expression.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.query;

import java.io.Serializable;


/**
 * Abstract base class for expressions used in a workflow query.
 * Expressions can be negate and/or nested. The default is not negate.
 * <p></p>
 * Expressions which are supported by all stores are {@link FieldExpression} and {@link NestedExpression}.
 * <p></p>
 * Store specific expressions like XPathExpression can be added.
 *
 * @author Christine Zimmermann
 */
public abstract class Expression implements Serializable {
    //~ Instance fields ////////////////////////////////////////////////////////

    protected boolean negate = false;

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

    protected Expression() {
    }

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

    public boolean isNegate() {
        return negate;
    }

    abstract public boolean isNested();
}