org.springframework.data.convert.ValueConversionContext Maven / Gradle / Ivy
/*
* Copyright 2022-2023 the original author or authors.
*
* 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
*
* https://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.springframework.data.convert;
import org.springframework.data.mapping.PersistentProperty;
import org.springframework.data.util.TypeInformation;
import org.springframework.lang.Nullable;
/**
* The {@link ValueConversionContext} provides access to the store-specific {@link PersistentProperty} and allows to
* call the store-default conversion through the {@literal read}/{@literal write} methods.
*
* Store implementations should provide their own flavor of {@link ValueConversionContext} enhancing the existing API,
* implementing delegates for {@link #read(Object, TypeInformation)}, {@link #write(Object, TypeInformation)}.
*
* @author Christoph Strobl
* @author Oliver Drotbohm
* @see org.springframework.data.mapping.PersistentProperty
*/
public interface ValueConversionContext
> {
/**
* Return the {@link PersistentProperty} to be handled.
*
* @return will never be {@literal null}.
* @see org.springframework.data.mapping.PersistentProperty
*/
P getProperty();
/**
* Write the value as an instance of the {@link PersistentProperty#getTypeInformation() property type}.
*
* @param value {@link Object value} to write; can be {@literal null}.
* @return can be {@literal null}.
* @throws IllegalStateException if value cannot be written as an instance of the
* {@link PersistentProperty#getTypeInformation() property type}.
* @see PersistentProperty#getTypeInformation()
* @see #write(Object, TypeInformation)
*/
@Nullable
default Object write(@Nullable Object value) {
return write(value, getProperty().getTypeInformation());
}
/**
* Write the value as an instance of {@link Class type}.
*
* @param value {@link Object value} to write; can be {@literal null}.
* @param target {@link Class type} of value to be written; must not be {@literal null}.
* @return can be {@literal null}.
* @throws IllegalStateException if value cannot be written as an instance of {@link Class type}.
* @see #write(Object, TypeInformation)
* @see TypeInformation
*/
@Nullable
default T write(@Nullable Object value, Class target) {
return write(value, TypeInformation.of(target));
}
/**
* Write the value as an instance of {@link TypeInformation type}.
*
* @param value {@link Object value} to write; can be {@literal null}.
* @param target {@link TypeInformation type} of value to be written; must not be {@literal null}.
* @return can be {@literal null}.
* @throws IllegalStateException if value cannot be written as an instance of {@link TypeInformation type}.
* @see TypeInformation
*/
@Nullable
default T write(@Nullable Object value, TypeInformation target) {
if (value == null || target.getType().isInstance(value)) {
return target.getType().cast(value);
}
throw new IllegalStateException(String.format(
"%s does not provide write function that allows value conversion to target type (%s)", getClass(), target));
}
/**
* Reads the value as an instance of the {@link PersistentProperty#getTypeInformation() property type}.
*
* @param value {@link Object value} to be read; can be {@literal null}.
* @return can be {@literal null}.
* @throws IllegalStateException if value cannot be read as an instance of the
* {@link PersistentProperty#getTypeInformation() property type}.
* @see PersistentProperty#getTypeInformation()
* @see #read(Object, TypeInformation)
*/
@Nullable
default Object read(@Nullable Object value) {
return read(value, getProperty().getTypeInformation());
}
/**
* Reads the value as an instance of {@link Class type}.
*
* @param value {@link Object value} to be read; can be {@literal null}.
* @param target {@link Class type} of value to be read; must not be {@literal null}.
* @return can be {@literal null}.
* @throws IllegalStateException if value cannot be read as an instance of {@link Class type}.
* @see #read(Object, TypeInformation)
* @see TypeInformation
*/
@Nullable
default T read(@Nullable Object value, Class target) {
return read(value, TypeInformation.of(target));
}
/**
* Reads the value as an instance of {@link TypeInformation type}.
*
* @param value {@link Object value} to be read; can be {@literal null}.
* @param target {@link TypeInformation type} of value to be read; must not be {@literal null}.
* @return can be {@literal null}.
* @throws IllegalStateException if value cannot be read as an instance of {@link TypeInformation type}.
* @see TypeInformation
*/
@Nullable
default T read(@Nullable Object value, TypeInformation target) {
if (value == null || target.getType().isInstance(value)) {
return target.getType().cast(value);
}
throw new IllegalStateException(String.format(
"%s does not provide read function that allows value conversion to target type (%s)", getClass(), target));
}
}