selecttag.java

这是一个轻便的j2ee的web应用框架,是一个在多个项目中运用的实际框架,采用struts,hebinate,xml等技术,有丰富的tag,role,navigation,session,dictio

/*
 * $Header: /sfroot/cvs/esimple/src/core/com/esimple/framework/web/taglib/html/SelectTag.java,v 1.1.1.1 2004/09/08 06:38:19 lava Exp $
 * $Revision: 1.1.1.1 $
 * $Date: 2004/09/08 06:38:19 $
 *
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Struts", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
 * ITS 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package com.esimple.framework.web.taglib.html;

import java.lang.reflect.InvocationTargetException;
import javax.servlet.jsp.JspException;
import org.apache.commons.beanutils.BeanUtils;
import org.apache.struts.util.MessageResources;
import org.apache.struts.util.RequestUtils;
import org.apache.struts.util.ResponseUtils;

/**
 * Custom tag that represents an HTML select element, associated with a
 * bean property specified by our attributes.  This tag must be nested
 * inside a form tag.
 *
 * @author Craig R. McClanahan
 * @author David Graham
 * @version $Revision: 1.1.1.1 $ $Date: 2004/09/08 06:38:19 $
 */
public class SelectTag extends BaseHandlerTag {


    // ----------------------------------------------------- Instance Variables


    /**
     * The actual values we will match against, calculated in doStartTag().
     */
    protected String match[] = null;


    /**
     * The message resources for this package.
     */
    protected static MessageResources messages =
     MessageResources.getMessageResources(Constants.Package + ".LocalStrings");


    /**
     * Should multiple selections be allowed.  Any non-null value will
     * trigger rendering this.
     */
    protected String multiple = null;

    public String getMultiple() {
        return (this.multiple);
    }

    public void setMultiple(String multiple) {
        this.multiple = multiple;
    }


    /**
     * The name of the bean containing our underlying property.
     */
    protected String name = Constants.BEAN_KEY;

    public String getName() {
        return (this.name);
    }

    public void setName(String name) {
        this.name = name;
    }


    /**
     * The property name we are associated with.
     */
    protected String property = null;


    /**
     * The saved body content of this tag.
     */
    protected String saveBody = null;


    /**
     * How many available options should be displayed when this element
     * is rendered?
     */
    protected String size = null;

    public String getSize() {
        return (this.size);
    }

    public void setSize(String size) {
        this.size = size;
    }


    /**
     * The value to compare with for marking an option selected.
     */
    protected String value = null;


    // ------------------------------------------------------------- Properties


    /**
     * Does the specified value match one of those we are looking for?
     *
     * @param value Value to be compared.
     */
    public boolean isMatched(String value) {
        if ((this.match == null) || (value == null)) {
            return false;
        }
        
        for (int i = 0; i < this.match.length; i++) {
            if (value.equals(this.match[i]))
                return true;
        }
        
        return false;
    }


    /**
     * Return the property name.
     */
    public String getProperty() {

        return (this.property);

    }


    /**
     * Set the property name.
     *
     * @param property The new property name
     */
    public void setProperty(String property) {

        this.property = property;

    }


    /**
     * Return the comparison value.
     */
    public String getValue() {

        return (this.value);

    }


    /**
     * Set the comparison value.
     *
     * @param value The new comparison value
     */
    public void setValue(String value) {

        this.value = value;

    }


    // --------------------------------------------------------- Public Methods


    /**
     * Render the beginning of this select tag.
     * <p>
     * Support for indexed property since Struts 1.1
     *
     * @exception JspException if a JSP exception has occurred
     */
    public int doStartTag() throws JspException {

        ResponseUtils.write(pageContext, renderSelectStartElement());

        // Store this tag itself as a page attribute
        pageContext.setAttribute(Constants.SELECT_KEY, this);

        this.calculateMatchValues();

        return (EVAL_BODY_TAG);
    }

    /**
     * Create an appropriate select start element based on our parameters.
     * @throws JspException
     * @since Struts 1.1
     */
    protected String renderSelectStartElement() throws JspException {
        StringBuffer results = new StringBuffer("<select");
        
        results.append(" name=\"");
        // * @since Struts 1.1
        if (this.indexed) {
            prepareIndex(results, name);
        }
        results.append(property);
        results.append("\"");
        if (accesskey != null) {
            results.append(" accesskey=\"");
            results.append(accesskey);
            results.append("\"");
        }
        if (multiple != null) {
            results.append(" multiple=\"multiple\"");
        }
        if (size != null) {
            results.append(" size=\"");
            results.append(size);
            results.append("\"");
        }
        if (tabindex != null) {
            results.append(" tabindex=\"");
            results.append(tabindex);
            results.append("\"");
        }
        results.append(prepareEventHandlers());
        results.append(prepareStyles());
        results.append(">");
        
        return results.toString();
    }

    /**
     * Calculate the match values we will actually be using.
     * @throws JspException
     */
    private void calculateMatchValues() throws JspException {
        if (this.value != null) {
            this.match = new String[1];
            this.match[0] = this.value;
            
        } else {
            Object bean = RequestUtils.lookup(pageContext, name, null);
            if (bean == null) {
                JspException e =
                    new JspException(messages.getMessage("getter.bean", name));
                    
                RequestUtils.saveException(pageContext, e);
                throw e;
            }

            try {
                this.match = BeanUtils.getArrayProperty(bean, property);
                if (this.match == null) {
                    this.match = new String[0];
                }

            } catch (IllegalAccessException e) {
                RequestUtils.saveException(pageContext, e);
                throw new JspException(
                    messages.getMessage("getter.access", property, name));

            } catch (InvocationTargetException e) {
                Throwable t = e.getTargetException();
                RequestUtils.saveException(pageContext, t);
                throw new JspException(
                    messages.getMessage("getter.result", property, t.toString()));

            } catch (NoSuchMethodException e) {
                RequestUtils.saveException(pageContext, e);
                throw new JspException(
                    messages.getMessage("getter.method", property, name));
            }
        }
    }


    /**
     * Save any body content of this tag, which will generally be the
     * option(s) representing the values displayed to the user.
     *
     * @exception JspException if a JSP exception has occurred
     */
    public int doAfterBody() throws JspException {

        if (bodyContent != null) {
            String value = bodyContent.getString();
            if (value == null) {
                value = "";
            }
            
            this.saveBody = value.trim();
        }
        
        return (SKIP_BODY);
    }


    /**
     * Render the end of this form.
     *
     * @exception JspException if a JSP exception has occurred
     */
    public int doEndTag() throws JspException {

        // Remove the page scope attributes we created
        pageContext.removeAttribute(Constants.SELECT_KEY);

        // Render a tag representing the end of our current form
        StringBuffer results = new StringBuffer();
        if (saveBody != null) {
            results.append(saveBody);
        }
        results.append("</select>");

        ResponseUtils.write(pageContext, results.toString());

        return (EVAL_PAGE);
    }

    /**
     * Release any acquired resources.
     */
    public void release() {

        super.release();
        match = null;
        multiple = null;
        name = Constants.BEAN_KEY;
        property = null;
        saveBody = null;
        size = null;
        value = null;

    }

}