java.lang.Object
- javax.servlet.jsp.tagext.TagSupport
- - org.springframework.web.servlet.tags.RequestContextAwareTag
  - - org.springframework.web.servlet.tags.HtmlEscapingAwareTag
    - - org.springframework.web.servlet.tags.form.AbstractFormTag

All Implemented Interfaces:
Serializable, IterationTag, JspTag, Tag, TryCatchFinally
Direct Known Subclasses:
AbstractDataBoundFormElementTag
```
public abstract class AbstractFormTag
extends HtmlEscapingAwareTag
```
Base class for all JSP form tags. Provides utility methods for null-safe EL evaluation and for accessing and working with a TagWriter.
Subclasses should implement the writeTagContent(TagWriter) to perform actual tag rendering.
Subclasses (or test classes) can override the createTagWriter() method to redirect output to a Writer other than the JspWriter associated with the current PageContext.
Since:
2.0
Author:
Rob Harrop, Juergen Hoeller
See Also:
Serialized Form

Field Summary
- Fields inherited from class org.springframework.web.servlet.tags.RequestContextAwareTag
  logger, REQUEST_CONTEXT_PAGE_ATTRIBUTE
- Fields inherited from class javax.servlet.jsp.tagext.TagSupport
  id, pageContext
- Fields inherited from interface javax.servlet.jsp.tagext.IterationTag
  EVAL_BODY_AGAIN
- Fields inherited from interface javax.servlet.jsp.tagext.Tag
  EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE

Constructor Summary
Constructors
Constructor Description
AbstractFormTag()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`protected TagWriter`	`createTagWriter()`	Create the `TagWriter` which all output will be written to.
`protected int`	`doStartTagInternal()`	Provide a simple template method that calls `createTagWriter()` and passes the created `TagWriter` to the `writeTagContent(TagWriter)` method.
`protected Object`	`evaluate(String attributeName, Object value)`	Evaluate the supplied value for the supplied attribute name.
`protected String`	`getDisplayString(Object value)`	Get the display value of the supplied `Object`, HTML escaped as required.
`protected String`	`getDisplayString(Object value, PropertyEditor propertyEditor)`	Get the display value of the supplied `Object`, HTML escaped as required.
`protected boolean`	`isDefaultHtmlEscape()`	Overridden to default to `true` in case of no explicit default given.
`protected void`	`writeOptionalAttribute(TagWriter tagWriter, String attributeName, String value)`	Optionally writes the supplied value under the supplied attribute name into the supplied `TagWriter`.
`protected abstract int`	`writeTagContent(TagWriter tagWriter)`	Subclasses should implement this method to perform tag content rendering.

Methods inherited from class org.springframework.web.servlet.tags.HtmlEscapingAwareTag
htmlEscape, isHtmlEscape, isResponseEncodedHtmlEscape, setHtmlEscape

Methods inherited from class org.springframework.web.servlet.tags.RequestContextAwareTag
doCatch, doFinally, doStartTag, getRequestContext

Methods inherited from class javax.servlet.jsp.tagext.TagSupport
doAfterBody, doEndTag, findAncestorWithClass, getId, getParent, getValue, getValues, release, removeValue, setId, setPageContext, setParent, setValue

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - AbstractFormTag
```
public AbstractFormTag()
```
- Method Detail
  - evaluate
```
protected Object evaluate(String attributeName,
                          Object value)
                   throws JspException
```
    Evaluate the supplied value for the supplied attribute name.
    The default implementation simply returns the given value as-is.
    Throws:
    JspException
  - writeOptionalAttribute
```
protected final void writeOptionalAttribute(TagWriter tagWriter,
                                            String attributeName,
                                            String value)
                                     throws JspException
```
    Optionally writes the supplied value under the supplied attribute name into the supplied TagWriter. In this case, the supplied value is evaluated first and then the String representation is written as the attribute value. If the resultant String representation is null or empty, no attribute is written.
    Throws:
    JspException
    See Also:
    TagWriter.writeOptionalAttributeValue(String, String)
  - createTagWriter
```
protected TagWriter createTagWriter()
```
    Create the TagWriter which all output will be written to. By default, the TagWriter writes its output to the JspWriter for the current PageContext. Subclasses may choose to change the Writer to which output is actually written.
  - doStartTagInternal
```
protected final int doStartTagInternal()
                                throws Exception
```
    Provide a simple template method that calls createTagWriter() and passes the created TagWriter to the writeTagContent(TagWriter) method.
    Specified by:
    doStartTagInternal in class RequestContextAwareTag
    Returns:
    the value returned by writeTagContent(TagWriter)
    Throws:
    Exception - any exception, any checked one other than a JspException gets wrapped in a JspException by doStartTag
    See Also:
    TagSupport.doStartTag()
  - getDisplayString
```
protected String getDisplayString(Object value)
```
    Get the display value of the supplied Object, HTML escaped as required. This version is notPropertyEditor-aware.
  - getDisplayString
```
protected String getDisplayString(Object value,
                                  PropertyEditor propertyEditor)
```
    Get the display value of the supplied Object, HTML escaped as required. If the supplied value is not a String and the supplied PropertyEditor is not null then the PropertyEditor is used to obtain the display value.
  - isDefaultHtmlEscape
```
protected boolean isDefaultHtmlEscape()
```
    Overridden to default to true in case of no explicit default given.
    Overrides:
    isDefaultHtmlEscape in class HtmlEscapingAwareTag
    See Also:
    RequestContextAwareTag.getRequestContext()
  - writeTagContent
```
protected abstract int writeTagContent(TagWriter tagWriter)
                                throws JspException
```
    Subclasses should implement this method to perform tag content rendering.
    Returns:
    valid tag render instruction as per Tag.doStartTag().
    Throws:
    JspException

Class AbstractFormTag

Field Summary

Fields inherited from class org.springframework.web.servlet.tags.RequestContextAwareTag

Fields inherited from class javax.servlet.jsp.tagext.TagSupport

Fields inherited from interface javax.servlet.jsp.tagext.IterationTag

Fields inherited from interface javax.servlet.jsp.tagext.Tag

Constructor Summary

Method Summary

Methods inherited from class org.springframework.web.servlet.tags.HtmlEscapingAwareTag

Methods inherited from class org.springframework.web.servlet.tags.RequestContextAwareTag

Methods inherited from class javax.servlet.jsp.tagext.TagSupport

Methods inherited from class java.lang.Object

Constructor Detail

AbstractFormTag

Method Detail

evaluate

writeOptionalAttribute

createTagWriter

doStartTagInternal

getDisplayString

getDisplayString

isDefaultHtmlEscape

writeTagContent