org.hibernate.engine.spi.IdentifierValue.java Source code

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Here is the source code for org.hibernate.engine.spi.IdentifierValue.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.engine.spi;

import java.io.Serializable;

import org.hibernate.internal.CoreLogging;

import org.jboss.logging.Logger;

/**
 * A strategy for determining if an identifier value is an identifier of
 * a new transient instance or a previously persistent transient instance.
 * The strategy is determined by the <tt>unsaved-value</tt> attribute in
 * the mapping file.
 *
 * @author Gavin King
 */
public class IdentifierValue implements UnsavedValueStrategy {
    private static final Logger LOG = CoreLogging.logger(IdentifierValue.class);

    private final Serializable value;

    /**
     * Always assume the transient instance is newly instantiated
     */
    public static final IdentifierValue ANY = new IdentifierValue() {
        @Override
        public final Boolean isUnsaved(Object id) {
            LOG.trace("ID unsaved-value strategy ANY");
            return Boolean.TRUE;
        }

        @Override
        public Serializable getDefaultValue(Object currentValue) {
            return (Serializable) currentValue;
        }

        @Override
        public String toString() {
            return "SAVE_ANY";
        }
    };

    /**
     * Never assume the transient instance is newly instantiated
     */
    public static final IdentifierValue NONE = new IdentifierValue() {
        @Override
        public final Boolean isUnsaved(Object id) {
            LOG.trace("ID unsaved-value strategy NONE");
            return Boolean.FALSE;
        }

        @Override
        public Serializable getDefaultValue(Object currentValue) {
            return (Serializable) currentValue;
        }

        @Override
        public String toString() {
            return "SAVE_NONE";
        }
    };

    /**
     * Assume the transient instance is newly instantiated if the identifier
     * is null.
     */
    public static final IdentifierValue NULL = new IdentifierValue() {
        @Override
        public final Boolean isUnsaved(Object id) {
            LOG.trace("ID unsaved-value strategy NULL");
            return id == null;
        }

        @Override
        public Serializable getDefaultValue(Object currentValue) {
            return null;
        }

        @Override
        public String toString() {
            return "SAVE_NULL";
        }
    };

    /**
     * Assume nothing.
     */
    public static final IdentifierValue UNDEFINED = new IdentifierValue() {
        @Override
        public final Boolean isUnsaved(Object id) {
            LOG.trace("ID unsaved-value strategy UNDEFINED");
            return null;
        }

        @Override
        public Serializable getDefaultValue(Object currentValue) {
            return null;
        }

        @Override
        public String toString() {
            return "UNDEFINED";
        }
    };

    protected IdentifierValue() {
        this.value = null;
    }

    /**
     * Assume the transient instance is newly instantiated if
     * its identifier is null or equal to <tt>value</tt>
     */
    public IdentifierValue(Serializable value) {
        this.value = value;
    }

    /**
     * Does the given identifier belong to a new instance?
     */
    @Override
    public Boolean isUnsaved(Object id) {
        LOG.tracev("ID unsaved-value: {0}", value);
        return id == null || id.equals(value);
    }

    @Override
    public Serializable getDefaultValue(Object currentValue) {
        return value;
    }

    @Override
    public String toString() {
        return "identifier unsaved-value: " + value;
    }
}