fieldexpression.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;


/**
 * Field expressions are used when constructing a workflow query on the fields
 * of persistent workflow instances like (START_DATE, OWNER,....).
 * Field expressions have three attributes. These are:
 * <li>operator: This is the operator to apply on the expression.
 * <li>field: The workflow field to test agains
 * <li>Context: The context to search in, which can be one history, current steps, or a workflow instance.
 *
 * @author Christine Zimmermann
 */
public class FieldExpression extends Expression {
    //~ Static fields/initializers /////////////////////////////////////////////

    // field operators

    /**
     * Constant for the equality operator.
     */
    public final static int EQUALS = 1;

    /**
     * Constant for the less than operator.
     */
    public final static int LT = 2;

    /**
     * Constant for the greater than operator.
     */
    public final static int GT = 3;

    /**
     * Constant for the not equals operator.
     */
    public final static int NOT_EQUALS = 5;

    // fields

    /**
     * Constant for the workflow owner field.
     */
    public final static int OWNER = 1;

    /**
     * Constant for the workflow start date field.
     */
    public final static int START_DATE = 2;

    /**
     * Constant for the workflow finish date field.
     */
    public final static int FINISH_DATE = 3;

    /**
     * Constant for the workflow action field.
     */
    public final static int ACTION = 4;

    /**
     * Constant for the workflow step field.
     */
    public final static int STEP = 5;

    /**
     * Constant for the workflow caller field.
     */
    public final static int CALLER = 6;

    /**
     * Constant for the workflow status field.
     */
    public final static int STATUS = 7;

    /**
     * Constant for the workflow name field.
     */
    public final static int NAME = 8;

    /**
    * Constant for the state field.
    */
    public final static int STATE = 9;

    /**
    * Constant for the workflow due date field.
    */
    public final static int DUE_DATE = 10;

    // field context

    /**
     * Constant for the history steps context.
     * Specifying this context means that the search
     * should be performed against the workflow steps.
     */
    public final static int HISTORY_STEPS = 1;

    /**
     * Constant for the history steps context.
     * Specifying this context means that the search
     * should be performed against the workflow current steps.
     */
    public final static int CURRENT_STEPS = 2;

    /**
     * Constant for the workflow entry context.
     * Specifying this context means that the search
     * should be performed against the workflow entries.
     */
    public final static int ENTRY = 3;

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

    private Object value;
    private int context;
    private int field;
    private int operator;

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

    public FieldExpression() {
    }

    public FieldExpression(int field, int context, int operator, Object value) {
        this.context = context;
        this.operator = operator;
        this.field = field;
        this.value = value;
    }

    public FieldExpression(int field, int context, int operator, Object value, boolean negate) {
        this(field, context, operator, value);
        super.negate = negate;
    }

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

    public void setContext(int context) {
        this.context = context;
    }

    public int getContext() {
        return context;
    }

    public void setField(int field) {
        this.field = field;
    }

    public int getField() {
        return field;
    }

    public boolean isNested() {
        return false;
    }

    public void setOperator(int operator) {
        this.operator = operator;
    }

    public int getOperator() {
        return operator;
    }

    public void setValue(Object value) {
        this.value = value;
    }

    public Object getValue() {
        return value;
    }
}