/*
 * Grapht, an open source dependency injector.
 * Copyright 2010-2012 Regents of the University of Minnesota and contributors
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
package org.grouplens.grapht.util;

import java.io.Serializable;
import java.lang.reflect.Field;

/**
 * Proxy class for serializing fields.
 */
public class FieldProxy implements Serializable {
    private static final long serialVersionUID = 1L;

    private final ClassProxy declaringClass;
    private final String fieldName;
    private final ClassProxy fieldType;
    private transient Field field;

    private FieldProxy(ClassProxy cls, String n, ClassProxy type) {
        declaringClass = cls;
        fieldName = n;
        fieldType = type;
    }

    @Override
    public String toString() {
        return String.format("FieldProxy(%s of %s)", fieldName, declaringClass.getClassName());
    }

    /**
     * Resolve this proxy into a {@link Field} instance.
     * @return The {@link Field} represented by this proxy.
     * @throws ClassNotFoundException If the proxy's declaring type cannot be resolved.
     * @throws NoSuchFieldException If the field does not exist on the declaring type.
     */
    public Field resolve() throws ClassNotFoundException, NoSuchFieldException {
        if (field == null) {
            Class<?> cls = declaringClass.resolve();
            field = cls.getDeclaredField(fieldName);
            // REVIEW Original code verified the field type. Is this necessary?
        }
        return field;
    }

    /**
     * Construct a proxy for a field.
     * @param field The field to proxy.
     * @return The field proxy representing {@code field}.
     */
    public static FieldProxy forField(Field field) {
        FieldProxy proxy = new FieldProxy(ClassProxy.forClass(field.getDeclaringClass()),
                                          field.getName(),
                                          ClassProxy.forClass(field.getType()));
        proxy.field = field;
        return proxy;
    }
}

/*
 * Grapht, an open source dependency injector.
 * Copyright 2010-2012 Regents of the University of Minnesota and contributors
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
package org.grouplens.grapht.util;

import java.io.Serializable;
import java.lang.reflect.Field;

/**
 * Proxy class for serializing fields.
 */
public class FieldProxy implements Serializable {
    private static final long serialVersionUID = 1L;

    private final ClassProxy declaringClass;
    private final String fieldName;
    private final ClassProxy fieldType;
    private transient Field field;

    private FieldProxy(ClassProxy cls, String n, ClassProxy type) {
        declaringClass = cls;
        fieldName = n;
        fieldType = type;
    }

    @Override
    public String toString() {
        return String.format("FieldProxy(%s of %s)", fieldName, declaringClass.getClassName());
    }

    /**
     * Resolve this proxy into a {@link Field} instance.
     * @return The {@link Field} represented by this proxy.
     * @throws ClassNotFoundException If the proxy's declaring type cannot be resolved.
     * @throws NoSuchFieldException If the field does not exist on the declaring type.
     */
    public Field resolve() throws ClassNotFoundException, NoSuchFieldException {
        if (field == null) {
            Class<?> cls = declaringClass.resolve();
            field = cls.getDeclaredField(fieldName);
        }
        // REVIEW Do we want to test equality or assignability?
        if (!field.getType().equals(fieldType.resolve())) {
            throw new NoSuchFieldException("type mismatch on " + field.toString());
        }
        return field;
    }

    /**
     * Construct a proxy for a field.
     * @param field The field to proxy.
     * @return The field proxy representing {@code field}.
     */
    public static FieldProxy forField(Field field) {
        FieldProxy proxy = new FieldProxy(ClassProxy.forClass(field.getDeclaringClass()),
                                          field.getName(),
                                          ClassProxy.forClass(field.getType()));
        proxy.field = field;
        return proxy;
    }
}

Verify field assignability