ConversionGenerator.java

/*******************************************************************************
 * Copyright (c) 2017 Red Hat.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Red Hat - Initial Contribution
 *******************************************************************************/
package org.eclipse.che.api.languageserver.generator;

import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.WildcardType;
import java.util.List;

/**
 * Base class for conversion generators. Subclasses are responsible for
 * generating conversion code for a single property of a dto.
 *
 * @author Thomas Mäder
 */
public abstract class ConversionGenerator {

    protected ConversionGenerator() {
    }

    protected Type containedType(Type paramType) {
        if (paramType == null || !List.class.isAssignableFrom(getRawClass(paramType))) {
            return null;
        }
        if (paramType instanceof ParameterizedType) {
            ParameterizedType genericType = (ParameterizedType)paramType;
            return getUpperBound(genericType.getActualTypeArguments()[0]);
        }
        if (paramType instanceof Class<?>) {
            Class<?> clazz = (Class<?>)paramType;
            Type c = containedType(clazz.getGenericSuperclass());
            if (c != null) {
                return c;
            }
            for (Type intf : clazz.getGenericInterfaces()) {
                c = containedType(intf);
                if (c != null) {
                    return c;
                }
            }
        }
        return null;
    }

    private Type getUpperBound(Type type) {
        if (type instanceof WildcardType) {
            return ((WildcardType)type).getUpperBounds()[0];
        }
        return type;
    }

    protected Class<?> getRawClass(Type type) {
        if (type instanceof ParameterizedType) {
            return getRawClass(((ParameterizedType)type).getRawType());
        } else if (type instanceof WildcardType) {
            return getRawClass(((WildcardType)type).getUpperBounds()[0]);
        }
        return (Class<?>)type;
    }

    protected boolean isSimpleNumberType(Class<?> clazz) {
        return clazz == double.class || clazz == int.class || clazz == float.class || clazz == long.class;
    }

    protected String getterName(Class<?> receiverClass, Method m) {
        if (boolean.class == m.getParameterTypes()[0] || Boolean.class == m.getParameterTypes()[0]) {
            String root = m.getName().substring(3);
            try {
                return receiverClass.getMethod("is" + root, new Class<?>[]{}).getName();
            } catch (NoSuchMethodException e) {
                try {
                    return receiverClass.getMethod("get" + root, new Class<?>[]{}).getName();
                } catch (NoSuchMethodException e1) {
                    StringBuilder b = new StringBuilder(root);
                    b.setCharAt(0, Character.toLowerCase(root.charAt(0)));
                    return b.toString();
                }
            }
        }
        return m.getName().replaceFirst("set", "get");
    }

    protected String fieldName(Method setterMethod) {
        StringBuilder name = new StringBuilder(setterMethod.getName().substring(3));
        name.setCharAt(0, Character.toLowerCase(name.charAt(0)));
        return name.toString();
    }


}