Application: gvSIG desktop

package org.gvsig.expressionevaluator.impl.function.obj;

import java.lang.reflect.Method;

import org.apache.commons.lang3.Range;

import org.gvsig.expressionevaluator.Function;

import org.gvsig.expressionevaluator.Interpreter;

import org.gvsig.expressionevaluator.spi.AbstractFunction;

public class InvokeMethodFunction extends AbstractFunction {

    private final Object obj;

    private final String methodname;

    public InvokeMethodFunction(Object obj, String methodName) {

        super(

            Function.GROUP_OTHER, "invokeMethod", Range.between(0, Integer.MAX_VALUE)

        );

        this.obj = obj;

        this.methodname = methodName;

    }

    public InvokeMethodFunction() {

        super(

            Function.GROUP_OTHER, "invokeMethod", Range.between(2, Integer.MAX_VALUE)

        );

        this.obj = null;

        this.methodname = null;

    }

    @Override

    public Object call(Interpreter interpreter, Object[] args) throws Exception {

        Object theObj = this.obj;

        String theMethodName = this.methodname;

        int firstArg = 0;

        if( theObj==null && theMethodName==null ) {

            theObj = getObject(args, 0);

            theMethodName = getStr(args, 1);

            firstArg = 2;

        }

        if( theMethodName == null ) {

            throw new NullPointerException("A method name was expected to invoke and a null was received");

        }

        if( theObj==null ) {

            throw new NullPointerException("An object pointer was expected to invoke method "+theMethodName+" and a null was received");

        }

        Class[] parameterTypes = new Class[args.length-firstArg];

        Object[] parameters = new Object[args.length-firstArg];

        for (int i = 0; i < parameters.length; i++) {

            Object parameter = args[i+firstArg];

            parameters[i] = parameter;

            if( parameter==null ) {

                parameterTypes[i] = null;

            } else {

                parameterTypes[i] = parameter.getClass();

            }

        }

        Class<?> theClass = theObj.getClass();

        Method method = theClass.getMethod(theMethodName, parameterTypes);

        Object value = method.invoke(theObj, parameters);

        return value;

    }

}