MetaProperty.java
/*
* Copyright 2001-present Stephen Colebourne
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.joda.beans;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.List;
import java.util.NoSuchElementException;
import org.joda.beans.impl.BasicProperty;
import org.joda.convert.StringConvert;
/**
* A meta-property, defining those aspects of a property which are not specific
* to a particular bean, such as the property type and name.
*
* @param <P> the type of the property content
*/
public interface MetaProperty<P> {
/**
* Creates a property that binds this meta-property to a specific bean.
* <p>
* This method returns a {@code Property} instance that connects this meta-property to the specified bean.
* The result can be queried and passed around without further reference to the bean.
*
* @param bean the bean to create the property for, not null
* @return the property, not null
*/
public default Property<P> createProperty(Bean bean) {
return BasicProperty.of(bean, this);
}
//-----------------------------------------------------------------------
/**
* Gets the meta-bean which owns this meta-property.
* <p>
* Each meta-property is fully owned by a single bean.
*
* @return the meta-bean, not null
*/
public abstract MetaBean metaBean();
/**
* Gets the property name.
* <p>
* The JavaBean style methods getFoo() and setFoo() will lead to a property
* name of 'foo' and so on.
*
* @return the name of the property, not empty
*/
public abstract String name();
/**
* Get the type that declares the property, represented as a {@code Class}.
* <p>
* This is the type of the bean where the property is declared.
*
* @return the type declaring the property, not null
*/
public abstract Class<?> declaringType();
/**
* Get the type of the property represented as a {@code Class}.
* <p>
* This is the type of the property.
* For example, the surname of a person would typically be a {@code String}.
*
* @return the type of the property, not null
*/
public abstract Class<P> propertyType();
/**
* Gets the generic types of the property.
* <p>
* This provides access to the generic type declared in the source code.
*
* @return the full generic type of the property, unmodifiable, not null
*/
public abstract Type propertyGenericType();
/**
* Gets the style of the property, such as read-only, read-write or write-only.
* <p>
* Rather than testing against specific values, it is strongly recommended to
* call the helper methods on the returned style.
*
* @return the property style, not null
*/
public abstract PropertyStyle style();
//-----------------------------------------------------------------------
/**
* Gets the annotations of the property.
* <p>
* The annotations are queried from the property.
* This is typically accomplished by querying the annotations of the underlying
* instance variable however any strategy is permitted.
*
* @return the annotations, unmodifiable, not null
*/
public abstract List<Annotation> annotations();
/**
* Gets an annotation from the property.
* <p>
* The annotations are queried from the property.
* This is typically accomplished by querying the annotations of the underlying
* instance variable however any strategy is permitted..
*
* @param <A> the annotation type
* @param annotationClass the annotation class to find, not null
* @return the annotation, not null
* @throws NoSuchElementException if the annotation is not specified
*/
@SuppressWarnings("unchecked")
public default <A extends Annotation> A annotation(Class<A> annotationClass) {
List<Annotation> annotations = annotations();
for (Annotation annotation : annotations) {
if (annotationClass.isInstance(annotation)) {
return (A) annotation;
}
}
throw new NoSuchElementException("Unknown annotation: " + annotationClass.getName());
}
//-----------------------------------------------------------------------
/**
* Gets the value of the property for the specified bean.
* <p>
* For a standard JavaBean, this is equivalent to calling <code>getFoo()</code> on the bean.
* Alternate implementations may perform any logic to obtain the value.
*
* @param bean the bean to query, not null
* @return the value of the property on the specified bean, may be null
* @throws ClassCastException if the bean is of an incorrect type
* @throws UnsupportedOperationException if the property is write-only
*/
public abstract P get(Bean bean);
/**
* Sets the value of the property on the specified bean.
* <p>
* The value must be of the correct type for the property.
* For a standard JavaBean, this is equivalent to calling <code>setFoo()</code> on the bean.
* Alternate implementations may perform any logic to change the value.
*
* @param bean the bean to update, not null
* @param value the value to set into the property on the specified bean, may be null
* @throws ClassCastException if the bean is of an incorrect type
* @throws ClassCastException if the value is of an invalid type for the property
* @throws UnsupportedOperationException if the property is read-only
* @throws RuntimeException if the value is rejected by the property (use appropriate subclasses)
*/
public abstract void set(Bean bean, Object value);
/**
* Sets the value of the property on the associated bean and returns the previous value.
* <p>
* The value must be of the correct type for the property.
* This is a combination of the {@code get} and {@code set} methods that matches the definition
* of {@code put} in a {@code Map}.
*
* @param bean the bean to update, not null
* @param value the value to set into the property on the specified bean, may be null
* @return the old value of the property, may be null
* @throws ClassCastException if the bean is of an incorrect type
* @throws ClassCastException if the value is of an invalid type for the property
* @throws UnsupportedOperationException if the property is read-only
* @throws RuntimeException if the value is rejected by the property (use appropriate subclasses)
*/
public default P put(Bean bean, Object value) {
P old = get(bean);
set(bean, value);
return old;
}
//-----------------------------------------------------------------------
/**
* Gets the value of the property for the specified bean converted to a string.
* <p>
* This converts the result of {@link #get(Bean)} to a standard format string.
* Conversion uses Joda-Convert.
* Not all object types can be converted to a string, see Joda-Convert.
* <p>
* For a standard JavaBean, this is equivalent to calling <code>getFoo()</code> on the bean.
* Alternate implementations may perform any logic to obtain the value.
*
* @param bean the bean to query, not null
* @return the value of the property on the specified bean, may be null
* @throws ClassCastException if the bean is of an incorrect type
* @throws UnsupportedOperationException if the property is write-only
* @throws RuntimeException if the value cannot be converted to a string (use appropriate subclasses)
*/
public default String getString(Bean bean) {
return getString(bean, JodaBeanUtils.stringConverter());
}
/**
* Gets the value of the property for the specified bean converted to a string.
* <p>
* This converts the result of {@link #get(Bean)} to a standard format string using the supplied converter.
* Not all object types can be converted to a string, see Joda-Convert.
* <p>
* For a standard JavaBean, this is equivalent to calling <code>getFoo()</code> on the bean.
* Alternate implementations may perform any logic to obtain the value.
*
* @param bean the bean to query, not null
* @param stringConvert the converter to use, not null
* @return the value of the property on the specified bean, may be null
* @throws ClassCastException if the bean is of an incorrect type
* @throws UnsupportedOperationException if the property is write-only
* @throws RuntimeException if the value cannot be converted to a string (use appropriate subclasses)
*/
public default String getString(Bean bean, StringConvert stringConvert) {
P value = get(bean);
return stringConvert.convertToString(propertyType(), value);
}
/**
* Sets the value of the property on the specified bean from a string by conversion.
* <p>
* This converts the string to the correct type for the property and then sets it
* using {@link #set(Bean, Object)}. Conversion uses Joda-Convert.
*
* @param bean the bean to update, not null
* @param value the value to set into the property on the specified bean, may be null
* @throws ClassCastException if the bean is of an incorrect type
* @throws ClassCastException if the value is of an invalid type for the property
* @throws UnsupportedOperationException if the property is read-only
* @throws RuntimeException if the value is rejected by the property (use appropriate subclasses)
*/
public default void setString(Bean bean, String value) {
setString(bean, value, JodaBeanUtils.stringConverter());
}
/**
* Sets the value of the property on the specified bean from a string by conversion.
* <p>
* This converts the string to the correct type for the property using the supplied converter and then sets it
* using {@link #set(Bean, Object)}.
*
* @param bean the bean to update, not null
* @param value the value to set into the property on the specified bean, may be null
* @param stringConvert the converter, not null
* @throws ClassCastException if the bean is of an incorrect type
* @throws ClassCastException if the value is of an invalid type for the property
* @throws UnsupportedOperationException if the property is read-only
* @throws RuntimeException if the value is rejected by the property (use appropriate subclasses)
*/
public default void setString(Bean bean, String value, StringConvert stringConvert) {
set(bean, stringConvert.convertFromString(propertyType(), value));
}
//-----------------------------------------------------------------------
/**
* Checks if this meta-property equals another.
* <p>
* This compares the property name and declaring type.
* It does not compare the property or bean types.
*
* @param obj the other meta-property, null returns false
* @return true if equal
*/
@Override
public abstract boolean equals(Object obj);
/**
* Returns a suitable hash code.
*
* @return the hash code
*/
@Override
public abstract int hashCode();
}