com.github.spjoe.BeanPropertyAnnotationCache Maven / Gradle / Ivy

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A library which provides caching for annotation on getters of java bean properties. It also creates byte code (via reflectAsm) to call getter and setter of the annotated java bean property
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/*
    Copyright 2016 Camillo Dell'mour

    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 com.github.spjoe;

import com.github.spjoe.getter.*;
import com.github.spjoe.setter.*;

import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Supplier;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;

public class BeanPropertyAnnotationCache {
    private final Map, Optional> annotations = new ConcurrentHashMap();
    private final Map, GetterCall> getters = new ConcurrentHashMap();
    private final Map, SetterCall> setters = new ConcurrentHashMap();
    private final Class annotationClass;

    public BeanPropertyAnnotationCache(final Class annotationClass) {
        this.annotationClass = annotationClass;
    }

    public  Optional getAnnotation(final Class derivedType) {
        return annotations.computeIfAbsent(derivedType, this::createOptionalAnnotation);
    }

    public  Optional getAnnotation(final DERIVED instance) {
        return getAnnotation((Class) instance.getClass());
    }

    public  GetterResult get(final BASE instance) {
        return (GetterResult) getters.computeIfAbsent((Class) instance.getClass(), this::createGetter).get(instance);
    }

    public  SetterResult set(final DERIVED instance, final PROPERTY_TYPE propertyValue ) {
        return setters.computeIfAbsent((Class) instance.getClass(), this::createSetter).set(instance, propertyValue);
    }

    private  SetterCall createSetter(final Class derivedType) {
        return firstOptional(() -> getGetterWithAnnotation(derivedType, annotationClass).findAny().flatMap(getter -> setterOfGetter(getter, derivedType))
                                                    .map(MethodSetterCall::new),
                             () -> getFieldsWithAnnotation(derivedType, annotationClass).findAny().map(this::createFieldSetter))
                .orElseGet(NoSetterCall::new);
    }

    private  GetterCall createGetter(final Class derivedType) {
        return firstOptional(() -> getGetterWithAnnotation(derivedType, annotationClass).findAny().map(MethodGetterCall::new),
                             () -> getFieldsWithAnnotation(derivedType, annotationClass).findAny().map(this::createFieldGetter))
                .orElseGet(NoGetterCall::new);
    }

    private  GetterCall createFieldGetter(final Field field) {
        GetterCall retVal;
        try {
            retVal = new FieldGetterCall<>(field);
        } catch (IllegalArgumentException e) {
            retVal = new FieldReflectionGetterCall<>(field);
        }

        return retVal;
    }

    private  SetterCall createFieldSetter(final Field field) {
        SetterCall retVal;
        try {
            retVal = new FieldSetterCall<>(field);
        } catch (IllegalArgumentException e) {
            retVal = new FieldReflectionSetterCall<>(field);
        }

        return retVal;
    }

    private  Optional createOptionalAnnotation(Class derivedType) {
        return getGetterWithAnnotation(derivedType, annotationClass).findAny().map(m -> m.getAnnotation(annotationClass)).map(Optional::of)
                .orElseGet(() -> getFieldsWithAnnotation(derivedType, annotationClass).findAny().map(f -> f.getAnnotation(annotationClass)));
    }

    private  Optional setterOfGetter(final Method getter, final Class derivedClass) {
        String setterName = convertToSetterName(getter.getName());
        return getMethodWithName(derivedClass, setterName);
    }

    private static String convertToSetterName(final String getterName) {
        int nameIndex = getterName.startsWith("is") ? 2 : 3;
        return "set" + getterName.substring(nameIndex);
    }

    private static Optional getMethodWithName(final Class clazz, final String name) {
        return getAccessibleMethods(clazz).filter(m -> m.getName().equals(name)).findAny();
    }

    private static Stream getGetterWithAnnotation(final Class clazz, final Class annotationClass) {
        return getGetterMethods(clazz).filter(m -> m.isAnnotationPresent(annotationClass));
    }

    private static Stream getFieldsWithAnnotation(final Class clazz, final Class annotationClass) {
        return getAccessibleFields(clazz).filter(f -> f.isAnnotationPresent(annotationClass));
    }

    private static Stream getGetterMethods(final Class clazz) {
        return getAccessibleMethods(clazz).filter(m -> m.getName().startsWith("get") || m.getName().startsWith("is"));
    }

    private static Stream getAccessibleMethods(final Class clazz) {
        Iterable> iterable = () -> new SuperClassIterator(clazz);
        Stream> classHierarchy = StreamSupport.stream(iterable.spliterator(), false);
        return classHierarchy.flatMap(c -> Stream.of(c.getDeclaredMethods()));
    }

    private static Stream getAccessibleFields(final Class clazz) {
        Iterable> iterable = () -> new SuperClassIterator(clazz);
        Stream> classHierarchy = StreamSupport.stream(iterable.spliterator(), false);
        return classHierarchy.flatMap(c -> Stream.of(c.getDeclaredFields()));
    }

    private static class SuperClassIterator implements Iterator> {
        private Class clazz;

        public SuperClassIterator(final Class clazz) {
            this.clazz = clazz;
        }

        @Override
        public boolean hasNext() {
            return clazz != null;
        }

        @Override
        public Class next() {
            Class retVal = clazz;
            clazz = clazz.getSuperclass();
            return retVal;
        }
    }

    private static  Optional firstOptional(final Supplier>... suppliers) {
        return Arrays.asList(suppliers).stream().map(Supplier::get).flatMap(o -> o.map(Stream::of).orElseGet(Stream::empty)).findFirst();
    }
}