeholder end marker
String value = null;
// Simple key
i = renderTemplate(src, token, nil, i+lenPlaceholderStartToken, endTokens, end, context);
String sToken = token.toString().trim();
String sEnd = end.toString().trim();
// This is method name
if(sEnd.equals("("))
{ // Method
functionStack.add(new MethodExpressionDescriptor(sToken));
}
else // Try to resolve value
{
if(sToken.startsWith(placeholderStartToken))
{
value = render(sToken, context);
}
else if(sToken.startsWith(prefix))
{
if(functionStack.size() > 0)
{
functionStack.peek().params.add(sToken.substring(1));
}
return i;
}
else
{
value = getParam(sToken, context);
}
}
if (sEnd.length() == 0 || sEnd.equals(placeholderEndToken))
{
// No method found but found the end of placeholder token
if(functionStack.size() == 0)
{
if(value != null)
{
dst.append(value);
}
else
{
dst.append(nil);
}
}
else
{
functionStack.peek().params.add(value);
}
}
else
{
if(value != null)
{
value = value.trim();
}
if(end.substring(0, 1).equals("(") ||
end.substring(0, 1).equals(marker))
{
// right hand side is remainder of placeholder
StringBuffer tmp = new StringBuffer();
end = new StringBuffer();
i = renderTemplate(src, tmp, nil, i, endTokens, end, context);
}
if(end.substring(0, 1).equals(")"))
{
if ( functionStack.size() > 0 )
{
// Pop method out of stack to invoke
MethodExpressionDescriptor descriptor = functionStack.pop();
if(functionStack.size() > 0 )
{
functionStack.peek().params.add(invokeMethodEvaluator(descriptor.function, descriptor.params.toArray(new String[0]), context));
}
else
{
dst.append(invokeMethodEvaluator(descriptor.function, descriptor.params.toArray(new String[0]), context));
}
end = new StringBuffer();
StringBuffer tmp = new StringBuffer();
i = renderTemplate(src, tmp, nil, i, endTokens, end, context);
}
}
}
return i;
}
protected String invokeMethodEvaluator(String method, String[] params, RenderContext... context){
StringBuffer result = new StringBuffer();
result.append("[ ")
.append(method)
.append(" ( ");
if(params != null)
{
for(int i=0; i<params.length; i++)
{
result.append(params[i]);
if(i != params.length-1)
{
result.append(" , ");
}
}
}
result.append(" ) ")
.append(" ] ");
return result.toString();
}
}