com.bea.wlw.netui.tags.databinding.invoke
Class AbstractCallMethod

java.lang.Object
  javax.servlet.jsp.tagext.TagSupport
      javax.servlet.jsp.tagext.BodyTagSupport
          com.bea.wlw.netui.tags.AbstractBaseTag
              com.bea.wlw.netui.tags.databinding.invoke.AbstractCallMethod

All Implemented Interfaces:

HtmlConstants, Serializable, javax.servlet.jsp.tagext.BodyTag, javax.servlet.jsp.tagext.IterationTag, javax.servlet.jsp.tagext.JspTag, javax.servlet.jsp.tagext.Tag

Direct Known Subclasses:

CallControl, CallMethod

public abstract class AbstractCallMethod
extends AbstractBaseTag

An abstract base class for tags that are capable of reflectively invoking methods. Specializations of this tag provide method implementations that locate the object on which to invoke the method and that handle any return value from the invoked method.

The CallMethod tag can have child tags of type MethodParameter; these tags must be in the same order as the parameter list in the method signature of the method that will be invoked. To invoke an overloaded method, the MethodParamter#setType() property must be set to the String name of the type to pass to the method. If the type attribute values on nested MethodParameter tags do not match any method signature, an error will be reported in the page.

Attribute Descriptions
Attribute	Required	Runtime Expression Evaluation	Data Bindable
method	No	No	No
	The method to invoke on an object.
failOnError	No	No	No
	A boolean that if true will cause the tag to report any method invocation errors in-line in the rendered page.
resultId	No	No	No
	The PageContext attribute name where the result, if non-null, is stored.

See Also:

Serialized Form

Nested Class Summary

protected static class

AbstractCallMethod.ParamNode An internal struct that represents a parameter that will be passed to a reflective method invocation call.

Field Summary

Fields inherited from class com.bea.wlw.netui.tags.AbstractBaseTag

ATTR_GENERAL, ATTR_GENERAL_EXPRESSION, ATTR_JAVASCRIPT, ATTR_STYLE, JAVASCRIPT_STATUS, NETUI_UNIQUE_CNT

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

bodyContent

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

id, pageContext

Fields inherited from interface com.bea.wlw.netui.tags.html.HtmlConstants

ACCEPT, ACCESSKEY, ACTION, ALIGN, ALINK, ALT, ANCHOR, BACKGROUND, BASE, BGCOLOR, BODY, BORDER, BR, CAPTION, CELLPADDING, CELLSPACING, CHAR, CHAROFF, CHARSET, CHECKED, CLASS, COLS, COORDS, DIR, DISABLED, DIV, ENCTYPE, FOR, FORM, FORM_GET, FORM_POST, FRAME, HEIGHT, HREF, HREFLANG, HSPACE, HTML, ID, IMAGE, INPUT, INPUT_BUTTON, INPUT_CHECKBOX, INPUT_FILE, INPUT_HIDDEN, INPUT_IMAGE, INPUT_PASSWORD, INPUT_RADIO, INPUT_RESET, INPUT_SUBMIT, INPUT_TEXT, ISMAP, LABEL, LANG, LINK, LONGDESC, MAXLENGTH, METHOD, NAME, ONBLUR, ONCHANGE, ONCLICK, ONDBLCLICK, ONFOCUS, ONKEYDOWN, ONKEYPRESS, ONKEYUP, ONLOAD, ONMOUSEDOWN, ONMOUSEMOVE, ONMOUSEOUT, ONMOUSEOVER, ONMOUSEUP, ONRESET, ONSELECT, ONSUBMIT, ONUNLOAD, OPTION, READONLY, REL, REV, ROWS, RULES, SELECT, SHAPE, SIZE, SPAN, SRC, STYLE, SUMMARY, TABINDEX, TABLE, TARGET, TD, TEXT, TEXTAREA, TITLE, TR, TYPE, USEMAP, VALIGN, VALUE, VLINK, VSPACE, WIDTH

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

EVAL_BODY_BUFFERED, EVAL_BODY_TAG

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

AbstractCallMethod()

Method Summary

void	addParameter(String type, Object parameter) Add a paramter that will be passed as an argument to the method that will be invoked.
int	doEndTag() Reflectively invokes the method specified by the method attribute, getMethod().
int	doStartTag() Causes the body of this tag to be rendered; only MethodParameter tags are allowed to be contained inside of this tag.
protected Method	findMethod(Object target, String methodName, boolean verifyTypes) The default findMethod implementation is an uncached search of all of the methods available on the Class of the target
boolean	getFailOnError() Get whether or not errors invoking a method are reported in-line when the tag renders.
String	getMethod() Gets the name of the method to invoke on the target object.
protected abstract String	getObjectName() Get the name of the object that is the target of the invocation.
protected List	getParameterNodes() Internal, read-only property used by subclasses to get the list of parameters to be used when reflectively invoking a method.
String	getResultId() Get the identifier at which the result of invoking the method can be found.
protected void	handleReturnValue(Object result) A method that allows concrete classes to handle the result of the reflective invocation in an implementation specific way.
protected void	localRelease() Reset all of the fields of this tag.
protected abstract Object	resolveObject() Resolve the object on which the method should be invoked.
void	setFailOnError(boolean failOnError) Sets whether or not to report exceptions to the page when errors occur invoking a method on an object.
void	setMethod(String method) Sets the name of a method to invoke on the target object.
void	setResultId(String resultId) Sets the identifier at which the result of invoking the method will stored.

Methods inherited from class com.bea.wlw.netui.tags.AbstractBaseTag

addTagIdMapping, containsExpression, evaluateAttributeToString, evaluateExpression, filter, filter, formatErrorString, formatString, getAttribute, getErrorsReport, getExpressionEvaluator, getJavaScriptUtils, getNearestForm, getNextId, getQualifiedBundleName, getScriptReporter, getTagName, getUserLocale, hasErrors, isExpression, prepForRendering, registerAttribute, registerError, registerTagError, release, removeAttribute, renderAttribute, renderAttributes, reportErrors, rewriteName, setPageContext, updateExpression, write

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

doAfterBody, doInitBody, getBodyContent, getPreviousOut, setBodyContent

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

findAncestorWithClass, getId, getParent, getValue, getValues, removeValue, setId, setParent, setValue

Methods inherited from class java.lang.Object

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

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

getParent, setParent

Constructor Detail

AbstractCallMethod

public AbstractCallMethod()

Method Detail

resolveObject

protected abstract Object resolveObject()
                                 throws ObjectNotFoundException

Resolve the object on which the method should be invoked. If there are errors resolving this object, this method will throw an ObjectNotFoundException.

If the object is not found but no exception occurred, this method should return null.

Returns:

the object on which to reflectively invoke the method.

Throws:

ObjectNotFoundException - if an exception occurred attempting to resolve an object

getObjectName

protected abstract String getObjectName()

Get the name of the object that is the target of the invocation. This is a generic method for this tag that enables more specific error reporting.

Returns:

a name for the object on which the method will be invoked.

handleReturnValue

protected void handleReturnValue(Object result)

A method that allows concrete classes to handle the result of the reflective invocation in an implementation specific way.

The default beahavior is to set the return value resulting from invoking the method in the PageContext attribute map of the current JSP page. The result is set as an attribute if the result is not null and the getResultId() String is not null. If the value returned from calling a method is null and the getResultId() is non-null, the javax.servlet.jsp.Pagecontext#removeAttribute(java.lang.String) is called to remove the attribute from the attribute map.

Parameters:

result - the object that was returned by calling the method on the object

getParameterNodes

protected List getParameterNodes()

Internal, read-only property used by subclasses to get the list of parameters to be used when reflectively invoking a method. If the method takes no parameters, this list will be of size zero.

Returns:

the list of parameters

setResultId

public void setResultId(String resultId)

Sets the identifier at which the result of invoking the method will stored.

Parameters:

resultId - a String that names an attribute in the PageContext's attribute map where any resulting object will be stored.

Beadoc.attributedescription:

The data returned by the method is loaded into the PageContext object, under this property name.

Beadoc.attributesyntaxvalue:

string_resultId

Beadoc.databindable:

false

getResultId

public String getResultId()

Get the identifier at which the result of invoking the method can be found.

Returns:

a String where the result object can be found in the PageContext attribute map.

setFailOnError

public void setFailOnError(boolean failOnError)

Sets whether or not to report exceptions to the page when errors occur invoking a method on an object.

Parameters:

failOnError - a boolean that defines whether or not exceptions should be thrown when invocation fails.

Beadoc.attributedescription:

Boolean. If set to true, any errors occuring while invoking the control method will be be reported in-line on the JSP page.

Beadoc.attributesyntaxvalue:

boolean_failOnError

Beadoc.databindable:

false

getFailOnError

public boolean getFailOnError()

Get whether or not errors invoking a method are reported in-line when the tag renders.

Returns:

a boolean that if true will report errors encountered during the tag's execution.

setMethod

public void setMethod(String method)

Sets the name of a method to invoke on the target object.

Parameters:

method - the name of the method to invoke

Beadoc.attributedescription:

The name of the method to invoke

Beadoc.attributesyntaxvalue:

string_method

Beadoc.databindable:

false

getMethod

public String getMethod()

Gets the name of the method to invoke on the target object.

Returns:

the name of the method to invoke

addParameter

public void addParameter(String type,
                         Object parameter)

Add a paramter that will be passed as an argument to the method that will be invoked. This method is implemented to allow the the MethodParameter tags to register their parameters. This object is passed in the position that it appeared in the set of child MethodParameter tags.

Parameters:

type - a String of the type or class name of this parameter

parameter - an object that should be passed as an argument to the invoked method

See Also:

MethodParameter

doStartTag

public int doStartTag()
               throws javax.servlet.jsp.JspException

Causes the body of this tag to be rendered; only MethodParameter tags are allowed to be contained inside of this tag. The body content is never rendered.

Specified by:

doStartTag in interface javax.servlet.jsp.tagext.Tag

Overrides:

doStartTag in class javax.servlet.jsp.tagext.BodyTagSupport

Returns:

EVAL_BODY_BUFFERED

Throws:

javax.servlet.jsp.JspException

See Also:

MethodParameter

doEndTag

public int doEndTag()
             throws javax.servlet.jsp.JspException

Reflectively invokes the method specified by the method attribute, getMethod(). The arguments passed to the method are taken from any nested MethodParameter tags. When the parameters which are added by the MethodParameter tags are String types, an attempt is made to convert each of these parameters into the type expected by the method. This conversion is done using the TypeUtils.convertToObject(java.lang.String, java.lang.Class) method. If a String can not be converted do the type expected by the method, an exception is thrown and the error is reported in the tag. Any return value that results from invoking the given method is passed to the subclass implementation of the method handleReturnValue(java.lang.Object).

Specified by:

doEndTag in interface javax.servlet.jsp.tagext.Tag

Overrides:

doEndTag in class javax.servlet.jsp.tagext.BodyTagSupport

Returns:

EVAL_PAGE to continue evaluating the page

Throws:

javax.servlet.jsp.JspException - if there are errors. All exceptions that may be thrown in the process of reflectively invoking the method and performing type conversion are reported as @see javax.servlet.jsp.JspException.

See Also:

getMethod(), handleReturnValue(java.lang.Object), MethodParameter, ObjectNotFoundException, TypeUtils.convertToObject(java.lang.String, java.lang.Class), String

localRelease

protected void localRelease()

Reset all of the fields of this tag.

Overrides:

localRelease in class AbstractBaseTag

findMethod

protected Method findMethod(Object target,
                            String methodName,
                            boolean verifyTypes)

The default findMethod implementation is an uncached search of all of the methods available on the Class of the target

Parameters:

target - the object from which to find the method

methodName - the name of the method to find

verifyTypes - a boolean that if true will match the type names in addition to the String method name

Returns:

a Method object matching the methodName and types, if verifyTypes is true. null otherwise.