org.springframework.data.convert.ConverterBuilder Maven / Gradle / Ivy
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/*
* Copyright 2017-2024 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 java.util.Optional;
import java.util.Set;
import java.util.function.Function;
import org.springframework.core.convert.converter.GenericConverter;
import org.springframework.core.convert.converter.GenericConverter.ConvertiblePair;
import org.springframework.util.Assert;
/**
* API to easily set up {@link GenericConverter} instances using Java 8 lambdas, mostly in bidirectional fashion for
* easy registration as custom type converters of the Spring Data mapping subsystem. The registration starts either with
* the definition of a reading or writing converter that can then be completed.
*
* @author Oliver Gierke
* @since 2.0
* @see #reading(Class, Class, Function)
* @see #writing(Class, Class, Function)
* @soundtrack John Mayer - Moving On and Getting Over (The Search for Everything)
*/
public interface ConverterBuilder {
/**
* Creates a new {@link ReadingConverterBuilder} to produce a converter to read values of the given source (the store
* type) into the given target (the domain type).
*
* @param source must not be {@literal null}.
* @param target must not be {@literal null}.
* @param function must not be {@literal null}.
* @return
*/
static ReadingConverterBuilder reading(Class source, Class target,
Function function) {
Assert.notNull(source, "Source type must not be null");
Assert.notNull(target, "Target type must not be null");
Assert.notNull(function, "Conversion function must not be null");
return new DefaultConverterBuilder<>(new ConvertiblePair(source, target), Optional.empty(), Optional.of(function));
}
/**
* Creates a new {@link WritingConverterBuilder} to produce a converter to write values of the given source (the
* domain type) into the given target (the store type).
*
* @param source must not be {@literal null}.
* @param target must not be {@literal null}.
* @param function must not be {@literal null}.
* @return
*/
static WritingConverterBuilder writing(Class source, Class target,
Function function) {
Assert.notNull(source, "Source type must not be null");
Assert.notNull(target, "Target type must not be null");
Assert.notNull(function, "Conversion function must not be null");
return new DefaultConverterBuilder<>(new ConvertiblePair(target, source), Optional.of(function), Optional.empty());
}
/**
* Returns all {@link GenericConverter} instances to be registered for the current {@link ConverterBuilder}.
*
* @return
*/
Set getConverters();
/**
* Exposes a writing converter.
*
* @author Oliver Gierke
* @since 2.0
*/
interface WritingConverterAware {
/**
* Returns the writing converter already created.
*
* @return
*/
GenericConverter getWritingConverter();
}
/**
* Exposes a reading converter.
*
* @author Oliver Gierke
* @since 2.0
*/
interface ReadingConverterAware {
/**
* Returns the reading converter already created.
*
* @return
*/
GenericConverter getReadingConverter();
}
/**
* Interface to represent an intermediate setup step of {@link ConverterAware} defining a reading converter first.
*
* @author Oliver Gierke
* @since 2.0
*/
interface ReadingConverterBuilder extends ConverterBuilder, ReadingConverterAware {
/**
* Creates a new {@link ConverterAware} by registering the given {@link Function} to add a write converter.
*
* @param function must not be {@literal null}.
* @return
*/
ConverterAware andWriting(Function function);
}
/**
* Interface to represent an intermediate setup step of {@link ConverterAware} defining a writing converter first.
*
* @author Oliver Gierke
* @since 2.0
*/
interface WritingConverterBuilder extends ConverterBuilder, WritingConverterAware {
/**
* Creates a new {@link ConverterAware} by registering the given {@link Function} to add a write converter.
*
* @param function must not be {@literal null}.
* @return
*/
ConverterAware andReading(Function function);
}
/**
* A {@link ConverterBuilder} aware of both a reading and writing converter.
*
* @author Oliver Gierke
* @since 2.0
*/
interface ConverterAware extends ConverterBuilder, ReadingConverterAware, WritingConverterAware {}
}