org.apache.struts2.components

## Class ComboBox

- java.lang.Object
- - org.apache.struts2.components.Component
  - - org.apache.struts2.components.UIBean
    - - org.apache.struts2.components.TextField
      - - org.apache.struts2.components.ComboBox

-     public class ComboBox
      extends TextField

  The combo box is basically an HTML INPUT of type text and HTML SELECT grouped together to give you a combo box functionality. You can place text in the INPUT control by using the SELECT control or type it in directly in the text field.

  In this example, the SELECT will be populated from id=year attribute. Counter is itself an Iterator. It will span from first to last. The population is done via javascript, and requires that this tag be surrounded by a <form>.

  Note that unlike the <s:select/> tag, there is no ability to define the individual <option> tags' id attribute or content separately. Each of these is simply populated from the toString() method of the list item. Presumably this is because the select box isn't intended to actually submit useful data, but to assist the user in filling out the text field.

  Examples

       JSP:
       <-- Example One -->
       <s:bean name="struts.util.Counter" var="year">
         <s:param name="first" value="text('firstBirthYear')"/>
         <s:param name="last" value="2000"/>

         <s:combobox label="Birth year" size="6" maxlength="4" name="birthYear" list="#year"/>
       </s:bean>

       <-- Example Two -->
       <s:combobox
           label="My Favourite Fruit"
           name="myFavouriteFruit"
           list="{'apple','banana','grape','pear'}"
           headerKey="-1"
           headerValue="--- Please Select ---"
           emptyOption="true"
           value="banana" />

       <-- Example Two -->
       <s:combobox
          label="My Favourite Color"
          name="myFavouriteColor"
          list="#{'red':'red','green':'green','blue':'blue'}"
          headerKey="-1"
          headerValue="--- Please Select ---"
          emptyOption="true"
          value="green" />

       Velocity:
       #tag( ComboBox "label=Birth year" "size=6" "maxlength=4" "name=birthYear" "list=#year" )

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected String` | `emptyOption`
    `protected String` | `headerKey`
    `protected String` | `headerValue`
    `protected String` | `list`
    `protected String` | `listKey`
    `protected String` | `listValue`
    `static String` | `TEMPLATE`

    - ### Fields inherited from class org.apache.struts2.components.TextField

      `maxlength, readonly, size, type`

    - ### Fields inherited from class org.apache.struts2.components.UIBean

      `accesskey, ATTR_FIELD_VALUE, ATTR_NAME_VALUE, ATTR_VALUE, cssClass, cssErrorClass, cssErrorStyle, cssStyle, defaultTemplateDir, defaultUITheme, disabled, dynamicAttributes, errorPosition, id, javascriptTooltip, key, label, labelPosition, labelSeparator, name, onblur, onchange, onclick, ondblclick, onfocus, onkeydown, onkeypress, onkeyup, onmousedown, onmousemove, onmouseout, onmouseover, onmouseup, onselect, request, requiredLabel, requiredPosition, response, tabindex, template, templateDir, templateEngineManager, templateSuffix, theme, title, tooltip, tooltipConfig, tooltipCssClass, tooltipDelay, tooltipIconPath, uiStaticContentPath, uiThemeExpansionToken, value`

    - ### Fields inherited from class org.apache.struts2.components.Component

      `actionMapper, COMPONENT_STACK, devMode, escapeHtmlBody, parameters, performClearTagStateForTagPoolingServers, stack, standardAttributesMap, throwExceptionOnELFailure`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `ComboBox(ValueStack stack, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `evaluateExtraParams()`
    `protected Object` | `findListValue()`
    `protected String` | `getDefaultTemplate()` A contract that requires each concrete UI Tag to specify which template should be used as a default.
    `void` | `setEmptyOption(String emptyOption)`
    `void` | `setHeaderKey(String headerKey)`
    `void` | `setHeaderValue(String headerValue)`
    `void` | `setList(String list)`
    `void` | `setListKey(String listKey)`
    `void` | `setListValue(String listValue)`

    - ### Methods inherited from class org.apache.struts2.components.TextField

      `setMaxlength, setReadonly, setSize, setType`

    - ### Methods inherited from class org.apache.struts2.components.UIBean

      `addFormParameter, applyValueParameter, buildTemplateName, copyParams, enableAncestorFormCustomOnsubmit, end, ensureAttributeSafelyNotEscaped, escape, evaluateNameValue, evaluateParams, getId, getTemplate, getTemplateDir, getTheme, getTooltipConfig, getValueClassType, lazyEvaluation, mergeTemplate, populateComponentHtmlId, setAccesskey, setCssClass, setCssErrorClass, setCssErrorStyle, setCssStyle, setDefaultTemplateDir, setDefaultUITheme, setDisabled, setDynamicAttributes, setErrorPosition, setId, setJavascriptTooltip, setKey, setLabel, setLabelPosition, setLabelSeparator, setName, setOnblur, setOnchange, setOnclick, setOndblclick, setOnfocus, setOnkeydown, setOnkeypress, setOnkeyup, setOnmousedown, setOnmousemove, setOnmouseout, setOnmouseover, setOnmouseup, setOnselect, setRequiredLabel, setRequiredPosition, setStaticContentPath, setStyle, setTabindex, setTemplate, setTemplateDir, setTemplateEngineManager, setTheme, setTitle, setTooltip, setTooltipConfig, setTooltipCssClass, setTooltipDelay, setTooltipIconPath, setUIThemeExpansionToken, setValue`

    - ### Methods inherited from class org.apache.struts2.components.Component

      `addAllParameters, addParameter, completeExpression, determineActionURL, determineNamespace, end, escapeHtmlBody, fieldError, findAncestor, findString, findString, findValue, findValue, findValue, getAttributes, getComponentStack, getNamespace, getParameters, getPerformClearTagStateForTagPoolingServers, getStack, getStandardAttributes, isAcceptableExpression, isValidTagAttribute, popComponentStack, setActionMapper, setDevMode, setEscapeHtmlBody, setNotExcludedAcceptedPatterns, setPerformClearTagStateForTagPoolingServers, setThrowExceptionsOnELFailure, setUrlHelper, start, stripExpression, toString, usesBody`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### TEMPLATE

          public static final String TEMPLATE

      See Also:
        Constant Field Values

    - #### list

          protected String list

    - #### listKey

          protected String listKey

    - #### listValue

          protected String listValue

    - #### headerKey

          protected String headerKey

    - #### headerValue

          protected String headerValue

    - #### emptyOption

          protected String emptyOption

  - ### Constructor Detail

    - #### ComboBox

          public ComboBox(ValueStack stack,
                          javax.servlet.http.HttpServletRequest request,
                          javax.servlet.http.HttpServletResponse response)

  - ### Method Detail

    - #### getDefaultTemplate

          protected String getDefaultTemplate()

      Description copied from class: `UIBean`
      A contract that requires each concrete UI Tag to specify which template should be used as a default. For example, the CheckboxTab might return "checkbox.vm" while the RadioTag might return "radio.vm". This value not begin with a '/' unless you intend to make the path absolute rather than relative to the current theme.
      Overrides:
        `getDefaultTemplate` in class `TextField`
      Returns:
        The name of the template to be used as the default.

    - #### evaluateExtraParams

          public void evaluateExtraParams()

      Overrides:
        `evaluateExtraParams` in class `TextField`

    - #### findListValue

          protected Object findListValue()

    - #### setList

          public void setList(String list)

    - #### setEmptyOption

          public void setEmptyOption(String emptyOption)

    - #### setHeaderKey

          public void setHeaderKey(String headerKey)

    - #### setHeaderValue

          public void setHeaderValue(String headerValue)

    - #### setListKey

          public void setListKey(String listKey)

    - #### setListValue

          public void setListValue(String listValue)

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