de.openknowledge.jaxrs.versioning.conversion.FieldVersionProperty.java Source code

Introduction

Here is the source code for de.openknowledge.jaxrs.versioning.conversion.FieldVersionProperty.java

Source

/*
 * Copyright (C) open knowledge GmbH
 * 
 * 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 de.openknowledge.jaxrs.versioning.conversion;

import static org.apache.commons.lang3.Validate.notNull;

import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.lang.reflect.ParameterizedType;
import java.util.Collection;
import java.util.Date;

import org.apache.commons.lang3.ClassUtils;

/**
 * @author Arne Limburg - open knowledge GmbH
 * @author Philipp Geers - open knowledge GmbH
 */
public class FieldVersionProperty implements VersionProperty {

    private String name;

    private Class<?> type;

    private Field field;

    public FieldVersionProperty(Field field) {
        this.field = notNull(field);
        this.name = field.getName();
        this.type = field.getType();
    }

    @Override
    public String getName() {
        return name;
    }

    @Override
    public Class<?> getType() {
        return type;
    }

    @Override
    public Class<?> getCollectionElementType() {
        // TODO improve generics resolution
        ParameterizedType type = (ParameterizedType) field.getGenericType();
        return (Class<?>) type.getActualTypeArguments()[0];
    }

    @Override
    public boolean isSimple() {
        return isSimple(type);
    }

    @Override
    public boolean isCollection() {
        return Collection.class.isAssignableFrom(type);
    }

    @Override
    public boolean isCollectionOfSimpleTypes() {
        return isCollection() && isSimple(getCollectionElementType());
    }

    @Override
    public boolean isDefault(Object base) {
        if (!type.isPrimitive()) {
            return get(base) == null;
        }
        Object value = get(base);
        if (value instanceof Boolean) {
            return !((Boolean) value).booleanValue();
        } else if (value instanceof Character) {
            return ((Character) value).equals('\u0000');
        } else {
            return ((Number) value).doubleValue() == 0;
        }
    }

    @Override
    public Object get(Object base) {
        try {
            return field.get(base);
        } catch (IllegalAccessException e) {
            throw new IllegalStateException(e);
        }
    }

    @Override
    public void set(Object base, Object value) {
        try {
            field.set(base, convert(value));
        } catch (IllegalAccessException e) {
            throw new IllegalStateException(e);
        }
    }

    @Override
    public <A extends Annotation> A getAnnotation(Class<A> type) {
        return field.getAnnotation(type);
    }

    public String toString() {
        return getClass().getSimpleName() + "[name=" + name + "]";
    }

    private boolean isSimple(Class<?> type) {
        return type == String.class || type == Date.class || ClassUtils.isPrimitiveOrWrapper(type);
    }

    private Object convert(Object value) {
        if (value == null || !isSimple() || type.isAssignableFrom(value.getClass())) {
            return value;
        }
        Class<?> targetType = type.isPrimitive() ? ClassUtils.primitiveToWrapper(type) : type;
        try {
            return targetType.getConstructor(String.class).newInstance(value.toString());
        } catch (ReflectiveOperationException e) {
            throw new IllegalStateException(e);
        }
    }
}