package org.exist.xquery.modules.counter;
import org.apache.log4j.Logger;
import org.exist.EXistException;
import org.exist.dom.QName;
import org.exist.storage.BrokerPool;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.BooleanValue;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.IntegerValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
/**
* @author Jasper Linthorst (jasper.linthorst@gmail.com)
*
*/
public class CounterFunctions extends BasicFunction {
private Counters counters = null;
protected static final Logger logger = Logger.getLogger(CounterFunctions.class);
public final static FunctionSignature createCounter =
new FunctionSignature(
new QName("create", CounterModule.NAMESPACE_URI, CounterModule.PREFIX),
"Create a unique counter named $counter-name.",
new SequenceType[]{
new FunctionParameterSequenceType("counter-name", Type.ITEM, Cardinality.EXACTLY_ONE,
"Name of the counter.")
},
new FunctionReturnSequenceType(Type.LONG, Cardinality.ZERO_OR_ONE,
"the value of the newly created counter."));
public final static FunctionSignature createCounterAndInit =
new FunctionSignature(
new QName("create", CounterModule.NAMESPACE_URI, CounterModule.PREFIX),
"Create a unique counter named $counter-name and initialize it with value $init-value.",
new SequenceType[]{
new FunctionParameterSequenceType("counter-name", Type.ITEM, Cardinality.EXACTLY_ONE,
"Name of the counter."),
new FunctionParameterSequenceType("init-value", Type.LONG, Cardinality.EXACTLY_ONE,
"The initial value of the counter.")
},
new FunctionReturnSequenceType(Type.LONG, Cardinality.ZERO_OR_ONE,
"the value of the newly created counter."));
public final static FunctionSignature nextValue =
new FunctionSignature(
new QName("next-value", CounterModule.NAMESPACE_URI, CounterModule.PREFIX),
"Increment the counter $counter-name and return its new value.",
new SequenceType[]{
new FunctionParameterSequenceType("counter-name", Type.ITEM, Cardinality.EXACTLY_ONE,
"Name of the counter.")
},
new FunctionReturnSequenceType(Type.LONG, Cardinality.ZERO_OR_ONE,
"the new value of the specified counter," +
" or -1 if the counter does not exist."));
public final static FunctionSignature destroyCounter =
new FunctionSignature(
new QName("destroy", CounterModule.NAMESPACE_URI, CounterModule.PREFIX),
"Destroy the counter named $counter-name.",
new SequenceType[]{
new FunctionParameterSequenceType("counter-name", Type.ITEM, Cardinality.EXACTLY_ONE,
"Name of the counter.")
},
new FunctionReturnSequenceType(Type.BOOLEAN, Cardinality.ZERO_OR_ONE,
"boolean value true() if removal as successful, otherwise return value false()."));
public CounterFunctions(XQueryContext context, FunctionSignature signature) {
super(context, signature);
// Setup counters
String counterDir = (String) context.getBroker().getConfiguration()
.getProperty(BrokerPool.PROPERTY_DATA_DIR);
logger.debug("Counters directory: "+counterDir);
// Get reference to counters object
try {
if(counters==null){
counters = Counters.getInstance(counterDir);
}
} catch (EXistException ex) {
logger.error("Unable to initialize counters. "+ex.getMessage(), ex);
}
}
/* (non-Javadoc)
* @see org.exist.xquery.BasicFunction#eval(org.exist.xquery.value.Sequence[], org.exist.xquery.value.Sequence)
*/
public Sequence eval(Sequence[] args, Sequence contextSequence)
throws XPathException {
// Precondition check
if(counters==null){
throw new XPathException("Counters are not initialized.");
}
String counterName = args[0].getStringValue();
if (getSignature().equals(createCounter)) {
try {
if (counterName.contains(Counters.DELIMITER)) {
throw new EXistException("Invalid name for counter, character '"
+ Counters.DELIMITER + "' is not allowed.");
} else {
return new IntegerValue(counters.createCounter(counterName), Type.LONG);
}
} catch (EXistException e) {
logger.error(e.getMessage());
return Sequence.EMPTY_SEQUENCE;
}
} else if (getSignature().equals(createCounterAndInit)) {
try {
Long initValue = Long.parseLong(args[1].getStringValue());
if (counterName.contains(Counters.DELIMITER)) {
throw new EXistException("Invalid name for counter, character '"
+ Counters.DELIMITER + "' is not allowed.");
} else {
return new IntegerValue( counters.createCounter(counterName, initValue), Type.LONG);
}
} catch (EXistException e) {
logger.error(e.getMessage());
return Sequence.EMPTY_SEQUENCE;
}
} else {
try {
if (getSignature().equals(destroyCounter)) {
return new BooleanValue(counters.destroyCounter(counterName));
} else if (getSignature().equals(nextValue)) {
return new IntegerValue(counters.nextValue(counterName), Type.LONG);
} else {
return Sequence.EMPTY_SEQUENCE;
}
} catch (Exception e) {
logger.error(e.getMessage(), e);
return Sequence.EMPTY_SEQUENCE;
}
}
}
}