public abstract Class ObjectExpression

INTERNAL: Add the expression as a derived child of this expression. i.e. e.get("name"), "name" is a derived child of "e".

INTERNAL: Return the expression to join the main table of this node to any auxiliary tables.

INTERNAL: Used in case outer joins should be printed in FROM clause. Each of the additional tables mapped to expressions that joins it.

Overrides org.eclipse.persistence.expressions.Expression.anyOf.

PUBLIC: Return an expression representing traversal of a 1:many or many:many relationship. This allows you to query whether any of the "many" side of the relationship satisfies the remaining criteria.

Example:

    Expression: employee.anyOf("managedEmployees").get("firstName").equal("Bob")
    Java: no direct equivalent
    SQL: SELECT DISTINCT ... WHERE (t2.MGR_ID = t1.ID) AND (t2.F_NAME = 'Bob')

Parameters

shouldJoinBeIndependent:boolean

indicates whether a new expression should be created.

Annotations

@Override

Overrides org.eclipse.persistence.expressions.Expression.anyOfAllowingNone.

ADVANCED: Return an expression representing traversal of a 1:many or many:many relationship. This allows you to query whether any of the "many" side of the relationship satisfies the remaining criteria.

Example:

    Expression: employee.anyOf("managedEmployees").get("firstName").equal("Bob")
    Java: no direct equivalent
    SQL: SELECT DISTINCT ... WHERE (t2.MGR_ID (+) = t1.ID) AND (t2.F_NAME = 'Bob')

Parameters

shouldJoinBeIndependent:boolean

indicates whether a new expression should be created.

Annotations

@Override

Overrides org.eclipse.persistence.expressions.Expression.assignTableAliasesStartingAt.

INTERNAL: Assign aliases to any tables which I own. Start with t(initialValue), and return the new value of the counter , i.e. if initialValue is one and I have tables ADDRESS and EMPLOYEE I will assign them t1 and t2 respectively, and return 3.

Annotations

@Override

Overrides org.eclipse.persistence.internal.expressions.DataExpression.clearAliases.

INTERNAL:

Annotations

@Override

INTERNAL Return the descriptor which contains this query key, look in the inheritance hierarchy of rootDescriptor for the descriptor.

Overrides org.eclipse.persistence.internal.expressions.DataExpression.equals.

INTERNAL: Return if the expression is equal to the other. This is used to allow dynamic expression's SQL to be cached.

Parameters

expression:Object

Doc from java.lang.Object.equals.

the reference object with which to compare.

Returns:boolean

Doc from java.lang.Object.equals.

true if this object is the same as the obj argument; false otherwise.

Annotations

@Override

Overrides org.eclipse.persistence.expressions.Expression.get.

Return the expression from the attribute dervied from this expression.

Parameters

forceInnerJoin:boolean

Doc from org.eclipse.persistence.expressions.Expression.get.

- allows the get to not force an inner-join (if getAllowingNull was used elsewhere).

Annotations

@Override

Return any tables in addition to the descriptor's tables, such as the mappings join table.

Overrides org.eclipse.persistence.expressions.Expression.getAllowingNull.

Doc from org.eclipse.persistence.expressions.Expression.getAllowingNull.

ADVANCED: Return an expression that wraps the attribute or query key name. This is only applicable to 1:1 relationships, and allows the target of the relationship to be null if there is no corresponding relationship in the database. Implemented via an outer join in the database.

Example:

 builder.getAllowingNull("address").get("city").equal("Ottawa");

Annotations

@Override

Overrides org.eclipse.persistence.internal.expressions.DataExpression.getDescriptor.

Annotations

@Override

Overrides org.eclipse.persistence.expressions.Expression.getFields.

INTERNAL: Not to be confused with the public getField(String) This returns a collection of all fields associated with this object. Really only applies to query keys representing an object or to expression builders.

Annotations

@Override

INTERNAL: Parses an expression to return the first non-AggregateObjectMapping expression after the base ExpressionBuilder. This is used by joining and batch fetch to get the list of mappings that really need to be processed (non-aggregates).

Parameters

aggregateMappingsEncountered:List<E>

- collection of aggregateObjectMapping expressions encountered in the returned expression between the first expression and the ExpressionBuilder

Returns:ObjectExpression

first non-AggregateObjectMapping expression after the base ExpressionBuilder from the fullExpression

Overrides org.eclipse.persistence.expressions.Expression.getOwnedTables.

Return any tables that are defined by this expression (and not its base).

Annotations

@Override

Return null by default, only QueryKeyExpression can have a relation table.

Overrides org.eclipse.persistence.expressions.Expression.getSelectionFields.

INTERNAL:

Annotations

@Override

Overrides org.eclipse.persistence.internal.expressions.DataExpression.hasBeenAliased.

Doc from org.eclipse.persistence.expressions.Expression.hasBeenAliased.

INTERNAL: Answers if the database tables associated with this expression have been aliased. This insures the same tables are not aliased twice.

Annotations

@Override

Return false by default, only possible for QueryKeyExpression.

INTERNAL Return true if it uses a cast class and query is downcasting. It will look into inheritance hierarchy of the root descriptor.

Overrides org.eclipse.persistence.expressions.Expression.isObjectExpression.

Doc from org.eclipse.persistence.expressions.Expression.isObjectExpression.

INTERNAL:

Annotations

@Override

INTERNAL Return true if treat was used on this expression

INTERNAL: indicates whether additional expressions for multitable inheritance should be used and are available

Overrides org.eclipse.persistence.expressions.Expression.join.

Defines a join between this expression and the target expression based on the ON clause.

Annotations

@Override

Overrides org.eclipse.persistence.expressions.Expression.leftJoin.

Defines a join between this expression and the target expression based on the ON clause.

Annotations

@Override

INTERNAL: The method was added to circumvent derivedFields and derivedTables being protected.

See Also

org.eclipse.persistence.expressions.ExpressionBuilder#registerIn(Map alreadyDone)

INTERNAL: set the flag indicating whether subclasses should be joined

Overrides org.eclipse.persistence.expressions.Expression.treat.

Return an expression that allows you to treat its base as if it were a subclass of the class returned by the base This can only be called on an ExpressionBuilder, the result of expression.get(String), expression.getAllowingNull(String), the result of expression.anyOf("String") or the result of expression.anyOfAllowingNull("String") downcast uses Expression.type() internally to guarantee the results are of the specified class.

Example:

    Expression: employee.get("project").as(LargeProject.class).get("budget").equal(1000)
    Java: ((LargeProject)employee.getProjects().get(0)).getBudget() == 1000
    SQL: LPROJ.PROJ_ID (+)= PROJ.PROJ_ID AND L_PROJ.BUDGET = 1000 AND PROJ.TYPE = "L"

Annotations

@Override

Overrides org.eclipse.persistence.expressions.Expression.type.

PUBLIC: Return an expression that wraps the inheritance type field in an expression.

Example:

 builder.getClassForInheritance().equal(SmallProject.class);

Annotations

@Override