Java
Java
PC/SC Wait for Smart Card Status Change (Inserted, Removed from Reader, etc.)
See more SCard Examples
Demonstrates how to synchronously wait for a status change, such as for a smart card to be inserted into a reader, or removed from a reader.Note: This functionality was introduced in Chilkat v9.5.0.87.
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import com.chilkatsoft.*;
public class ChilkatExample {
static {
try {
System.loadLibrary("chilkat");
} catch (UnsatisfiedLinkError e) {
System.err.println("Native code library failed to load.\n" + e);
System.exit(1);
}
}
public static void main(String argv[])
{
boolean success = false;
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
CkSCard scard = new CkSCard();
// First establish a context to the PC/SC Resource Manager
success = scard.EstablishContext("user");
if (success == false) {
System.out.println(scard.lastErrorText());
return;
}
// First we'll examine the state of all connected readers to see which have smartcards already inserted..
// Get JSON containing information about the smartcards currently inserted into readers.
// This also includes information about USB security tokens.
CkJsonObject json = new CkJsonObject();
success = scard.FindSmartcards(json);
if (success == false) {
System.out.println(scard.lastErrorText());
return;
}
// When writing this example, I have 3 smart card readers plugged into my system.
// One of them has a smart card inserted.
// Here's the JSON returned by FindSmartcards...
// {
// "reader": [
// {
// "name": "Alcor Micro USB Smart Card Reader 0",
// "state": "empty"
// },
// {
// "name": "Generic Smart Card Reader Interface 0",
// "state": "present",
// "vendorName": "Generic",
// "serialNumber": "3230303730383138303030303030303030",
// "systemName": "Generic Smart Card Reader Interface 0",
// "card": {
// "atr": "3BFC180000813180459067464A00641606F2727E00E0",
// "windows": {
// "miniDriver": "tagliov70px.dll",
// "cryptoProvider": "Microsoft Base Smart Card Crypto Provider",
// "keyStorageProvider": "Microsoft Smart Card Key Storage Provider"
// }
// }
// },
// {
// "name": "SCM Microsystems Inc. SCR33x USB Smart Card Reader 0",
// "state": "empty"
// }
// ]
// }
json.put_EmitCompact(false);
System.out.println(json.emit());
System.out.println(" ");
// We can iterate over the JSON to find the readers with a smart card already inserted..
String name;
CkStringBuilder sbState = new CkStringBuilder();
int i = 0;
int count_i = json.SizeOfArray("reader");
while (i < count_i) {
json.put_I(i);
name = json.stringOf("reader[i].name");
sbState.Clear();
json.StringOfSb("reader[i].state",sbState);
if (sbState.Contains("present",true) == true) {
System.out.println(name + " has a smart card inserted.");
}
else {
System.out.println(name + " does not have a smart card inserted.");
}
i = i+1;
}
System.out.println(" ");
// Now let's begin the code to wait for a change (where a smart card gets inserted or removed)
// Get the list of all readers.
CkStringTable stReaders = new CkStringTable();
success = scard.ListReaders(stReaders);
if (success == false) {
System.out.println(scard.lastErrorText());
return;
}
// Show the reader names..
int numReaders = stReaders.get_Count();
i = 0;
while (i < numReaders) {
System.out.println(i + ": " + stReaders.stringAt(i));
i = i+1;
}
// Sample output from the above loop.
// 0: Alcor Micro USB Smart Card Reader 0
// 1: Generic Smart Card Reader Interface 0
// 2: SCM Microsystems Inc. SCR33x USB Smart Card Reader 0
//
// Synchronously wait 30 seconds for a card to be inserted or removed from any of the above readers.
CkJsonObject json2 = new CkJsonObject();
success = scard.GetStatusChange(30000,stReaders,json2);
if (success == false) {
System.out.println(scard.lastErrorText());
return;
}
System.out.println(" ");
// Let's see what happened...
json2.put_EmitCompact(false);
System.out.println(json2.emit());
System.out.println(" ");
// This is what json2 contains.
// A card was inserted into the reader named "SCM Microsystems Inc. SCR33x USB Smart Card Reader 0"
// The "numChanged" indicates that one reader's status changed.
// The "changed":true indicates the reader that changed. The state is now "present".
// {
// "numChanged": 1,
// "reader": [
// {
// "name": "Alcor Micro USB Smart Card Reader 0",
// "changed": false,
// "state": "empty"
// },
// {
// "name": "Generic Smart Card Reader Interface 0",
// "changed": false,
// "state": "present",
// "atr": "3BFC180000813180459067464A00641606F2727E00E0"
// },
// {
// "name": "SCM Microsystems Inc. SCR33x USB Smart Card Reader 0",
// "changed": true,
// "state": "present",
// "atr": "3BDF96FF8131FE455A018048494443313158587300011B09"
// }
// ]
// }
// Find the reader that changed...
boolean changed;
String state;
String atr;
int numChanged = json2.IntOf("numChanged");
System.out.println("number of readers with a changed state: " + numChanged);
i = 0;
count_i = json2.SizeOfArray("reader");
while (i < count_i) {
json2.put_I(i);
changed = json2.BoolOf("reader[i].changed");
if (changed == true) {
name = json2.stringOf("reader[i].name");
state = json2.stringOf("reader[i].state");
System.out.println("Changed: ");
System.out.println(" reader name: " + name);
System.out.println(" new state: " + state);
// If a card is now in this reader, we should have the ATR of the card..
if (json2.HasMember("reader[i].atr") == true) {
atr = json2.stringOf("reader[i].atr");
System.out.println(" ATR of card inserted into this reader: " + atr);
}
}
i = i+1;
}
// The output from the above loop:
// number of readers with a changed state: 1
// Changed:
// reader name: SCM Microsystems Inc. SCR33x USB Smart Card Reader 0
// new state: present
// ATR of card inserted into this reader: 3BDF96FF8131FE455A018048494443313158587300011B09
// Applications should always release the context when finished.
success = scard.ReleaseContext();
if (success == false) {
System.out.println(scard.lastErrorText());
}
}
}