Struts example source code file (Select.java)

This example Struts source code file (Select.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

array, array, boolean, collection, collection, http, if, key, render, request, response, select, servlet, string, string, strutstagattribute, strutstagattribute, template

The Struts Select.java source code

/*
 * $Id: Select.java 651946 2008-04-27 13:41:38Z apetrelli $
 *
 * 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.struts2.components;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.views.annotations.StrutsTag;
import org.apache.struts2.views.annotations.StrutsTagAttribute;

import com.opensymphony.xwork2.util.ValueStack;

/**
 * <!-- START SNIPPET: javadoc -->
 *
 * Render an HTML input tag of type select.
 *
 * <!-- END SNIPPET: javadoc -->
 *
 * <p/> Examples
 * <pre>
 * <!-- START SNIPPET: example -->
 *
 * <s:select label="Pets"
 *        name="petIds"
 *        list="petDao.pets"
 *        listKey="id"
 *        listValue="name"
 *        multiple="true"
 *        size="3"
 *        required="true"
 *        value="%{petDao.pets.{id}}"
 * />
 *
 * <s:select label="Months"
 *        name="months"
 *        headerKey="-1" headerValue="Select Month"
 *        list="#{'01':'Jan', '02':'Feb', [...]}"
 *        value="selectedMonth"
 *        required="true"
 * />
 *
 * // The month id (01, 02, ...) returned by the getSelectedMonth() call
 * // against the stack will be auto-selected
 *
 * <!-- END SNIPPET: example -->
 * </pre>
 *
 * <p/>
 *
 * <!-- START SNIPPET: exnote -->
 *
 * Note: For any of the tags that use lists (select probably being the most ubiquitous), which uses the OGNL list
 * notation (see the "months" example above), it should be noted that the map key created (in the months example,
 * the '01', '02', etc.) is typed. '1' is a char, '01' is a String, "1" is a String. This is important since if
 * the value returned by your "value" attribute is NOT the same type as the key in the "list" attribute, they
 * WILL NOT MATCH, even though their String values may be equivalent. If they don't match, nothing in your list
 * will be auto-selected.<p/>
 *
 * <!-- END SNIPPET: exnote -->
 *
 */
@StrutsTag(
    name="select",
    tldTagClass="org.apache.struts2.views.jsp.ui.SelectTag",
    description="Render a select element",
    allowDynamicAttributes=true)
public class Select extends ListUIBean {
    final public static String TEMPLATE = "select";

    protected String emptyOption;
    protected String headerKey;
    protected String headerValue;
    protected String multiple;
    protected String size;

    public Select(ValueStack stack, HttpServletRequest request, HttpServletResponse response) {
        super(stack, request, response);
    }

    protected String getDefaultTemplate() {
        return TEMPLATE;
    }

    public void evaluateExtraParams() {
        super.evaluateExtraParams();

        if (emptyOption != null) {
            addParameter("emptyOption", findValue(emptyOption, Boolean.class));
        }

        if (multiple != null) {
            addParameter("multiple", findValue(multiple, Boolean.class));
        }

        if (size != null) {
            addParameter("size", findString(size));
        }

        if ((headerKey != null) && (headerValue != null)) {
            addParameter("headerKey", findString(headerKey));
            addParameter("headerValue", findString(headerValue));
        }
    }

    @StrutsTagAttribute(description="Whether or not to add an empty (--) option after the header option", type="Boolean", defaultValue="false")
    public void setEmptyOption(String emptyOption) {
        this.emptyOption = emptyOption;
    }

    @StrutsTagAttribute(description=" Key for first item in list. Must not be empty! '-1' and '' is correct, '' is bad.")
    public void setHeaderKey(String headerKey) {
        this.headerKey = headerKey;
    }

    @StrutsTagAttribute(description="Value expression for first item in list")
    public void setHeaderValue(String headerValue) {
        this.headerValue = headerValue;
    }

    @StrutsTagAttribute(description=" Creates a multiple select. The tag will pre-select multiple values" +
                " if the values are passed as an Array or a Collection(of appropriate types) via the value attribute. If one of the keys equals" +
                " one of the values in the Collection or Array it wil be selected", type="Boolean", defaultValue="false")
    public void setMultiple(String multiple) {
        this.multiple = multiple;
    }

    @StrutsTagAttribute(description="Size of the element box (# of elements to show)", type="Integer")
    public void setSize(String size) {
        this.size = size;
    }
}