typeresolver.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;

import com.opensymphony.workflow.loader.ClassLoaderUtil;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

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


/**
 * Date: Aug 3, 2004
 * Time: 11:04:43 PM
 *
 * @author hani
 */
public class TypeResolver {
    //~ Static fields/initializers /////////////////////////////////////////////

    private static final Log log = LogFactory.getLog(TypeResolver.class);
    private static TypeResolver resolver = new TypeResolver();

    //~ Instance fields ////////////////////////////////////////////////////////

    protected Map conditions = new HashMap();
    protected Map functions = new HashMap();
    protected Map registers = new HashMap();
    protected Map validators = new HashMap();

    //~ Constructors ///////////////////////////////////////////////////////////

    public TypeResolver() {
        validators.put("remote-ejb", "com.opensymphony.workflow.util.ejb.remote.RemoteEJBValidator");
        validators.put("local-ejb", "com.opensymphony.workflow.util.ejb.local.LocalEJBValidator");
        validators.put("jndi", "com.opensymphony.workflow.util.jndi.JNDIValidator");
        validators.put("beanshell", "com.opensymphony.workflow.util.beanshell.BeanShellValidator");
        validators.put("bsf", "com.opensymphony.workflow.util.bsf.BSFValidator");
        conditions.put("remote-ejb", "com.opensymphony.workflow.util.ejb.remote.RemoteEJBCondition");
        conditions.put("local-ejb", "com.opensymphony.workflow.util.ejb.local.LocalEJBCondition");
        conditions.put("jndi", "com.opensymphony.workflow.util.jndi.JNDICondition");
        conditions.put("beanshell", "com.opensymphony.workflow.util.beanshell.BeanShellCondition");
        conditions.put("bsf", "com.opensymphony.workflow.util.bsf.BSFCondition");
        registers.put("remote-ejb", "com.opensymphony.workflow.util.ejb.remote.RemoteEJBRegister");
        registers.put("local-ejb", "com.opensymphony.workflow.util.ejb.local.LocalEJBRegister");
        registers.put("jndi", "com.opensymphony.workflow.util.jndi.JNDIRegister");
        registers.put("beanshell", "com.opensymphony.workflow.util.beanshell.BeanShellRegister");
        registers.put("bsf", "com.opensymphony.workflow.util.bsf.BSFRegister");
        functions.put("remote-ejb", "com.opensymphony.workflow.util.ejb.remote.RemoteEJBFunctionProvider");
        functions.put("local-ejb", "com.opensymphony.workflow.util.ejb.local.LocalEJBFunctionProvider");
        functions.put("jndi", "com.opensymphony.workflow.util.jndi.JNDIFunctionProvider");
        functions.put("beanshell", "com.opensymphony.workflow.util.beanshell.BeanShellFunctionProvider");
        functions.put("bsf", "com.opensymphony.workflow.util.bsf.BSFFunctionProvider");
    }

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

    public Condition getCondition(String type, Map args) throws WorkflowException {
        String className = (String) conditions.get(type);

        if (className == null) {
            className = (String) args.get(Workflow.CLASS_NAME);
        }

        if (className == null) {
            throw new WorkflowException("No type or class.name argument specified to TypeResolver");
        }

        return (Condition) loadObject(className);
    }

    public FunctionProvider getFunction(String type, Map args) throws WorkflowException {
        String className = (String) functions.get(type);

        if (className == null) {
            className = (String) args.get(Workflow.CLASS_NAME);
        }

        if (className == null) {
            throw new WorkflowException("No type or class.name argument specified to TypeResolver");
        }

        return (FunctionProvider) loadObject(className);
    }

    public Register getRegister(String type, Map args) throws WorkflowException {
        String className = (String) registers.get(type);

        if (className == null) {
            className = (String) args.get(Workflow.CLASS_NAME);
        }

        if (className == null) {
            throw new WorkflowException("No type or class.name argument specified to TypeResolver");
        }

        return (Register) loadObject(className);
    }

    public static void setResolver(TypeResolver resolver) {
        TypeResolver.resolver = resolver;
    }

    public static TypeResolver getResolver() {
        return resolver;
    }

    public Validator getValidator(String type, Map args) throws WorkflowException {
        String className = (String) validators.get(type);

        if (className == null) {
            className = (String) args.get(Workflow.CLASS_NAME);
        }

        if (className == null) {
            throw new WorkflowException("No type or class.name argument specified to TypeResolver");
        }

        return (Validator) loadObject(className);
    }

    protected Object loadObject(String clazz) {
        try {
            return ClassLoaderUtil.loadClass(clazz.trim(), getClass()).newInstance();
        } catch (Exception e) {
            log.error("Could not load class '" + clazz + "'", e);

            return null;
        }
    }
}