/*
* 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.geode.cache.query;
// import java.util.*;
import org.apache.geode.cache.*;
/**
* An index that is built over the data stored in a GemFire {@link Region}.
* <p>
* For a description of the types of indexes that GemFire currently supports, see
* {@linkplain IndexType}.
* <p>
* An index is specified using a name, indexedExpression, fromClause, and optionally a
* projectionAttributes.
* <p>
* The name uniquely identifies the index to for the statistics services in GemFire.
* <p>
* The indexedExpression is the lookup value for the index. The way that an indexedExpression is
* specified and used varies depending on the type of index. For more information, see
* {@linkplain IndexType}.
* <p>
* The fromClause specifies the collection(s) of objects that the index ranges over, and must
* contain one and only one region path.
* <p>
* The optional projectAttributes specifies a tranformation that is done on the values and is used
* for pre-computing a corresponding projection as defined in a query.
*
* @see QueryService#createIndex(String, IndexType, String, String)
* @see IndexType
*
* @since GemFire 4.0
*/
public interface Index {
/**
* Returns the unique name of this index
*/
public String getName();
/**
* Get the index type
*
* @return the type of index
*/
public IndexType getType();
/**
* The Region this index is on
*
* @return the Region for this index
*/
public Region<?, ?> getRegion();
/**
* Get statistics information for this index.
*
* @throws UnsupportedOperationException for indexes created on Maps. Example: Index on Maps with
* expression p['key']. <br>
* On Map type indexes the stats are created at individual key level that can be viewed in
* VSD stats.
*/
public IndexStatistics getStatistics();
/**
* Get the original fromClause for this index.
*/
public String getFromClause();
/**
* Get the canonicalized fromClause for this index.
*/
public String getCanonicalizedFromClause();
/**
* Get the original indexedExpression for this index.
*/
public String getIndexedExpression();
/**
* Get the canonicalized indexedExpression for this index.
*/
public String getCanonicalizedIndexedExpression();
/**
* Get the original projectionAttributes for this expression.
*
* @return the projectionAttributes, or "*" if there were none specified at index creation.
*/
public String getProjectionAttributes();
/**
* Get the canonicalized projectionAttributes for this expression.
*
* @return the projectionAttributes, or "*" if there were none specified at index creation.
*/
public String getCanonicalizedProjectionAttributes();
}