/**
 * Licensed to Apereo under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright ownership. Apereo
 * licenses this file to you 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 the
 * following location:
 *
 * <p>http://www.apache.org/licenses/LICENSE-2.0
 *
 * <p>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.apereo.portal.portlet.rendering.worker;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.beans.factory.BeanNameAware;

/**
 * Base class for copying data from a {@link ThreadLocal} in the calling thread into the worker
 * thread.
 *
 */
public abstract class ThreadLocalPortletExecutionInterceptor<T>
        extends PortletExecutionInterceptorAdaptor implements BeanNameAware {
    private static final String CURRENT_THREAD =
            ThreadLocalPortletExecutionInterceptor.class.getName() + ".CURRENT_THREAD";

    private String contextAttributeName = this.getClass().getName();

    /** Get the current value from the ThreadLocal store */
    protected abstract T getThreadLocalValue(
            HttpServletRequest request,
            HttpServletResponse response,
            IPortletExecutionContext context);

    /**
     * Set the specified value into the ThreadLocal store. If the value is null the store may remove
     * the ThreadLocal reference
     */
    protected abstract void setThreadLocalValue(
            HttpServletRequest request,
            HttpServletResponse response,
            IPortletExecutionContext context,
            T value);

    public void setContextAttributeName(String contextAttributeName) {
        this.contextAttributeName = contextAttributeName;
    }

    @Override
    public void setBeanName(String name) {
        if (this.contextAttributeName != null) {
            this.contextAttributeName = name;
        }
    }

    @Override
    public final void preSubmit(
            HttpServletRequest request,
            HttpServletResponse response,
            IPortletExecutionContext context) {
        context.setExecutionAttribute(CURRENT_THREAD, Thread.currentThread());

        final T preSubmitData = this.getThreadLocalValue(request, response, context);
        context.setExecutionAttribute(this.contextAttributeName, preSubmitData);
    }

    @Override
    public final void preExecution(
            HttpServletRequest request,
            HttpServletResponse response,
            IPortletExecutionContext context) {
        final Thread currentThread = (Thread) context.getExecutionAttribute(CURRENT_THREAD);

        if (Thread.currentThread() != currentThread) {
            final T preExecuteData = this.getThreadLocalValue(request, response, context);
            final T preSubmitData = (T) context.getExecutionAttribute(this.contextAttributeName);
            this.setThreadLocalValue(request, response, context, preSubmitData);
            context.setExecutionAttribute(this.contextAttributeName, preExecuteData);
        }
    }

    @Override
    public final void postExecution(
            HttpServletRequest request,
            HttpServletResponse response,
            IPortletExecutionContext context,
            Exception e) {
        final Thread currentThread = (Thread) context.getExecutionAttribute(CURRENT_THREAD);

        if (Thread.currentThread() != currentThread) {
            final T preExecuteData = (T) context.getExecutionAttribute(this.contextAttributeName);
            this.setThreadLocalValue(request, response, context, preExecuteData);
        }
    }
}