org.hibernate.id.enhanced.Optimizer.java Source code

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Here is the source code for org.hibernate.id.enhanced.Optimizer.java

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/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.id.enhanced;

import java.io.Serializable;

import org.hibernate.id.IntegralDataTypeHolder;

/**
 * Performs optimization on an optimizable identifier generator.  Typically
 * this optimization takes the form of trying to ensure we do not have to
 * hit the database on each and every request to get an identifier value.
 * <p/>
 * Optimizers work on constructor injection.  They should provide
 * a constructor with the following arguments <ol>
 * <li>java.lang.Class - The return type for the generated values</li>
 * <li>int - The increment size</li>
 * </ol>
 *
 * @author Steve Ebersole
 */
public interface Optimizer {
    /**
     * Generate an identifier value accounting for this specific optimization.
     *
     * All known implementors are synchronized. Consider carefully if a new
     * implementation could drop this requirement.
     *
     * @param callback Callback to access the underlying value source.
     * @return The generated identifier value.
     */
    public Serializable generate(AccessCallback callback);

    /**
     * A common means to access the last value obtained from the underlying
     * source.  This is intended for testing purposes, since accessing the
     * underlying database source directly is much more difficult.
     *
     * @return The last value we obtained from the underlying source;
     * null indicates we have not yet consulted with the source.
     */
    public IntegralDataTypeHolder getLastSourceValue();

    /**
     * Retrieves the defined increment size.
     *
     * @return The increment size.
     */
    public int getIncrementSize();

    /**
     * Are increments to be applied to the values stored in the underlying
     * value source?
     *
     * @return True if the values in the source are to be incremented
     * according to the defined increment size; false otherwise, in which
     * case the increment is totally an in memory construct.
     */
    public boolean applyIncrementSizeToSourceValues();
}