com.facebook.presto.jdbc.internal.spi.TableIdentity Maven / Gradle / Ivy

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/*
 * 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.facebook.presto.jdbc.internal.spi;

/**
 * A TableIdentity keeps all the information needed to determine if a table
 * has changed.
 * 
 * The TableIdentity is saved as serialized bytes.
 * 
 * TableIdentity can be used to ensure that the tables used in view definition
 * have not changed (i.e. dropped and added back again) since the view was created.
 * However, TableIdentity can be the same after a table is renamed.
 */
public interface TableIdentity
{
    /**
     * Serialize the table identity in a manner which is backwards compatible across releases.
     */
    byte[] serialize();

    /**
     * Compare the identities of tables, even for deserialized instances from different releases.
     */
    boolean equals(Object o);

    /**
     * Must be implemented to properly compare the equality of TableIdentity.
     */
    int hashCode();
}