src/main/java/com/sleepycat/persist/model/EntityMetadata.java

/*-
 * Copyright (C) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
 *
 * This file was distributed by Oracle as part of a version of Oracle Berkeley
 * DB Java Edition made available at:
 *
 * http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
 *
 * Please see the LICENSE file included in the top-level directory of the
 * appropriate version of Oracle Berkeley DB Java Edition for a copy of the
 * license and additional information.
 */

package com.sleepycat.persist.model;

import java.io.Serializable;
import java.util.Map;

/**
 * The metadata for a persistent entity class.  An entity class may be
 * specified with the {@link Entity} annotation.
 *
 * <p>{@code EntityMetadata} objects are thread-safe.  Multiple threads may
 * safely call the methods of a shared {@code EntityMetadata} object.</p>
 *
 * @author Mark Hayes
 */
public class EntityMetadata implements Serializable {

    private static final long serialVersionUID = 4224509631681963159L;

    private String className;
    private PrimaryKeyMetadata primaryKey;
    private Map<String, SecondaryKeyMetadata> secondaryKeys;

    /**
     * Used by an {@code EntityModel} to construct entity metadata.
     *
     * @param className the class name.
     * @param primaryKey the primary key metadata.
     * @param secondaryKeys the secondary key metadata.
     */
    public EntityMetadata(String className,
                          PrimaryKeyMetadata primaryKey,
                          Map<String, SecondaryKeyMetadata> secondaryKeys) {
        this.className = className;
        this.primaryKey = primaryKey;
        this.secondaryKeys = secondaryKeys;
    }

    /**
     * Returns the name of the entity class.
     *
     * @return the name of the entity class.
     */
    public String getClassName() {
        return className;
    }

    /**
     * Returns the primary key metadata for this entity.  Note that the primary
     * key field may be declared in this class or in a subclass. This metadata
     * may be specified using the {@link PrimaryKey} annotation.
     *
     * @return the primary key metadata.
     */
    public PrimaryKeyMetadata getPrimaryKey() {
        return primaryKey;
    }

    /**
     * Returns an unmodifiable map of key name to secondary key metadata, or
     * an empty map if no secondary keys are defined for this entity.  The
     * returned map contains a mapping for each secondary key of this entity,
     * including secondary keys declared in subclasses and superclasses.  This
     * metadata may be specified using {@link SecondaryKey} annotations.
     *
     * @return the secondary key metadata.
     */
    public Map<String, SecondaryKeyMetadata> getSecondaryKeys() {
        return secondaryKeys;
    }

    @Override
    public boolean equals(Object other) {
        if (other instanceof EntityMetadata) {
            EntityMetadata o = (EntityMetadata) other;
            return ClassMetadata.nullOrEqual(className, o.className) &&
                   ClassMetadata.nullOrEqual(primaryKey, o.primaryKey) &&
                   ClassMetadata.nullOrEqual(secondaryKeys, o.secondaryKeys);
        } else {
            return false;
        }
    }

    @Override
    public int hashCode() {
        return ClassMetadata.hashCode(className) +
               ClassMetadata.hashCode(primaryKey) +
               ClassMetadata.hashCode(secondaryKeys);
    }
}