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Questions tagged [composite]

The Composite pattern is a design pattern that allows a group of objects to be treated in the same way as a single instance of an object. It is one of the Gang of Four's structural design patterns.

Overview

The Composite pattern is a design pattern that allows a group of objects to be treated in the same way as a single instance of an object.

It is one of the Gang of Four's structural , first published in Gamma et al.'s book "Design Patterns: Elements of Reusable Object-Oriented Software".

The Composite pattern may sometimes coincide with the use of composite data types and composite variables.

See also

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How to clear the canvas for redrawing

After experimenting with composite operations and drawing images on the canvas I'm now trying to remove images and compositing. How do I do this? I need to clear the canvas for redrawing other images; this can go on for a while so I don't think…
richard
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How do composite indexes work?

I've created composite indexes (indices for you mathematical folk) on tables before with an assumption of how they worked. I was just curious if my assumption is correct or not. I assume that when you list the order of columns for the index, you are…
Joe Phillips
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When should I use composite design pattern?

I don't understand when I should use composite design pattern. What kinds of benefits will I get from this design pattern? I visited this website but it only tells me about the structure of the design pattern and not the scenarios in which it is…
kevin
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Difference between the Composite Pattern and Decorator Pattern?

What is the difference between the Composite Pattern and Decorator Pattern?
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Relations on composite keys using sqlalchemy

I have this simple model of Author - Books and can't find a way to make firstName and lastName a composite key and use it in relation. Any ideas? from sqlalchemy import create_engine, ForeignKey, Column, String, Integer from sqlalchemy.orm import…
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SQL join with composite primary key

I have to join two tables. But in one table primary key is not there,composite primary key is there,means three columns put together uniquely define a row of that table. I have those three columns in the other table too.rest nothing is common. Is…
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Design patterns: Composite vs. Composition

I am finishing a course on design patterns, and while reviewing the notes came across something I missed during the semester: Composite vs. Composition. What I managed to understand is that composite is when an object actually encapsulates whole…
Baruch
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How to make a composite manifest for Microsoft smooth streaming

I am new to Microsoft Smooth Streaming and have questions about the making of composite manifests. Following the guidance from here. I was able to make a composite manifest of a single clip element that played in Silverlight player. However, when I…
Lich
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Implementing MEF with ASP.NET MVC?

I am trying to find out if anyone has any experience or ideas of using MEF (Managed Extensible Framework (Microsoft's new plugin framework) with ASP.NET MVC. I need to create a standard ASP.NET MVC, which I have. But I need to offer additional…
mark smith
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Check if a Postgres composite field is null/empty

With postgres composite types you can basically build a field with the structure being defined as another table. I have the composite field called "recipient" of type "person". This recipient field is often left empty in my specific scenario. What…
rockstardev
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how can I set up multiple listeners for one event?

I want to set up multiple listeners for one event, and have found that using composite listener is the key. Could anyone give me an example?
Vicky
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MySQL: how to index an "OR" clause

I'm executing the following query SELECT COUNT(*) FROM table WHERE field1='value' AND (field2 >= 1000 OR field3 >= 2000) There is one index over field1 and another composited over field2&field3. I see MySQL always selects the field1 index and then…
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When are interfaces needed?

(In the context of .NET for what its worth) I tend to not use inheritance and rarely use interfaces. I came across someone who thinks interfaces are the best thing since spit. He uses them everywhere. I don't understand this and hence the…
4thSpace
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How do I configure a RollingFileAppender to roll by date and size with log4net?

I am configure log4net to use a composite RollingFileAppender so that the current file is always named logfile.log and all subsequent files are named logfile-YYYY.MM.dd.seq.log where seq is the sequence number if a log exceeds a certain size within…
Ryan Taylor
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composed_of in Rails - when to use it?

When should you use ActiveRecord's composed_of class method?
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