Re: Why can I not use attributes lang and maxRows in a custom tag
- Original Message - From: Jan Luehe [EMAIL PROTECTED] Subject: Re: Why can I not use attributes lang and maxRows in a custom tag Tomcat 4.1.12 does not accept a custom tag with attributes lang or maxRows. When I asked about this on the Tomcat users list I was informed that it also does not accept the attribute class. Specifically if I define those attributes then when the jsp is compiled I get an unable to find setter error. If I replace them with similar but meaningless attribute names the page compiles correctly. This can't be true. For example, JSTL defines an attribute named 'maxRows' for its sql:query action. I am not aware of any naming restrictions for custom tag attributes. Are you sure the tag handler for your custom action defines an approriate setter method for the attributes in question? I kept experimenting and found exactly what it was that Tomcat disliked about my attribute. It was not the name. It was not the presence or absence of the set method. It was that there was also a get method which did not return String! Since Tomcat does not use the get method I do not understand why it cares whether or not one is present or what its signature is. But as soon as I change the name of the get method so it did not match the set method Tomcat merrily accepted the tag. For me this is now an issue of documentation. I have searched the JSP 1.2 spec using every term I can think of and I cannot find where it specifies the characteristics of the set method for an attribute on a custom tag. I have therefore been depending upon the description of this capability in Marty Hall's book. If the JSP specification, and Tomcat, have a legitimate reason for looking at the characteristics of the get method when deciding whether or not to use the set method, then that should be documented. Otherwise the behavior is frankly mysterious. Thank you for responding. When a week went by without a response I unsubscribed from the list, so the CC on this message may be discarded. -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED]
Re: Why can I not use attributes lang and maxRows in a custom tag
If Tomcat uses the beans API in Java to do the reflection for calling these methods, then that is probably why. It insists on having a valid get and set method for an attribute for some reason. I ran into this once when I only wanted to have getters with no setters, and I couldn't find a way around it other than to use reflection directly (mind you, I was in a hurry, so I didn't try too hard). -- Rob Jim Cobban [EMAIL PROTECTED]To: Jan Luehe [EMAIL PROTECTED] cc: [EMAIL PROTECTED] Subject: Re: Why can I not use attributes lang and maxRows in a custom tag 23/11/2002 11:17 AM Please respond to Tomcat Developers List - Original Message - From: Jan Luehe [EMAIL PROTECTED] Subject: Re: Why can I not use attributes lang and maxRows in a custom tag Tomcat 4.1.12 does not accept a custom tag with attributes lang or maxRows. When I asked about this on the Tomcat users list I was informed that it also does not accept the attribute class. Specifically if I define those attributes then when the jsp is compiled I get an unable to find setter error. If I replace them with similar but meaningless attribute names the page compiles correctly. This can't be true. For example, JSTL defines an attribute named 'maxRows' for its sql:query action. I am not aware of any naming restrictions for custom tag attributes. Are you sure the tag handler for your custom action defines an approriate setter method for the attributes in question? I kept experimenting and found exactly what it was that Tomcat disliked about my attribute. It was not the name. It was not the presence or absence of the set method. It was that there was also a get method which did not return String! Since Tomcat does not use the get method I do not understand why it cares whether or not one is present or what its signature is. But as soon as I change the name of the get method so it did not match the set method Tomcat merrily accepted the tag. For me this is now an issue of documentation. I have searched the JSP 1.2 spec using every term I can think of and I cannot find where it specifies the characteristics of the set method for an attribute on a custom tag. I have therefore been depending upon the description of this capability in Marty Hall's book. If the JSP specification, and Tomcat, have a legitimate reason for looking at the characteristics of the get method when deciding whether or not to use the set method, then that should be documented. Otherwise the behavior is frankly mysterious. Thank you for responding. When a week went by without a response I unsubscribed from the list, so the CC on this message may be discarded. -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED] If you received this e-mail in error please delete it and notify the sender as soon as possible. The contents of this e-mail may be confidential and the unauthorized use, copying, or dissemination of it and any attachments to it, is prohibited. Internet communications are not secure and Hyperion does not, therefore, accept legal responsibility for the contents of this message nor for any damage caused by viruses. The views expressed here do not necessarily represent those of Hyperion. For more information about Hyperion, please visit our Web site at www.hyperion.com -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED]
Re: Why can I not use attributes lang and maxRows in a custom tag
- Original Message - From: Craig R. McClanahan [EMAIL PROTECTED] Subject: Re: Why can I not use attributes lang and maxRows in a custom tag Tomcat cares because JSP custom tags are required to implement the standard JavaBean naming patterns for property-related methods, as defined in the JavaBeans Specification. http://java.sun.com/products/javabeans/ For me this is now an issue of documentation. I have searched the JSP 1.2 spec using every term I can think of and I cannot find where it specifies the characteristics of the set method for an attribute on a custom tag. I have therefore been depending upon the description of this capability in Marty Hall's book. If the JSP specification, and Tomcat, have a legitimate reason for looking at the characteristics of the get method when deciding whether or not to use the set method, then that should be documented. Otherwise the behavior is frankly mysterious. In the JSP 1.2 spec, section JSP.10.1: A tag handler has some properties that are exposed to the page as attributes on an action; these properties are managed by the JSP container (via generated code). The setter methods used to set the properties are discovered using the JavaBeans introspector machinery. The last sentence refers to the java.beans.Introspector class, which refers you to the JavaBeans spec. Thank you for the pointers. I appreciate that exploiting the existing support for Beans is the obvious way for Tomcat to acquire this information about the class, even if Tomcat never uses the get method. I merely hope that the documentation can be improved to be a little less obscure so that other programmers like myself, who do not have the time to become intimately familar with all aspects of Java technology, can be brought up to speed with less wasted effort. -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED]
Re: Why can I not use attributes lang and maxRows in a custom tag
The Java beans API requires getters. It does not require setters. No setter means the property is read-only. There's no such thing as write-only in the Java beans API. A getter is the only way to determine what the type of the property is since there can be only one getter with a particular name. The Java beans API is all about deducing all of this information at runtime... so it must be able to figure this out. (For PropertyDescriptors and such.) Not 100% useful as a way to do simple reflection though. -Paul [EMAIL PROTECTED] wrote: If Tomcat uses the beans API in Java to do the reflection for calling these methods, then that is probably why. It insists on having a valid get and set method for an attribute for some reason. I ran into this once when I only wanted to have getters with no setters, and I couldn't find a way around it other than to use reflection directly (mind you, I was in a hurry, so I didn't try too hard). -- Rob Jim Cobban [EMAIL PROTECTED]To: Jan Luehe [EMAIL PROTECTED] cc: [EMAIL PROTECTED] Subject: Re: Why can I not use attributes lang and maxRows in a custom tag 23/11/2002 11:17 AM Please respond to Tomcat Developers List - Original Message - From: Jan Luehe [EMAIL PROTECTED] Subject: Re: Why can I not use attributes lang and maxRows in a custom tag Tomcat 4.1.12 does not accept a custom tag with attributes lang or maxRows. When I asked about this on the Tomcat users list I was informed that it also does not accept the attribute class. Specifically if I define those attributes then when the jsp is compiled I get an unable to find setter error. If I replace them with similar but meaningless attribute names the page compiles correctly. This can't be true. For example, JSTL defines an attribute named 'maxRows' for its sql:query action. I am not aware of any naming restrictions for custom tag attributes. Are you sure the tag handler for your custom action defines an approriate setter method for the attributes in question? I kept experimenting and found exactly what it was that Tomcat disliked about my attribute. It was not the name. It was not the presence or absence of the set method. It was that there was also a get method which did not return String! Since Tomcat does not use the get method I do not understand why it cares whether or not one is present or what its signature is. But as soon as I change the name of the get method so it did not match the set method Tomcat merrily accepted the tag. For me this is now an issue of documentation. I have searched the JSP 1.2 spec using every term I can think of and I cannot find where it specifies the characteristics of the set method for an attribute on a custom tag. I have therefore been depending upon the description of this capability in Marty Hall's book. If the JSP specification, and Tomcat, have a legitimate reason for looking at the characteristics of the get method when deciding whether or not to use the set method, then that should be documented. Otherwise the behavior is frankly mysterious. Thank you for responding. When a week went by without a response I unsubscribed from the list, so the CC on this message may be discarded. -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED] If you received this e-mail in error please delete it and notify the sender as soon as possible. The contents of this e-mail may be confidential and the unauthorized use, copying, or dissemination of it and any attachments to it, is prohibited. Internet communications are not secure and Hyperion does not, therefore, accept legal responsibility for the contents of this message nor for any damage caused by viruses. The views expressed here do not necessarily represent those of Hyperion. For more information about Hyperion, please visit our Web site at www.hyperion.com -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED] -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED]
Re: Why can I not use attributes lang and maxRows in a custom tag
Jim, Tomcat 4.1.12 does not accept a custom tag with attributes lang or maxRows. When I asked about this on the Tomcat users list I was informed that it also does not accept the attribute class. Specifically if I define those attributes then when the jsp is compiled I get an unable to find setter error. If I replace them with similar but meaningless attribute names the page compiles correctly. This can't be true. For example, JSTL defines an attribute named 'maxRows' for its sql:query action. I am not aware of any naming restrictions for custom tag attributes. Are you sure the tag handler for your custom action defines an approriate setter method for the attributes in question? Jan -- To unsubscribe, e-mail: mailto:[EMAIL PROTECTED] For additional commands, e-mail: mailto:[EMAIL PROTECTED]
Why can I not use attributes lang and maxRows in a custom tag
Tomcat 4.1.12 does not accept a custom tag with attributes lang or maxRows. When I asked about this on the Tomcat users list I was informed that it also does not accept the attribute class. Specifically if I define those attributes then when the jsp is compiled I get an unable to find setter error. If I replace them with similar but meaningless attribute names the page compiles correctly. I have searched the JSP 1.2 and Tomcat 4 documentation exhaustively and I cannot find any indication that these attributes are not allowed. The names I want are the ones I feel will be most intuitive to my users. The lang keyword is to be used to specify the natural language of the interface and the maxRows attribute is to be used to specify the maximum number of rows from a database query which are to be displayed. I really want to use these attribute names. If there is a list of forbidden attribute names this should be documented somewhere. Jim Cobban [EMAIL PROTECTED] 34 Palomino Dr. Kanata, ON, CANADA K2M 1M1 +1-613-592-9438
