httpworkflowfactory.java

一个很好实用的工作流OSWORKFLOW开发例子.有着非常优秀的灵活性.

/*
 * Copyright (c) 2002-2003 by OpenSymphony
 * All rights reserved.
 */
package com.opensymphony.workflow.loader;

import com.opensymphony.workflow.FactoryException;

import java.io.*;

import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;


/**
 * @author Hani Suleiman
 *         Date: Dec 17, 2004
 *         Time: 12:00:36 AM
 */
public class HTTPWorkflowFactory extends AbstractWorkflowFactory {
    //~ Instance fields ////////////////////////////////////////////////////////

    protected Map workflows;
    protected boolean reload;

    //~ Methods ////////////////////////////////////////////////////////////////

    public void setLayout(String workflowName, Object layout) {
    }

    public Object getLayout(String workflowName) {
        return null;
    }

    public boolean isModifiable(String name) {
        return true;
    }

    public String getName() {
        return null;
    }

    public WorkflowDescriptor getWorkflow(String name, boolean validate) throws FactoryException {
        HTTPWorkflowConfig c = (HTTPWorkflowConfig) workflows.get(name);

        if (c == null) {
            throw new FactoryException("Unknown workflow name \"" + name + '\"');
        }

        if (c.descriptor != null) {
            loadWorkflow(c);
        }

        c.descriptor.setName(name);

        return c.descriptor;
    }

    public String[] getWorkflowNames() throws FactoryException {
        int i = 0;
        String[] res = new String[workflows.keySet().size()];
        Iterator it = workflows.keySet().iterator();

        while (it.hasNext()) {
            res[i++] = (String) it.next();
        }

        return res;
    }

    public void createWorkflow(String name) {
    }

    public void initDone() throws FactoryException {
    }

    public boolean removeWorkflow(String name) throws FactoryException {
        throw new FactoryException("remove workflow not supported");
    }

    /* (non-Javadoc)
     * @see com.opensymphony.workflow.loader.AbstractWorkflowFactory#renameWorkflow(java.lang.String, java.lang.String)
     */
    public void renameWorkflow(String oldName, String newName) {
    }

    /* (non-Javadoc)
     * @see com.opensymphony.workflow.loader.AbstractWorkflowFactory#save()
     */
    public void save() {
    }

    /* (non-Javadoc)
     * @see com.opensymphony.workflow.loader.AbstractWorkflowFactory#saveWorkflow(java.lang.String, com.opensymphony.workflow.loader.WorkflowDescriptor, boolean)
     */
    public boolean saveWorkflow(String name, WorkflowDescriptor descriptor, boolean replace) throws FactoryException {
        HTTPWorkflowConfig c = (HTTPWorkflowConfig) workflows.get(name);

        if ((c != null) && !replace) {
            return false;
        }

        if (c == null) {
            throw new UnsupportedOperationException("Saving of new workflow is not currently supported");
        }

        Writer out;

        // [KAP] comment this line to disable all the validation while saving a workflow
        //descriptor.validate();
        try {
            out = new OutputStreamWriter(null, "utf-8");
        } catch (UnsupportedEncodingException ex) {
            throw new FactoryException("utf-8 encoding not supported, contact your JVM vendor!");
        }

        writeXML(descriptor, out);

        //write it out to a new file, to ensure we don't end up with a messed up file if we're interrupted halfway for some reason
        //now lets rename
        return true;
    }

    protected static String get(String urlValue, Map data) throws IOException {
        BufferedReader input;

        StringBuffer value = new StringBuffer(urlValue);

        if (data.size() > 0) {
            if (value.indexOf("?") == -1) {
                value.append("?");
            } else {
                value.append("&");
            }
        }

        Iterator i = data.entrySet().iterator();

        while (i.hasNext()) {
            Map.Entry entry = (Map.Entry) i.next();
            value.append(entry.getKey()).append('=');
            value.append(URLEncoder.encode((String) entry.getValue(), "utf-8"));

            if (i.hasNext()) {
                value.append("&");
            }
        }

        URL url = new URL(urlValue);
        URLConnection connection = url.openConnection();
        connection.setDoOutput(true);
        connection.setUseCaches(false);

        input = new BufferedReader(new InputStreamReader(connection.getInputStream()));

        StringBuffer output = new StringBuffer();
        String line;

        while (null != (line = input.readLine())) {
            output.append(line).append('\n');
        }

        input.close();

        return output.toString();
    }

    protected static String post(String urlValue, Map data) throws IOException {
        BufferedReader input;

        URL url = new URL(urlValue);
        URLConnection connection = url.openConnection();
        connection.setDoInput(true);
        connection.setDoOutput(true);
        connection.setUseCaches(false);
        connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

        DataOutputStream out = new DataOutputStream(connection.getOutputStream());

        StringBuffer content = new StringBuffer();
        Iterator i = data.entrySet().iterator();

        while (i.hasNext()) {
            Map.Entry entry = (Map.Entry) i.next();
            content.append(entry.getKey()).append('=');
            content.append(URLEncoder.encode((String) entry.getValue(), "utf-8"));

            if (i.hasNext()) {
                content.append("&");
            }
        }

        out.writeBytes(content.toString());
        out.flush();
        out.close();

        input = new BufferedReader(new InputStreamReader(connection.getInputStream()));

        StringBuffer output = new StringBuffer();
        String line;

        while (null != (line = input.readLine())) {
            output.append(line).append('\n');
        }

        input.close();

        return output.toString();
    }

    protected String readLayoutBuffer(final String url, final String docId) throws Exception {
        Map map = new HashMap();
        map.put("docId", docId);
        map.put("command", "layout");

        return get(url, map);
    }

    protected String readWorkflowBuffer(final String url, final String docId) throws Exception {
        Map map = new HashMap();
        map.put("docId", docId);
        map.put("command", "workflow");

        return get(url, map);
    }

    protected String writeWorkflowDescriptor(final String url, final String docId, final String name, final String workflowXML) throws Exception {
        String ret = null;

        Map map = new HashMap();
        map.put("docId", docId);
        map.put("data", workflowXML);
        map.put("command", "workflow");

        return post(url, map);
    }

    protected String writeWorkflowLayout(final String url, final String docId, final String name, final String layoutXML) throws Exception {
        Map map = new HashMap();
        map.put("docId", docId);
        map.put("data", layoutXML);
        map.put("command", "layout");

        return post(url, map);
    }

    protected void writeXML(WorkflowDescriptor descriptor, Writer out) {
        PrintWriter writer = new PrintWriter(new BufferedWriter(out));
        writer.println(WorkflowDescriptor.XML_HEADER);
        writer.println(WorkflowDescriptor.DOCTYPE_DECL);
        descriptor.writeXML(writer, 0);
        writer.flush();
        writer.close();
    }

    private void loadWorkflow(HTTPWorkflowConfig c) throws FactoryException {
        /*
        try
        {
          c.descriptor = WorkflowLoader.load(c.url);
        }
        catch (Exception e)
        {
          throw new FactoryException("Error in workflow descriptor: " + c.url, e);
        }
        */
    }

    //~ Inner Classes //////////////////////////////////////////////////////////

    static class HTTPWorkflowConfig {
        String docId;
        String name;
        String service_addr;
        WorkflowDescriptor descriptor;

        //long lastModified;
        public HTTPWorkflowConfig(String service_addr, String name, String docId) {
            this.service_addr = service_addr;
            this.name = name;
            this.docId = docId;
        }
    }
}