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*
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*
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*
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package org.hsqldb;
import org.hsqldb.HsqlNameManager.HsqlName;
/**
* Maintains a sequence of numbers.
*
* @author fredt@users
* @since 1.7.2
* @version 1.7.2
*/
public class NumberSequence {
HsqlName name;
// original start value - used in CREATE and ALTER commands
private long startValue;
// present value
private long currValue;
// last value
private long lastValue;
private long increment;
private int dataType;
/**
* constructor with initial value and increment;
*/
public NumberSequence(HsqlName name, long value, long increment,
int type) {
this.name = name;
startValue = currValue = lastValue = value;
this.increment = increment;
dataType = type;
}
/**
* principal getter for the next sequence value
*/
synchronized long getValue() {
long value = currValue;
currValue += increment;
return value;
}
/**
* getter for a given value
*/
synchronized long getValue(long value) {
if (value >= currValue) {
currValue = value;
currValue += increment;
return value;
} else {
return value;
}
}
/** @todo fredt - check against max value of type */
Object getValueObject() {
long value = currValue;
currValue += increment;
Object result;
if (dataType == Types.INTEGER) {
result = new Integer((int) value);
} else {
result = new Long(value);
}
return result;
}
/**
* reset to start value
*/
void reset() {
// no change if called before getValue() or called twice
lastValue = currValue = startValue;
}
/**
* get next value without incrementing
*/
public long peek() {
return currValue;
}
/**
* true if one or more values were retreived since the last resetWasUsed
*/
boolean wasUsed() {
return lastValue != currValue;
}
/**
* reset the wasUsed flag
*/
void resetWasUsed() {
lastValue = currValue;
}
/**
* reset to new initial value
*/
public void reset(long value) {
startValue = currValue = lastValue = value;
}
void reset(long value, long increment) {
reset(value);
this.increment = increment;
}
int getType() {
return dataType;
}
public HsqlName getName() {
return name;
}
public String getSchemaName() {
return name.schema.name;
}
long getIncrement() {
return increment;
}
}