AbstractCallMethod Class

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

public abstract class AbstractCallMethod

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 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.

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.

Hierarchy: Object
  TagSupport
    BodyTagSupport
      AbstractBaseTag
        AbstractCallMethod

All Implemented Interfaces: BodyTag, IterationTag, Serializable, Tag

Direct Known Subclasses: CallControl, CallMethod

Field Summary

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

ATTR_GENERAL, ATTR_GENERAL_EXPRESSION, ATTR_JAVASCRIPT, ATTR_STYLE, CLASS, ID, JAVASCRIPT_STATUS, NAME, NETUI_UNIQUE_CNT, ONCLICK, ONDBLCLICK, ONKEYDOWN, ONKEYPRESS, ONKEYUP, ONMOUSEDOWN, ONMOUSEMOVE, ONMOUSEOUT, ONMOUSEOVER, ONMOUSEUP, STYLE, TABINDEX

Fields from javax.servlet.jsp.tagext.BodyTagSupport

bodyContent

Fields from javax.servlet.jsp.tagext.TagSupport

id, pageContext

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

EVAL_BODY_BUFFERED, EVAL_BODY_TAG

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

EVAL_BODY_AGAIN

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

EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE

Constructor Summary

AbstractCallMethod()

Method Summary

`public void`	`addParameter`(`String` type, `Object` parameter) Add a paramter that will be passed as an argument to the method that will be invoked.
`public int`	`doEndTag`() Reflectively invokes the method specified by the `method` attribute, `AbstractCallMethod.getMethod()`.
`public 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`
`public boolean`	`getFailOnError`() Get whether or not errors invoking a method are reported in-line when the tag renders.
`public 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.
`public 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.
`public void`	`setFailOnError`(boolean failOnError) Sets whether or not to report exceptions to the page when errors occur invoking a method on an object.
`public void`	`setMethod`(`String` method) Sets the name of a method to invoke on the target object.
`public void`	`setResultId`(`String` resultId) Sets the identifier at which the result of invoking the method will stored.

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

addTagIdMapping, evaluateAttributeToString, filter, filter, getJavaScriptUtils, getNearestForm, getScriptReporter, getTagName, getUserLocale, registerTagError, release, renderAttribute, rewriteName, write

Methods from javax.servlet.jsp.tagext.BodyTagSupport

doAfterBody, doInitBody, getBodyContent, getPreviousOut, release, setBodyContent

Methods from javax.servlet.jsp.tagext.TagSupport

doAfterBody, doEndTag, doStartTag, findAncestorWithClass, getId, getParent, getValue, getValues, release, removeValue, setId, setPageContext, setParent, setValue

Methods from class java.lang.Object

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

Methods from interface javax.servlet.jsp.tagext.BodyTag

doInitBody, setBodyContent

Methods from interface javax.servlet.jsp.tagext.IterationTag

doAfterBody

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

doEndTag, doStartTag, getParent, release, setPageContext, setParent

Constructor Detail

AbstractCallMethod

public AbstractCallMethod()

Method Detail

addParameter(String, Object) Method

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

Related Topics

MethodParameter

doEndTag() Method

public int doEndTag()
     throws JspException

Reflectively invokes the method specified by the method attribute, AbstractCallMethod.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(String, 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 AbstractCallMethod.handleReturnValue(Object).

Overrides: BodyTagSupport.doEndTag()

Returns

EVAL_PAGE to continue evaluating the page

Exceptions

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.

doStartTag() Method

public int doStartTag()
     throws 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.

Overrides: BodyTagSupport.doStartTag()

Returns

EVAL_BODY_BUFFERED

Exceptions

JspException

Related Topics

MethodParameter

findMethod(Object, String, boolean) Method

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.

getFailOnError() Method

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.

getMethod() Method

public String getMethod()

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

Returns

the name of the method to invoke

getObjectName() Method

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.

getParameterNodes() Method

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

getResultId() Method

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.

handleReturnValue(Object) Method

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 CallMethod.getResultId() String is not null. If the value returned from calling a method is null and the CallMethod.getResultId() is non-null, the is called to remove the attribute from the attribute map.

Parameters

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

localRelease() Method

protected void localRelease()

Reset all of the fields of this tag.

Overrides: AbstractBaseTag.localRelease()

resolveObject() Method

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.

Exceptions

ObjectNotFoundException: if an exception occurred attempting to resolve an object

setFailOnError(boolean) Method

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.

setMethod(String) Method

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

setResultId(String) Method

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.

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

Field Summary

Constructor Summary

Method Summary

Constructor Detail

AbstractCallMethod

Method Detail

addParameter(String, Object) Method

Parameters

doEndTag() Method

Returns

Exceptions

doStartTag() Method

Returns

Exceptions

findMethod(Object, String, boolean) Method

Parameters

Returns

getFailOnError() Method

Returns

getMethod() Method

Returns

getObjectName() Method

Returns

getParameterNodes() Method

Returns

getResultId() Method

Returns

handleReturnValue(Object) Method

Parameters

localRelease() Method

resolveObject() Method

Returns

Exceptions

setFailOnError(boolean) Method

Parameters

setMethod(String) Method

Parameters

setResultId(String) Method

Parameters

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