optionscollectiontag.java

基于java的组态软件。使用了hibernate和spring技术

/*
 * Created on 2005-8-8
 *
 * TODO To change the template for this generated file go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
package web.taglib;

/**
 * <p>Title: OptionsCollectionTag.java</p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: SCUT Copyright (c) 2005</p>
 *
 * <p>Company: KHC</p>
 * 
 * @author yukizh
 * 
 * @version 1.0
 */
import java.lang.reflect.InvocationTargetException;
import java.util.Arrays;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Map;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;

import org.apache.commons.beanutils.PropertyUtils;
import org.apache.commons.collections.IteratorUtils;

import org.apache.struts.taglib.TagUtils;
import org.apache.struts.util.MessageResources;

public class OptionsCollectionTag extends TagSupport {

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

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

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

    /**
     * Should the label values be filtered for HTML sensitive characters?
     */
    private String selectname = "";
    private String onchange = "";
    private String selectValue = "";


    protected boolean filter = true;

    public boolean getFilter() {
        return filter;
    }

    public void setFilter(boolean filter) {
        this.filter = filter;
    }

    /**
     * The name of the bean property containing the label.
     */
    protected String label = "label";

    public String getLabel() {
        return label;
    }

    public void setLabel(String label) {
        this.label = label;
    }

    /**
     * The name of the bean containing the values collection.
     */
    protected String name = "";

    public String getName() {
        return name;
    }

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

    /**
     * The name of the property to use to build the values collection.
     */
    protected String property = null;

    public String getProperty() {
        return property;
    }

    public void setProperty(String property) {
        this.property = property;
    }

    /**
     * The style associated with this tag.
     */
    private String style = null;

    public String getStyle() {
        return style;
    }

    public void setStyle(String style) {
        this.style = style;
    }

    /**
     * The named style class associated with this tag.
     */
    private String styleClass = null;

    public String getStyleClass() {
        return styleClass;
    }

    public void setStyleClass(String styleClass) {
        this.styleClass = styleClass;
    }

    /**
     * The name of the bean property containing the value.
     */
    protected String value = "value";

    public String getValue() {
        return value;
    }

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

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

    /**
     * Process the start of this tag.
     *
     * @exception JspException if a JSP exception has occurred
     */
    public int doStartTag() throws JspException {

        // Acquire the select tag we are associated with
//        SelectTag selectTag = (SelectTag) pageContext.getAttribute(Constants.SELECT_KEY);

//        if (selectTag == null) {
//            JspException e = new JspException(messages.getMessage("optionsCollectionTag.select"));
//            TagUtils.getInstance().saveException(pageContext, e);
//            throw e;
//        }

        // Acquire the collection containing our options
        Object collection = TagUtils.getInstance().lookup(pageContext, name, property, null);

        if (collection == null) {
            JspException e =
                new JspException(messages.getMessage("optionsCollectionTag.collection"));
            TagUtils.getInstance().saveException(pageContext, e);
            throw e;
        }

        // Acquire an iterator over the options collection
        Iterator iter = getIterator(collection);

        StringBuffer sb = new StringBuffer();
        sb.append("<select name="+selectname);
        if(!onchange.equals("")){
          sb.append(" onchange=\""+onchange+"\">");
        }
        else{
          sb.append(">");
        }
        // Render the options
        while (iter.hasNext()) {

            Object bean = iter.next();
            Object beanLabel = null;
            Object beanValue = null;

            // Get the label for this option
            try {
                beanLabel = PropertyUtils.getProperty(bean, label);
                if (beanLabel == null) {
                    beanLabel = "";
                }
            } catch (IllegalAccessException e) {
                JspException jspe =
                    new JspException(messages.getMessage("getter.access", label, bean));
                TagUtils.getInstance().saveException(pageContext, jspe);
                throw jspe;
            } catch (InvocationTargetException e) {
                Throwable t = e.getTargetException();
                JspException jspe =
                    new JspException(messages.getMessage("getter.result", label, t.toString()));
                TagUtils.getInstance().saveException(pageContext, jspe);
                throw jspe;
            } catch (NoSuchMethodException e) {
                JspException jspe =
                    new JspException(messages.getMessage("getter.method", label, bean));
                TagUtils.getInstance().saveException(pageContext, jspe);
                throw jspe;
            }

            // Get the value for this option
            try {
                beanValue = PropertyUtils.getProperty(bean, value);
                if (beanValue == null) {
                    beanValue = "";
                }
            } catch (IllegalAccessException e) {
                JspException jspe =
                    new JspException(messages.getMessage("getter.access", value, bean));
                TagUtils.getInstance().saveException(pageContext, jspe);
                throw jspe;
            } catch (InvocationTargetException e) {
                Throwable t = e.getTargetException();
                JspException jspe =
                    new JspException(messages.getMessage("getter.result", value, t.toString()));
                TagUtils.getInstance().saveException(pageContext, jspe);
                throw jspe;
            } catch (NoSuchMethodException e) {
                JspException jspe =
                    new JspException(messages.getMessage("getter.method", value, bean));
                TagUtils.getInstance().saveException(pageContext, jspe);
                throw jspe;
            }

            String stringLabel = beanLabel.toString();
            String stringValue = beanValue.toString();

            // Render this option
            addOption(sb, stringLabel, stringValue, selectValue.equals(stringValue));
        }
        sb.append("</select>");
        TagUtils.getInstance().write(pageContext, sb.toString());

        return SKIP_BODY;
    }

    /**
     * Release any acquired resources.
     */
    public void release() {
        super.release();
        filter = true;
        label = "label";
        name = "beanname";
        property = null;
        style = null;
        styleClass = null;
        value = "value";
    }

    // ------------------------------------------------------ Protected Methods

    /**
     * Add an option element to the specified StringBuffer based on the
     * specified parameters.
     *<p>
     * Note that this tag specifically does not support the
     * <code>styleId</code> tag attribute, which causes the HTML
     * <code>id</code> attribute to be emitted.  This is because the HTML
     * specification states that all "id" attributes in a document have to be
     * unique.  This tag will likely generate more than one <code>option</code>
     * element element, but it cannot use the same <code>id</code> value.  It's
     * conceivable some sort of mechanism to supply an array of <code>id</code>
     * values could be devised, but that doesn't seem to be worth the trouble.
     *
     * @param sb StringBuffer accumulating our results
     * @param value Value to be returned to the server for this option
     * @param label Value to be shown to the user for this option
     * @param matched Should this value be marked as selected?
     */
    protected void addOption(StringBuffer sb, String label, String value, boolean matched) {

        sb.append("<option value=\"");
        if (filter) {
            sb.append(TagUtils.getInstance().filter(value));
        } else {
            sb.append(value);
        }
        sb.append("\"");
        if (matched) {
            sb.append(" selected=\"selected\"");
        }
        if (style != null) {
            sb.append(" style=\"");
            sb.append(style);
            sb.append("\"");
        }
        if (styleClass != null) {
            sb.append(" class=\"");
            sb.append(styleClass);
            sb.append("\"");
        }

        sb.append(">");

        if (filter) {
            sb.append(TagUtils.getInstance().filter(label));
        } else {
            sb.append(label);
        }

        sb.append("</option>\r\n");

    }

    /**
     * Return an iterator for the options collection.
     *
     * @param collection Collection to be iterated over
     *
     * @exception JspException if an error occurs
     */
    protected Iterator getIterator(Object collection) throws JspException {

        if (collection.getClass().isArray()) {
            collection = Arrays.asList((Object[]) collection);
        }

        if (collection instanceof Collection) {
            return (((Collection) collection).iterator());

        } else if (collection instanceof Iterator) {
            return ((Iterator) collection);

        } else if (collection instanceof Map) {
            return (((Map) collection).entrySet().iterator());

        } else if (collection instanceof Enumeration) {
            return IteratorUtils.asIterator((Enumeration) collection);

        } else {
            throw new JspException(
                messages.getMessage("optionsCollectionTag.iterator", collection.toString()));
        }
    }
  public String getSelectname() {
    return selectname;
  }
  public void setSelectname(String selectname) {
    this.selectname = selectname;
  }
  public String getOnchange() {
    return onchange;
  }
  public void setOnchange(String onchange) {
    this.onchange = onchange;
  }
  public String getSelectValue() {
    return selectValue;
  }
  public void setSelectValue(String selectValue) {
    this.selectValue = selectValue;
  }

}