netbeans/jemmy/ClassReference.java

/*
 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package org.netbeans.jemmy;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 *
 * Allows access to classes by reflection.
 *
 * @author Alexandre Iline (alexandre.iline@oracle.com)
 */
public class ClassReference {

    private Class<?> cl;
    private Object instance;

    /**
     * Constructor.
     *
     * @param o Object to work with.
     */
    public ClassReference(Object o) {
        super();
        instance = o;
        cl = o.getClass();
    }

    /**
     * Contructor. The object created by this constructor can be used to access
     * static methods and fields only.
     *
     * @param className name of class
     * @exception ClassNotFoundException
     */
    public ClassReference(String className)
            throws ClassNotFoundException {
        super();
        cl = Class.forName(className);
        instance = null;
    }

    /**
     * Executes class's {@code main(java.lang.String[])} method with a
     * zero-length {@code java.lang.String} array as a parameter.
     *
     * @exception NoSuchMethodException
     * @exception InvocationTargetException
     */
    public void startApplication()
            throws InvocationTargetException, NoSuchMethodException {
        String[] params = new String[0];
        startApplication(params);
    }

    /**
     * Executes class's {@code main(java.lang.String[])} method.
     *
     * @param params The {@code java.lang.String} array to pass to
     * {@code main(java.lang.String[])}.
     * @exception NoSuchMethodException
     * @exception InvocationTargetException
     */
    public void startApplication(String[] params)
            throws InvocationTargetException, NoSuchMethodException {
        String[] real_params;
        if (params == null) {
            real_params = new String[0];
        } else {
            real_params = params;
        }
        String[][] methodParams = {real_params};
        Class<?>[] classes = {real_params.getClass()};
        try {
            invokeMethod("main", methodParams, classes);
        } catch (IllegalAccessException | IllegalStateException e) {
            e.printStackTrace();
        }
    }

    /**
     * Locates method by name and parameter types and executes it.
     *
     * @param method_name Name of method.
     * @param params Method parameters.
     * @param params_classes Method parameters types.
     * @return the return value from an invocation of the Method.<BR>
     * If {@code method_name} method is void, {@code null} is
     * returned.<BR>
     * If {@code method_name} method returns a primitive type, then return
     * wrapper class instance.
     * @throws InvocationTargetException when the invoked method throws an
     * exception.
     * @throws NoSuchMethodException when the method cannot be found.
     * @throws IllegalAccessException when access to the class or method is
     * lacking.
     * @throws SecurityException if access to the package or method is denied.
     * @exception IllegalAccessException
     * @exception NoSuchMethodException
     * @exception InvocationTargetException
     */
    public Object invokeMethod(String method_name, Object[] params, Class<?>[] params_classes)
            throws InvocationTargetException, NoSuchMethodException, IllegalAccessException {
        if (params == null) {
            params = new Object[0];
        }
        if (params_classes == null) {
            params_classes = new Class<?>[0];
        }
        Method method = cl.getMethod(method_name,
                params_classes);
        return method.invoke(instance, params);
    }

    /**
     * Locates constructor by parameter types and creates an instance.
     *
     * @param params An array of Method parameters.
     * @param params_classes An array of Method parameter types.
     * @return a new class instance.
     * @throws InvocationTargetException when the invoked constructor throws an
     * exception.
     * @throws NoSuchMethodException when the constructor cannot be found.
     * @throws IllegalAccessException when access to the class or constructor is
     * lacking.
     * @throws InstantiationException when the constructor is for an abstract
     * class.
     * @throws SecurityException if access to the package or constructor is
     * denied.
     * @exception IllegalAccessException
     * @exception NoSuchMethodException
     * @exception InstantiationException
     * @exception InvocationTargetException
     */
    public Object newInstance(Object[] params, Class<?>[] params_classes)
            throws InvocationTargetException, NoSuchMethodException,
            IllegalAccessException, InstantiationException {
        if (params == null) {
            params = new Object[0];
        }
        if (params_classes == null) {
            params_classes = new Class<?>[0];
        }
        Constructor<?> constructor = cl.getConstructor(params_classes);
        return constructor.newInstance(params);
    }

    /**
     * Returns the field value.
     *
     * @param field_name The name of the field.
     * @return the field value
     * @see #setField
     * @throws NoSuchFieldException when the field cannot be found.
     * @throws IllegalAccessException when access to the class or constructor is
     * lacking.
     * @throws SecurityException if access to the package or field is denied.
     * @exception IllegalAccessException
     * @exception NoSuchFieldException
     */
    public Object getField(String field_name)
            throws NoSuchFieldException, IllegalAccessException {
        return cl.getField(field_name).get(instance);
    }

    /**
     * Change a field's value.
     *
     * @param field_name The name of the field.
     * @param newValue The fields new value.
     * @see #getField
     * @throws NoSuchFieldException when the field cannot be found.
     * @throws IllegalAccessException when access to the class or constructor is
     * lacking.
     * @throws SecurityException if access to the package or field is denied.
     * @exception IllegalAccessException
     * @exception NoSuchFieldException
     */
    public void setField(String field_name, Object newValue)
            throws NoSuchFieldException, IllegalAccessException {
        cl.getField(field_name).set(instance, newValue);
    }

    /**
     * Returns all superclasses.
     *
     * @return an array of superclasses, starting with the reference class and
     * ending with {@code java.lang.Object}.
     */
    public Class<?>[] getClasses() {
        Class<?> cls = cl;
        int count = 0;
        do {
            count++;
            cls = cls.getSuperclass();
        } while (cls != null);
        Class<?>[] result = new Class<?>[count];
        cls = cl;
        for (int i = 0; i < count; i++) {
            result[i] = cls;
            cls = cls.getSuperclass();
        }
        return result;
    }
}