是否可以为条形图中的每个类别自定义标签？ [英] Is it possible to customize label for each category in bar chart?

问题描述

最近我要求创建一个显示每个项目数据的条形图。这是一个例子：

Recently I get a requirement to create a bar chart that show data for each project. Here's an example :

如您所见，类别是项目的名称，系列是该项目中不同类型的数据。

As you can see, the Category is the name of the project, and Series are different types of data in that project.

但是，由于系统剂量不能保证项目名称的唯一性，因此将其用作类别可能会导致问题，我将无法使用项目名称为不同的项目生成URL。另一方面，如果我使用唯一ID作为类别，我将无法显示项目名称。这让我陷入困境。

However, since system dose not guarantee the uniqueness of project name, using it as categories can cause problem, and I will not able to use project name to generate URL for different projects. On the other hand, If I use unique id as category, I won't able to display the project name. This put me into a difficult situation.

所以我的问题是：

有没有办法生成自定义JFreeChart中的类别标签？

Is there a way to generate customize category label on the fly in JFreeChart ?

与 CategoryItemLabelGenerator 类似，但类别本身。所以我可以使用唯一ID作为类别，但在图表中显示项目名称。

Something similar to CategoryItemLabelGenerator but for category itself. So I can use unique Id as category, but display project name in chart.

推荐答案

答案取决于您选择的 CategoryDataset 实现 KeyedValues2D 界面。接口期望密钥是唯一的，默认实现 DefaultKeyedValues2D ，要求密钥为 Comparable 且不可变。

The answer depends on how your chosen CategoryDataset implements the KeyedValues2D interface. The interface expects the keys to be unique, and the default implementation, DefaultKeyedValues2D, requires that the keys be Comparable and immutable.

唯一字符串实例是典型的具体参数类型，但 JFreeChart 强制执行唯一约束。一种方法是将 String 包装在一个实现 Comparable 的类中，并强制执行唯一性。 类值是示例利用底层的 Double 实现。您的实现需要一个额外的属性来区分一个项目形成另一个，可能使用源关系的主键。您可以覆盖 toString（）以获取名称的格式化表示。

Unique String instances are the typical concrete parameter type, but nothing in JFreeChart enforces the unique constraint. One approach wold be to wrap your String in a class that implements Comparable and also enforces uniqueness. The class Value is an example that leverages the underlying Double implementation. Your implementation would require an additional attribute to distinguish one project form another, perhaps using the primary key of the source relation. You could override toString() to get a formatted representation of the name.

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