org.apache.logging.log4j.message

Class ParameterizedMessage

java.lang.Object

org.apache.logging.log4j.message.ParameterizedMessage

All Implemented Interfaces:

Serializable, Message, StringBuilderFormattable

public class ParameterizedMessage
extends Object
implements Message, StringBuilderFormattable

Handles messages that consist of a format string containing '{}' to represent each replaceable token, and the parameters.

This class was originally written for Lilith by Joern Huxhorn where it is licensed under the LGPL. It has been relicensed here with his permission providing that this attribution remain.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	ERROR_MSG_SEPARATOR Separator for error messages.
static String	ERROR_PREFIX Prefix for errors.
static String	ERROR_SEPARATOR Separator for errors.
static String	ERROR_SUFFIX Suffix for errors.
static String	RECURSION_PREFIX Prefix for recursion.
static String	RECURSION_SUFFIX Suffix for recursion.

Constructor Summary

Constructors

Constructor and Description
ParameterizedMessage(String messagePattern, Object... arguments) Constructs a ParameterizedMessage which contains the arguments converted to String as well as an optional Throwable.
ParameterizedMessage(String messagePattern, Object arg) Constructor with a pattern and a single parameter.
ParameterizedMessage(String messagePattern, Object[] arguments, Throwable throwable) Creates a parameterized message.
ParameterizedMessage(String messagePattern, Object arg0, Object arg1) Constructor with a pattern and two parameters.
ParameterizedMessage(String messagePattern, String[] arguments, Throwable throwable) Deprecated. Use constructor ParameterizedMessage(String, Object[], Throwable) instead

Method Summary

Modifier and Type	Method and Description
static int	countArgumentPlaceholders(String messagePattern) Counts the number of unescaped placeholders in the given messagePattern.
static String	deepToString(Object o) This method performs a deep toString of the given Object.
boolean	equals(Object o)
static String	format(String messagePattern, Object[] arguments) Replace placeholders in the given messagePattern with arguments.
void	formatTo(StringBuilder buffer) Writes a text representation of this object into the specified StringBuilder, ideally without allocating temporary objects.
String	getFormat() Returns the message pattern.
String	getFormattedMessage() Returns the formatted message.
Object[]	getParameters() Returns the message parameters.
Throwable	getThrowable() Returns the Throwable that was given as the last argument, if any.
int	hashCode()
static String	identityToString(Object obj) This method returns the same as if Object.toString() would not have been overridden in obj.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

RECURSION_PREFIX

public static final String RECURSION_PREFIX

Prefix for recursion.

See Also:

Constant Field Values

RECURSION_SUFFIX

public static final String RECURSION_SUFFIX

Suffix for recursion.

See Also:

Constant Field Values

ERROR_PREFIX

public static final String ERROR_PREFIX

Prefix for errors.

See Also:

Constant Field Values

ERROR_SEPARATOR

public static final String ERROR_SEPARATOR

Separator for errors.

See Also:

Constant Field Values

ERROR_MSG_SEPARATOR

public static final String ERROR_MSG_SEPARATOR

Separator for error messages.

See Also:

Constant Field Values

ERROR_SUFFIX

public static final String ERROR_SUFFIX

Suffix for errors.

See Also:

Constant Field Values

Constructor Detail

ParameterizedMessage

@Deprecated
public ParameterizedMessage(String messagePattern,
                                        String[] arguments,
                                        Throwable throwable)

Deprecated. Use constructor ParameterizedMessage(String, Object[], Throwable) instead

Creates a parameterized message.

Parameters:

messagePattern - The message "format" string. This will be a String containing "{}" placeholders where parameters should be substituted.

arguments - The arguments for substitution.

throwable - A Throwable.

ParameterizedMessage

public ParameterizedMessage(String messagePattern,
                            Object[] arguments,
                            Throwable throwable)

Creates a parameterized message.

Parameters:

messagePattern - The message "format" string. This will be a String containing "{}" placeholders where parameters should be substituted.

arguments - The arguments for substitution.

throwable - A Throwable.

ParameterizedMessage

public ParameterizedMessage(String messagePattern,
                            Object... arguments)

Constructs a ParameterizedMessage which contains the arguments converted to String as well as an optional Throwable.

If the last argument is a Throwable and is NOT used up by a placeholder in the message pattern it is returned in getThrowable() and won't be contained in the created String[]. If it is used up getThrowable() will return null even if the last argument was a Throwable!

Parameters:

messagePattern - the message pattern that to be checked for placeholders.

arguments - the argument array to be converted.

ParameterizedMessage

public ParameterizedMessage(String messagePattern,
                            Object arg)

Constructor with a pattern and a single parameter.

Parameters:

messagePattern - The message pattern.

arg - The parameter.

ParameterizedMessage

public ParameterizedMessage(String messagePattern,
                            Object arg0,
                            Object arg1)

Constructor with a pattern and two parameters.

Parameters:

messagePattern - The message pattern.

arg0 - The first parameter.

arg1 - The second parameter.

Method Detail

getFormat

public String getFormat()

Returns the message pattern.

Specified by:

getFormat in interface Message

Returns:

the message pattern.

getParameters

public Object[] getParameters()

Returns the message parameters.

Specified by:

getParameters in interface Message

Returns:

the message parameters.

getThrowable

public Throwable getThrowable()

Returns the Throwable that was given as the last argument, if any. It will not survive serialization. The Throwable exists as part of the message primarily so that it can be extracted from the end of the list of parameters and then be added to the LogEvent. As such, the Throwable in the event should not be used once the LogEvent has been constructed.

Specified by:

getThrowable in interface Message

Returns:

the Throwable, if any.

getFormattedMessage

public String getFormattedMessage()

Returns the formatted message.

Specified by:

getFormattedMessage in interface Message

Returns:

the formatted message.

formatTo

public void formatTo(StringBuilder buffer)

Description copied from interface: StringBuilderFormattable

Writes a text representation of this object into the specified StringBuilder, ideally without allocating temporary objects.

Specified by:

formatTo in interface StringBuilderFormattable

Parameters:

buffer - the StringBuilder to write into

format

public static String format(String messagePattern,
                            Object[] arguments)

Replace placeholders in the given messagePattern with arguments.

Parameters:

messagePattern - the message pattern containing placeholders.

arguments - the arguments to be used to replace placeholders.

Returns:

the formatted message.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

countArgumentPlaceholders

public static int countArgumentPlaceholders(String messagePattern)

Counts the number of unescaped placeholders in the given messagePattern.

Parameters:

messagePattern - the message pattern to be analyzed.

Returns:

the number of unescaped placeholders.

deepToString

public static String deepToString(Object o)

This method performs a deep toString of the given Object. Primitive arrays are converted using their respective Arrays.toString methods while special handling is implemented for "container types", i.e. Object[], Map and Collection because those could contain themselves.

It should be noted that neither AbstractMap.toString() nor AbstractCollection.toString() implement such a behavior. They only check if the container is directly contained in itself, but not if a contained container contains the original one. Because of that, Arrays.toString(Object[]) isn't safe either. Confusing? Just read the last paragraph again and check the respective toString() implementation.

This means, in effect, that logging would produce a usable output even if an ordinary System.out.println(o) would produce a relatively hard-to-debug StackOverflowError.

Parameters:

o - The object.

Returns:

The String representation.

identityToString

public static String identityToString(Object obj)

This method returns the same as if Object.toString() would not have been overridden in obj.

Note that this isn't 100% secure as collisions can always happen with hash codes.

Copied from Object.hashCode():

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the Java™ programming language.)

Parameters:

obj - the Object that is to be converted into an identity string.

Returns:

the identity string as also defined in Object.toString()

toString

public String toString()

Overrides:

toString in class Object