inputhelper.java

一个工作流设计及定义的系统,可以直接与数据库结合进行系统工作流程的定义及应用.

/*
 * Copyright (c) 2005, John Mettraux, OpenWFE.org
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 * 
 * . Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.  
 * 
 * . Redistributions in binary form must reproduce the above copyright notice, 
 *   this list of conditions and the following disclaimer in the documentation 
 *   and/or other materials provided with the distribution.
 * 
 * . Neither the name of the "OpenWFE" nor the names of its contributors may be
 *   used to endorse or promote products derived from this software without
 *   specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * $Id: InputHelper.java,v 1.8 2005/05/17 16:40:54 jmettraux Exp $
 */

//
// InputHelper.java
//
// [e-mail]
//
// generated with 
// jtmpl 1.0.04 31.10.2002 John Mettraux ([e-mail])
//

package openwfe.org.input;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;

import org.python.core.Py;
import org.python.core.PyObject;
import org.python.util.PythonInterpreter;

import openwfe.org.Utils;


/**
 * A singleton to be used by jsp / servlets
 * Now, it's a facade to a jython implementation of the input system
 *
 * <p><font size=2>CVS Info :
 * <br>$Author: jmettraux $
 * <br>$Date: 2005/05/17 16:40:54 $
 * <br>$Id: InputHelper.java,v 1.8 2005/05/17 16:40:54 jmettraux Exp $ </font>
 *
 * @author [e-mail]
 */
public class InputHelper
{

    private final static org.apache.log4j.Logger log = org.apache.log4j.Logger
        .getLogger(InputHelper.class.getName());

    //
    // CONSTANTS

    public final static String INPUT_PY 
        = "input.py";

    public final static String INPUT_PY_PATH
        = "input.py.path";

    private static InputHelper singleton = null;

    //
    // FIELDS

    private String source = null;
    private long sourceLastModified = 0L;
    private PythonInterpreter interpreter;
    private String syspath = null;

    //
    // CONSTRUCTORS

    public InputHelper (ServletContext context)
    {
        super();

        this.source = context.getInitParameter(INPUT_PY);
        this.source = context.getRealPath(source);

        if (this.source == null)
        {
            log.warn
                ("\n========================================================="+
                 "\nParameter '"+INPUT_PY+"' is missing from WEB-INF/web.xml."+
                 "\nIt is mandatory and indicates where the input.py file"+
                 "\nlies."+
                 "\n=========================================================");
            return;
        }

        log.info("source is "+this.source);

        final String spath = context.getInitParameter(INPUT_PY_PATH).trim();
        if (spath != null)
        {
            final StringBuffer sb = new StringBuffer();
            sb.append(".");

            final String[] ss = spath.trim().split(":");
            for (int i=0; i<ss.length; i++)
            {
                sb.append(java.io.File.pathSeparatorChar);
                sb.append(context.getRealPath(ss[i]));
            }
            this.syspath = sb.toString();
        }

        log.info("sys.path is "+this.syspath);

        refresh();
    }

    //
    // METHODS

    /**
     * displays the appropriate input tag for a given field.<br>
     * It processes the field value down to basic types.<br>
     * The workitem is typed as 'Object', because the python method
     * behind can handle workitems and also MapAttribute instances.
     */
    public void displayInputTag 
        (boolean viewOnly,
         HttpServletRequest req, 
         java.io.Writer writer,
         Object workitem, 
         String fieldName)
    {
        PyObject method = this.interpreter.get("displayInputTag");

        PyObject[] args = new PyObject[5];
        args[0] = Py.java2py(new Boolean(viewOnly));
        args[1] = Py.java2py(req);
        args[2] = Py.java2py(writer);
        args[3] = Py.java2py(workitem);
        args[4] = Py.java2py(fieldName);
        method.__call__(args);
    }

    //private void enforceEncoding (final HttpServletRequest req)
    //{
    //}

    public void parseRequest 
        (final Object workitem, final HttpServletRequest req)
    {
        try
        {
            req.setCharacterEncoding(Utils.getEncoding());
        }
        catch (final java.io.UnsupportedEncodingException e)
        {
            log.warn("parseRequest() trouble : "+e);
        }

        PyObject method = this.interpreter.get("parseRequest");

        PyObject[] args = new PyObject[2];
        args[0] = Py.java2py(workitem);
        args[1] = Py.java2py(req);
        method.__call__(args);
    }

    public void displayDeleteTag 
        (java.io.Writer writer, Object workitem, String fieldName)
    {
        PyObject method = this.interpreter.get("displayDeleteTag");

        PyObject[] args = new PyObject[3];
        args[0] = Py.java2py(writer);
        args[1] = Py.java2py(workitem);
        args[2] = Py.java2py(fieldName);
        method.__call__(args);
    }

    /**
     * If necessary, reloads the source
     */
    protected void refresh ()
    {
        java.io.File f = new java.io.File(this.source);

        long lastModified = f.lastModified();

        if (this.interpreter == null ||
            lastModified > this.sourceLastModified)
        {
            this.sourceLastModified = lastModified;

            //
            // setup interpreter

            //org.python.core.PySystemState.initialize();

            final java.util.Properties props = new java.util.Properties();

            if (this.syspath != null)
                props.put("python.path", this.syspath);
            PythonInterpreter.initialize
                (System.getProperties(), props, new String[] { "" });

            this.interpreter = new PythonInterpreter();
            this.interpreter.exec("jython = 1");

            // 
            // eval 'input.py'
            
            this.interpreter.execfile(this.source);
        }
    }

    //
    // STATIC METHODS

    /**
     * Returns the singleton instance of the InputHelper (an instance
     * per servlet context).
     */
    public static InputHelper getInstance (final ServletContext context)
    {
        if (singleton == null)
            singleton = new InputHelper(context);
        singleton.refresh();
        return singleton;
    }

    /* *
     * Ensures that the given String is correctly encoded.
     * /
    public static String encodeString (final PyObject po)
    {
        final Object o = po.__tojava__(String.class);
        final String s = (String)o;

        if (s == null) return null;

        return new String(s.getBytes(Utils.getEncoding()), "UTF-8");
    }
     */

}