Examples of org.eclipse.persistence.expressions.Expression

Package org.eclipse.persistence.expressions

Examples of org.eclipse.persistence.expressions.Expression

org.eclipse.persistence.expressions.Expression
Purpose: Define an object-level representation of a database query where clause.

Description: An expression is a tree-like structure that defines the selection criteria for a query against objects in the database. The expression has the advantage over SQL by being at the object-level, i.e. the object model attributes and relationships can be used to be query on instead of the database field names. Because it is an object, not a string the expression has the advantage that is can be easily manipulated through code to easily build complex selection criterias.

Responsibilities:
- Store the selection criteria in a tree-like structure.
- Support public manipulation protocols for all comparison and function operators.
- Use opperator overloading to support all primitive types as well as objects.

                }
                // ignore the first token since we are assuming read all query
                // e.g. In e.phoneNumbers we will assume "e" refers to the base of the query
                String previousToken = tokenizer.nextToken();
                ClassDescriptor descriptor = raq.getDescriptor();
                Expression expression = raq.getExpressionBuilder();
                while (tokenizer.hasMoreTokens()){
                    String token = tokenizer.nextToken();
                    ForeignReferenceMapping frMapping = null;
                    DatabaseMapping mapping = descriptor.getObjectBuilder().getMappingForAttributeName(token);
                    if (mapping == null){
                        throw QueryException.queryHintNavigatedNonExistantRelationship(query, QueryHints.BATCH, valueToApply, previousToken + "." + token);
                    } else if (!mapping.isForeignReferenceMapping()){
                        throw QueryException.queryHintNavigatedIllegalRelationship(query, QueryHints.BATCH, valueToApply, previousToken + "." + token);
                    } else {
                        frMapping = (ForeignReferenceMapping)mapping;
                    }
                    descriptor = frMapping.getReferenceDescriptor();
                    if (frMapping.isCollectionMapping()){
                        expression = expression.anyOf(token);
                    } else {
                        expression = expression.get(token);
                    }
                    previousToken = token;
                }
                raq.addBatchReadAttribute(expression);
            } else {

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                }
                // ignore the first token since we are assuming read all query
                // e.g. In e.phoneNumbers we will assume "e" refers to the base of the query
                String previousToken = tokenizer.nextToken();
                ClassDescriptor descriptor = olrq.getDescriptor();
                Expression expression = olrq.getExpressionBuilder();
                while (tokenizer.hasMoreTokens()){
                    String token = tokenizer.nextToken();
                    ForeignReferenceMapping frMapping = null;
                    DatabaseMapping mapping = descriptor.getObjectBuilder().getMappingForAttributeName(token);
                    if (mapping == null){
                        throw QueryException.queryHintNavigatedNonExistantRelationship(query, QueryHints.FETCH, valueToApply, previousToken + "." + token);
                    } else if (!mapping.isForeignReferenceMapping()){
                        throw QueryException.queryHintNavigatedIllegalRelationship(query, QueryHints.FETCH, valueToApply, previousToken + "." + token);
                    } else {
                        frMapping = (ForeignReferenceMapping)mapping;
                    }
                    descriptor = frMapping.getReferenceDescriptor();
                    if (frMapping.isCollectionMapping()){
                        expression = expression.anyOf(token);
                    } else {
                        expression = expression.get(token);
                    }
                    previousToken = token;
                }
                olrq.addJoinedAttribute(expression);
            } else {

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                }
                // ignore the first token since we are assuming read all query
                // e.g. In e.phoneNumbers we will assume "e" refers to the base of the query
                String previousToken = tokenizer.nextToken();
                ClassDescriptor descriptor = olrq.getDescriptor();
                Expression expression = olrq.getExpressionBuilder();
                while (tokenizer.hasMoreTokens()){
                    String token = tokenizer.nextToken();
                    ForeignReferenceMapping frMapping = null;
                    DatabaseMapping mapping = descriptor.getObjectBuilder().getMappingForAttributeName(token);
                    if (mapping == null){
                        throw QueryException.queryHintNavigatedNonExistantRelationship(query, QueryHints.LEFT_FETCH, valueToApply, previousToken + "." + token);
                    } else if (!mapping.isForeignReferenceMapping()){
                        throw QueryException.queryHintNavigatedIllegalRelationship(query, QueryHints.LEFT_FETCH, valueToApply, previousToken + "." + token);
                    } else {
                        frMapping = (ForeignReferenceMapping)mapping;
                    }
                    descriptor = frMapping.getReferenceDescriptor();
                    if (frMapping.isCollectionMapping()){
                        expression = expression.anyOfAllowingNone(token);
                    } else {
                        expression = expression.getAllowingNull(token);
                    }
                    previousToken = token;
                }
                olrq.addJoinedAttribute(expression);
            } else {

View Full Code Here

    protected void initializeSelectionCriteria(AbstractSession session) {
        if (this.getSourceToTargetKeyFields().isEmpty()) {
            throw DescriptorException.noForeignKeysAreSpecified(this);
        }


        Expression criteria;
        Expression builder = new ExpressionBuilder();
        Iterator keyIterator = getSourceToTargetKeyFields().keySet().iterator();
        while (keyIterator.hasNext()) {
            DatabaseField foreignKey = (DatabaseField)keyIterator.next();
            DatabaseField targetKey = (DatabaseField)getSourceToTargetKeyFields().get(foreignKey);


            Expression expression = builder.getField(targetKey).equal(builder.getParameter(foreignKey));
            criteria = expression.and(getSelectionCriteria());
            setSelectionCriteria(criteria);
        }
    }

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     */
    protected void initializePrivateOwnedCriteria() {
        if (!isForeignKeyRelationship()) {
            setPrivateOwnedCriteria(getSelectionCriteria());
        } else {
            Expression pkCriteria = getDescriptor().getObjectBuilder().getPrimaryKeyExpression();
            ExpressionBuilder builder = new ExpressionBuilder();
            Expression backRef = builder.getManualQueryKey(getAttributeName() + "-back-ref", getDescriptor());
            Expression newPKCriteria = pkCriteria.rebuildOn(backRef);
            Expression twistedSelection = backRef.twist(getSelectionCriteria(), builder);
            if (getDescriptor().getQueryManager().getAdditionalJoinExpression() != null) {
                // We don't have to twist the additional join because it's all against the same node, which is our base
                // but we do have to rebuild it onto the manual query key
                Expression rebuiltAdditional = getDescriptor().getQueryManager().getAdditionalJoinExpression().rebuildOn(backRef);
                if (twistedSelection == null) {
                    twistedSelection = rebuiltAdditional;
                } else {
                    twistedSelection = twistedSelection.and(rebuiltAdditional);
                }

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     */
    protected ReadObjectQuery getQuery() {
        if (m_query == null) {
            m_query = new ReadObjectQuery(m_parentClass);
            
            Expression selectionCriteria = null;
            Iterator keys = m_queryKeyFields.keySet().iterator();
            ExpressionBuilder builder = new ExpressionBuilder();
            
            while (keys.hasNext()) {
                String keyField = ((DatabaseField) keys.next()).getQualifiedName();
                
                if (selectionCriteria == null) {
                    selectionCriteria = builder.getField(keyField).equal(builder.getParameter(keyField));
                } else {
                    selectionCriteria.and(builder.getField(keyField).equal(builder.getParameter(keyField)));
                }
                
                m_query.addArgument(keyField);
            }

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      */
     public void initUnmappedFieldsQuery(UnitOfWorkImpl uow) {
         if(m_unmappedFieldsQuery == null) {
             m_unmappedFieldsQuery = new DataReadQuery();


             Expression whereClause = null;
             Expression builder = new ExpressionBuilder();
             Iterator<DatabaseField> itPrimaryKey = m_descriptor.getPrimaryKeyFields().iterator();
             while (itPrimaryKey.hasNext()) {
                 DatabaseField primaryKey = itPrimaryKey.next();
                 Expression expression = builder.getField(primaryKey).equal(builder.getParameter(primaryKey));
                 whereClause = expression.and(whereClause);
                 m_unmappedFieldsQuery.addArgument(primaryKey.getQualifiedName());
             }


             SQLSelectStatement statement = new SQLSelectStatement();
             Iterator<DatabaseField> itUnmappedFields = m_unmappedQueryKeyFields.values().iterator();

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    }


    public void addJoinedAttributeExpression(Expression attributeExpression) {
        if(!getJoinedAttributeExpressions().contains(attributeExpression)) {
            if((attributeExpression instanceof BaseExpression)) {
                Expression baseExpression = ((BaseExpression)attributeExpression).getBaseExpression();
                if(baseExpression != null && !baseExpression.isExpressionBuilder()) {
                    addJoinedAttributeExpression(baseExpression);
                }
            }
            getJoinedAttributeExpressions().add(attributeExpression);
        }

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        if (getBaseQuery().hasPartialAttributeExpressions()) {
            fieldIndex = getDescriptor().getPrimaryKeyFields().size(); // Query will select pks
            //next check for any partial attributes that are not joined attributes
            Iterator partialAttributes = ((ObjectLevelReadQuery)getBaseQuery()).getPartialAttributeExpressions().iterator();
            while(partialAttributes.hasNext()){
                Expression expression = (Expression)partialAttributes.next();
                if (expression.isQueryKeyExpression()){
                    if (!getJoinedMappingExpressions().contains(expression) && ! getJoinedAttributeExpressions().contains(expression)){
                        fieldIndex += ((QueryKeyExpression)expression).getFields().size();
                    }
                }
            }

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     */
    public void prepareJoinExpressions(AbstractSession session) {
        // The prepareJoinExpression check for outer-joins to set this to true.
        setIsOuterJoinedAttributeQuery(false);
        for (int index = 0; index < getJoinedAttributeExpressions().size(); index++) {
            Expression expression = getJoinedAttributeExpressions().get(index);
            if(expression.isObjectExpression()) {
                ((ObjectExpression)expression).setShouldUseOuterJoinForMultitableInheritance(true);
            }
            prepareJoinExpression(expression, session);
        }
        for (int index = 0; index < getJoinedMappingExpressions().size(); index++) {
            Expression expression = getJoinedMappingExpressions().get(index);
            if(expression.isObjectExpression()) {
                ((ObjectExpression)expression).setShouldUseOuterJoinForMultitableInheritance(true);
            }
            prepareJoinExpression(expression, session);
        }
    }

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