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The Apache Log4j Implementation
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.logging.log4j.core.appender.db.jpa.converter;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.ListIterator;
import javax.persistence.AttributeConverter;
import javax.persistence.Converter;
import org.apache.logging.log4j.core.util.Loader;
import org.apache.logging.log4j.util.Strings;
/**
* A JPA 2.1 attribute converter for {@link Throwable}s in {@link org.apache.logging.log4j.core.LogEvent}s. This
* converter is capable of converting both to and from {@link String}s.
*/
@Converter(autoApply = false)
public class ThrowableAttributeConverter implements AttributeConverter {
private static final int CAUSED_BY_STRING_LENGTH = 10;
private static final Field THROWABLE_CAUSE;
private static final Field THROWABLE_MESSAGE;
static {
try {
THROWABLE_CAUSE = Throwable.class.getDeclaredField("cause");
THROWABLE_CAUSE.setAccessible(true);
THROWABLE_MESSAGE = Throwable.class.getDeclaredField("detailMessage");
THROWABLE_MESSAGE.setAccessible(true);
} catch (final NoSuchFieldException e) {
throw new IllegalStateException("Something is wrong with java.lang.Throwable.", e);
}
}
@Override
public String convertToDatabaseColumn(final Throwable throwable) {
if (throwable == null) {
return null;
}
final StringBuilder builder = new StringBuilder();
this.convertThrowable(builder, throwable);
return builder.toString();
}
private void convertThrowable(final StringBuilder builder, final Throwable throwable) {
builder.append(throwable.toString()).append('\n');
for (final StackTraceElement element : throwable.getStackTrace()) {
builder.append("\tat ").append(element).append('\n');
}
if (throwable.getCause() != null) {
builder.append("Caused by ");
this.convertThrowable(builder, throwable.getCause());
}
}
@Override
public Throwable convertToEntityAttribute(final String s) {
if (Strings.isEmpty(s)) {
return null;
}
final List lines = Arrays.asList(s.split("(\n|\r\n)"));
return this.convertString(lines.listIterator(), false);
}
private Throwable convertString(final ListIterator lines, final boolean removeCausedBy) {
String firstLine = lines.next();
if (removeCausedBy) {
firstLine = firstLine.substring(CAUSED_BY_STRING_LENGTH);
}
final int colon = firstLine.indexOf(":");
String throwableClassName;
String message = null;
if (colon > 1) {
throwableClassName = firstLine.substring(0, colon);
if (firstLine.length() > colon + 1) {
message = firstLine.substring(colon + 1).trim();
}
} else {
throwableClassName = firstLine;
}
final List stackTrace = new ArrayList<>();
Throwable cause = null;
while (lines.hasNext()) {
final String line = lines.next();
if (line.startsWith("Caused by ")) {
lines.previous();
cause = convertString(lines, true);
break;
}
stackTrace.add(
StackTraceElementAttributeConverter.convertString(line.trim().substring(3).trim())
);
}
return this.getThrowable(throwableClassName, message, cause,
stackTrace.toArray(new StackTraceElement[stackTrace.size()]));
}
private Throwable getThrowable(final String throwableClassName, final String message, final Throwable cause,
final StackTraceElement[] stackTrace) {
try {
@SuppressWarnings("unchecked")
final Class throwableClass = (Class) Loader.loadClass(throwableClassName);
if (!Throwable.class.isAssignableFrom(throwableClass)) {
return null;
}
Throwable throwable;
if (message != null && cause != null) {
throwable = this.getThrowable(throwableClass, message, cause);
if (throwable == null) {
throwable = this.getThrowable(throwableClass, cause);
if (throwable == null) {
throwable = this.getThrowable(throwableClass, message);
if (throwable == null) {
throwable = this.getThrowable(throwableClass);
if (throwable != null) {
THROWABLE_MESSAGE.set(throwable, message);
THROWABLE_CAUSE.set(throwable, cause);
}
} else {
THROWABLE_CAUSE.set(throwable, cause);
}
} else {
THROWABLE_MESSAGE.set(throwable, message);
}
}
} else if (cause != null) {
throwable = this.getThrowable(throwableClass, cause);
if (throwable == null) {
throwable = this.getThrowable(throwableClass);
if (throwable != null) {
THROWABLE_CAUSE.set(throwable, cause);
}
}
} else if (message != null) {
throwable = this.getThrowable(throwableClass, message);
if (throwable == null) {
throwable = this.getThrowable(throwableClass);
if (throwable != null) {
THROWABLE_MESSAGE.set(throwable, cause);
}
}
} else {
throwable = this.getThrowable(throwableClass);
}
if (throwable == null) {
return null;
}
throwable.setStackTrace(stackTrace);
return throwable;
} catch (final Exception e) {
return null;
}
}
private Throwable getThrowable(final Class throwableClass, final String message, final Throwable cause) {
try {
@SuppressWarnings("unchecked")
final
Constructor[] constructors = (Constructor[]) throwableClass.getConstructors();
for (final Constructor constructor : constructors) {
final Class[] parameterTypes = constructor.getParameterTypes();
if (parameterTypes.length == 2) {
if (String.class == parameterTypes[0] && Throwable.class.isAssignableFrom(parameterTypes[1])) {
return constructor.newInstance(message, cause);
} else if (String.class == parameterTypes[1] &&
Throwable.class.isAssignableFrom(parameterTypes[0])) {
return constructor.newInstance(cause, message);
}
}
}
return null;
} catch (final Exception e) {
return null;
}
}
private Throwable getThrowable(final Class throwableClass, final Throwable cause) {
try {
@SuppressWarnings("unchecked")
final
Constructor[] constructors = (Constructor[]) throwableClass.getConstructors();
for (final Constructor constructor : constructors) {
final Class[] parameterTypes = constructor.getParameterTypes();
if (parameterTypes.length == 1 && Throwable.class.isAssignableFrom(parameterTypes[0])) {
return constructor.newInstance(cause);
}
}
return null;
} catch (final Exception e) {
return null;
}
}
private Throwable getThrowable(final Class throwableClass, final String message) {
try {
return throwableClass.getConstructor(String.class).newInstance(message);
} catch (final Exception e) {
return null;
}
}
private Throwable getThrowable(final Class throwableClass) {
try {
return throwableClass.newInstance();
} catch (final Exception e) {
return null;
}
}
}