com.nabla.wapp.server.general.Util.java Source code

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Here is the source code for com.nabla.wapp.server.general.Util.java

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/**
* Copyright 2012 nabla
*
* 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.
*
*/
package com.nabla.wapp.server.general;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.Writer;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public abstract class Util {

    private static final Log log = LogFactory.getLog(Util.class);

    public static Class getFirstGenericDeclaration(Class clazz) {
        return getGenericDeclaration(clazz, 0);
    }

    public static Class getGenericDeclaration(Class clazz, int position) {
        Assert.argumentNotNull(clazz);
        Assert.state(position >= 0);

        Type classGenType = clazz.getGenericSuperclass();

        // special CGLIB workaround -- get generic superclass of superclass
        if (clazz.getName().contains("$$EnhancerByCGLIB$$")) {
            classGenType = clazz.getSuperclass().getGenericSuperclass();
        }

        if (classGenType instanceof ParameterizedType) {
            Type[] params = ((ParameterizedType) classGenType).getActualTypeArguments();

            if ((params != null) && (params.length > position)) {
                return (Class) params[position];
            }
        }

        for (Type ifGenType : clazz.getGenericInterfaces()) {
            if (ifGenType instanceof ParameterizedType) {
                Type[] params = ((ParameterizedType) ifGenType).getActualTypeArguments();

                if ((params != null) && (params.length > position)) {
                    return (Class) params[position];
                }
            }
        }

        if (log.isErrorEnabled())
            log.error("fail to find class of generic parameter " + position + " of class '" + clazz.getSimpleName()
                    + "'");

        return null;
    }

    public static String formatInternalErrorDescription(final Throwable x) {
        if (x == null)
            return null;
        final Writer buffer = new StringWriter();
        final PrintWriter pw = new PrintWriter(buffer);
        x.printStackTrace(pw);
        return buffer.toString();
    }

    public static String formatInternalErrorDescription(final String cause) {
        return Thread.currentThread().getStackTrace()[2].toString() + ": " + cause;
    }

    public static Calendar dateToCalendar(final Date dt) {
        final Calendar ret = new GregorianCalendar();
        ret.setTime(dt);
        return ret;
    }

    public static java.sql.Date calendarToSqlDate(final Calendar dt) {
        return new java.sql.Date(dt.getTime().getTime());
    }
}