public interface Transformer { /** * Transforms the input object (leaving it unchanged) into some output object. * * @param input the object to be transformed, should be left unchanged * @return a transformed object * @throws ClassCastException (runtime) if the input is the wrong class * @throws IllegalArgumentException (runtime) if the input is invalid * @throws FunctorException (runtime) if the transform cannot be completed */ public Object transform(Object input);
}
接口的作用是 Transforms the input object (leaving it unchanged) into some output object.
/** * Transforms the input to result by invoking a method on the input. * * @param input the input object to transform * @return the transformed result, null if null input */ public Object transform(Object input) { if (input == null) { return null; } try { Class cls = input.getClass(); Method method = cls.getMethod(iMethodName, iParamTypes); return method.invoke(input, iArgs); } catch (NoSuchMethodException ex) { throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" + input.getClass() + "' does not exist"); } catch (IllegalAccessException ex) { throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" + input.getClass() + "' cannot be accessed"); } catch (InvocationTargetException ex) { throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" + input.getClass() + "' threw an exception", ex); } }
/** * Constructor that performs no validation. * Use <code>getInstance</code> if you want that. * * @param constantToReturn the constant to return each time */ public ConstantTransformer(Object constantToReturn) { super(); iConstant = constantToReturn; }
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/** * Transforms the input by ignoring it and returning the stored constant instead. * * @param input the input object which is ignored * @return the stored constant */ public Object transform(Object input) { return iConstant; }
/** * Constructor that performs no validation. * Use <code>getInstance</code> if you want that. * * @param transformers the transformers to chain, not copied, no nulls */ public ChainedTransformer(Transformer[] transformers) { super(); iTransformers = transformers; }
/** * Transforms the input to result via each decorated transformer * * @param object the input object passed to the first transformer * @return the transformed result */ public Object transform(Object object) { for (int i = 0; i < iTransformers.length; i++) { object = iTransformers[i].transform(object); } return object; }
/** * Override to transform the value when using <code>setValue</code>. * * @param value the value to transform * @return the transformed value * @since Commons Collections 3.1 */ protected Object checkSetValue(Object value) { return valueTransformer.transform(value); }
// Check to make sure that types have not evolved incompatibly
AnnotationType annotationType = null; try { annotationType = AnnotationType.getInstance(type); } catch(IllegalArgumentException e) { // Class is no longer an annotation type; all bets are off return; }
for (Map.Entry<String, Object> memberValue : memberValues.entrySet()) { String name = memberValue.getKey(); Class<?> memberType = memberTypes.get(name); if (memberType != null) { // i.e. member still exists Object value = memberValue.getValue(); if (!(memberType.isInstance(value) || value instanceof ExceptionProxy)) { // 此处触发一些列的Transformer memberValue.setValue( new AnnotationTypeMismatchExceptionProxy( value.getClass() + "[" + value + "]").setMember( annotationType.members().get(name))); } } } }
readObject()函数中对memberValues的每一项调用了setValue()函数
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public Object setValue(Object value) { value = parent.checkSetValue(value); return entry.setValue(value); }
