dynamic-attributes | 易学教程

How Do I make dynamic-attributes Work in JSP Tag Files?

阅读更多关于 How Do I make dynamic-attributes Work in JSP Tag Files?

问题 So according to my JSP reference book, as well as every other reference I can find on the web, I'm supposed to be able to do something like: <%@ tag dynamic-attributes="dynamicAttributesVar" %> and then when someone uses an attribute that I didn't define in an attribute directive, I should be able to access that attribute from the "dynamicAttributesVar" map: <%= dynamicAttributesVar.get("someUnexpectedAttribute") %> However, that doesn't work, at all; I just get a "dynamicAttributesVar cannot

How Do I make dynamic-attributes Work in JSP Tag Files?

阅读更多关于 How Do I make dynamic-attributes Work in JSP Tag Files?

So according to my JSP reference book, as well as every other reference I can find on the web, I'm supposed to be able to do something like: <%@ tag dynamic-attributes="dynamicAttributesVar" %> and then when someone uses an attribute that I didn't define in an attribute directive, I should be able to access that attribute from the "dynamicAttributesVar" map: <%= dynamicAttributesVar.get("someUnexpectedAttribute") %> However, that doesn't work, at all; I just get a "dynamicAttributesVar cannot be resolved" error when I try. Now, I did discover (by looking at the generated Java class for the tag

Dynamic attributes with Rails and Mongoid

阅读更多关于 Dynamic attributes with Rails and Mongoid

I'm learning MongoDB through the Mongoid Ruby gem with Rails (Rails 3 beta 3), and I'm trying to come up with a way to create dynamic attributes on a model based on fields from another model, which I thought a schema-less database would be a good choice for. So for example, I'd have the models: class Account include Mongoid::Document field :name, :type => String field :token, :type => String field :info_needed, :type => Array embeds_many :members end class Member include Mongoid::Document embedded_in :account, :inverse_of => :members end I'm looking to take the "info_needed" attribute of the

getattr() versus dict lookup, which is faster?

阅读更多关于 getattr() versus dict lookup, which is faster?

问题 A somewhat noobish, best practice question. I dynamically look up object attribute values using object.__dict__[some_key] as a matter of habit. Now I am wondering which is better/faster: my current habit or getattr(object,some_key) . If one is better, why? >>> class SomeObject: ... pass ... >>> so = SomeObject() >>> so.name = 'an_object' >>> getattr(so,'name') 'an_object' >>> so.__dict__['name'] 'an_object' 回答1: You are much better off using getattr() instead of going directly to the __dict__

Dynamic attributes with Rails and Mongoid

阅读更多关于 Dynamic attributes with Rails and Mongoid

问题 I'm learning MongoDB through the Mongoid Ruby gem with Rails (Rails 3 beta 3), and I'm trying to come up with a way to create dynamic attributes on a model based on fields from another model, which I thought a schema-less database would be a good choice for. So for example, I'd have the models: class Account include Mongoid::Document field :name, :type => String field :token, :type => String field :info_needed, :type => Array embeds_many :members end class Member include Mongoid::Document

Rails find_or_create_by more than one attribute?

阅读更多关于 Rails find_or_create_by more than one attribute?

问题 There is a handy dynamic attribute in active-record called find_or_create_by: Model.find_or_create_by_<attribute>(:<attribute> => \"\") But what if I need to find_or_create by more than one attribute? Say I have a model to handle a M:M relationship between Group and Member called GroupMember. I could have many instances where member_id = 4, but I don\'t ever want more than once instance where member_id = 4 and group_id = 7. I\'m trying to figure out if it\'s possible to do something like this