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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.commons.id;

/**
 * Abstract superclass for StringIdentifierGenerator implementations.
 *
 * @author Commons-Id team
 * @version $Id: AbstractStringIdentifierGenerator.java 480488 2006-11-29 08:57:26Z bayard $
 */
public abstract class AbstractStringIdentifierGenerator implements StringIdentifierGenerator {

    /**
     * Maximum length for a numeric string representing a long value.
     */
    protected static final int MAX_LONG_NUMERIC_VALUE_LENGTH =
    Long.toString(Long.MIN_VALUE).length();

    /**
     * Number of alphanumeric characters.
     */
    protected static final int ALPHA_NUMERIC_CHARSET_SIZE = 36;

    /**
     * Maximum length for an alphanumeric string representing a long value.
     */
    protected static final int MAX_LONG_ALPHANUMERIC_VALUE_LENGTH =
    Long.toString(Long.MAX_VALUE, ALPHA_NUMERIC_CHARSET_SIZE).length();

    /**
     * Maximum length for a numeric string representing an integer value.
     */
    protected static final int MAX_INT_NUMERIC_VALUE_LENGTH =
    Integer.toString(Integer.MIN_VALUE).length();

    /**
     * Maximum length for an alphanumeric string representing an integer value.
     */
    protected static final int MAX_INT_ALPHANUMERIC_VALUE_LENGTH =
    Integer.toString(Integer.MAX_VALUE, ALPHA_NUMERIC_CHARSET_SIZE).length();

    /**
     * Default size of an alphanumeric identifier.
     */
    protected static final int DEFAULT_ALPHANUMERIC_IDENTIFIER_SIZE = 15;

    /**
     * Constructor.
     */
    protected AbstractStringIdentifierGenerator() {
        super();
    }

    public abstract String nextStringIdentifier();

    /**
     * Returns the maximum length (number or characters) for an identifier
     * from this sequence.
     * 
     * The default implementation returns {@link #INFINITE_MAX_LENGTH}. Implementations
     * with bounded length identifiers should override this method to
     * return the maximum length of a generated identifier.
     *
     * @return {@inheritDoc}
     */
    public long maxLength() {
        return INFINITE_MAX_LENGTH;
    }

    /**
     * Returns the minimum length (number of characters) for an identifier
     * from this sequence.
     *
     * The default implementation returns 0. Implementations
     * with identifiers having a postive minimum length should override this
     * method to return the maximum length of a generated identifier.
     *
     * @return {@inheritDoc}
     */
    public long minLength() {
        return 0;
    }

    public Object nextIdentifier() {
        return nextStringIdentifier();
    }
}