Type Coercion"
From Documentation
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EL expressions will coerce the type automatically. Here is the summary of the coercion rules. | EL expressions will coerce the type automatically. Here is the summary of the coercion rules. | ||
| + | |||
| + | <blockquote> | ||
| + | ---- | ||
| + | '''Note:''' The coercion is also applied to function arguments. For example, <code>{c:doSomething(null)}</code> will cause <code>doSomething("")</code> being called if it expects a String object. | ||
| + | </blockquote> | ||
{| border='1px' | width="100%" | {| border='1px' | width="100%" | ||
Latest revision as of 11:04, 27 May 2011
EL expressions will coerce the type automatically. Here is the summary of the coercion rules.
Note: The coercion is also applied to function arguments. For example,
{c:doSomething(null)}will causedoSomething("")being called if it expects a String object.
| Boolean | Character | Number | String | |
|---|---|---|---|---|
| Boolean | obj[1] | ERROR | ERROR | obj.toString() |
| Character | ERROR | obj | (short)obj | obj.toString() |
| Number | obj | ERROR | (char)obj | obj.toString() |
| String (not empty) | Boolean.valueOf(obj) | obj.charAt(0) | Number[2].valueOf(x) | obj |
| String (empty) | false | (char)0 | 0 | "" (obj) |
| null | false | (char)0 | 0 | "" |
| Other | ERROR | ERROR | ERROR | obj.toString() |
- The handling of an empty string and null is the same
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