tapestry-ioc/src/main/java/org/apache/tapestry5/ioc/services/PlasticProxyFactory.java

// Copyright 2011, 2012 The Apache Software Foundation
//
// 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 org.apache.tapestry5.ioc.services;

import org.apache.tapestry5.ioc.Location;
import org.apache.tapestry5.ioc.ObjectCreator;
import org.apache.tapestry5.ioc.annotations.IncompatibleChange;
import org.apache.tapestry5.plastic.ClassInstantiator;
import org.apache.tapestry5.plastic.PlasticClassListenerHub;
import org.apache.tapestry5.plastic.PlasticClassTransformation;
import org.apache.tapestry5.plastic.PlasticClassTransformer;

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

/**
 * A service used to create proxies of varying types. As a secondary concern, manages to identify the
 * location of methods and constructors, which is important for exception reporting.
 *
 * @since 5.3
 */
public interface PlasticProxyFactory extends PlasticClassListenerHub
{
    /**
     * Returns the class loader used when creating new classes, this is a child class loader
     * of another class loader (usually, the thread's context class loader).
     */
    ClassLoader getClassLoader();

    /**
     * Creates a proxy object that implements the indicated interface, then invokes the callback to further
     * configure the proxy.
     *
     * @param interfaceType
     *         interface implemented by proxy
     * @param callback
     *         configures the proxy
     * @return instantiator that can be used to create an instance of the proxy class
     */
    <T> ClassInstantiator<T> createProxy(Class<T> interfaceType, PlasticClassTransformer callback);

    /**
     * Creates a proxy object that implements the indicated interface and indicated service implementation type,
     * then invokes the callback to further configure the proxy.
     *
     * @param interfaceType
     *         interface implemented by proxy
     * @param implementationType
     *         a class that implements the interfaceType. It can be null.
     * @param callback
     *         configures the proxy
     * @return instantiator that can be used to create an instance of the proxy class
     */
    @IncompatibleChange(release = "5.4", details = "TAP5-2029")
    <T> ClassInstantiator<T> createProxy(Class<T> interfaceType, Class<? extends T> implementationType, PlasticClassTransformer callback);

    /**
     * Creates the underlying {@link PlasticClassTransformation} for an interface proxy. This should only be
     * used in the cases where encapsulating the PlasticClass construction into a {@linkplain PlasticClassTransformer
     * callback} is not feasible (which is the case for some of the older APIs inside Tapestry IoC).
     *
     * @param interfaceType
     *         class proxy will extend from
     * @return transformation from which an instantiator may be created
     */
    <T> PlasticClassTransformation<T> createProxyTransformation(Class<T> interfaceType);

    /**
     * Creates the underlying {@link PlasticClassTransformation} for an interface proxy with a given
     * implementation class. This should only be
     * used in the cases where encapsulating the PlasticClass construction into a {@linkplain PlasticClassTransformer
     * callback} is not feasible (which is the case for some of the older APIs inside Tapestry IoC).
     *
     * @param interfaceType
     *         class proxy will extend from
     * @param implementationType
     *         a class that implements the interfaceType. It can be null.
     * @return transformation from which an instantiator may be created
     */
    @IncompatibleChange(release = "5.4", details = "TAP5-2029")
    <T> PlasticClassTransformation<T> createProxyTransformation(Class<T> interfaceType, Class<? extends T> implementationType);

    /**
     * Creates a proxy instance that delegates all methods through a corresponding
     * ObjectCreator. Each method invocation on the proxy will route through {@link ObjectCreator#createObject()} (the
     * creator implementation may decide to
     * cache the return value as appropriate).
     *
     * @param <T>
     *         type of proxy
     * @param interfaceType
     *         interface class for proxy
     * @param creator
     *         object responsible for creating the real object
     * @param description
     *         the <code>toString()</code> of the proxy
     * @return proxy instance
     */
    <T> T createProxy(Class<T> interfaceType, ObjectCreator<T> creator, String description);
    
    /**
     * Creates a proxy instance that delegates all methods through a corresponding
     * ObjectCreator. Each method invocation on the proxy will route through {@link ObjectCreator#createObject()} (the
     * creator implementation may decide to
     * cache the return value as appropriate).
     *
     * @param <T>
     *         type of proxy
     * @param interfaceType
     *         interface class for proxy
     * @param implementationType
     *         class that implements the interface type. It may be null
     * @param creator
     *         object responsible for creating the real object
     * @param description
     *         the <code>toString()</code> of the proxy
     * @return proxy instance
     */
    @IncompatibleChange(release = "5.4", details = "Added for TAP5-2029")
    <T> T createProxy(Class<T> interfaceType, Class<? extends T> implementationType, ObjectCreator<T> creator, String description);

    /**
     * Converts a method to a {@link Location}, which includes information about the source file name and line number.
     *
     * @param method
     *         to look up
     * @return the location (identifying the method and possibly, the line number within the method)
     */
    Location getMethodLocation(Method method);

    /**
     * Return a string representation for the constructor (including class and parameters) and (if available) file name
     * and line number.
     *
     * @return the location (identifying the constructor and possibly, the line number within the method)
     */
    Location getConstructorLocation(Constructor constructor);

    /**
     * Clears any cached information stored by the proxy factory; this is useful in Tapestry development mode
     * when a class loader may have been discarded (because the proxy factory may indirectly keep references
     * to classes loaded by the old class loader).
     *
     * @since 5.3.3
     */
    void clearCache();
}