com.qwazr.utils.ExceptionUtils.java Source code

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Here is the source code for com.qwazr.utils.ExceptionUtils.java

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/**
 * Copyright 2014-2016 Emmanuel Keller / QWAZR
 * <p/>
 * 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
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * 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.qwazr.utils;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;

import com.qwazr.utils.http.HttpResponseEntityException;
import org.slf4j.Logger;

public class ExceptionUtils extends org.apache.commons.lang3.exception.ExceptionUtils {

    public final static String getLocation(StackTraceElement[] stackTrace, String prefix) {
        for (StackTraceElement element : stackTrace)
            if (element.getClassName().startsWith(prefix))
                return element.toString();
        return null;
    }

    public final static String getFirstLocation(StackTraceElement[] stackTrace) {
        for (StackTraceElement element : stackTrace) {
            String ele = element.toString();
            if (ele != null && ele.length() > 0)
                return ele;
        }
        return null;
    }

    public final static String getFullStackTrace(StackTraceElement[] stackTrace) {
        StringWriter sw = null;
        PrintWriter pw = null;
        try {
            sw = new StringWriter();
            pw = new PrintWriter(sw);
            for (StackTraceElement element : stackTrace)
                pw.println(element);
            return sw.toString();
        } finally {
            IOUtils.close(pw, sw);
        }
    }

    @SuppressWarnings("unchecked")
    public static <T extends Exception> T throwException(Exception exception, Class<T> exceptionClass) throws T {
        if (exception == null)
            return null;
        if (exceptionClass.isInstance(exception))
            throw (T) exception;
        try {
            return exceptionClass.getConstructor(Exception.class).newInstance(exception);
        } catch (InstantiationException e) {
            throw new RuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        } catch (IllegalArgumentException e) {
            throw new RuntimeException(e);
        } catch (InvocationTargetException e) {
            throw new RuntimeException(e);
        } catch (NoSuchMethodException e) {
            throw new RuntimeException(e);
        } catch (SecurityException e) {
            throw new RuntimeException(e);
        }
    }

    public static Exception getCauseIfException(Exception e) {
        if (e == null)
            return null;
        Throwable cause = e.getCause();
        return cause instanceof Exception ? (Exception) cause : e;
    }

    public static List<String> getStackTraces(Throwable throwable) {
        StackTraceElement[] stElements = throwable.getStackTrace();
        if (stElements == null)
            return null;
        List<String> stList = new ArrayList<String>(stElements.length);
        for (StackTraceElement stElement : stElements)
            stList.add(stElement.toString());
        return stList;
    }

    public static class ExceptionHolder<T extends Exception> {

        private final Logger logger;
        private volatile T holdException;

        public ExceptionHolder(Logger logger) {
            this.logger = logger;
            this.holdException = null;
        }

        /**
         * Hold the new exception. If there was a previous exception, a log warn
         * is emited
         *
         * @param newException the new exception to old
         */
        public void switchAndWarn(T newException) {
            if (holdException != null)
                logger.warn(holdException.getMessage(), holdException);
            holdException = newException;
        }

        /**
         * @return the previously hold exception
         */
        public T getException() {
            return holdException;
        }

    }
}