Invoke method by method name using reflection - Java Reflection

Java examples for Reflection:Method Name

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Description

Invoke method by method name using reflection

Demo Code

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.util.Locale;
import static java.lang.System.out;
import static java.lang.System.err;

public class Deet<T> {
    private boolean testDeet(Locale l) {
        // getISO3Language() may throw a MissingResourceException
        out.format("Locale = %s, ISO Language Code = %s%n",
                l.getDisplayName(), l.getISO3Language());
        return true;
    }//w w  w  .  j  av  a 2s . co  m

    private int testFoo(Locale l) {
        return 0;
    }

    private boolean testBar() {
        return true;
    }

    public static void main(String... args) {
        if (args.length != 4) {
            err.format("Usage: java Deet <classname> <langauge> <country> <variant>%n");
            return;
        }

        try {
            Class<?> c = Class.forName(args[0]);
            Object t = c.newInstance();

            Method[] allMethods = c.getDeclaredMethods();
            for (Method m : allMethods) {
                String mname = m.getName();
                if (!mname.startsWith("test")
                        || (m.getGenericReturnType() != boolean.class)) {
                    continue;
                }
                Type[] pType = m.getGenericParameterTypes();
                if ((pType.length != 1)
                        || Locale.class.isAssignableFrom(pType[0]
                                .getClass())) {
                    continue;
                }

                out.format("invoking %s()%n", mname);
                try {
                    m.setAccessible(true);
                    Object o = m.invoke(t, new Locale(args[1], args[2],
                            args[3]));
                    out.format("%s() returned %b%n", mname, (Boolean) o);

                    // Handle any exceptions thrown by method to be invoked.
                } catch (InvocationTargetException x) {
                    Throwable cause = x.getCause();
                    err.format("invocation of %s failed: %s%n", mname,
                            cause.getMessage());
                }
            }

            // production code should handle these exceptions more gracefully
        } catch (ClassNotFoundException x) {
            x.printStackTrace();
        } catch (InstantiationException x) {
            x.printStackTrace();
        } catch (IllegalAccessException x) {
            x.printStackTrace();
        }
    }
}

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 *
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 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle or the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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