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/*
 * 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.openjpa.kernel;

import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.commons.collections.map.LinkedMap;
import org.apache.openjpa.conf.OpenJPAConfiguration;
import org.apache.openjpa.kernel.exps.Subquery;
import org.apache.openjpa.kernel.exps.AbstractExpressionVisitor;
import org.apache.openjpa.kernel.exps.AggregateListener;
import org.apache.openjpa.kernel.exps.Constant;
import org.apache.openjpa.kernel.exps.ExpressionFactory;
import org.apache.openjpa.kernel.exps.ExpressionParser;
import org.apache.openjpa.kernel.exps.FilterListener;
import org.apache.openjpa.kernel.exps.InMemoryExpressionFactory;
import org.apache.openjpa.kernel.exps.Path;
import org.apache.openjpa.kernel.exps.QueryExpressions;
import org.apache.openjpa.kernel.exps.Resolver;
import org.apache.openjpa.kernel.exps.StringContains;
import org.apache.openjpa.kernel.exps.Val;
import org.apache.openjpa.kernel.exps.Value;
import org.apache.openjpa.kernel.exps.WildcardMatch;
import org.apache.openjpa.lib.rop.ListResultObjectProvider;
import org.apache.openjpa.lib.rop.RangeResultObjectProvider;
import org.apache.openjpa.lib.rop.ResultObjectProvider;
import org.apache.openjpa.lib.util.Localizer;
import org.apache.openjpa.meta.ClassMetaData;
import org.apache.openjpa.meta.FieldMetaData;
import org.apache.openjpa.meta.JavaTypes;
import org.apache.openjpa.util.ImplHelper;
import org.apache.openjpa.util.InvalidStateException;
import org.apache.openjpa.util.UnsupportedException;
import org.apache.openjpa.util.UserException;

/**
 * Implementation of an expression-based query, which can handle
 * String-based query expressions such as JPQL and JDOQL.
 * This implementation is suitable for in-memory operation.
 * Override the following methods to also support datastore operation:
 * 
    *
  • Override {@link #supportsDataStoreExecution} to return * true.
  • *
  • Override {@link #executeQuery}, {@link #executeDelete}, and * {@link #executeUpdate} to execute the query against the data store. * Keep in mind that the parameters passed to this method might be in use * by several threads in different query instances. Thus components like * the expression factory must either be thread safe, or this method must * synchronize on them.
  • *
  • Override {@link #getDataStoreActions} to return a representation of * the actions that will be taken on the data store. For use in visual * tools.
  • *
  • Override {@link #getExpressionFactory} to return a factory for creating * expressions in the datastore's language. The factory must be cachable.
  • *
* * @author Abe White */ public class ExpressionStoreQuery extends AbstractStoreQuery { private static final Localizer _loc = Localizer.forPackage (ExpressionStoreQuery.class); // maintain support for a couple of deprecated extensions private static final FilterListener[] _listeners = new FilterListener[]{ new StringContains(), new WildcardMatch(), }; private final ExpressionParser _parser; private transient Object _parsed; /** * Construct a query with a parser for the language. */ public ExpressionStoreQuery(ExpressionParser parser) { _parser = parser; } /** * Resolver used in parsing. */ public Resolver getResolver() { return new Resolver() { public Class classForName(String name, String[] imports) { return ctx.classForName(name, imports); } public FilterListener getFilterListener(String tag) { return ctx.getFilterListener(tag); } public AggregateListener getAggregateListener(String tag) { return ctx.getAggregateListener(tag); } public OpenJPAConfiguration getConfiguration() { return ctx.getStoreContext().getConfiguration(); } public QueryContext getQueryContext() { return ctx; } }; } /** * Allow direct setting of parsed state for facades that do parsing. * The facade should call this method twice: once with the query string, * and again with the parsed state. */ public boolean setQuery(Object query) { _parsed = query; return true; } public FilterListener getFilterListener(String tag) { for (int i = 0; i < _listeners.length; i++) if (_listeners[i].getTag().equals(tag)) return _listeners[i]; return null; } public Object newCompilation() { if (_parsed != null) return _parsed; return _parser.parse(ctx.getQueryString(), this); } public void populateFromCompilation(Object comp) { _parser.populate(comp, this); } public void invalidateCompilation() { _parsed = null; } public boolean supportsInMemoryExecution() { return true; } public Executor newInMemoryExecutor(ClassMetaData meta, boolean subs) { return new InMemoryExecutor(this, meta, subs, _parser, ctx.getCompilation()); } public Executor newDataStoreExecutor(ClassMetaData meta, boolean subs) { return new DataStoreExecutor(this, meta, subs, _parser, ctx.getCompilation()); } //////////////////////// // Methods for Override //////////////////////// /** * Execute the given expression against the given candidate extent. * * @param ex current executor * @param base the base type the query should match * @param types the independent candidate types * @param subclasses true if subclasses should be included in the results * @param facts the expression factory used to build the query for * each base type * @param parsed the parsed query values * @param params parameter values, or empty array * @param range result range * @return a provider for matching objects */ protected ResultObjectProvider executeQuery(Executor ex, ClassMetaData base, ClassMetaData[] types, boolean subclasses, ExpressionFactory[] facts, QueryExpressions[] parsed, Object[] params, Range range) { throw new UnsupportedException(); } /** * Execute the given expression against the given candidate extent * and delete the instances. * * @param ex current executor * @param base the base type the query should match * @param types the independent candidate types * @param subclasses true if subclasses should be included in the results * @param facts the expression factory used to build the query for * each base type * @param parsed the parsed query values * @param params parameter values, or empty array * @return a number indicating the number of instances deleted, * or null to execute the delete in memory */ protected Number executeDelete(Executor ex, ClassMetaData base, ClassMetaData[] types, boolean subclasses, ExpressionFactory[] facts, QueryExpressions[] parsed, Object[] params) { return null; } /** * Execute the given expression against the given candidate extent * and updates the instances. * * @param ex current executor * @param base the base type the query should match * @param types the independent candidate types * @param subclasses true if subclasses should be included in the results * @param facts the expression factory used to build the query for * each base type * @param parsed the parsed query values * @param params parameter values, or empty array * @return a number indicating the number of instances updated, * or null to execute the update in memory. */ protected Number executeUpdate(Executor ex, ClassMetaData base, ClassMetaData[] types, boolean subclasses, ExpressionFactory[] facts, QueryExpressions[] parsed, Object[] params) { return null; } /** * Return the commands that will be sent to the datastore in order * to execute the query, typically in the database's native language. * * @param base the base type the query should match * @param types the independent candidate types * @param subclasses true if subclasses should be included in the results * @param facts the expression factory used to build the query for * each base type * @param parsed the parsed query values * @param params parameter values, or empty array * @param range result range * @return a textual description of the query to execute */ protected String[] getDataStoreActions(ClassMetaData base, ClassMetaData[] types, boolean subclasses, ExpressionFactory[] facts, QueryExpressions[] parsed, Object[] params, Range range) { return StoreQuery.EMPTY_STRINGS; } /** * Return the assignable types for the given metadata whose expression * trees must be compiled independently. */ protected ClassMetaData[] getIndependentExpressionCandidates (ClassMetaData type, boolean subclasses) { return new ClassMetaData[]{ type }; } /** * Return an {@link ExpressionFactory} to use to create an expression to * be executed against an extent. Each factory will be used to compile * one filter only. The factory must be cachable. */ protected ExpressionFactory getExpressionFactory(ClassMetaData type) { throw new UnsupportedException(); } /** * Provides support for queries that hold query information * in a {@link QueryExpressions} instance. * * @author Marc Prud'hommeaux */ public static abstract class AbstractExpressionExecutor extends AbstractExecutor implements Executor { /** * Return the parsed query expressions for our candidate types. */ protected abstract QueryExpressions[] getQueryExpressions(); /** * Return the query expressions for one candidate type, or die if none. */ private QueryExpressions assertQueryExpression() { QueryExpressions[] exp = getQueryExpressions(); if (exp == null || exp.length < 1) throw new InvalidStateException(_loc.get("no-expressions")); return exp[0]; } /** * Throw proper exception if given value is a collection/map/array. */ protected void assertNotContainer(Value val, StoreQuery q) { // variables represent container elements, not the container itself if (val.isVariable()) return; Class type; if (val instanceof Path) { FieldMetaData fmd = ((Path) val).last(); type = (fmd == null) ? val.getType() : fmd.getDeclaredType(); } else type = val.getType(); switch (JavaTypes.getTypeCode(type)) { case JavaTypes.ARRAY: case JavaTypes.COLLECTION: case JavaTypes.MAP: throw new UserException(_loc.get("container-projection", q.getContext().getQueryString())); } } public final void validate(StoreQuery q) { QueryExpressions exps = assertQueryExpression(); ValidateGroupingExpressionVisitor.validate(q.getContext(), exps); } public void getRange(StoreQuery q, Object[] params, Range range) { QueryExpressions exps = assertQueryExpression(); if (exps.range.length == 0) return; if (exps.range.length == 2 && exps.range[0] instanceof Constant && exps.range[1] instanceof Constant) { try { range.start = ((Number) ((Constant) exps.range[0]). getValue(params)).longValue(); range.end = ((Number) ((Constant) exps.range[1]). getValue(params)).longValue(); return; } catch (ClassCastException cce) { // fall through to exception below } catch (NullPointerException npe) { // fall through to exception below } } throw new UserException(_loc.get("only-range-constants", q.getContext().getQueryString())); } public final Class getResultClass(StoreQuery q) { return assertQueryExpression().resultClass; } public final boolean[] getAscending(StoreQuery q) { return assertQueryExpression().ascending; } public final String getAlias(StoreQuery q) { return assertQueryExpression().alias; } public final String[] getProjectionAliases(StoreQuery q) { return assertQueryExpression().projectionAliases; } public final int getOperation(StoreQuery q) { return assertQueryExpression().operation; } public final boolean isAggregate(StoreQuery q) { return assertQueryExpression().isAggregate(); } public final boolean hasGrouping(StoreQuery q) { return assertQueryExpression().grouping.length > 0; } public final LinkedMap getParameterTypes(StoreQuery q) { return assertQueryExpression().parameterTypes; } public final Map getUpdates(StoreQuery q) { return assertQueryExpression().updates; } public final ClassMetaData[] getAccessPathMetaDatas(StoreQuery q) { QueryExpressions[] exps = getQueryExpressions(); if (exps.length == 1) return exps[0].accessPath; List metas = null; for (int i = 0; i < exps.length; i++) metas = Filters.addAccessPathMetaDatas(metas, exps[i].accessPath); if (metas == null) return StoreQuery.EMPTY_METAS; return (ClassMetaData[]) metas.toArray (new ClassMetaData[metas.size()]); } public boolean isPacking(StoreQuery q) { return false; } /** * Throws an exception if select or having clauses contain * non-aggregate, non-grouped paths. */ private static class ValidateGroupingExpressionVisitor extends AbstractExpressionVisitor { private final QueryContext _ctx; private boolean _grouping = false; private Set _grouped = null; private Value _agg = null; /** * Throw proper exception if query does not meet validation. */ public static void validate(QueryContext ctx, QueryExpressions exps) { if (exps.grouping.length == 0) return; ValidateGroupingExpressionVisitor visitor = new ValidateGroupingExpressionVisitor(ctx); visitor._grouping = true; for (int i = 0; i < exps.grouping.length; i++) exps.grouping[i].acceptVisit(visitor); visitor._grouping = false; if (exps.having != null) { Class cls = exps.having.getClass(); if (cls.getName().endsWith("Expression")) cls = cls.getSuperclass(); Object value2 = null; Method getValue2 = null; try { getValue2 = cls.getMethod("getValue2"); getValue2.setAccessible(true); value2 = getValue2.invoke(exps.having, (Object[]) null); } catch (NoSuchMethodException name) { // skip } catch (IllegalAccessException iae) { // skip } catch (InvocationTargetException ite) { // skip } if (value2 != null && value2 instanceof Subquery) ; // complex having with subquery, validation is performed by DBMS else exps.having.acceptVisit(visitor); } for (int i = 0; i < exps.projections.length; i++) exps.projections[i].acceptVisit(visitor); } public ValidateGroupingExpressionVisitor(QueryContext ctx) { _ctx = ctx; } public void enter(Value val) { if (_grouping) { if (val instanceof Path) { if (_grouped == null) _grouped = new HashSet(); _grouped.add(val); } } else if (_agg == null) { if (val.isAggregate()) _agg = val; else if (val instanceof Path && (_grouped == null || !_grouped.contains(val))) { throw new UserException(_loc.get("bad-grouping", _ctx.getCandidateType(), _ctx.getQueryString())); } } } public void exit(Value val) { if (val == _agg) _agg = null; } } } /** * Runs the expression query in memory. */ private static class InMemoryExecutor extends AbstractExpressionExecutor implements Executor, Serializable { private final ClassMetaData _meta; private final boolean _subs; private final InMemoryExpressionFactory _factory; private final QueryExpressions[] _exps; private final Class[] _projTypes; public InMemoryExecutor(ExpressionStoreQuery q, ClassMetaData candidate, boolean subclasses, ExpressionParser parser, Object parsed) { _meta = candidate; _subs = subclasses; _factory = new InMemoryExpressionFactory(); _exps = new QueryExpressions[] { parser.eval(parsed, q, _factory, _meta) }; if (_exps[0].projections.length == 0) _projTypes = StoreQuery.EMPTY_CLASSES; else { AssertNoVariablesExpressionVisitor novars = new AssertNoVariablesExpressionVisitor(q.getContext()); _projTypes = new Class[_exps[0].projections.length]; for (int i = 0; i < _exps[0].projections.length; i++) { _projTypes[i] = _exps[0].projections[i].getType(); assertNotContainer(_exps[0].projections[i], q); _exps[0].projections[i].acceptVisit(novars); } for (int i = 0; i < _exps[0].grouping.length; i++) _exps[0].grouping[i].acceptVisit(novars); } } protected QueryExpressions[] getQueryExpressions() { return _exps; } public ResultObjectProvider executeQuery(StoreQuery q, Object[] params, Range range) { // execute in memory for candidate collection; // also execute in memory for transactional extents Collection coll = q.getContext().getCandidateCollection(); Iterator itr; if (coll != null) itr = coll.iterator(); else itr = q.getContext().getStoreContext(). extentIterator(_meta.getDescribedType(), _subs, q.getContext().getFetchConfiguration(), q.getContext().getIgnoreChanges()); // find matching objects List results = new ArrayList(); StoreContext ctx = q.getContext().getStoreContext(); try { Object obj; while (itr.hasNext()) { obj = itr.next(); if (_factory.matches(_exps[0], _meta, _subs, obj, ctx, params)) results.add(obj); } } finally { ImplHelper.close(itr); } // group results results = _factory.group(_exps[0], results, ctx, params); // apply having to filter groups if (_exps[0].having != null) { List matches = new ArrayList(results.size()); Collection c; itr = results.iterator(); while (itr.hasNext()) { c = (Collection) itr.next(); if (_factory.matches(_exps[0], c, ctx, params)) matches.add(c); } results = matches; } // apply projections, order results, and filter duplicates results = _factory.project(_exps[0], results, ctx, params); results = _factory.order(_exps[0], results, ctx, params); results = _factory.distinct(_exps[0], coll == null, results); ResultObjectProvider rop = new ListResultObjectProvider(results); if (range.start != 0 || range.end != Long.MAX_VALUE) rop = new RangeResultObjectProvider(rop, range.start,range.end); return rop; } public String[] getDataStoreActions(StoreQuery q, Object[] params, Range range) { // in memory queries have no datastore actions to perform return StoreQuery.EMPTY_STRINGS; } public Object getOrderingValue(StoreQuery q, Object[] params, Object resultObject, int orderIndex) { // if this is a projection, then we have to order on something // we selected if (_exps[0].projections.length > 0) { String ordering = _exps[0].orderingClauses[orderIndex]; for (int i = 0; i < _exps[0].projectionClauses.length; i++) if (ordering.equals(_exps[0].projectionClauses[i])) return ((Object[]) resultObject)[i]; throw new InvalidStateException(_loc.get ("merged-order-with-result", q.getContext().getLanguage(), q.getContext().getQueryString(), ordering)); } // use the parsed ordering expression to extract the ordering value Val val = (Val) _exps[0].ordering[orderIndex]; return val.evaluate(resultObject, resultObject, q.getContext(). getStoreContext(), params); } public Class[] getProjectionTypes(StoreQuery q) { return _projTypes; } /** * Throws an exception if a variable is found. */ private static class AssertNoVariablesExpressionVisitor extends AbstractExpressionVisitor { private final QueryContext _ctx; public AssertNoVariablesExpressionVisitor(QueryContext ctx) { _ctx = ctx; } public void enter(Value val) { if (!val.isVariable()) return; throw new UnsupportedException(_loc.get("inmem-agg-proj-var", _ctx.getCandidateType(), _ctx.getQueryString())); } } } /** * The DataStoreExecutor executes the query against the * implementation's overridden {@link #executeQuery} method. * * @author Marc Prud'hommeaux */ public static class DataStoreExecutor extends AbstractExpressionExecutor implements Executor, Serializable { private ClassMetaData _meta; private ClassMetaData[] _metas; private boolean _subs; private ExpressionParser _parser; private ExpressionFactory[] _facts; private QueryExpressions[] _exps; private Class[] _projTypes; private Value[] _inMemOrdering; public DataStoreExecutor(ExpressionStoreQuery q, ClassMetaData meta, boolean subclasses, ExpressionParser parser, Object parsed) { _metas = q.getIndependentExpressionCandidates(meta, subclasses); if (_metas.length == 0) throw new UserException(_loc.get("query-unmapped", meta)); _meta = meta; _subs = subclasses; _parser = parser; _facts = new ExpressionFactory[_metas.length]; for (int i = 0; i < _facts.length; i++) _facts[i] = q.getExpressionFactory(_metas[i]); _exps = new QueryExpressions[_metas.length]; for (int i = 0; i < _exps.length; i++) _exps[i] = parser.eval(parsed, q, _facts[i], _metas[i]); if (_exps[0].projections.length == 0) _projTypes = StoreQuery.EMPTY_CLASSES; else { _projTypes = new Class[_exps[0].projections.length]; for (int i = 0; i < _exps[0].projections.length; i++) { assertNotContainer(_exps[0].projections[i], q); _projTypes[i] = _exps[0].projections[i].getType(); } } } protected QueryExpressions[] getQueryExpressions() { return _exps; } public ResultObjectProvider executeQuery(StoreQuery q, Object[] params, Range range) { range.lrs &= !isAggregate(q) && !hasGrouping(q); return ((ExpressionStoreQuery) q).executeQuery(this, _meta, _metas, _subs, _facts, _exps, params, range); } public Number executeDelete(StoreQuery q, Object[] params) { Number num = ((ExpressionStoreQuery) q).executeDelete(this, _meta, _metas, _subs, _facts, _exps, params); if (num == null) return q.getContext().deleteInMemory(q, this, params); return num; } public Number executeUpdate(StoreQuery q, Object[] params) { Number num = ((ExpressionStoreQuery) q).executeUpdate(this, _meta, _metas, _subs, _facts, _exps, params); if (num == null) return q.getContext().updateInMemory(q, this, params); return num; } public String[] getDataStoreActions(StoreQuery q, Object[] params, Range range) { return ((ExpressionStoreQuery) q).getDataStoreActions(_meta, _metas, _subs, _facts, _exps, params, range); } public Object getOrderingValue(StoreQuery q, Object[] params, Object resultObject, int orderIndex) { // if this is a projection, then we have to order on something // we selected if (_exps[0].projections.length > 0) { String ordering = _exps[0].orderingClauses[orderIndex]; for (int i = 0; i < _exps[0].projectionClauses.length; i++) if (ordering.equals(_exps[0].projectionClauses[i])) return ((Object[]) resultObject)[i]; throw new InvalidStateException(_loc.get ("merged-order-with-result", q.getContext().getLanguage(), q.getContext().getQueryString(), ordering)); } // need to parse orderings? synchronized (this) { if (_inMemOrdering == null) { ExpressionFactory factory = new InMemoryExpressionFactory(); _inMemOrdering = _parser.eval(_exps[0].orderingClauses, (ExpressionStoreQuery) q, factory, _meta); } if (_inMemOrdering == null) _inMemOrdering = _exps[0].ordering; } // use the parsed ordering expression to extract the ordering value Val val = (Val) _inMemOrdering[orderIndex]; return val.evaluate(resultObject, resultObject, q.getContext().getStoreContext(), params); } public Class[] getProjectionTypes(StoreQuery q) { return _projTypes; } } }




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