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HSQLDB example source code file (NumberSequence.java)
The HSQLDB NumberSequence.java source code/* Copyright (c) 2001-2008, The HSQL Development Group * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the HSQL Development Group nor the names of its * contributors may be used to endorse or promote products derived from this * software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG, * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ 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; } } Other HSQLDB examples (source code examples)Here is a short list of links related to this HSQLDB NumberSequence.java source code file: |
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