com.im.df.api.dml
Class Operators.StructureOperator

java.lang.Object
  com.im.df.api.dml.DFOperator
      com.im.df.api.dml.Operators.StructureOperator

Enclosing class:

Operators

public static class Operators.StructureOperator
extends DFOperator

Class for all Structure based operators

Constructor Summary

Operators.StructureOperator(String displayName)

Method Summary

Class<? extends DFFieldDataTypeCapability>	getReturnType(List<DFTerm> operands) Compute the return type of the term.
boolean	isFieldAcceptableAsOperand(DFField field) This is just an utility method which must be implemented by subclasses.
Object[]	parseOperands(DFField field, String operands)
String	toString(List<DFTerm> operands)
void	validate(DFDataTree dataTree, List<DFTerm> operands, Map<String,Object> options, TermErrors errors) Validate the operands in context of this operator.

Methods inherited from class com.im.df.api.dml.DFOperator

correctNumberOfOperands, getDisplayName, getDisplayNameInExpression, getMaxOperands, getMinOperands, getToStringPart, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Operators.StructureOperator

public Operators.StructureOperator(String displayName)

Method Detail

getReturnType

public Class<? extends DFFieldDataTypeCapability> getReturnType(List<DFTerm> operands)

Description copied from class: DFOperator

Compute the return type of the term. Can return null if it cannot be determined.

Specified by:

getReturnType in class DFOperator

Parameters:

operands - The operands for the computation of return type. The result can be different for different set of operands.

Returns:

The class which is subclass of DFFieldDataTypeCapability or null

validate

public void validate(DFDataTree dataTree,
                     List<DFTerm> operands,
                     Map<String,Object> options,
                     TermErrors errors)

Description copied from class: DFOperator

Validate the operands in context of this operator. It's up to operator to decide if it accepts the given operands or not. This method is called from DFTerm.validate(com.im.df.api.ddl.DFDataTree).

Overrides:

validate in class DFOperator

Parameters:

dataTree - The datatree where this operator will be used

operands - The list of operands

options - Options of this query term (DFTermExpression.getOptions()

errors - The errors object which contains the result of the validation

isFieldAcceptableAsOperand

public boolean isFieldAcceptableAsOperand(DFField field)

Description copied from class: DFOperator

This is just an utility method which must be implemented by subclasses. It test if the given field is acceptable as operand for this DFOperator. It can return true even for fields which are recognized as invalid later. This is just rough test in the beginning of validation to filter inappropriate fields.

For example some operator takes two operands of different types (text, integer,...), but both must be of the same type. In this case this method returns true for all text, integer etc. fields, but if you use combination of [text, integer] as operands, it will be invalid.

Specified by:

isFieldAcceptableAsOperand in class DFOperator

Parameters:

field - The field to be tested

Returns:

True if field seems to be acceptable, false otherwise.

toString

public String toString(List<DFTerm> operands)

Overrides:

toString in class DFOperator

parseOperands

public Object[] parseOperands(DFField field,
                              String operands)
                       throws IllegalArgumentException

Specified by:

parseOperands in class DFOperator

Throws:

IllegalArgumentException