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.ExecutionContext;
040    import org.datanucleus.query.expression.Expression;
041    import org.datanucleus.query.expression.PrimaryExpression;
042    
043    /**
044     * Evaluator for "String.length(str) {oper} {compareTo}".
045     */
046    public class StringLengthEvaluator extends AbstractMethodEvaluator {
047    
048            /* (non-Javadoc)
049             * @see org.cumulus4j.store.query.method.AbstractMethodEvaluator#requiresComparisonArgument()
050             */
051            @Override
052            public boolean requiresComparisonArgument() {
053                    return true;
054            }
055    
056            /* (non-Javadoc)
057             * @see org.cumulus4j.store.query.method.MethodEvaluator#evaluate(org.cumulus4j.store.query.QueryEvaluator, org.cumulus4j.store.query.eval.InvokeExpressionEvaluator, org.datanucleus.query.expression.Expression, org.cumulus4j.store.query.eval.ResultDescriptor)
058             */
059            @Override
060            public Set<Long> evaluate(QueryEvaluator queryEval,
061                            InvokeExpressionEvaluator invokeExprEval, Expression invokedExpr,
062                            ResultDescriptor resultDesc) {
063                    if (invokeExprEval.getExpression().getArguments().size() != 0)
064                            throw new IllegalStateException("String.length() expects no arguments, but there are " +
065                                            invokeExprEval.getExpression().getArguments().size());
066    
067                    if (invokedExpr instanceof PrimaryExpression) {
068                            return new MethodResolver(invokeExprEval, queryEval, (PrimaryExpression) invokedExpr,
069                                            compareToArgument, resultDesc.isNegated()).query();
070                    }
071                    else {
072                            if (!invokeExprEval.getLeft().getResultSymbols().contains(resultDesc.getSymbol()))
073                                    return null;
074    
075                            return queryEvaluate(invokeExprEval, queryEval, resultDesc.getFieldMeta(),
076                                            compareToArgument, resultDesc.isNegated());
077                    }
078            }
079    
080            private Set<Long> queryEvaluate(
081                            InvokeExpressionEvaluator invokeExprEval,
082                            QueryEvaluator queryEval,
083                            FieldMeta fieldMeta,
084                            Object compareToArgument, // the yyy in 'length() >= yyy'
085                            boolean negate
086            ) {
087                    CryptoContext cryptoContext = queryEval.getCryptoContext();
088                    ExecutionContext executionContext = queryEval.getExecutionContext();
089                    IndexEntryFactory indexEntryFactory = queryEval.getStoreManager().getIndexFactoryRegistry().getIndexEntryFactory(
090                                    executionContext, fieldMeta, true
091                    );
092    
093                    Query q = queryEval.getPersistenceManagerForIndex().newQuery(indexEntryFactory.getIndexEntryClass());
094                    q.setFilter(
095                                    "this.keyStoreRefID == :keyStoreRefID && this.fieldMeta == :fieldMeta && " +
096                                    "this.indexKey.length() " +
097                                    ExpressionHelper.getOperatorAsJDOQLSymbol(invokeExprEval.getParent().getExpression().getOperator(), negate) +
098                                    " :compareToArgument"
099                    );
100                    Map<String, Object> params = new HashMap<String, Object>(2);
101                    params.put("keyStoreRefID", cryptoContext.getKeyStoreRefID());
102                    params.put("fieldMeta", fieldMeta);
103                    params.put("compareToArgument", compareToArgument);
104    
105                    @SuppressWarnings("unchecked")
106                    Collection<? extends IndexEntry> indexEntries = (Collection<? extends IndexEntry>) q.executeWithMap(params);
107    
108                    Set<Long> result = new HashSet<Long>();
109                    for (IndexEntry indexEntry : indexEntries) {
110                            IndexValue indexValue = queryEval.getEncryptionHandler().decryptIndexEntry(cryptoContext, indexEntry);
111                            result.addAll(indexValue.getDataEntryIDs());
112                    }
113                    q.closeAll();
114                    return result;
115            }
116    
117            private class MethodResolver extends PrimaryExpressionResolver
118            {
119                    private InvokeExpressionEvaluator invokeExprEval;
120                    private Object compareToArgument;
121                    private boolean negate;
122    
123                    public MethodResolver(
124                                    InvokeExpressionEvaluator invokeExprEval,
125                                    QueryEvaluator queryEvaluator, PrimaryExpression primaryExpression,
126                                    Object compareToArgument, // the yyy in 'length() >= yyy'
127                                    boolean negate
128                    )
129                    {
130                            super(queryEvaluator, primaryExpression);
131                            this.invokeExprEval = invokeExprEval;
132                            this.compareToArgument = compareToArgument;
133                            this.negate = negate;
134                    }
135    
136                    @Override
137                    protected Set<Long> queryEnd(FieldMeta fieldMeta, ClassMeta classMeta) {
138                            return queryEvaluate(invokeExprEval, queryEvaluator, fieldMeta, compareToArgument, negate);
139                    }
140            }
141    }