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/*
@ITMillApache2LicenseForJavaFiles@
*/
package com.vaadin.data.util;
import java.lang.reflect.Constructor;
import com.vaadin.data.Property;
/**
* A simple data object containing one typed value. This class is a
* straightforward implementation of the the {@link com.vaadin.data.Property}
* interface.
*
* @author IT Mill Ltd.
* @version
* @VERSION@
* @since 3.0
*/
@SuppressWarnings("serial")
public class ObjectProperty<T> extends AbstractProperty {
/**
* The value contained by the Property.
*/
private T value;
/**
* Data type of the Property's value.
*/
private final Class<T> type;
/**
* Creates a new instance of ObjectProperty with the given value. The type
* of the property is automatically initialized to be the type of the given
* value.
*
* @param value
* the Initial value of the Property.
*/
@SuppressWarnings("unchecked")
// the cast is safe, because an object of type T has class Class<T>
public ObjectProperty(T value) {
this(value, (Class<T>) value.getClass());
}
/**
* Creates a new instance of ObjectProperty with the given value and type.
*
* Any value of type Object is accepted because, if the type class contains
* a string constructor, the toString of the value is used to create the new
* value. See {@link #setValue(Object)}.
*
* @param value
* the Initial value of the Property.
* @param type
* the type of the value. The value must be assignable to given
* type.
*/
public ObjectProperty(Object value, Class<T> type) {
// Set the values
this.type = type;
setValue(value);
}
/**
* Creates a new instance of ObjectProperty with the given value, type and
* read-only mode status.
*
* Any value of type Object is accepted, see
* {@link #ObjectProperty(Object, Class)}.
*
* @param value
* the Initial value of the property.
* @param type
* the type of the value. <code>value</code> must be assignable
* to this type.
* @param readOnly
* Sets the read-only mode.
*/
public ObjectProperty(Object value, Class<T> type, boolean readOnly) {
this(value, type);
setReadOnly(readOnly);
}
/**
* Returns the type of the ObjectProperty. The methods <code>getValue</code>
* and <code>setValue</code> must be compatible with this type: one must be
* able to safely cast the value returned from <code>getValue</code> to the
* given type and pass any variable assignable to this type as an argument
* to <code>setValue</code>.
*
* @return type of the Property
*/
public final Class<T> getType() {
return type;
}
/**
* Gets the value stored in the Property.
*
* @return the value stored in the Property
*/
public T getValue() {
return value;
}
/**
* Sets the value of the property. This method supports setting from
* <code>String</code> if either <code>String</code> is directly assignable
* to property type, or the type class contains a string constructor.
*
* @param newValue
* the New value of the property.
* @throws <code>Property.ReadOnlyException</code> if the object is in
* read-only mode
* @throws <code>Property.ConversionException</code> if the newValue can't
* be converted into the Property's native type directly or through
* <code>String</code>
*/
public void setValue(Object newValue) throws Property.ReadOnlyException,
Property.ConversionException {
// Checks the mode
if (isReadOnly()) {
throw new Property.ReadOnlyException();
}
// Tries to assign the compatible value directly
if (newValue == null || type.isAssignableFrom(newValue.getClass())) {
@SuppressWarnings("unchecked")
// the cast is safe after an isAssignableFrom check
T value = (T) newValue;
this.value = value;
} else {
try {
// Gets the string constructor
final Constructor<T> constr = getType().getConstructor(
new Class[] { String.class });
// Creates new object from the string
value = constr
.newInstance(new Object[] { newValue.toString() });
} catch (final java.lang.Exception e) {
throw new Property.ConversionException(e);
}
}
fireValueChange();
}
}
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