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However it is important to understand when you must implement a implement a Factory Bean.
A Factory Bean is required if the plugin you have implemented takes a constructor which is not a String or an object which Spring can convert into from a String. The IdP String infrastructure has a reasonably wide set of functions to convert from Strings to other types:
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And assume you want to program configure from an XML segment like this
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<plugin:Parent numerator="22" denominator="7" name="pi"/> |
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final String id = StringSupport.trimOrNull(child.getAttributeNS(null, "name")); builder.addPropertyValue("id", id); final String num = StringSupport.trimOrNull(child.getAttributeNS(null, "numerator")); final String denom = StringSupport.trimOrNull(child.getAttributeNS(null, "denominator")); final Rational rational = new Rational(); rational.setDenominator(Integer.decode(denom)); rational.setNumerator(Integer.decode(num)); builder.addPropertyValue("rational", rational); |
This will not work if the deployer wants to use property replacement
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<plugin:Parent numerator="%{idp.numerator}" denominator="7" name="pi"/> |
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If the object being built inside the parser is a simple bean which can configured with Strings and auto converted types, then it can be created by a secondary builder. In the example above
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final BeanDefinitionBuilder rationalDefn = BeanDefinitionBuilder.genericBeanDefinition(Rational.class); rationalDefn.addPropertyValue("denominator", denom); rationalDefn.addPropertyValue("numerator", num); builder.addPropertyValue("rational", rationalDefn.getBeanDefinition()); |
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In our example, the FactoryBean might look like this:
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public class ParentFactoryBean extends AbstractComponentAwareFactoryBean<Parent> {
private int denominator;
private int numerator;
public void setDenominator(int what) {
denominator = what;
}
public void setNumerator(int what) {
numerator = what;
}
@Override public Class<?> getObjectType() {
return Parent.class;
}
@Override protected Parent doCreateInstance() throws Exception {
final Rational rational = new Rational();
rational.setNumerator(numerator);
rational.setDenominator(denominator);
Parent parent = new Parent();
parent.setRational(rational);
return parent;
}
} |
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