Examples with ContextAwareHelperFunction eu.esdihumboldt.cst.functions.groovy.helper.ContextAwareHelperFunction used on opensource projects

Example 1 with ContextAwareHelperFunction

use of eu.esdihumboldt.cst.functions.groovy.helper.ContextAwareHelperFunction in project hale by halestudio.

the class HelperFunctionsExtension method loadFunction.

/**
 * Load helper function via reflection from a method.
 *
 * @param callMethod the method (probably) defining a helper function
 * @param helperClass the class defining the method
 * @return the loaded helper function or <code>null</code>
 */
@Nullable
protected HelperFunctionWrapper loadFunction(final Method callMethod, Class<?> helperClass) {
    int modifiers = callMethod.getModifiers();
    // a candidate -> check parameters
    Class<?>[] params = callMethod.getParameterTypes();
    if (params != null && params.length <= 2) {
        // has maximum two parameters
        // last parameter may be context parameter
        final boolean hasContextParam = params.length >= 1 && params[params.length - 1].equals(HelperContext.class);
        // check if there is an actual main parameter
        final boolean hasMainParam = (hasContextParam && params.length == 2) || (!hasContextParam && params.length == 1);
        final boolean isStatic = Modifier.isStatic(modifiers);
        // Get the specification from field
        String specFieldOrMethodName = callMethod.getName() + SPEC_END;
        Object fieldV = null;
        try {
            Field field = helperClass.getField(specFieldOrMethodName);
            int fieldModifiers = field.getModifiers();
            if (Modifier.isStatic(fieldModifiers) && Modifier.isFinal(fieldModifiers)) {
                fieldV = field.get(null);
            }
        } catch (Exception e) {
        // do nothing
        }
        final Object fieldValue = fieldV;
        // Get spec from method
        Method meth = null;
        boolean isSpecStatic = false;
        try {
            meth = helperClass.getMethod(specFieldOrMethodName, new Class[] { String.class });
            int specModifier = meth.getModifiers();
            isSpecStatic = Modifier.isStatic(specModifier);
        } catch (Exception e) {
        // do nothing
        }
        final Method specMethod = meth;
        final boolean isSpecMethodStatic = isSpecStatic;
        HelperFunction<Object> function = new ContextAwareHelperFunction<Object>() {

            @Override
            public Object call(Object arg, HelperContext context) throws Exception {
                Object helper = null;
                if (!isStatic) {
                    helper = helperClass.newInstance();
                }
                if (hasMainParam) {
                    if (hasContextParam) {
                        return callMethod.invoke(helper, arg, context);
                    } else {
                        return callMethod.invoke(helper, arg);
                    }
                } else {
                    if (hasContextParam) {
                        return callMethod.invoke(helper, context);
                    } else {
                        return callMethod.invoke(helper);
                    }
                }
            }

            @Override
            public Specification getSpec(String name) throws Exception {
                if (fieldValue != null && fieldValue instanceof Specification) {
                    return ((Specification) fieldValue);
                } else if (specMethod != null) {
                    if (isSpecMethodStatic) {
                        return (Specification) specMethod.invoke(null, name);
                    } else {
                        Object helper = helperClass.newInstance();
                        return (Specification) specMethod.invoke(helper, name);
                    }
                }
                return null;
            }
        };
        // method name
        String name = callMethod.getName().substring(1);
        return new HelperFunctionWrapper(function, name);
    }
    return null;
}