Source Code for Apache Log4j Core Implementation

Apache Log4j Core Implementation provides the functional components of the logging system. Users are free to create their own plugins and include them in the logging configuration. Apache Log4j Core is a required module to use Apache Log4j.

Bytecode (Java 8) for Apache Log4j Core Implementation is provided in a separate JAR file like log4j-core-2.14.1.jar.

Source Code files for Apache Log4j API are provided in both binary packge like apache-log4j-2.14.1-bin.zip and source package like apache-log4j-2.14.1-src.zip. You can download them at Apache Log4j Website.

You can also browse Source Code files for Apache Log4j Core Implementation 2.14.1 below.

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org/apache/logging/log4j/core/impl/ThrowableProxy.java

/*
 * 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.impl;

import java.io.Serializable;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.Stack;

import org.apache.logging.log4j.core.pattern.PlainTextRenderer;
import org.apache.logging.log4j.core.pattern.TextRenderer;
import org.apache.logging.log4j.util.StackLocatorUtil;
import org.apache.logging.log4j.util.Strings;

/**
 * Wraps a Throwable to add packaging information about each stack trace element.
 *
 * <p>
 * A proxy is used to represent a throwable that may not exist in a different class loader or JVM. When an application
 * deserializes a ThrowableProxy, the throwable may not be set, but the throwable's information is preserved in other
 * fields of the proxy like the message and stack trace.
 * </p>
 *
 * <p>
 * TODO: Move this class to org.apache.logging.log4j.core because it is used from LogEvent.
 * </p>
 * <p>
 * TODO: Deserialize: Try to rebuild Throwable if the target exception is in this class loader?
 * </p>
 */
public class ThrowableProxy implements Serializable {

    private static final char EOL = '\n';

    private static final String EOL_STR = String.valueOf(EOL);

    private static final long serialVersionUID = -2752771578252251910L;

    private final ThrowableProxy causeProxy;

    private int commonElementCount;

    private final ExtendedStackTraceElement[] extendedStackTrace;

    private final String localizedMessage;

    private final String message;

    private final String name;

    private final ThrowableProxy[] suppressedProxies;

    private final transient Throwable throwable;

    /**
     * For JSON and XML IO via Jackson.
     */
    @SuppressWarnings("unused")
    private ThrowableProxy() {
        this.throwable = null;
        this.name = null;
        this.extendedStackTrace = null;
        this.causeProxy = null;
        this.message = null;
        this.localizedMessage = null;
        this.suppressedProxies = ThrowableProxyHelper.EMPTY_THROWABLE_PROXY_ARRAY;
    }

    /**
     * Constructs the wrapper for the Throwable that includes packaging data.
     *
     * @param throwable The Throwable to wrap, must not be null.
     */
    public ThrowableProxy(final Throwable throwable) {
        this(throwable, null);
    }

    /**
     * Constructs the wrapper for the Throwable that includes packaging data.
     *
     * @param throwable The Throwable to wrap, must not be null.
     * @param visited   The set of visited suppressed exceptions.
     */
    ThrowableProxy(final Throwable throwable, final Set<Throwable> visited) {
        this.throwable = throwable;
        this.name = throwable.getClass().getName();
        this.message = throwable.getMessage();
        this.localizedMessage = throwable.getLocalizedMessage();
        final Map<String, ThrowableProxyHelper.CacheEntry> map = new HashMap<>();
        final Stack<Class<?>> stack = StackLocatorUtil.getCurrentStackTrace();
        this.extendedStackTrace = ThrowableProxyHelper.toExtendedStackTrace(this, stack, map, null, throwable.getStackTrace());
        final Throwable throwableCause = throwable.getCause();
        final Set<Throwable> causeVisited = new HashSet<>(1);
        this.causeProxy = throwableCause == null ? null : new ThrowableProxy(throwable, stack, map, throwableCause,
            visited, causeVisited);
        this.suppressedProxies = ThrowableProxyHelper.toSuppressedProxies(throwable, visited);
    }

    /**
     * Constructs the wrapper for a Throwable that is referenced as the cause by another Throwable.
     *
     * @param parent            The Throwable referencing this Throwable.
     * @param stack             The Class stack.
     * @param map               The cache containing the packaging data.
     * @param cause             The Throwable to wrap.
     * @param suppressedVisited TODO
     * @param causeVisited      TODO
     */
    private ThrowableProxy(final Throwable parent, final Stack<Class<?>> stack,
                           final Map<String, ThrowableProxyHelper.CacheEntry> map,
                           final Throwable cause, final Set<Throwable> suppressedVisited,
                           final Set<Throwable> causeVisited) {
        causeVisited.add(cause);
        this.throwable = cause;
        this.name = cause.getClass().getName();
        this.message = this.throwable.getMessage();
        this.localizedMessage = this.throwable.getLocalizedMessage();
        this.extendedStackTrace = ThrowableProxyHelper.toExtendedStackTrace(this, stack, map, parent.getStackTrace(), cause.getStackTrace());
        final Throwable causeCause = cause.getCause();
        this.causeProxy = causeCause == null || causeVisited.contains(causeCause) ? null : new ThrowableProxy(parent,
            stack, map, causeCause, suppressedVisited, causeVisited);
        this.suppressedProxies = ThrowableProxyHelper.toSuppressedProxies(cause, suppressedVisited);
    }

    @Override
    public boolean equals(final Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (this.getClass() != obj.getClass()) {
            return false;
        }
        final ThrowableProxy other = (ThrowableProxy) obj;
        if (!Objects.equals(this.causeProxy, other.causeProxy)) {
            return false;
        }
        if (this.commonElementCount != other.commonElementCount) {
            return false;
        }
        if (!Objects.equals(this.name, other.name)) {
            return false;
        }
        if (!Arrays.equals(this.extendedStackTrace, other.extendedStackTrace)) {
            return false;
        }
        if (!Arrays.equals(this.suppressedProxies, other.suppressedProxies)) {
            return false;
        }
        return true;
    }

    /**
     * Formats the specified Throwable.
     *  @param sb    StringBuilder to contain the formatted Throwable.
     * @param cause The Throwable to format.
     * @param suffix
     */
    public void formatWrapper(final StringBuilder sb, final ThrowableProxy cause, final String suffix) {
        this.formatWrapper(sb, cause, null, PlainTextRenderer.getInstance(), suffix);
    }

    /**
     * Formats the specified Throwable.
     *  @param sb             StringBuilder to contain the formatted Throwable.
     * @param cause          The Throwable to format.
     * @param ignorePackages The List of packages to be suppressed from the trace.
     * @param suffix
     */
    @SuppressWarnings("ThrowableResultOfMethodCallIgnored")
    public void formatWrapper(final StringBuilder sb, final ThrowableProxy cause, final List<String> ignorePackages, final String suffix) {
        this.formatWrapper(sb, cause, ignorePackages, PlainTextRenderer.getInstance(), suffix);
    }

    /**
     * Formats the specified Throwable.
     * @param sb StringBuilder to contain the formatted Throwable.
     * @param cause The Throwable to format.
     * @param ignorePackages The List of packages to be suppressed from the stack trace.
     * @param textRenderer The text renderer.
     * @param suffix Append this to the end of each stack frame.
     */
    @SuppressWarnings("ThrowableResultOfMethodCallIgnored")
    public void formatWrapper(final StringBuilder sb, final ThrowableProxy cause, final List<String> ignorePackages,
            final TextRenderer textRenderer, final String suffix) {
        formatWrapper(sb, cause, ignorePackages, textRenderer, suffix, EOL_STR);
    }

    /**
     * Formats the specified Throwable.
     * @param sb StringBuilder to contain the formatted Throwable.
     * @param cause The Throwable to format.
     * @param ignorePackages The List of packages to be suppressed from the stack trace.
     * @param textRenderer The text renderer.
     * @param suffix Append this to the end of each stack frame.
     * @param lineSeparator The end-of-line separator.
     */
    @SuppressWarnings("ThrowableResultOfMethodCallIgnored")
    public void formatWrapper(final StringBuilder sb, final ThrowableProxy cause, final List<String> ignorePackages,
                              final TextRenderer textRenderer, final String suffix, final String lineSeparator) {
        ThrowableProxyRenderer.formatWrapper(sb,  cause, ignorePackages, textRenderer, suffix, lineSeparator);
    }

    public ThrowableProxy getCauseProxy() {
        return this.causeProxy;
    }

    /**
     * Formats the Throwable that is the cause of this Throwable.
     *
     * @return The formatted Throwable that caused this Throwable.
     * @param suffix
     */
    public String getCauseStackTraceAsString(final String suffix) {
        return this.getCauseStackTraceAsString(null, PlainTextRenderer.getInstance(), suffix, EOL_STR);
    }

    /**
     * Formats the Throwable that is the cause of this Throwable.
     *
     * @param packages The List of packages to be suppressed from the trace.
     * @param suffix Append this to the end of each stack frame.
     * @return The formatted Throwable that caused this Throwable.
     */
    public String getCauseStackTraceAsString(final List<String> packages, final String suffix) {
        return getCauseStackTraceAsString(packages, PlainTextRenderer.getInstance(), suffix, EOL_STR);
    }

    /**
     * Formats the Throwable that is the cause of this Throwable.
     *
     * @param ignorePackages The List of packages to be suppressed from the trace.
     * @param textRenderer The text renderer.
     * @param suffix Append this to the end of each stack frame.
     * @return The formatted Throwable that caused this Throwable.
     */
    public String getCauseStackTraceAsString(final List<String> ignorePackages, final TextRenderer textRenderer, final String suffix) {
        return getCauseStackTraceAsString(ignorePackages, textRenderer, suffix, EOL_STR);
    }

    /**
     * Formats the Throwable that is the cause of this Throwable.
     *
     * @param ignorePackages The List of packages to be suppressed from the stack trace.
     * @param textRenderer The text renderer.
     * @param suffix Append this to the end of each stack frame.
     * @param lineSeparator The end-of-line separator.
     * @return The formatted Throwable that caused this Throwable.
     */
    public String getCauseStackTraceAsString(final List<String> ignorePackages, final TextRenderer textRenderer, final String suffix, final String lineSeparator) {
        final StringBuilder sb = new StringBuilder();
        ThrowableProxyRenderer.formatCauseStackTrace(this, sb, ignorePackages, textRenderer, suffix, lineSeparator);
        return sb.toString();
    }

    /**
     * Returns the number of elements that are being omitted because they are common with the parent Throwable's stack
     * trace.
     *
     * @return The number of elements omitted from the stack trace.
     */
    public int getCommonElementCount() {
        return this.commonElementCount;
    }

    /**
     * Set the value of {@link ThrowableProxy#commonElementCount}.
     *
     * Method is package-private, to be used internally for initialization.
     *
     * @param value New value of commonElementCount.
     */
    void setCommonElementCount(final int value) {
        this.commonElementCount = value;
    }

    /**
     * Gets the stack trace including packaging information.
     *
     * @return The stack trace including packaging information.
     */
    public ExtendedStackTraceElement[] getExtendedStackTrace() {
        return this.extendedStackTrace;
    }

    /**
     * Formats the stack trace including packaging information.
     *
     * @return The formatted stack trace including packaging information.
     */
    public String getExtendedStackTraceAsString() {
        return this.getExtendedStackTraceAsString(null, PlainTextRenderer.getInstance(), Strings.EMPTY, EOL_STR);
    }

    /**
     * Formats the stack trace including packaging information.
     *
     * @return The formatted stack trace including packaging information.
     * @param suffix Append this to the end of each stack frame.
     */
    public String getExtendedStackTraceAsString(final String suffix) {
        return this.getExtendedStackTraceAsString(null, PlainTextRenderer.getInstance(), suffix, EOL_STR);
    }

    /**
     * Formats the stack trace including packaging information.
     *
     * @param ignorePackages List of packages to be ignored in the trace.
     * @param suffix Append this to the end of each stack frame.
     * @return The formatted stack trace including packaging information.
     */
    public String getExtendedStackTraceAsString(final List<String> ignorePackages, final String suffix) {
        return getExtendedStackTraceAsString(ignorePackages, PlainTextRenderer.getInstance(), suffix, EOL_STR);
    }

    /**
     * Formats the stack trace including packaging information.
     *
     * @param ignorePackages List of packages to be ignored in the trace.
     * @param textRenderer The message renderer.
     * @param suffix Append this to the end of each stack frame.
     * @return The formatted stack trace including packaging information.
     */
    public String getExtendedStackTraceAsString(final List<String> ignorePackages, final TextRenderer textRenderer, final String suffix) {
        return getExtendedStackTraceAsString(ignorePackages, textRenderer, suffix, EOL_STR);
    }

    /**
     * Formats the stack trace including packaging information.
     *
     * @param ignorePackages List of packages to be ignored in the trace.
     * @param textRenderer The message renderer.
     * @param suffix Append this to the end of each stack frame.
     * @param lineSeparator The end-of-line separator.
     * @return The formatted stack trace including packaging information.
     */
    public String getExtendedStackTraceAsString(final List<String> ignorePackages, final TextRenderer textRenderer, final String suffix, final String lineSeparator) {
        final StringBuilder sb = new StringBuilder(1024);
        formatExtendedStackTraceTo(sb, ignorePackages, textRenderer, suffix, lineSeparator);
        return sb.toString();
    }

    /**
     * Formats the stack trace including packaging information.
     *
     * @param sb Destination.
     * @param ignorePackages List of packages to be ignored in the trace.
     * @param textRenderer The message renderer.
     * @param suffix Append this to the end of each stack frame.
     * @param lineSeparator The end-of-line separator.
     */
    public void formatExtendedStackTraceTo(final StringBuilder sb, final List<String> ignorePackages, final TextRenderer textRenderer, final String suffix, final String lineSeparator) {
        ThrowableProxyRenderer.formatExtendedStackTraceTo(this, sb, ignorePackages, textRenderer, suffix, lineSeparator);
    }

    public String getLocalizedMessage() {
        return this.localizedMessage;
    }

    public String getMessage() {
        return this.message;
    }

    /**
     * Return the FQCN of the Throwable.
     *
     * @return The FQCN of the Throwable.
     */
    public String getName() {
        return this.name;
    }

    public StackTraceElement[] getStackTrace() {
        return this.throwable == null ? null : this.throwable.getStackTrace();
    }

    /**
     * Gets proxies for suppressed exceptions.
     *
     * @return proxies for suppressed exceptions.
     */
    public ThrowableProxy[] getSuppressedProxies() {
        return this.suppressedProxies;
    }

    /**
     * Formats the suppressed Throwables.
     *
     * @return The formatted suppressed Throwables.
     * @param suffix
     */
    public String getSuppressedStackTrace(final String suffix) {
        final ThrowableProxy[] suppressed = this.getSuppressedProxies();
        if (suppressed == null || suppressed.length == 0) {
            return Strings.EMPTY;
        }
        final StringBuilder sb = new StringBuilder("Suppressed Stack Trace Elements:").append(EOL);
        for (final ThrowableProxy proxy : suppressed) {
            sb.append(proxy.getExtendedStackTraceAsString(suffix));
        }
        return sb.toString();
    }

    /**
     * The throwable or null if this object is deserialized from XML or JSON.
     *
     * @return The throwable or null if this object is deserialized from XML or JSON.
     */
    public Throwable getThrowable() {
        return this.throwable;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + (this.causeProxy == null ? 0 : this.causeProxy.hashCode());
        result = prime * result + this.commonElementCount;
        result = prime * result + (this.extendedStackTrace == null ? 0 : Arrays.hashCode(this.extendedStackTrace));
        result = prime * result + (this.suppressedProxies == null ? 0 : Arrays.hashCode(this.suppressedProxies));
        result = prime * result + (this.name == null ? 0 : this.name.hashCode());
        return result;
    }

    @Override
    public String toString() {
        final String msg = this.message;
        return msg != null ? this.name + ": " + msg : this.name;
    }
}

org/apache/logging/log4j/core/impl/ThrowableProxy.java

 

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File name: log4j-core-2.14.1-sources.jar
File size: 1281358 bytes
Release date: 2021-03-06
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