net.sf.jguiraffe.transform

Class ChainValidator

java.lang.Object

net.sf.jguiraffe.transform.ChainValidator

All Implemented Interfaces:

Validator

public class ChainValidator
extends Object
implements Validator

A special Validator implementation that allows combining multiple primitive validators.

An instance of this class can be initialized with an arbitrary number of child validators. In its implementation of the isValid() method the child validators are invoked one after the other. Configuration options control whether validation should stop when the first validation error was detected or whether in any case all child validators are to be invoked (in the latter case really all error messages caused by validation errors can be collected.)

In the TransformerContext passed to this validator's isValid() method the PROP_SHORT_EVAL property will be checked. If it is defined, it overrides the flag set using the setShortEvaluation(boolean) method.

Version:

$Id: ChainValidator.java 205 2012-01-29 18:29:57Z oheger $

Author:

Oliver Heger

Field Summary

Fields

Modifier and Type	Field and Description
static String	PROP_SHORT_EVAL Constant for the short evaluation property.

Constructor Summary

Constructors

Constructor and Description
ChainValidator() Creates a new instance of ChainValidator.

Method Summary

Modifier and Type	Method and Description
void	addChildValidator(Validator child) Adds a child validator to this chain validator.
void	addChildValidator(Validator child, Map<String,Object> props) Adds a child validator to this chain validator and sets special properties for the new child.
protected boolean	doShortEvaluation(TransformerContext ctx) Checks whether short evaluation should be performed by the isValid() method.
Validator	getChildValidator(int index) Returns the child validator at the given index.
protected TransformerContext	getContextForChildValidator(int index, TransformerContext ctx) Returns the TransformerContext to be used for the specified child validator.
boolean	isShortEvaluation() Returns the shortEvaluation flag.
ValidationResult	isValid(Object o, TransformerContext ctx) Validates the passed in object.
void	setShortEvaluation(boolean shortEvaluation) Sets the shortEvaluation flag.
int	size() Returns the number of child validators.

Methods inherited from class java.lang.Object

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

Field Detail

PROP_SHORT_EVAL

public static final String PROP_SHORT_EVAL

Constant for the short evaluation property.

See Also:

Constant Field Values

Constructor Detail

ChainValidator

public ChainValidator()

Creates a new instance of ChainValidator.

Method Detail

isShortEvaluation

public boolean isShortEvaluation()

Returns the shortEvaluation flag.

Returns:

the flag for short evaluation

setShortEvaluation

public void setShortEvaluation(boolean shortEvaluation)

Sets the shortEvaluation flag. This flag controls the behavior of the isValid() method in case of validation errors. If it is set, validation is aborted when the first child validator detects an error. Otherwise all child validators will be invoked and the results are collected.

Parameters:

shortEvaluation - the value of the flag

addChildValidator

public void addChildValidator(Validator child)

Adds a child validator to this chain validator.

Parameters:

child - the child validator to be added (must not be null)

Throws:

IllegalArgumentException - if the validator to be added is null

addChildValidator

public void addChildValidator(Validator child,
                              Map<String,Object> props)

Adds a child validator to this chain validator and sets special properties for the new child. If defined, these properties will be available through the TransformerContext passed to the isValid() method of the child.

Parameters:

child - the child validator to be added (must not be null)

props - a map with properties for the new child validator

Throws:

IllegalArgumentException - if the validator to be added is null

size

public int size()

Returns the number of child validators.

Returns:

the number of child validators

getChildValidator

public Validator getChildValidator(int index)

Returns the child validator at the given index. The index is 0-based and can be in the range 0 <= index < size().

Parameters:

index - the index of the child validator

Returns:

the child at this index

Throws:

IndexOutOfBoundsException - if the index is invalid

isValid

public ValidationResult isValid(Object o,
                                TransformerContext ctx)

Validates the passed in object. This implementation delegates to the child validators.

Specified by:

isValid in interface Validator

Parameters:

o - the object to be validated

ctx - the transformer context

Returns:

an object with the results of the validation

getContextForChildValidator

protected TransformerContext getContextForChildValidator(int index,
                                                         TransformerContext ctx)

Returns the TransformerContext to be used for the specified child validator. If the child was added with custom properties, a specialized context will be created allowing access to these properties. Otherwise the default context will be returned.

Parameters:

index - the index of the child validator

ctx - the original context

Returns:

a context for this child validator

Throws:

IndexOutOfBoundsException - if the index is invalid

doShortEvaluation

protected boolean doShortEvaluation(TransformerContext ctx)

Checks whether short evaluation should be performed by the isValid() method. This implementation checks whether the PROP_SHORT_EVAL property is defined in the passed in context. If not, isShortEvaluation() will be called.

Parameters:

ctx - the current transformer context

Returns:

a flag whether short evaluation should be performed