org.crazyyak.dev.common.exceptions.ExceptionUtils Maven / Gradle / Ivy

Go to download
/*
 * Copyright 2012 Jacob D Parr
 *
 * 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 org.crazyyak.dev.common.exceptions;

import java.io.*;
import java.util.*;
import org.crazyyak.dev.common.ReflectUtils;
import org.crazyyak.dev.common.StringUtils;

import static java.lang.String.format;

public class ExceptionUtils {
  
  private ExceptionUtils() {
  }
  
  public static void assertIsFile(File file) throws NotAFileException, FileNotFoundException {
    assertPathExists(file);
    if (file.isFile() == false) {
      throw new NotAFileException(file);
    }
  }
  
  public static void assertIsDirectory(File file) throws NotADirectoryException, FileNotFoundException {
    assertPathExists(file);
    if (file.isDirectory() == false) {
      throw new NotADirectoryException(file);
    }
  }
  
  public static void assertPathExists(File file) throws FileNotFoundException {
    if (file.exists() == false) {
      String msg = format("The path \"%s\" does not exist.", file.getAbsolutePath());
      throw new FileNotFoundException(msg);
    }
  }

  public static void assertNotZeroLength(String value, String name) {
    if (value == null) {
      String msg = String.format("The value \"%s\" cannot be null.", name);
      throw new NullPointerException(msg);
    
    } else if (value.isEmpty()) {
      String msg = String.format("The value \"%s\" is an empty string.", name);
      throw new NullPointerException(msg);
    }
  }

  public static  T assertNotNull(T value, String name) {
    if (value == null) {
      String msg = String.format("The value \"%s\" cannot be null.", name);
      throw trimStackTrace(new NullPointerException(msg));
    }
    return value;
  }

  public static void assertPositive(long value, String name) {
    if (value <= 0) {
      String msg = String.format("The value \"%s\" cannot be less than zero.", name);
      throw trimStackTrace(new IllegalArgumentException(msg));
    }
  }

  public static void assertNegative(long value, String name) {
    if (value >= 0) {
      String msg = String.format("The value \"%s\" cannot be greater than zero.", name);
      throw trimStackTrace(new IllegalArgumentException(msg));
    }
  }

  private static  T trimStackTrace(T ex) {
    List elements = new ArrayList();
    Collections.addAll(elements, ex.getStackTrace());
    elements.remove(0);
    ex.setStackTrace(ReflectUtils.toArray(StackTraceElement.class, elements));
    return ex;
  }

  public static Throwable getRootCause(Throwable e) {
    Throwable cause = e.getCause();
    while (cause != null && cause != e) {
      e = cause;
      cause = e.getCause();
    }
    return e;
  }

  /**
   * Gets the message for an exception taking into consideration that
   * not all exceptions (ie NPE) will have a message in which case the
   * class's name will be used in lue of no message.
   */
  public static String getMessage(Throwable e) {
    String msg = e.getMessage();
    return StringUtils.isBlank(msg) ? e.getClass().getName() : msg;
  }

  /**
   * Gets the message for an exception's root exception taking into
   * consideration that not all exceptions (ie NPE) will have a message
   * in which case the class's name will be used in lue of no message.
   */
  public static String getRootMessage(Throwable e) {
    e = getRootCause(e);
    String msg = e.getMessage();
    return StringUtils.isBlank(msg) ? e.getClass().getName() : msg;
  }

  public static String getStackTrace(Throwable e) {
    StringWriter writer = new StringWriter();
    PrintWriter pw = new PrintWriter(writer);
    e.printStackTrace(pw);
    return writer.toString();
  }

  public static List getRootCauses(Throwable e) {

    Throwable last = e.getCause();

    List list = new ArrayList();
    list.add(e);

    while (last != e && last != null) {
      list.add(last);
      e = last;
      last = e.getCause();
    }

    return list;
  }
}