library/src/main/java/org/apache/apex/malhar/lib/appdata/schemas/Schema.java

/**
 * 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.apex.malhar.lib.appdata.schemas;

import java.util.Map;

/**
 * This interface represents schemas such as: {@link DimensionalSchema} and {@link SnapShotSchema}.
 * @since 3.0.0
 */
public interface Schema
{
  /**
   * Default schema ID.
   */
  public static final int DEFAULT_SCHEMA_ID = 0;

  public static final String FIELD_SCHEMA_KEYS = "schemaKeys";
  public static final String FIELD_SCHEMA = "schema";
  public static final String FIELD_SCHEMA_TAGS = "tags";

  /**
   * The id of the schema. This is relevant for operators which support serving multiple schemas,
   * in which each schema will need a unique id.
   * @return The id of the schema.
   */
  public int getSchemaID();

  /**
   * Gets the type of the schema (e.x. point, dimensions).
   * @return The type of the schema.
   */
  public String getSchemaType();

  /**
   * Gets the version of the schema.
   * @return The version of the schema.
   */
  public String getSchemaVersion();

  /**
   * Gets the AppData json to serve in response to a schema query.
   * @return The AppData json to serve in response to a schema query.
   */
  public String getSchemaJSON();

  /**
   * Gets the schema keys which are used to send queries targeted to this schema.
   * @return The schema keys which are used to send queries targeted to this schema.
   */
  public Map<String, String> getSchemaKeys();

  /**
   * Sets the schema keys for this schema.
   * @param schemaKeys The schema keys for this schema.
   */
  public void setSchemaKeys(Map<String, String> schemaKeys);
}