THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
Logging involves the automatic recording of progress as an application runs. Tapestry
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Logging of Tapestry Components and Pages
Tapestry makes extensive use of SLF4J to log details about the creation and operation of your page and component classes.
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The default configuration for logging uses Log4J as the logging toolkit, though this can be changed.
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The logger name for a page or component matches the fully qualified class name. You can configure this in log4j.properties:
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log4j.category.org.apache.tapestry5.integration.app1.pages.MerryChristmas=trace |
Injecting Loggers
You may mark a field of type Logger with the @Inject annotation. The proper Logger for your page or component will be injected.
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public class MyPage
{
@Inject
private Logger logger;
. . .
void onSuccessFromForm()
{
logger.info("Changes saved successfully");
}
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Tapestry performs a transformation on your classes as they are loaded, and sometimes you want to gain insight into what it has done. Tapestry uses a secondary logger, consisting of the class name with the prefix "tapestry.transformer.", to log (at debug level) the results of transforming the class.
Example:
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[DEBUG] Index // class version 49.0 (49)
// access flags 0x11
public final class org/apache/tapestry5/integration/app1/pages/Index$Invocation_containingPageDidLoad_123fd9264de3fa20 extends org/apache/tapestry5/internal/plastic/AbstractMethodInvocation implements org/apache/tapestry5/plastic/MethodInvocation {
// access flags 0x1
public <init>(Ljava/lang/Object;Lorg/apache/tapestry5/plastic/InstanceContext;Lorg/apache/tapestry5/internal/plastic/MethodInvocationBundle;)V
ALOAD 0
ALOAD 1
ALOAD 2
ALOAD 3
INVOKESPECIAL org/apache/tapestry5/internal/plastic/AbstractMethodInvocation.<init> (Ljava/lang/Object;Lorg/apache/tapestry5/plastic/InstanceContext;Lorg/apache/tapestry5/internal/plastic/MethodInvocationBundle;)V
RETURN
MAXSTACK = 0
MAXLOCALS = 0
// access flags 0x1
public setReturnValue(Ljava/lang/Object;)Lorg/apache/tapestry5/plastic/MethodInvocation;
NEW java/lang/IllegalArgumentException
DUP
LDC "Method public void containingPageDidLoad() of class org.apache.tapestry5.integration.app1.pages.Index is void, setting a return value is not allowed."
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Note that events that are not handled by a component will bubble up to the component's container; further logging for the same event will occur using the logger associated with the container. The page containing the initial component is the final step when logging.
Examples:
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[DEBUG] ActionLink Dispatch event: ComponentEvent[action from (self)]
[DEBUG] ActionDemo Dispatch event: ComponentEvent[action from actionlink]
[DEBUG] ActionDemo Invoking: org.apache.tapestry5.integration.app1.pages.nested.ActionDemo.onAction(java.lang.Long) (at ActionDemo.java:28)
[DEBUG] ActionDemo Dispatch event: ComponentEvent[passivate from (self)]
[DEBUG] ActionDemo Invoking: org.apache.tapestry5.integration.app1.pages.nested.ActionDemo.onPassivate() (at ActionDemo.java:38)
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Most logging is at the trace level, except for a debug-level entry at the end identifying the number of commands and the elapsed time.
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. . .
[TRACE] ActionDemo Executing: Text[Apache Software Foundation]
[TRACE] ActionDemo Executing: End
[TRACE] ActionDemo Executing: Text[
]
[TRACE] ActionDemo Executing: End
[TRACE] ActionDemo Executing: Text[
]
[TRACE] ActionDemo Executing: Start[http://www.w3.org/1999/xhtml div]
[TRACE] ActionDemo Executing: org.apache.tapestry5.internal.services.PageElementFactoryImpl$1@587e3a30
[TRACE] ActionDemo Executing: End
[TRACE] ActionDemo Executing: Text[
]
[TRACE] ActionDemo Executing: End
[TRACE] ActionDemo Executing: End
[TRACE] ActionDemo Executing: End
[TRACE] ActionDemo Executing: AfterRenderTemplate[nested/ActionDemo:border]
[TRACE] ActionDemo Executing: AfterRender[nested/ActionDemo:border]
[TRACE] ActionDemo Executing: CleanupRender[nested/ActionDemo:border]
[TRACE] ActionDemo Executing: org.apache.tapestry5.internal.structure.ComponentPageElementImpl$1@7efc0795
[TRACE] ActionDemo Executing: DTD[name=html; publicId=-//W3C//DTD XHTML 1.0 Strict//EN; systemId=http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd]
[TRACE] ActionDemo Executing: AfterRenderTemplate[nested/ActionDemo]
[TRACE] ActionDemo Executing: AfterRender[nested/ActionDemo]
[TRACE] ActionDemo Executing: CleanupRender[nested/ActionDemo]
[TRACE] ActionDemo Executing: org.apache.tapestry5.internal.structure.ComponentPageElementImpl$1@7efc0795
[DEBUG] ActionDemo Executed 276 rendering commands (max queue depth: 141) in 0.025 seconds
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