com.smartgwt.client.bean

Class BeanValueType<ValueType>

java.lang.Object

com.smartgwt.client.bean.BeanValueType<ValueType>

Direct Known Subclasses:

ArrayValueType, BooleanValueType, DateValueType, InterfaceValueType, JsoWrapperValueType, NumberValueType, OtherValueType, StringValueType

public abstract class BeanValueType<ValueType>
extends java.lang.Object

Class with static methods that help with various reflection-like tasks with respect to values used by BeanFactories (that is, the return types of getters, and the parameter types of setters).

The primary interface is through the static methods. In some cases, generated subclasses are required in order to work around GWT's limited reflection capabilities. Those classes are automatically generated by the by the BeanFactory generator when necessary. If you want to use BeanValueType outside of BeanFactory, then you'll need to use the BeanValueType.MetaFactory interface to register types.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BeanValueType.Convertability An enum used to indicate how well a BeanValueType can handle a conversion.
static interface	BeanValueType.MetaFactory Interface used to trigger the generation and registration of reflection metadata for argument types.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	BeanValueType()

Method Summary

Modifier and Type	Method and Description
protected java.lang.IllegalArgumentException	conversionException(java.lang.Object value)
static BeanValueType.Convertability	convertabilityFrom(java.lang.Class<?> klass, java.lang.Object value) How well could convertFrom convert the value to the klass?
BeanValueType.Convertability	convertabilityFrom(java.lang.Object value)
protected BeanValueType.Convertability	convertabilityToString()
static BeanValueType.Convertability	convertabilityToString(java.lang.Class<?> klass)
static java.lang.Object	convertFrom(java.lang.Class<?> klass, java.lang.Object value) Convert the value into an object of the class.
ValueType	convertFrom(java.lang.Object value)
static com.google.gwt.core.client.JavaScriptObject	convertMapToJavascriptObject(java.util.Map valueMap)
static java.lang.Object	convertToJava(com.google.gwt.core.client.JavaScriptObject obj) Performs basic conversion from a JavaScriptObject to an equivalent Java value, without taking into account any particularly desired Java types.
static com.google.gwt.core.client.JavaScriptObject	convertToJavaScriptArray(java.lang.Object[] array)
static com.google.gwt.core.client.JavaScriptObject	convertToJavaScriptObject(java.lang.Object value) Converts the value to a JavaScriptObject.
static java.lang.String	convertToString(java.lang.Object value) Converts the value to a string.
protected java.lang.String	doConvertToString(ValueType value)
static BeanValueType<?>	getBeanValueType(java.lang.Class<?> valueType)
protected abstract java.lang.Class<?>	getValueType()
static boolean	isA(com.google.gwt.core.client.JavaScriptObject value, java.lang.String scClassName) Is the SmartClient object an instance (or subclass) of the SmartClient class?
static boolean	isAssignableFrom(java.lang.Class<?> possibleSuperclass, java.lang.Class<?> possibleSubclass) Can objects of the possible sub-class be assigned to the possible super-class?
static boolean	isAssignableFrom(java.lang.Class<?> klass, java.lang.Object value) Can the value be assigned to the class? Or, to put it another way, would value instanceof Klass return true (if we had the class literal to work with)?
protected abstract boolean	isAssignableFrom(java.lang.Object value)
protected ValueType	nullValue()
static void	registerBasicValueTypes() Registers BeanValueTypes for boolean, double, float, long, Boolean, Double, Float, Long, Number, and String.
protected static void	registerBeanValueType(BeanValueType beanValueType)
static com.google.gwt.core.client.JavaScriptObject	wrapInJavascriptArray(java.lang.Object value) Converts the value to a JavaScriptObject, and wraps it in a JavaScript array.

Methods inherited from class java.lang.Object

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

Constructor Detail

BeanValueType

protected BeanValueType()

Method Detail

getBeanValueType

public static BeanValueType<?> getBeanValueType(java.lang.Class<?> valueType)

registerBeanValueType

protected static void registerBeanValueType(BeanValueType beanValueType)

registerBasicValueTypes

public static void registerBasicValueTypes()

Registers BeanValueTypes for boolean, double, float, long, Boolean, Double, Float, Long, Number, and String.

This is not automatic in order to allow for more dead-code elimination if not being used.

If you need BeanValueTypes for other types, you can register them via the BeanValueType.MetaFactory interface.

isAssignableFrom

public static boolean isAssignableFrom(java.lang.Class<?> klass,
                                       java.lang.Object value)

Can the value be assigned to the class? Or, to put it another way, would value instanceof Klass return true (if we had the class literal to work with)?

Parameters:

klass - The Class to be assigned to.

value - The value to be assigned

Throws:

java.lang.IllegalArgumentException - If the Class represents an interface, and no BeanValueType subclass has been generated to handle it.

isAssignableFrom

public static boolean isAssignableFrom(java.lang.Class<?> possibleSuperclass,
                                       java.lang.Class<?> possibleSubclass)

Can objects of the possible sub-class be assigned to the possible super-class?

Like Class.assignableFrom().

Parameters:

possibleSuperclass - The possible super-class, or lhs of the assignment

possibleSubclass - The possible sub-class, or rhs of the assignment

Throws:

java.lang.IllegalArgumentException - If one of the classes is an interface and the other is not. In that case, you need to use isAssignableFrom(Class<?>, Object) with the value to be assigned.

isA

public static boolean isA(com.google.gwt.core.client.JavaScriptObject value,
                          java.lang.String scClassName)

Is the SmartClient object an instance (or subclass) of the SmartClient class?

Parameters:

value - The SmartClient object

scClassName - The SmartClient class name (e.g. "ListGrid")

convertToJava

public static java.lang.Object convertToJava(com.google.gwt.core.client.JavaScriptObject obj)

Performs basic conversion from a JavaScriptObject to an equivalent Java value, without taking into account any particularly desired Java types.

This is similar to JSOHelper.convertToJava, but has several differences which are needed for BeanFactory to work properly. Note that this method may return a JavaScriptObject -- either the value itself, or possibly a new JavaScriptObject constructed from a config block. In those cases, it may be that convertFrom() can still do some further conversion on the return value, since it can take into account opportunities for conversion that are specific to the desired type. In other words, this is a generic conversion function.

Parameters:

object - A javascript value

Returns:

A generic conversion to an Object (which may still be a JavaScriptObject).

convertabilityFrom

public static BeanValueType.Convertability convertabilityFrom(java.lang.Class<?> klass,
                                                              java.lang.Object value)

How well could convertFrom convert the value to the klass?

This is used to choose the best setter amongst multiple setters, if there are multiple setters available.

Parameters:

klass - The desired class to convert to.

value - The value to be converted.

Returns:

A constant indicating how well the conversion could be performed.

Throws:

java.lang.IllegalArgumentException - If there is no BeanValueType subclass for the klass

convertFrom

public static java.lang.Object convertFrom(java.lang.Class<?> klass,
                                           java.lang.Object value)

Convert the value into an object of the class.

Note that not all conversions are actually supported ... you can check with convertabilityFrom(). The target classes which are supported are generally the classes which are used as value types in properties of BeanFactories that have been generated. The values supported depend on the target class.

Parameters:

klass - The class that you want to convert to.

value - The value that you want to convert.

Returns:

The converted value.

Throws:

java.lang.IllegalArgumentException - If there is no BeanValueType subclass for the klass, or if the BeanValueType is unable to convert the value.

convertabilityToString

public static BeanValueType.Convertability convertabilityToString(java.lang.Class<?> klass)

convertToString

public static java.lang.String convertToString(java.lang.Object value)

Converts the value to a string.

Of course, you can always call Object.toString(). However, a BeanValueType subclass might implement a different strategy.

Parameters:

value - The value to convert.

Returns:

A string representing the value.

wrapInJavascriptArray

public static com.google.gwt.core.client.JavaScriptObject wrapInJavascriptArray(java.lang.Object value)

Converts the value to a JavaScriptObject, and wraps it in a JavaScript array. The wrapping avoids problems with declaring a return type for generic Javascript values. The array is always a JavaScriptObject. If the converted value were returned directly, then in development mode it could be auto-converted back to a String, or a primitive numeric type, causing type errors no matter how the return value is declared here.

Parameters:

value - Value to convert

Returns:

A JavaScriptObject wrapped in a Javascript array

convertToJavaScriptArray

public static com.google.gwt.core.client.JavaScriptObject convertToJavaScriptArray(java.lang.Object[] array)

convertMapToJavascriptObject

public static com.google.gwt.core.client.JavaScriptObject convertMapToJavascriptObject(java.util.Map valueMap)

convertToJavaScriptObject

public static com.google.gwt.core.client.JavaScriptObject convertToJavaScriptObject(java.lang.Object value)

Converts the value to a JavaScriptObject. Note that not all values will convert to JavaScriptObject, becuase the JSNI glue code will auto-convert them back. This returns values only when they really do convert to JavaScriptObject (so, not strings, or numbers).

Parameters:

value - Value to convert

Returns:

A JavaScriptObject

getValueType

protected abstract java.lang.Class<?> getValueType()

isAssignableFrom

protected abstract boolean isAssignableFrom(java.lang.Object value)

nullValue

protected ValueType nullValue()

convertabilityToString

protected BeanValueType.Convertability convertabilityToString()

doConvertToString

protected java.lang.String doConvertToString(ValueType value)

convertabilityFrom

public BeanValueType.Convertability convertabilityFrom(java.lang.Object value)

convertFrom

public ValueType convertFrom(java.lang.Object value)

conversionException

protected java.lang.IllegalArgumentException conversionException(java.lang.Object value)