001    /*
002     * Cumulus4j - Securing your data in the cloud - http://cumulus4j.org
003     * Copyright (C) 2011 NightLabs Consulting GmbH
004     *
005     * This program is free software: you can redistribute it and/or modify
006     * it under the terms of the GNU Affero General Public License as
007     * published by the Free Software Foundation, either version 3 of the
008     * License, or (at your option) any later version.
009     *
010     * This program is distributed in the hope that it will be useful,
011     * but WITHOUT ANY WARRANTY; without even the implied warranty of
012     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
013     * GNU Affero General Public License for more details.
014     *
015     * You should have received a copy of the GNU Affero General Public License
016     * along with this program.  If not, see <http://www.gnu.org/licenses/>.
017     */
018    package org.cumulus4j.store.query.method;
019    
020    import java.util.Collection;
021    import java.util.HashMap;
022    import java.util.HashSet;
023    import java.util.Map;
024    import java.util.Set;
025    
026    import javax.jdo.Query;
027    
028    import org.cumulus4j.store.crypto.CryptoContext;
029    import org.cumulus4j.store.model.ClassMeta;
030    import org.cumulus4j.store.model.FieldMeta;
031    import org.cumulus4j.store.model.IndexEntry;
032    import org.cumulus4j.store.model.IndexEntryFactory;
033    import org.cumulus4j.store.model.IndexValue;
034    import org.cumulus4j.store.query.QueryEvaluator;
035    import org.cumulus4j.store.query.eval.ExpressionHelper;
036    import org.cumulus4j.store.query.eval.InvokeExpressionEvaluator;
037    import org.cumulus4j.store.query.eval.PrimaryExpressionResolver;
038    import org.cumulus4j.store.query.eval.ResultDescriptor;
039    import org.datanucleus.query.expression.Expression;
040    import org.datanucleus.query.expression.PrimaryExpression;
041    import org.datanucleus.store.ExecutionContext;
042    
043    /**
044     * Evaluator for "{String}.startsWith(arg)".
045     */
046    public class StringStartsWithEvaluator extends AbstractMethodEvaluator
047    {
048            /* (non-Javadoc)
049             * @see org.cumulus4j.store.query.method.MethodEvaluator#evaluate(org.cumulus4j.store.query.QueryEvaluator, org.datanucleus.query.expression.InvokeExpression, org.datanucleus.query.expression.Expression, org.cumulus4j.store.query.eval.ResultDescriptor)
050             */
051            @Override
052            public Set<Long> evaluate(QueryEvaluator queryEval, InvokeExpressionEvaluator invokeExprEval,
053                            Expression invokedExpr, ResultDescriptor resultDesc) {
054                    if (invokeExprEval.getExpression().getArguments().size() != 1)
055                            throw new IllegalStateException("startsWith(...) expects exactly one argument, but there are " +
056                                            invokeExprEval.getExpression().getArguments().size());
057    
058                    // Evaluate the invoke argument
059                    Object invokeArgument = ExpressionHelper.getEvaluatedInvokeArgument(queryEval, invokeExprEval.getExpression());
060    
061                    if (invokedExpr instanceof PrimaryExpression) {
062                            return new MethodResolver(queryEval, (PrimaryExpression) invokedExpr, invokeArgument, resultDesc.isNegated()).query();
063                    }
064                    else {
065                            if (!invokeExprEval.getLeft().getResultSymbols().contains(resultDesc.getSymbol()))
066                                    return null;
067                            return queryEvaluate(queryEval, resultDesc.getFieldMeta(), invokeArgument, resultDesc.isNegated());
068                    }
069            }
070    
071            private Set<Long> queryEvaluate(
072                            QueryEvaluator queryEval,
073                            FieldMeta fieldMeta,
074                            Object invokeArgument, // the xxx in 'startsWith(xxx)'
075                            boolean negate
076            ) {
077                    CryptoContext cryptoContext = queryEval.getCryptoContext();
078                    ExecutionContext executionContext = queryEval.getExecutionContext();
079                    IndexEntryFactory indexEntryFactory = queryEval.getStoreManager().getIndexFactoryRegistry().getIndexEntryFactory(
080                                    executionContext, fieldMeta, true
081                    );
082    
083                    Query q = queryEval.getPersistenceManagerForIndex().newQuery(indexEntryFactory.getIndexEntryClass());
084                    q.setFilter(
085                                    "this.keyStoreRefID == :keyStoreRefID && this.fieldMeta_fieldID == :fieldMeta_fieldID && " +
086                                    (negate ? "!this.indexKey.startsWith(:invokeArg)" : "this.indexKey.startsWith(:invokeArg) ")
087                    );
088                    Map<String, Object> params = new HashMap<String, Object>(3);
089                    params.put("keyStoreRefID", cryptoContext.getKeyStoreRefID());
090                    params.put("fieldMeta_fieldID", fieldMeta.getFieldID());
091                    params.put("invokeArg", invokeArgument);
092    
093                    @SuppressWarnings("unchecked")
094                    Collection<? extends IndexEntry> indexEntries = (Collection<? extends IndexEntry>) q.executeWithMap(params);
095    
096                    Set<Long> result = new HashSet<Long>();
097                    for (IndexEntry indexEntry : indexEntries) {
098                            IndexValue indexValue = queryEval.getEncryptionHandler().decryptIndexEntry(cryptoContext, indexEntry);
099                            result.addAll(indexValue.getDataEntryIDs());
100                    }
101                    q.closeAll();
102                    return result;
103            }
104    
105            private class MethodResolver extends PrimaryExpressionResolver
106            {
107                    private Object invokeArgument;
108                    private boolean negate;
109    
110                    public MethodResolver(
111                                    QueryEvaluator queryEvaluator, PrimaryExpression primaryExpression,
112                                    Object invokeArgument, // the xxx in 'startsWith(xxx)'
113                                    boolean negate
114                    )
115                    {
116                            super(queryEvaluator, primaryExpression);
117                            this.invokeArgument = invokeArgument;
118                            this.negate = negate;
119                    }
120    
121                    @Override
122                    protected Set<Long> queryEnd(FieldMeta fieldMeta, ClassMeta classMeta) {
123                            return queryEvaluate(queryEvaluator, fieldMeta, invokeArgument, negate);
124                    }
125            }
126    }