Java Reflection Constructor Get getConstructorFromSignature(Class clazz, String cstrSig)

Description

Get constructor from signature

License

Apache License

Parameter

Parameter	Description
clazz	a parameter
cstrSig	a parameter

Exception

Parameter	Description
ClassNotFoundException	an exception
NoSuchMethodException	an exception
SecurityException	an exception

Declaration

public static Constructor<?> getConstructorFromSignature(Class<?> clazz, String cstrSig)
        throws ClassNotFoundException, SecurityException, NoSuchMethodException 

Method Source Code

//package com.java2s;
/*// w ww. j a  v a2  s  .  c o  m
 * Copyright (C) 2012-2018 Gregory Hedlund <https://www.phon.ca>
 * Copyright (C) 2012 Jason Gedge <http://www.gedge.ca>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
    
 *    http://www.apache.org/licenses/LICENSE-2.0
    
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.lang.reflect.Constructor;

public class Main {
    /**
     * Get constructor from signature
     *
     * @param clazz
     * @param cstrSig
     * @return
     * @throws ClassNotFoundException
     * @throws NoSuchMethodException
     * @throws SecurityException
     */
    public static Constructor<?> getConstructorFromSignature(Class<?> clazz, String cstrSig)
            throws ClassNotFoundException, SecurityException, NoSuchMethodException {
        Constructor<?> retVal = null;

        final String methodName = getMethodNameFromSignature(cstrSig);
        if (!methodName.equals("<init>")) {
            throw new IllegalArgumentException("Not a constructor signature");
        }

        final Class<?>[] paramTypes = getParametersFromSignature(cstrSig);

        retVal = clazz.getConstructor(paramTypes);

        return retVal;
    }

    /**
     * Get method name from signature
     *
     * @param sig
     * @return
     */
    public static String getMethodNameFromSignature(String sig) {
        return sig.substring(0, sig.indexOf('('));
    }

    /**
     * Get paramters from signature
     *
     * @param sig
     * @return
     * @throws ClassNotFoundException
     *
     */
    public static Class<?>[] getParametersFromSignature(String sig) throws ClassNotFoundException {
        Class<?> retVal[] = new Class<?>[0];
        final String paramString = sig.substring(sig.indexOf('(') + 1, sig.lastIndexOf(')')).trim();
        if (paramString.length() > 0) {
            final String[] paramClassNames = paramString.split(",");
            retVal = new Class<?>[paramClassNames.length];
            for (int i = 0; i < paramClassNames.length; i++) {
                final String paramClassName = paramClassNames[i];

                if (paramClassName.equals("int")) {
                    retVal[i] = int.class;
                } else if (paramClassName.equals("double")) {
                    retVal[i] = double.class;
                } else if (paramClassName.equals("float")) {
                    retVal[i] = float.class;
                } else {
                    retVal[i] = Class.forName(paramClassName.trim());
                }
            }
        }
        return retVal;
    }
}

Related

1. getConstructor(String typeString)
2. getConstructorAccessor(Class enumClass, Class[] additionalParameterTypes)
3. getConstructorCalls(Class aClass)
4. getConstructorDescriptor(final Constructor c)
5. getConstructorForArguments( java.lang.reflect.Constructor[] constructors, Object... arguments)
6. getConstructorIfAvailable(Class clazz, Class... paramTypes)
7. getConstructorLabel(java.lang.reflect.Constructor con)
8. getConstructorOptional(Class cls, Class... argsTypes)
9. getConstructorOrFail(Class clazz, Class... argTypes)