Generalize DI usage

This commit ensures that:

* an `InstanceFactory` is created in the Log4j `Provider`,
* the same factory is injected as parameters to all
  the components of the chain `Log4jContextFactory`, `ContextSelector`,
  `LoggerContext` (child), `Configuration` (grand-child).
* `DI.createInstanceFactory` is called only when strictly necessary.

Author: ppkarwasz

log4j-1.2-api/src/main/java/org/apache/log4j/Category.java

@@ -237,7 +237,7 @@ public void assertLog(final boolean assertion, final String msg) {
      */
     public void callAppenders(final LoggingEvent event) {
         if (LogManager.isLog4jCorePresent()) {
-            CategoryUtil.log(logger, new LogEventWrapper(event));
+            CategoryUtil.log(logger, LogEventWrapper.adapt(event));
             return;
         }
         int writes = 0;

log4j-1.2-api/src/main/java/org/apache/log4j/PropertyConfigurator.java

@@ -47,6 +47,7 @@
 import org.apache.log4j.spi.RendererSupport;
 import org.apache.log4j.spi.ThrowableRenderer;
 import org.apache.log4j.spi.ThrowableRendererSupport;
+import org.apache.logging.log4j.core.LoggerContext;
 import org.apache.logging.log4j.core.config.Configuration;
 import org.apache.logging.log4j.core.net.UrlConnectionFactory;
 import org.apache.logging.log4j.util.StackLocatorUtil;
@@ -307,7 +308,7 @@ public void doConfigure(final Properties properties, final LoggerRepository logg
     Configuration doConfigure(
             final Properties properties, final LoggerRepository loggerRepository, final ClassLoader classLoader) {
         final PropertiesConfiguration configuration =
-                new PropertiesConfiguration(LogManager.getContext(classLoader), properties);
+                new PropertiesConfiguration((LoggerContext) LogManager.getContext(classLoader), properties);
         configuration.doConfigure();
 
         repository = loggerRepository;

log4j-1.2-api/src/main/java/org/apache/log4j/bridge/AppenderAdapter.java

@@ -85,7 +85,7 @@ protected Adapter(
 
         @Override
         public void append(final LogEvent event) {
-            appender.doAppend(new LogEventAdapter(event));
+            appender.doAppend(LogEventAdapter.adapt(event));
         }
 
         @Override

log4j-1.2-api/src/main/java/org/apache/log4j/bridge/LogEventAdapter.java

@@ -41,6 +41,10 @@ public class LogEventAdapter extends LoggingEvent {
 
     private final LogEvent event;
 
+    public static LoggingEvent adapt(final LogEvent event) {
+        return event instanceof final LogEventWrapper wrapper ? wrapper.getLoggingEvent() : new LogEventAdapter(event);
+    }
+
     public LogEventAdapter(final LogEvent event) {
         this.event = event;
     }
@@ -213,4 +217,13 @@ public Set getPropertyKeySet() {
     public Map getProperties() {
         return event.getContextData().toMap();
     }
+
+    public LoggingEvent toImmutable() {
+        final LogEvent immutable = event.toImmutable();
+        return event == immutable ? this : adapt(immutable);
+    }
+
+    LogEvent getLogEvent() {
+        return event;
+    }
 }

log4j-1.2-api/src/main/java/org/apache/log4j/bridge/LogEventWrapper.java

@@ -49,6 +49,10 @@ public class LogEventWrapper implements LogEvent {
     private final MutableThreadContextStack contextStack;
     private Thread thread;
 
+    public static LogEvent adapt(final LoggingEvent event) {
+        return event instanceof final LogEventAdapter adapter ? adapter.getLogEvent() : new LogEventWrapper(event);
+    }
+
     public LogEventWrapper(final LoggingEvent event) {
         this.event = event;
         this.contextData = new ContextDataMap(event.getProperties());
@@ -182,6 +186,10 @@ public long getNanoTime() {
         return 0;
     }
 
+    LoggingEvent getLoggingEvent() {
+        return event;
+    }
+
     private static class ContextDataMap extends HashMap<String, String> implements ReadOnlyStringMap {
 
         ContextDataMap(final Map<String, String> map) {

log4j-1.2-api/src/main/java/org/apache/log4j/config/Log4j1Configuration.java

@@ -16,13 +16,17 @@
  */
 package org.apache.log4j.config;
 
+import java.util.Optional;
 import org.apache.log4j.Level;
 import org.apache.log4j.builders.BuilderManager;
 import org.apache.logging.log4j.core.LoggerContext;
 import org.apache.logging.log4j.core.config.AbstractConfiguration;
 import org.apache.logging.log4j.core.config.Configuration;
 import org.apache.logging.log4j.core.config.ConfigurationSource;
 import org.apache.logging.log4j.core.config.Reconfigurable;
+import org.apache.logging.log4j.plugins.di.ConfigurableInstanceFactory;
+import org.apache.logging.log4j.plugins.di.DI;
+import org.apache.logging.log4j.util.PropertiesUtil;
 
 /**
  * Base Configuration for Log4j 1.
@@ -49,7 +53,15 @@ public Log4j1Configuration(
             final LoggerContext loggerContext,
             final ConfigurationSource configurationSource,
             final int monitorIntervalSeconds) {
-        super(loggerContext, configurationSource);
+        super(
+                loggerContext,
+                configurationSource,
+                Optional.ofNullable(loggerContext)
+                        .map(LoggerContext::getEnvironment)
+                        .orElseGet(PropertiesUtil::getProperties),
+                Optional.ofNullable(loggerContext)
+                        .map(ctx -> (ConfigurableInstanceFactory) ctx.getInstanceFactory())
+                        .orElseGet(DI::createInitializedFactory));
         initializeWatchers(this, configurationSource, monitorIntervalSeconds);
         manager = instanceFactory.getInstance(BuilderManager.class);
     }

log4j-1.2-api/src/main/java/org/apache/log4j/config/Log4j1ConfigurationFactory.java

@@ -19,9 +19,9 @@
 import java.io.IOException;
 import java.io.InputStream;
 import org.apache.logging.log4j.core.LoggerContext;
+import org.apache.logging.log4j.core.config.AbstractConfigurationFactory;
 import org.apache.logging.log4j.core.config.Configuration;
 import org.apache.logging.log4j.core.config.ConfigurationException;
-import org.apache.logging.log4j.core.config.ConfigurationFactory;
 import org.apache.logging.log4j.core.config.ConfigurationSource;
 import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilder;
 import org.apache.logging.log4j.core.config.builder.impl.BuiltConfiguration;
@@ -35,7 +35,7 @@
 //
 // Best Value?
 // @Order(50)
-public class Log4j1ConfigurationFactory extends ConfigurationFactory {
+public class Log4j1ConfigurationFactory extends AbstractConfigurationFactory {
 
     private static final String[] SUFFIXES = {".properties"};
 
@@ -51,7 +51,7 @@ public Configuration getConfiguration(final LoggerContext loggerContext, final C
     }
 
     @Override
-    protected String[] getSupportedTypes() {
+    public String[] getSupportedTypes() {
         return SUFFIXES;
     }
 }

log4j-1.2-api/src/main/java/org/apache/log4j/config/PropertiesConfiguration.java

@@ -81,12 +81,14 @@ public class PropertiesConfiguration extends Log4j1Configuration {
      * Constructs a new instance.
      *
      * @param loggerContext The LoggerContext.
-     * @param source The ConfigurationSource.
+     * @param configurationSource The ConfigurationSource.
      * @param monitorIntervalSeconds The monitoring interval in seconds.
      */
     public PropertiesConfiguration(
-            final LoggerContext loggerContext, final ConfigurationSource source, final int monitorIntervalSeconds) {
-        super(loggerContext, source, monitorIntervalSeconds);
+            final LoggerContext loggerContext,
+            final ConfigurationSource configurationSource,
+            final int monitorIntervalSeconds) {
+        this(loggerContext, configurationSource, monitorIntervalSeconds, null);
     }
 
     /**
@@ -96,18 +98,16 @@ public PropertiesConfiguration(
      * @param properties The ConfigurationSource, may be null.
      */
     public PropertiesConfiguration(final LoggerContext loggerContext, final Properties properties) {
-        super(loggerContext, ConfigurationSource.NULL_SOURCE, 0);
-        this.properties = properties;
+        this(loggerContext, ConfigurationSource.NULL_SOURCE, 0, properties);
     }
 
-    /**
-     * Constructs a new instance.
-     *
-     * @param loggerContext The LoggerContext.
-     * @param properties The ConfigurationSource.
-     */
-    public PropertiesConfiguration(org.apache.logging.log4j.spi.LoggerContext loggerContext, Properties properties) {
-        this((LoggerContext) loggerContext, properties);
+    private PropertiesConfiguration(
+            final LoggerContext loggerContext,
+            final ConfigurationSource configurationSource,
+            final int monitorIntervalSeconds,
+            final Properties properties) {
+        super(loggerContext, configurationSource, monitorIntervalSeconds);
+        this.properties = properties;
     }
 
     @Override
@@ -149,7 +149,7 @@ public Configuration reconfigure() {
 
     /**
      * Reads a configuration from a file. <b>The existing configuration is not cleared nor reset.</b> If you require a
-     * different behavior, then call {@link LogManager#resetConfiguration resetConfiguration} method before calling
+     * different behavior, then call {@link LogManager#resetConfiguration()}  resetConfiguration} method before calling
      * <code>doConfigure</code>.
      * <p>
      * The configuration file consists of statements in the format <code>key=value</code>. The syntax of different
@@ -373,7 +373,7 @@ private void parseLoggers(final Properties props) {
                 LoggerConfig loggerConfig = getLogger(loggerName);
                 if (loggerConfig == null) {
                     final boolean additivity = getAdditivityForLogger(props, loggerName);
-                    loggerConfig = new LoggerConfig(loggerName, org.apache.logging.log4j.Level.ERROR, additivity);
+                    loggerConfig = new LoggerConfig(loggerName, Level.ERROR, additivity, this);
                     addLogger(loggerName, loggerConfig);
                 }
                 parseLogger(props, loggerConfig, key, loggerName, value);

log4j-1.2-api/src/main/java/org/apache/log4j/config/PropertiesConfigurationFactory.java

@@ -17,8 +17,8 @@
 package org.apache.log4j.config;
 
 import org.apache.logging.log4j.core.LoggerContext;
+import org.apache.logging.log4j.core.config.AbstractConfigurationFactory;
 import org.apache.logging.log4j.core.config.Configuration;
-import org.apache.logging.log4j.core.config.ConfigurationFactory;
 import org.apache.logging.log4j.core.config.ConfigurationSource;
 import org.apache.logging.log4j.core.config.Order;
 import org.apache.logging.log4j.plugins.Namespace;
@@ -28,10 +28,10 @@
 /**
  * Configures Log4j from a log4j 1 format properties file.
  */
-@Namespace(ConfigurationFactory.NAMESPACE)
+@Namespace(AbstractConfigurationFactory.NAMESPACE)
 @Plugin("Log4j1PropertiesConfigurationFactory")
 @Order(2)
-public class PropertiesConfigurationFactory extends ConfigurationFactory {
+public class PropertiesConfigurationFactory extends AbstractConfigurationFactory {
 
     static final String FILE_EXTENSION = ".properties";
 
@@ -46,9 +46,9 @@ public class PropertiesConfigurationFactory extends ConfigurationFactory {
     protected static final String DEFAULT_PREFIX = "log4j";
 
     @Override
-    protected String[] getSupportedTypes() {
+    public String[] getSupportedTypes() {
         if (!PropertiesUtil.getProperties()
-                .getBooleanProperty(ConfigurationFactory.LOG4J1_EXPERIMENTAL, Boolean.FALSE)) {
+                .getBooleanProperty(AbstractConfigurationFactory.LOG4J1_EXPERIMENTAL, Boolean.FALSE)) {
             return null;
         }
         return new String[] {FILE_EXTENSION};
@@ -61,17 +61,17 @@ public Configuration getConfiguration(final LoggerContext loggerContext, final C
     }
 
     @Override
-    protected String getTestPrefix() {
+    public String getTestPrefix() {
         return TEST_PREFIX;
     }
 
     @Override
-    protected String getDefaultPrefix() {
+    public String getDefaultPrefix() {
         return DEFAULT_PREFIX;
     }
 
     @Override
-    protected String getVersion() {
+    public String getVersion() {
         return LOG4J1_VERSION;
     }
 }

log4j-1.2-api/src/main/java/org/apache/log4j/xml/XmlConfiguration.java

@@ -112,8 +112,10 @@ public class XmlConfiguration extends Log4j1Configuration {
     private final Properties props = null;
 
     public XmlConfiguration(
-            final LoggerContext loggerContext, final ConfigurationSource source, final int monitorIntervalSeconds) {
-        super(loggerContext, source, monitorIntervalSeconds);
+            final LoggerContext loggerContext,
+            final ConfigurationSource configurationSource,
+            final int monitorIntervalSeconds) {
+        super(loggerContext, configurationSource, monitorIntervalSeconds);
         appenderMap = new HashMap<>();
     }
 
@@ -563,7 +565,7 @@ private void parseCategory(final Element loggerElement) {
         final boolean additivity = OptionConverter.toBoolean(subst(loggerElement.getAttribute(ADDITIVITY_ATTR)), true);
         LoggerConfig loggerConfig = getLogger(catName);
         if (loggerConfig == null) {
-            loggerConfig = new LoggerConfig(catName, org.apache.logging.log4j.Level.ERROR, additivity);
+            loggerConfig = new LoggerConfig(catName, org.apache.logging.log4j.Level.ERROR, additivity, this);
             addLogger(catName, loggerConfig);
         } else {
             loggerConfig.setAdditive(additivity);