eloptionscollectiontag.java

structs源码

/*
 * $Id: ELOptionsCollectionTag.java 471754 2006-11-06 14:55:09Z husted $
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.strutsel.taglib.html;

import org.apache.struts.taglib.html.OptionsCollectionTag;
import org.apache.strutsel.taglib.utils.EvalHelper;

import javax.servlet.jsp.JspException;

/**
 * Tag for creating multiple <select> options from a collection. The
 * collection may be part of the enclosing form, or may be independent of the
 * form. Each element of the collection must expose a 'label' and a 'value',
 * the property names of which are configurable by attributes of this tag. <p>
 * The collection may be an array of objects, a Collection, an Enumeration, an
 * Iterator, or a Map. <p> <b>NOTE</b> - This tag requires a Java2 (JDK 1.2 or
 * later) platform. <p> This class is a subclass of the class
 * <code>org.apache.struts.taglib.html.OptionsCollectionTag</code> which
 * provides most of the described functionality.  This subclass allows all
 * attribute values to be specified as expressions utilizing the JavaServer
 * Pages Standard Library expression language.
 *
 * @version $Rev: 471754 $
 */
public class ELOptionsCollectionTag extends OptionsCollectionTag {
    /**
     * Instance variable mapped to "filter" tag attribute. (Mapping set in
     * associated BeanInfo class.)
     */
    private String filterExpr;

    /**
     * Instance variable mapped to "label" tag attribute. (Mapping set in
     * associated BeanInfo class.)
     */
    private String labelExpr;

    /**
     * Instance variable mapped to "name" tag attribute. (Mapping set in
     * associated BeanInfo class.)
     */
    private String nameExpr;

    /**
     * Instance variable mapped to "property" tag attribute. (Mapping set in
     * associated BeanInfo class.)
     */
    private String propertyExpr;

    /**
     * Instance variable mapped to "style" tag attribute. (Mapping set in
     * associated BeanInfo class.)
     */
    private String styleExpr;

    /**
     * Instance variable mapped to "styleClass" tag attribute. (Mapping set in
     * associated BeanInfo class.)
     */
    private String styleClassExpr;

    /**
     * Instance variable mapped to "value" tag attribute. (Mapping set in
     * associated BeanInfo class.)
     */
    private String valueExpr;

    /**
     * Getter method for "filter" tag attribute. (Mapping set in associated
     * BeanInfo class.)
     */
    public String getFilterExpr() {
        return (filterExpr);
    }

    /**
     * Getter method for "label" tag attribute. (Mapping set in associated
     * BeanInfo class.)
     */
    public String getLabelExpr() {
        return (labelExpr);
    }

    /**
     * Getter method for "name" tag attribute. (Mapping set in associated
     * BeanInfo class.)
     */
    public String getNameExpr() {
        return (nameExpr);
    }

    /**
     * Getter method for "property" tag attribute. (Mapping set in associated
     * BeanInfo class.)
     */
    public String getPropertyExpr() {
        return (propertyExpr);
    }

    /**
     * Getter method for "style" tag attribute. (Mapping set in associated
     * BeanInfo class.)
     */
    public String getStyleExpr() {
        return (styleExpr);
    }

    /**
     * Getter method for "styleClass" tag attribute. (Mapping set in
     * associated BeanInfo class.)
     */
    public String getStyleClassExpr() {
        return (styleClassExpr);
    }

    /**
     * Getter method for "value" tag attribute. (Mapping set in associated
     * BeanInfo class.)
     */
    public String getValueExpr() {
        return (valueExpr);
    }

    /**
     * Setter method for "filter" tag attribute. (Mapping set in associated
     * BeanInfo class.)
     */
    public void setFilterExpr(String filterExpr) {
        this.filterExpr = filterExpr;
    }

    /**
     * Setter method for "label" tag attribute. (Mapping set in associated
     * BeanInfo class.)
     */
    public void setLabelExpr(String labelExpr) {
        this.labelExpr = labelExpr;
    }

    /**
     * Setter method for "name" tag attribute. (Mapping set in associated
     * BeanInfo class.)
     */
    public void setNameExpr(String nameExpr) {
        this.nameExpr = nameExpr;
    }

    /**
     * Setter method for "property" tag attribute. (Mapping set in associated
     * BeanInfo class.)
     */
    public void setPropertyExpr(String propertyExpr) {
        this.propertyExpr = propertyExpr;
    }

    /**
     * Setter method for "style" tag attribute. (Mapping set in associated
     * BeanInfo class.)
     */
    public void setStyleExpr(String styleExpr) {
        this.styleExpr = styleExpr;
    }

    /**
     * Setter method for "styleClass" tag attribute. (Mapping set in
     * associated BeanInfo class.)
     */
    public void setStyleClassExpr(String styleClassExpr) {
        this.styleClassExpr = styleClassExpr;
    }

    /**
     * Setter method for "value" tag attribute. (Mapping set in associated
     * BeanInfo class.)
     */
    public void setValueExpr(String valueExpr) {
        this.valueExpr = valueExpr;
    }

    /**
     * Resets attribute values for tag reuse.
     */
    public void release() {
        super.release();
        setFilterExpr(null);
        setLabelExpr(null);
        setNameExpr(null);
        setPropertyExpr(null);
        setStyleExpr(null);
        setStyleClassExpr(null);
        setValueExpr(null);
    }

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

        return (super.doStartTag());
    }

    /**
     * Processes all attribute values which use the JSTL expression evaluation
     * engine to determine their values.
     *
     * @throws JspException if a JSP exception has occurred
     */
    private void evaluateExpressions()
        throws JspException {
        String string = null;
        Boolean bool = null;

        if ((bool =
                EvalHelper.evalBoolean("filter", getFilterExpr(), this,
                    pageContext)) != null) {
            setFilter(bool.booleanValue());
        }

        if ((string =
                EvalHelper.evalString("label", getLabelExpr(), this, pageContext)) != null) {
            setLabel(string);
        }

        if ((string =
                EvalHelper.evalString("name", getNameExpr(), this, pageContext)) != null) {
            setName(string);
        }

        if ((string =
                EvalHelper.evalString("property", getPropertyExpr(), this,
                    pageContext)) != null) {
            setProperty(string);
        }

        if ((string =
                EvalHelper.evalString("style", getStyleExpr(), this, pageContext)) != null) {
            setStyle(string);
        }

        if ((string =
                EvalHelper.evalString("styleClass", getStyleClassExpr(), this,
                    pageContext)) != null) {
            setStyleClass(string);
        }

        // Note that in contrast to other elements which have "style" and
        // "styleClass" attributes, this tag does not have a "styleId"
        // attribute.  This is because this produces the "id" attribute, which
        // has to be unique document-wide, but this tag can generate more than
        // one "option" element.  Thus, the base tag, "OptionsCollectionTag"
        // does not support this attribute.
        if ((string =
                EvalHelper.evalString("value", getValueExpr(), this, pageContext)) != null) {
            setValue(string);
        }
    }
}