src.org.jafer.sru.bridge.SRUtoSRWBridge Maven / Gradle / Ivy

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/**
 * JAFER Toolkit Project. Copyright (C) 2002, JAFER Toolkit Project, Oxford
 * University. This library 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 library 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 Lesser General Public License for more details. You should have
 * received a copy of the GNU Lesser General Public License along with this
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place, Suite 330, Boston, MA 02111-1307 USA
 */
package org.jafer.sru.bridge;

import java.net.MalformedURLException;
import java.net.URL;
import java.util.Map;

import org.jafer.sru.SRUException;
import org.jafer.sru.SRUtoSRWConfig;

/**
 * This class processes an SRU operation by calling the prefined SRW instance
 * and returning the result to the caller. The SOAP envelope will be excluded
 * from any responses.
 */
public class SRUtoSRWBridge extends V1Bridge
{

    /**
     * Stores a reference to the web service URL.
     */
    private URL serviceURL = null;

    /**
     * Stores a reference to key used to find the requested operation
     */
    private static final String OPERATION_KEY = "operation";

    /**
     * Stores a reference to key used to find the requested operation
     */
    private static final String VERSION_KEY = "version";

    /**
     * Stores a reference to explain operation name
     */
    private static final String EXPLAIN_OPERATION = "explain";

    /**
     * Stores a reference to explain operation name
     */
    private static final String DEFAULT_VERSION = "1.1";

    /**
     * Stores a reference to configuration information for the bridge
     */
    private SRUtoSRWConfig config = null;

    /**
     * Creates an instance of the SRUtoSRWBridge specifying the URL to use to
     * find the web service
     * 
     * @param url The url to use with this web service handler
     * @throws SRUException
     * @throws MalformedURLException
     */
    public SRUtoSRWBridge(String url) throws SRUException, MalformedURLException
    {
        serviceURL = new URL(url);
        this.config = new SRUtoSRWConfig();
    }

    /**
     * Processes the request given the map of parameters
     * 
     * @param parameters The paramaters that defines the SRU call in form Key to
     *        StringValue
     * @return The XML response generated by the request
     */
    public String processRequest(Map parameters)
    {
        String operation = "";
        try
        {
            // extract out from the parameters map the operation being performed
            operation = (String) parameters.get(OPERATION_KEY);
            // extract out from the parameters map the version of the operation
            // being performed
            String version = (String) parameters.get(VERSION_KEY);
            // if no operation has been specified or it is blank then default to
            // 'explain'
            if (operation == null || operation.length() == 0)
            {
                operation = EXPLAIN_OPERATION;
            }
            // if no version has been specified or it is blank then default to
            // '1.1'
            if (version == null || version.length() == 0)
            {
                version = DEFAULT_VERSION;
            }

            // create the request type for the operation
            OperationBridge bridge = (OperationBridge) createOperationBridgeClass(operation, version);
            // execute the operation using the bridge supplying parameters
            return bridge.execute(parameters, serviceURL);

        }
        catch (SRUException exc)
        {
            // internal error so return basic explain reponse
            exc.printStackTrace();
            return createExplainDiagnosticResponse("1", exc.getMessage(), "", exc);
        }
    }

    /**
     * Instantiates and returns the bridge class for the specified operation and
     * version
     * 
     * @param operation The operation being performed
     * @param version The operations version
     * @return The intantiated bridge class
     * @throws SRUException
     */
    private OperationBridge createOperationBridgeClass(String operation, String version) throws SRUException
    {
        // get the root operation config node
        String bridgeClassName = config.getOperationBridgeClass(operation, version);
        if (bridgeClassName == null)
        {
            throw new SRUException("Unable to find supporting bridge for " + operation + " operation in configuration");
        }
        // construct the request type;
        try
        {
            return (OperationBridge) (Class.forName(bridgeClassName).newInstance());
        }
        catch (Exception exc)
        {
            exc.printStackTrace();
            throw new SRUException("Unable to create bridge object for operation: " + operation);
        }
    }
}