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.

        }


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


        AbstractRecord modifyRow = new DatabaseRecord();


        if(queryType == pk) {
            Iterator<DatabaseField> it = getReferenceDescriptor().getPrimaryKeyFields().iterator();
            while(it.hasNext()) {
                DatabaseField pkField = it.next();
                DatabaseField sourceField = targetForeignKeyToSourceKeys.get(pkField);
                DatabaseField parameterField = sourceField != null ? sourceField : pkField;
                Expression expression = builder.getField(pkField).equal(builder.getParameter(parameterField));
                whereClause = expression.and(whereClause);
            }
            modifyRow.add(this.listOrderField, null);
        } else {
            Iterator<Map.Entry<DatabaseField, DatabaseField>> it = targetForeignKeyToSourceKeys.entrySet().iterator();
            while(it.hasNext()) {
                Map.Entry<DatabaseField, DatabaseField> entry = it.next();
                Expression expression = builder.getField(entry.getKey()).equal(builder.getParameter(entry.getValue()));
                whereClause = expression.and(whereClause);
            }
            Expression listOrderExpression;
            if(queryType == bulk) {
                listOrderExpression = builder.getField(this.listOrderField).between(builder.getParameter(min), builder.getParameter(max));
                modifyRow.add(this.listOrderField, ExpressionMath.add(builder.getField(this.listOrderField), builder.getParameter(shift)));
            } else {
                listOrderExpression = builder.getField(this.listOrderField).equal(builder.getParameter(min));
                modifyRow.add(this.listOrderField, null);
            }
            whereClause = listOrderExpression.and(whereClause);
        }


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

View Full Code Here

     * INTERNAL:
     * Selection criteria is created with target foreign keys and source keys.
     * This criteria is then used to read records from the target table.
     */
    protected void initializeSelectionCriteria(AbstractSession session) {
        Expression expression;
        Expression criteria;
        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(getSelectionCriteria());
            setSelectionCriteria(criteria);
        }
    }

View Full Code Here

     * INTERNAL:
     * Subclasses that need to add field to an expresison should override this method.
     */
    public void postInitialize(AbstractSession session) {
        if (includeTenantCriteria) {
            Expression expression = getDescriptor().getQueryManager().getAdditionalJoinExpression();
            ExpressionBuilder builder = (expression == null) ? new ExpressionBuilder() : expression.getBuilder();
        
            for (DatabaseField discriminatorField : tenantDiscriminatorFields.keySet()) {
                String property = tenantDiscriminatorFields.get(discriminatorField);
                // Add the tenant discriminator field context property as the parameter.
                // Do not initialize the database field with the property as it could be tenant.id 
                // and we do not want to de-qualify it.
                DatabaseField newField = new DatabaseField();
                newField.setName(property, session.getPlatform());
                Expression tenantIdExpression = builder.and(builder.getField(discriminatorField).equal(builder.getProperty(newField)));
                
                if (expression == null) {
                    expression = tenantIdExpression;
                } else {
                    expression = expression.and(tenantIdExpression);

View Full Code Here

            return false;
        }
        if (! ((this.referenceClass == query.referenceClass) || ((this.referenceClass != null) && this.referenceClass.equals(query.referenceClass)))) {
            return false;
        }
        Expression selectionCriteria = getSelectionCriteria();
        Expression otherSelectionCriteria = query.getSelectionCriteria();
        return ((selectionCriteria == otherSelectionCriteria) || ((selectionCriteria != null) && selectionCriteria.equals(otherSelectionCriteria)));
    }

View Full Code Here

        }
        int hashCode = 32;
        if (this.referenceClass != null) {
            hashCode = hashCode + this.referenceClass.hashCode();
        }
        Expression selectionCriteria = getSelectionCriteria();
        if (selectionCriteria != null) {
            hashCode = hashCode + selectionCriteria.hashCode();
        }
        return hashCode;
    }

View Full Code Here

            localFields.addElement(getDescriptor().getInheritancePolicy().getClassIndicatorField());
        }


        //Add attribute fields
        for(Iterator it = getPartialAttributeExpressions().iterator();it.hasNext();){
            Expression expression = (Expression)it.next();
            if (expression.isQueryKeyExpression()) {
                ((QueryKeyExpression)expression).getBuilder().setSession(session.getRootSession(null));
                ((QueryKeyExpression)expression).getBuilder().setQueryClass(getDescriptor().getJavaClass());
                DatabaseMapping mapping = ((QueryKeyExpression)expression).getMapping();
                if (!((QueryKeyExpression)expression).getBaseExpression().isExpressionBuilder()) {
                    if(foreignFields==null){
                        foreignFields = org.eclipse.persistence.internal.helper.NonSynchronizedVector.newInstance();
                    }
                    if(!isCustomSQL){
                        foreignFields.add(expression);
                    }else{
                        foreignFields.addAll(expression.getFields());
                    }
                }else{
                    if (mapping == null) {
                        throw QueryException.specifiedPartialAttributeDoesNotExist(this, expression.getName(), descriptor.getJavaClass().getName());
                    }
                    if(mapping.isForeignReferenceMapping() ){
                        if(foreignFields==null){
                            foreignFields = org.eclipse.persistence.internal.helper.NonSynchronizedVector.newInstance();
                        }
                        if(!isCustomSQL){
                            foreignFields.add(expression);
                        }else{
                            foreignFields.addAll(expression.getFields());
                        }
                    }else{
                        localFields.addAll(expression.getFields());
                    }
                }
            } else {
                throw QueryException.expressionDoesNotSupportPartialAttributeReading(expression);
            }

View Full Code Here

        }


        // Validate and prepare partial attribute expressions.
        if (hasPartialAttributeExpressions()) {
            for (int index = 0; index < getPartialAttributeExpressions().size(); index++) {
                Expression expression = getPartialAttributeExpressions().get(index);


                // Search if any of the expression traverse a 1-m.
                while (expression.isQueryKeyExpression() && (!expression.isExpressionBuilder())) {
                    if (((QueryKeyExpression)expression).shouldQueryToManyRelationship()) {
                      getJoinedAttributeManager().setIsToManyJoinQuery(true);
                    }
                    expression = ((QueryKeyExpression)expression).getBaseExpression();
                }

View Full Code Here

   */
  public void visit(LikeExpression expression) {


    // Create the first expression
    expression.getStringExpression().accept(this);
    Expression firstExpression = queryExpression;


    // Create the expression for the pattern value
    expression.getPatternValue().accept(this);
    Expression patternValue = queryExpression;


    // Create the LIKE expression with the escape character
    if (expression.hasEscapeCharacter()) {
      expression.getEscapeCharacter().accept(this);
      queryExpression = firstExpression.like(patternValue, queryExpression);

View Full Code Here

   */
  public void visit(LocateExpression expression) {


    // Create the string to find in the find in expression
    expression.getFirstExpression().accept(this);
    Expression findExpression = queryExpression;


    // Create the find in string expression
    expression.getSecondExpression().accept(this);
    Expression findInExpression = queryExpression;


    // Create the expression for the start position
    expression.getThirdExpression().accept(this);
    Expression startPositionExpression = queryExpression;


    // Create the LOCATE expression
    if (startPositionExpression != null) {
      queryExpression = findInExpression.locate(findExpression, startPositionExpression);
    }

View Full Code Here

   */
  public void visit(ModExpression expression) {


    // First create the Expression for the first expression
    expression.getFirstExpression().accept(this);
    Expression leftExpression = queryExpression;


    // Now create the Expression for the second expression
    expression.getSecondExpression().accept(this);
    Expression rightExpression = queryExpression;


    // Now create the MOD expression
    queryExpression = ExpressionMath.mod(leftExpression, rightExpression);


    // Set the expression type

View Full Code Here

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Related Classes of org.eclipse.persistence.expressions.Expression

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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