ovidiu 02/02/08 16:19:50
Added: src/scratchpad/schecoon/src/org/apache/cocoon/scheme/sitemap
ContinuationsManager.java
Log:
Manages the continuation objects.
Revision Changes Path
1.1
xml-cocoon2/src/scratchpad/schecoon/src/org/apache/cocoon/scheme/sitemap/ContinuationsManager.java
Index: ContinuationsManager.java
===================================================================
package org.apache.cocoon.scheme.sitemap;
import java.lang.Math;
import java.security.SecureRandom;
import java.util.HashMap;
import sisc.ContinuationException;
import sisc.Interpreter;
import sisc.ModuleAdapter;
import sisc.data.ImmutableString;
import sisc.data.Value;
/**
* Manages the continuation objects.
*
* @author <a href="mailto:[EMAIL PROTECTED]";>Ovidiu Predescu</a>
* @since February 8, 2002
*/
public class ContinuationsManager extends ModuleAdapter
{
static protected int CONTINUATION_ID_LENGTH = 20;
public String getModuleName()
{
return "Continuations Manager";
}
public float getModuleVersion()
{
return 1.0f;
}
public static final int
REGISTER = 1,
GET = 2,
REMOVE = 3;
/**
* Random generator for continuation identifiers.
*/
protected SecureRandom random = null;
/**
* Array of bytes used internally to generate the continuation
* identifier.
*/
protected byte[] bytes;
/**
* Association between string identifiers and continuation objects.
*/
protected HashMap continuations = new HashMap();
public ContinuationsManager()
throws Exception
{
random = SecureRandom.getInstance("SHA1PRNG");
random.setSeed(System.currentTimeMillis());
bytes = new byte[CONTINUATION_ID_LENGTH];
define("continuations:register", REGISTER);
define("continuations:get", GET);
define("continuations:remove", REMOVE);
}
/**
* The SISC evaluator function for this module. Executes the actual
* Java code corresponding to the Scheme functions defined by the
* module.
*
* @param primid an <code>int</code> value
* @param r an <code>Interpreter</code> value
* @return a <code>Value</code> value
* @exception ContinuationException if an error occurs
*/
public Value eval(int primid, Interpreter r)
throws ContinuationException
{
switch (r.vlr.length) {
// One argument functions
case 1:
switch (primid) {
case REGISTER:
return registerContinuation(r.vlr[0]);
case GET:
return getContinuationFromId(r.vlr[0]);
case REMOVE:
return removeContinuationId(r.vlr[0]);
}
}
throw new RuntimeException("Invalid number of arguments to function "
+ r.acc + ", got " + r.vlr.length);
}
/**
* Registers a continuation object and returns an identifier
* associated with it.
*
* @param kont a continuation object
* @return a <code>Value</code> value, representing the string identifier
*/
public Value registerContinuation(Value kont)
{
Value kontId;
char[] result = new char[bytes.length * 2];
String continuationId = null;
synchronized(continuations) {
do {
random.nextBytes(bytes);
for (int i = 0; i < CONTINUATION_ID_LENGTH; i++) {
byte ch = bytes[i];
result[2 * i] = Character.forDigit(Math.abs(ch >> 4), 16);
result[2 * i + 1] = Character.forDigit(Math.abs(ch & 0x0f), 16);
}
continuationId = new String(result);
} while (continuations.containsKey(continuationId));
continuations.put(continuationId, kont);
}
return new ImmutableString(continuationId);
}
/**
* Given a Scheme string identifier, return the corresponding
* continuation.
*
* @param id the string identifier
* @return the continuation object, or <code>null</code> if no such
* continuation is registered.
*/
public Value getContinuationFromId(Value id)
{
String continuationId = string(id);
return (Value)continuations.get(continuationId);
}
/**
* Given a continuation id, remove the associated continuation from
* the store.
*
* @param id the string identifier for the continuation
* @return the continuation object removed
*/
public Value removeContinuationId(Value id)
{
synchronized(continuations) {
return (Value)continuations.remove(string(id));
}
}
}
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