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/*
* Copyright 2006-2010 Amazon Technologies, Inc. or its affiliates.
* Amazon, Amazon.com and Carbonado are trademarks or registered trademarks
* of Amazon Technologies, Inc. or its affiliates. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.amazon.carbonado.sequence;
import com.amazon.carbonado.FetchException;
import com.amazon.carbonado.PersistException;
/**
* Produces values for sequences.
*
* @author Brian S O'Neill
* @author bcastill
* @see com.amazon.carbonado.Sequence
* @since 1.2
*/
public interface SequenceValueProducer {
/**
* Returns the next value from the sequence, which may wrap negative if all
* positive values are exhausted. When sequence wraps back to initial
* value, the sequence is fully exhausted, and an exception is thrown to
* indicate this.
*
* <p>Note: this method throws PersistException even for fetch failures
* since this method is called by insert operations. Insert operations can
* only throw a PersistException.
*
* @throws PersistException for fetch/persist failure or if sequence is exhausted.
*/
public long nextLongValue() throws PersistException;
/**
* Returns the next value from the sequence, which may wrap negative if all
* positive values are exhausted. When sequence wraps back to initial
* value, the sequence is fully exhausted, and an exception is thrown to
* indicate this.
*
* <p>Note: this method throws PersistException even for fetch failures
* since this method is called by insert operations. Insert operations can
* only throw a PersistException.
*
* @throws PersistException for fetch/persist failure or if sequence is
* exhausted for int values.
*/
public int nextIntValue() throws PersistException;
/**
* Returns the next decimal string value from the sequence, which remains
* positive. When sequence wraps back to initial value, the sequence is
* fully exhausted, and an exception is thrown to indicate this.
*
* <p>Note: this method throws PersistException even for fetch failures
* since this method is called by insert operations. Insert operations can
* only throw a PersistException.
*
* @throws PersistException for fetch/persist failure or if sequence is exhausted.
*/
public String nextDecimalValue() throws PersistException;
/**
* Returns the next numerical string value from the sequence, which remains
* positive. When sequence wraps back to initial value, the sequence is
* fully exhausted, and an exception is thrown to indicate this.
*
* <p>Note: this method throws PersistException even for fetch failures
* since this method is called by insert operations. Insert operations can
* only throw a PersistException.
*
* @param radix use 2 for binary, 10 for decimal, 16 for hex. Max is 36.
* @param minLength ensure string is at least this long (padded with zeros if
* necessary) to ensure proper string sort
* @throws PersistException for fetch/persist failure or if sequence is exhausted.
*/
public String nextNumericalValue(int radix, int minLength) throws PersistException;
/**
* Allow any unused reserved values to be returned for re-use. If the
* repository is shared by other processes, then reserved values might not
* be returnable.
*
* <p>This method should be called during the shutdown process of a
* repository, although calling it does not invalidate this
* SequenceValueGenerator. If getNextValue is called again, it will reserve
* values again.
*
* @return true if reserved values were returned
*/
public boolean returnReservedValues() throws FetchException, PersistException;
}
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