org.apereo.portal.url.processing.RequestParameterProcessorInterceptor.java Source code

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Here is the source code for org.apereo.portal.url.processing.RequestParameterProcessorInterceptor.java

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/**
 * 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:
 *
 *   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.apereo.portal.url.processing;

import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang.Validate;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

/**
 * Manages execution of {@link IRequestParameterProcessor}s.
 * 
 * @author Eric Dalquist
 * @version $Revision: 11918 $
 */
public class RequestParameterProcessorInterceptor extends HandlerInterceptorAdapter {
    protected final Log logger = LogFactory.getLog(this.getClass());

    private List<IRequestParameterProcessor> dynamicRequestParameterProcessors = Collections.emptyList();
    private int maxNumberOfProcessingCycles = 10;

    /**
     * @return the dynamicRequestParameterProcessors
     */
    public List<IRequestParameterProcessor> getDynamicRequestParameterProcessors() {
        return dynamicRequestParameterProcessors;
    }

    /**
     * @param dynamicRequestParameterProcessors the dynamicRequestParameterProcessors to set
     * @throws IllegalArgumentException if the List is null or contains null elements
     */
    public void setDynamicRequestParameterProcessors(
            List<IRequestParameterProcessor> dynamicRequestParameterProcessors) {
        Validate.notNull(dynamicRequestParameterProcessors, "IRequestParameterProcessor List can not be null");
        Validate.noNullElements(dynamicRequestParameterProcessors,
                "IRequestParameterProcessor List can not contain a null element");

        this.dynamicRequestParameterProcessors = dynamicRequestParameterProcessors;
    }

    /**
     * @return the maxNumberOfProcessingCycles
     */
    public int getMaxNumberOfProcessingCycles() {
        return maxNumberOfProcessingCycles;
    }

    /**
     * Set the max number of round-robin cycles on the controller list after which, if there
     * are still unfinished controllers the procedure is interrupted and a warning is logged,
     * execution will continue though. 
     * 
     * @param maxNumberOfProcessingCycles The maxNumberOfProcessingCycles to set.
     */
    public void setMaxNumberOfProcessingCycles(int maxNumberOfProcessingCycles) {
        this.maxNumberOfProcessingCycles = maxNumberOfProcessingCycles;
    }

    /**
     * Process the request first with the dynamic processors until all are complete and then the static processors.
     * 
     * @see org.apereo.portal.url.processing.IRequestParameterController#processParameters(org.apereo.portal.url.IWritableHttpServletRequest, javax.servlet.http.HttpServletResponse)
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        final List<IRequestParameterProcessor> incompleteDynamicProcessors = new LinkedList<IRequestParameterProcessor>(
                this.dynamicRequestParameterProcessors);

        //Loop while there are still dynamic processors to execute
        int cycles = 0;
        while (incompleteDynamicProcessors.size() > 0) {
            //Run all dynamic processors that are not yet complete
            for (final Iterator<IRequestParameterProcessor> processorItr = incompleteDynamicProcessors
                    .iterator(); processorItr.hasNext();) {
                final IRequestParameterProcessor requestParameterProcessor = processorItr.next();

                //If a dynamic processor completes remove it from the list.
                final boolean complete = requestParameterProcessor.processParameters(request, response);
                if (complete) {
                    processorItr.remove();
                }
            }

            cycles++;

            //If the max cycle count is reached log a warning and break out of the dynamic processing loop
            if (cycles >= this.maxNumberOfProcessingCycles) {
                this.logger.warn(incompleteDynamicProcessors.size()
                        + " IDynamicRequestParameterProcessors did not complete processing after " + cycles
                        + " attempts. Execution will continue but this situation should be reviewed. Incomplete Processors="
                        + incompleteDynamicProcessors, new Throwable("Stack Trace"));
                break;
            }
        }

        return true;
    }
}