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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.openjpa.kernel;
import java.io.Serializable;
import java.util.Iterator;
import java.util.Map;
import org.apache.openjpa.kernel.exps.AggregateListener;
import org.apache.openjpa.kernel.exps.Constant;
import org.apache.openjpa.kernel.exps.FilterListener;
import org.apache.openjpa.kernel.exps.QueryExpressions;
import org.apache.openjpa.kernel.exps.Value;
import org.apache.openjpa.lib.rop.ResultObjectProvider;
import org.apache.openjpa.lib.util.OrderedMap;
import org.apache.openjpa.lib.util.collections.LinkedMap;
import org.apache.openjpa.meta.ClassMetaData;
import org.apache.openjpa.meta.FieldMetaData;
/**
* Component that executes queries against the datastore. For
* expression-based queries, consider subclassing
* {@link ExpressionStoreManagerQuery}.
*
* @author Abe White
* @since 0.4.0
*/
public interface StoreQuery
extends QueryOperations, Serializable {
// linkedmap doesn't allow a size of 0, so use 1
// This is deprecated
LinkedMap EMPTY_PARAMS = new LinkedMap(1);
OrderedMap> EMPTY_ORDERED_PARAMS = new OrderedMap<>();
ClassMetaData[] EMPTY_METAS = new ClassMetaData[0];
String[] EMPTY_STRINGS = new String[0];
Object[] EMPTY_OBJECTS = new Object[0];
Class[] EMPTY_CLASSES = new Class[0];
boolean[] EMPTY_BOOLEANS = new boolean[0];
/**
* Return the query context that has been set.
*/
QueryContext getContext();
/**
* Set the current query context. This will be called before use.
*/
void setContext(QueryContext ctx);
/**
* This is invoked when the user or a facade creates a new query with
* an object that the system does not recognize. Return true if
* the object is recognized by the store, false otherwise.
*/
boolean setQuery(Object query);
/**
* Return the standard filter listener for the given tag, or null.
*/
FilterListener getFilterListener(String tag);
/**
* Return the standard filter listener for the given tag, or null.
*/
AggregateListener getAggregateListener(String tag);
/**
* Create a new key for caching compiled query information. May be null.
*/
Object newCompilationKey();
/**
* Create a new compilation for this query. May be null.
*/
Object newCompilation();
/**
* Get the current compilation for this query. If it is null, do not create.
*/
Object getCompilation();
/**
* Populate internal data from compilation.
*/
void populateFromCompilation(Object comp);
/**
* Invalidate any internal compilation state.
*/
void invalidateCompilation();
/**
* True if this query supports datastore execution, false if it
* can only run in memory.
*/
boolean supportsDataStoreExecution();
/**
* True if this query supports in-memory execution, false if it
* can only run against the datastore.
*/
boolean supportsInMemoryExecution();
/**
* Return an executor for in-memory execution of this query.
* Executors must be cachable and thread safe. If this class returns
* true from {@link #supportsAbstractExecutors}, the given metadata
* will always be for the candidate class of this query, or possibly
* null if the candidate class is not itself persistence capable (like
* an interface or abstract base class). Otherwise, the given type will
* be a mapped class.
*
* @param subs whether to include dependent mapped subclasses in the
* results; independent subclasses should never be included
*/
Executor newInMemoryExecutor(ClassMetaData meta, boolean subs);
/**
* Return an executor for datastore execution of this query.
* Executors must be cachable and thread safe. If this class returns
* true from {@link #supportsAbstractExecutors}, the given metadata
* will always be for the candidate class of this query, or possibly
* null if the candidate class is not itself persistence capable (like
* an interface or abstract base class). Otherwise, the given type will
* be a mapped class.
*
* @param subs whether to include dependent mapped subclasses in the
* results; independent subclasses should never be included
*/
Executor newDataStoreExecutor(ClassMetaData meta, boolean subs);
/**
* Return true if this query supports execution against abstract or
* interface types. Returns false by default, meaning we will only
* request executors for persistent classes. In this case, we will
* automatically combine the results of the executors for all
* implementing classes if we execute a query for an interface for
* abstract type.
*/
boolean supportsAbstractExecutors();
/**
* Whether this query requires a candidate class.
*/
boolean requiresCandidateType();
/**
* Whether this query requires parameters to be declared.
*/
boolean requiresParameterDeclarations();
/**
* Whether this query supports declared parameters.
*/
boolean supportsParameterDeclarations();
Object evaluate(Object value, Object ob, Object[] params,
OpenJPAStateManager sm);
/**
* A query result range.
*/
public static class Range {
public long start = 0L;
public long end = Long.MAX_VALUE;
public boolean lrs = false;
public Range() {
}
public Range(long start, long end) {
this.start = start;
this.end = end;
}
}
/**
* An executor provides a uniform interface to the mechanism for executing
* either an in-memory or datastore query. In the common case, the
* {@link #executeQuery} method will be called before other methods,
* though this is not guaranteed.
*
* @author Marc Prud'hommeaux
*/
public interface Executor {
/**
* Return the result of executing this query with the given parameter
* values. If this query is a projection and this executor does not
* pack results itself, each element of the returned result object
* provider should be an object array containing the projection values.
*
* @param lrs true if the query result should be treated as a
* large result set, assuming the query is not an
* aggregate and does not have grouping
* @see #isPacking
*/
ResultObjectProvider executeQuery(StoreQuery q, Object[] params,
Range range);
/**
* Deleted the objects that result from the execution of the
* query, retuning the number of objects that were deleted.
*/
Number executeDelete(StoreQuery q, Object[] params);
/**
* Updates the objects that result from the execution of the
* query, retuning the number of objects that were updated.
*/
Number executeUpdate(StoreQuery q, Object[] params);
/**
* Return a description of the commands that will be sent to
* the datastore in order to execute the query.
*/
String[] getDataStoreActions(StoreQuery q, Object[] params,
Range range);
/**
* Validate components of query.
*/
void validate(StoreQuery q);
/**
* Mutate the given range to set any range information stored in
* the query string and/or parameters.
*/
void getRange(StoreQuery q, Object[] params, Range range);
/**
* Extract the value of the orderIndexth ordering
* expression in {@link Query#getOrderingClauses} from the
* given result object. The result object will be an object from
* the result object provider returned from {@link #executeQuery}.
* This method is used when several result lists have to be merged
* in memory. If this exeuctor's parent query supports executors on
* abstract or interface classes, this method will not be used.
*
* @see StoreQuery#supportsAbstractExecutors
*/
Object getOrderingValue(StoreQuery q, Object[] params,
Object resultObject, int orderIndex);
/**
* Return the ordering direction for all ordering clauses, or empty
* array if none.
*/
boolean[] getAscending(StoreQuery q);
/**
* Return true if this executor packs projections into the result
* class itself. Executors for query languages that allow projections
* without result clauses must return true and perform the result
* packing themselves.
*/
boolean isPacking(StoreQuery q);
/**
* If this is not a projection but the candidate results are placed
* into a result class with an alias, return that alias.
*/
String getAlias(StoreQuery q);
/**
* Return the alias for each projection element, or empty array
* if not a projection.
*/
String[] getProjectionAliases(StoreQuery q);
/**
* Return the expected types of the projections used by this query,
* or an empty array if not a projection.
*/
Class[] getProjectionTypes(StoreQuery q);
/**
* Return an array of all persistent classes used in this query, or
* empty array if unknown.
*/
ClassMetaData[] getAccessPathMetaDatas(StoreQuery q);
/**
* Returns the operation this executor is meant to execute.
*
* @see QueryOperations
*/
int getOperation(StoreQuery q);
/**
* Return true if the compiled query is an aggregate.
*/
boolean isAggregate(StoreQuery q);
boolean isDistinct(StoreQuery q);
/**
* Whether the compiled query has grouping.
*/
boolean hasGrouping(StoreQuery q);
/**
* Return a map of parameter names to types. The returned
* {@link Map#entrySet}'s {@link Iterator} must return values in the
* order in which they were declared or used.
*/
OrderedMap> getOrderedParameterTypes(StoreQuery q);
/**
* Return a map of parameter names to types. The returned
* {@link Map#entrySet}'s {@link Iterator} must return values in the
* order in which they were declared or used.
*
* Warning: Deprecated. Use {@linkplain #getOrderedParameterTypes(StoreQuery)} instead.
*/
@Deprecated LinkedMap getParameterTypes(StoreQuery q);
/**
* Return an array from the given user parameter values.
* The array ordering is same as what this executor expects for its
* executeXXX() methods as its Object[] parameters.
* If the given userParams is null or empty return an empty array
* rather than null.
*
* @return array with parameter values ordered in the same way as this
* receiver's executeXXX() method expects.
*
* @since 2.0.0
*/
Object[] toParameterArray(StoreQuery q, Map userParams);
/**
* Returns the result class, if any.
*/
Class getResultClass(StoreQuery q);
ResultShape getResultShape(StoreQuery q);
/**
* Return a map of {@link FieldMetaData} to update
* {@link Constant}s, in cases where this query is for a bulk update.
*/
Map getUpdates (StoreQuery q);
/**
* Return the parsed query expressions for our candidate types.
* The expressions are available only after query has been parsed.
*
* @since 2.0.0
*/
QueryExpressions[] getQueryExpressions();
}
}