com.gemstone.gemfire.cache.query.Index Maven / Gradle / Ivy
/*
* Copyright (c) 2010-2015 Pivotal Software, Inc. All rights reserved.
*
* 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. See accompanying
* LICENSE file.
*/
package com.gemstone.gemfire.cache.query;
//import java.util.*;
import com.gemstone.gemfire.cache.*;
/**
* An index that is built over the data stored in a GemFire {@link
* Region}.
*
* For a description of the types of indexes that GemFire currently supports,
* see {@linkplain IndexType}.
*
* An index is specified using a name, indexedExpression, fromClause, and
* optionally a projectionAttributes.
*
* The name uniquely identifies the index to for the statistics services in GemFire.
*
* 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}.
*
* The fromClause specifies the collection(s) of objects that the index ranges
* over, and must contain one and only one region path.
*
* 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
*
* @author Eric Zoerner
* @since 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.
*/
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();
}