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.

      */
     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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     */
    private ForUpdateOfClause setupLockingClauseForJoinedExpressions(List joinedExpressions, AbstractSession session, ForUpdateOfClause lockingClause) {
        // Must iterate over all of the joined attributes, just check
        // if any of them have pessimistic locking defined on the descriptor.
        for (Iterator e = joinedExpressions.iterator(); e.hasNext();) {
            Expression expression = (Expression)e.next();


            // Expression has not yet been validated.
            if (expression.isObjectExpression()) {
                ObjectExpression joinedAttribute = (ObjectExpression)expression;


                // Expression may not have been initialized.
                joinedAttribute.getBuilder().setSession(session.getRootSession(null));
                if (joinedAttribute.getBuilder().getQueryClass() == null){

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        if (hasCustomAddTargetQuery) {
            return;
        }


        // Build where clause expression.
        Expression whereClause = null;
        Expression builder = new ExpressionBuilder();


        List<DatabaseField> targetPrimaryKeyFields = getReferenceDescriptor().getPrimaryKeyFields();
        int size = targetPrimaryKeyFields.size();
        for (int index = 0; index < size; index++) {
            DatabaseField targetPrimaryKey = targetPrimaryKeyFields.get(index);
            Expression expression = builder.getField(targetPrimaryKey).equal(builder.getParameter(targetPrimaryKey));
            whereClause = expression.and(whereClause);
        }


        AbstractRecord modifyRow = new DatabaseRecord();
        size = targetForeignKeyFields.size();
        for (int index = 0; index < size; index++) {

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        if (hasCustomRemoveTargetQuery) {
            return;
        }


        // Build where clause expression.
        Expression whereClause = null;
        Expression builder = new ExpressionBuilder();


        List<DatabaseField> targetPrimaryKeyFields = getReferenceDescriptor().getPrimaryKeyFields();
        int size = targetPrimaryKeyFields.size();
        for (int index = 0; index < size; index++) {
            DatabaseField targetPrimaryKey = targetPrimaryKeyFields.get(index);
            Expression expression = builder.getField(targetPrimaryKey).equal(builder.getParameter(targetPrimaryKey));
            whereClause = expression.and(whereClause);
        }


        AbstractRecord modifyRow = new DatabaseRecord();
        size = targetForeignKeyFields.size();
        for (int index = 0; index < size; index++) {
            DatabaseField targetForeignKey = targetForeignKeyFields.get(index);
            modifyRow.put(targetForeignKey, null);
            Expression expression = builder.getField(targetForeignKey).equal(builder.getParameter(targetForeignKey));
            whereClause = expression.and(whereClause);
        }


        SQLUpdateStatement statement = new SQLUpdateStatement();
        statement.setTable(getReferenceDescriptor().getDefaultTable());
        statement.setWhereClause(whereClause);

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        if (hasCustomRemoveAllTargetsQuery) {
            return;
        }


        // Build where clause expression.
        Expression whereClause = null;
        Expression builder = new ExpressionBuilder();


        AbstractRecord modifyRow = new DatabaseRecord();
        int size = targetForeignKeyFields.size();
        for (int index = 0; index < size; index++) {
            DatabaseField targetForeignKey = targetForeignKeyFields.get(index);
            modifyRow.put(targetForeignKey, null);
            Expression expression = builder.getField(targetForeignKey).equal(builder.getParameter(targetForeignKey));
            whereClause = expression.and(whereClause);
        }


        SQLUpdateStatement statement = new SQLUpdateStatement();
        statement.setTable(getReferenceDescriptor().getDefaultTable());
        statement.setWhereClause(whereClause);

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            if (getDescriptor().hasInheritance() && getDescriptor().getInheritancePolicy().hasView()) {
                throw DescriptorException.additionalCriteriaNotSupportedWithInheritanceViews(getDescriptor());
            }


            JPAQueryBuilder queryBuilder = session.getQueryBuilder();
            Expression selectionCriteria = queryBuilder.buildSelectionCriteria(
               getDescriptor().getAlias(),
               additionalCriteria,
               session
            );


            updatePropertyParameterExpression(selectionCriteria);
            additionalJoinExpression = selectionCriteria.and(additionalJoinExpression);
        }


        if (additionalJoinExpression != null) {
            // The make sure the additional join expression has the correct
            // context, rebuild the additional join expression on a new

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    /**
     * Delete all criteria is created with target foreign keys and source keys.
     * This criteria is then used to delete target records from the table.
     */
    protected Expression getDeleteAllCriteria(AbstractSession session) {
        Expression expression;
        Expression criteria = null;
        Expression builder = new ExpressionBuilder();


        for (Iterator keys = getTargetForeignKeyToSourceKeys().keySet().iterator(); keys.hasNext();) {
            DatabaseField targetForeignKey = (DatabaseField)keys.next();
            DatabaseField sourceKey = getTargetForeignKeyToSourceKeys().get(targetForeignKey);


            expression = builder.getField(targetForeignKey).equal(builder.getParameter(sourceKey));


            criteria = expression.and(criteria);
        }


        return criteria;

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org.eclipse.persistence.descriptors.DescriptorQueryManager

org.eclipse.persistence.descriptors.SingleTableMultitenantPolicy

org.eclipse.persistence.eis.mappings.EISOneToManyMapping

org.eclipse.persistence.eis.mappings.EISOneToOneMapping

org.eclipse.persistence.expressions.spatial.SpatialExpressionFactory

org.eclipse.persistence.internal.descriptors.CascadeLockingPolicy

org.eclipse.persistence.internal.expressions.ClassTypeExpression

org.eclipse.persistence.internal.expressions.MapEntryExpression

org.eclipse.persistence.internal.expressions.OuterJoinExpressionHolder

org.eclipse.persistence.internal.expressions.SQLUpdateStatement

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