Class ReflectionToStringBuilder
Object.toString() methods using reflection.
This class uses reflection to determine the fields to append. Because these fields are usually private, the class
uses AccessibleObject.setAccessible(java.lang.reflect.AccessibleObject[], boolean) to
change the visibility of the fields. This will fail under a security manager, unless the appropriate permissions are
set up correctly.
Using reflection to access (private) fields circumvents any synchronization protection guarding access to these fields. If a toString method cannot safely read a field, you should exclude it from the toString method, or use synchronization consistent with the class' lock management around the invocation of the method. Take special care to exclude non-thread-safe collection classes, because these classes may throw ConcurrentModificationException if modified while the toString method is executing.
A typical invocation for this method would look like:
public String toString() {
return ReflectionToStringBuilder.toString(this);
}
You can also use the builder to debug 3rd party objects:
System.out.println("An object: " + ReflectionToStringBuilder.toString(anObject));
A subclass can control field output by overriding the methods:
For example, this method does not include the password field in the returned String:
public String toString() {
return (new ReflectionToStringBuilder(this) {
protected boolean accept(Field f) {
return super.accept(f) && !f.getName().equals("password");
}
}).toString();
}
Alternatively the ToStringExclude annotation can be used to exclude fields from being incorporated in the
result.
It is also possible to use the ToStringSummary annotation to output the summary information instead of the
detailed information of a field.
The exact format of the toString is determined by the ToStringStyle passed into the constructor.
Note: the default ToStringStyle will only do a "shallow" formatting, i.e. composed objects are not
further traversed. To get "deep" formatting, use an instance of RecursiveToStringStyle.
- Since:
- 2.0
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Field Summary
Fields -
Constructor Summary
ConstructorsConstructorDescriptionReflectionToStringBuilder(Object object) Constructs a new instance.ReflectionToStringBuilder(Object object, ToStringStyle style) Constructs a new instance.ReflectionToStringBuilder(Object object, ToStringStyle style, StringBuffer buffer) Constructs a new instance.ReflectionToStringBuilder(T object, ToStringStyle style, StringBuffer buffer, Class<? super T> reflectUpToClass, boolean outputTransients, boolean outputStatics) Constructs a new instance.ReflectionToStringBuilder(T object, ToStringStyle style, StringBuffer buffer, Class<? super T> reflectUpToClass, boolean outputTransients, boolean outputStatics, boolean excludeNullValues) Constructs a new instance. -
Method Summary
Modifier and TypeMethodDescriptionprotected booleanReturns whether or not to append the givenField.protected voidappendFieldsIn(Class<?> clazz) Appends the fields and values defined by the given object of the given Class.String[]Gets the excludeFieldNames.String[]Gets the includeFieldNamesClass<?>Gets the last super class to stop appending fields for.protected ObjectCallsjava.lang.reflect.Field.get(Object).booleanGets whether or not to append static fields.booleanGets whether or not to append transient fields.booleanGets whether or not to append fields whose values are null.reflectionAppendArray(Object array) Appends to thetoStringanObjectarray.voidsetAppendStatics(boolean appendStatics) Sets whether or not to append static fields.voidsetAppendTransients(boolean appendTransients) Sets whether or not to append transient fields.setExcludeFieldNames(String... excludeFieldNamesParam) Sets the field names to exclude.voidsetExcludeNullValues(boolean excludeNullValues) Sets whether or not to append fields whose values are null.setIncludeFieldNames(String... includeFieldNamesParam) Sets the field names to include.voidsetUpToClass(Class<?> clazz) Sets the last super class to stop appending fields for.toString()Gets the String built by this builder.static StringBuilds atoStringvalue using the defaultToStringStylethrough reflection.static StringtoString(Object object, ToStringStyle style) Builds atoStringvalue through reflection.static StringtoString(Object object, ToStringStyle style, boolean outputTransients) Builds atoStringvalue through reflection.static StringtoString(Object object, ToStringStyle style, boolean outputTransients, boolean outputStatics) Builds atoStringvalue through reflection.static <T> StringtoString(T object, ToStringStyle style, boolean outputTransients, boolean outputStatics, boolean excludeNullValues, Class<? super T> reflectUpToClass) Builds atoStringvalue through reflection.static <T> StringtoString(T object, ToStringStyle style, boolean outputTransients, boolean outputStatics, Class<? super T> reflectUpToClass) Builds atoStringvalue through reflection.static StringtoStringExclude(Object object, String... excludeFieldNames) Builds a String for a toString method excluding the given field names.static StringtoStringExclude(Object object, Collection<String> excludeFieldNames) Builds a String for a toString method excluding the given field names.static StringtoStringInclude(Object object, String... includeFieldNames) Builds a String for a toString method including the given field names.static StringtoStringInclude(Object object, Collection<String> includeFieldNames) Builds a String for a toString method including the given field names.Methods inherited from class org.apache.commons.lang3.builder.ToStringBuilder
append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, append, appendAsObjectToString, appendSuper, appendToString, build, getDefaultStyle, getObject, getStringBuffer, getStyle, reflectionToString, reflectionToString, reflectionToString, reflectionToString, setDefaultStyle
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Field Details
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excludeFieldNames
Which field names to exclude from output. Intended for fields like"password".- Since:
- 3.0 this is protected instead of private
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includeFieldNames
Field names that will be included in the output. All fields are included by default.- Since:
- 3.13.0
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Constructor Details
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ReflectionToStringBuilder
Constructs a new instance.This constructor outputs using the default style set with
setDefaultStyle.- Parameters:
object- the Object to build atoStringfor, must not benull
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ReflectionToStringBuilder
Constructs a new instance.If the style is
null, the default style is used.- Parameters:
object- the Object to build atoStringfor, must not benullstyle- the style of thetoStringto create, may benull
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ReflectionToStringBuilder
Constructs a new instance.If the style is
null, the default style is used.If the buffer is
null, a new one is created.- Parameters:
object- the Object to build atoStringforstyle- the style of thetoStringto create, may benullbuffer- theStringBufferto populate, may benull
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ReflectionToStringBuilder
public ReflectionToStringBuilder(T object, ToStringStyle style, StringBuffer buffer, Class<? super T> reflectUpToClass, boolean outputTransients, boolean outputStatics) Constructs a new instance.- Type Parameters:
T- the type of the object- Parameters:
object- the Object to build atoStringforstyle- the style of thetoStringto create, may benullbuffer- theStringBufferto populate, may benullreflectUpToClass- the superclass to reflect up to (inclusive), may benulloutputTransients- whether to include transient fieldsoutputStatics- whether to include static fields- Since:
- 2.1
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ReflectionToStringBuilder
public ReflectionToStringBuilder(T object, ToStringStyle style, StringBuffer buffer, Class<? super T> reflectUpToClass, boolean outputTransients, boolean outputStatics, boolean excludeNullValues) Constructs a new instance.- Type Parameters:
T- the type of the object- Parameters:
object- the Object to build atoStringforstyle- the style of thetoStringto create, may benullbuffer- theStringBufferto populate, may benullreflectUpToClass- the superclass to reflect up to (inclusive), may benulloutputTransients- whether to include transient fieldsoutputStatics- whether to include static fieldsexcludeNullValues- whether to exclude fields who value is null- Since:
- 3.6
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Method Details
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toString
Builds atoStringvalue using the defaultToStringStylethrough reflection.It uses
AccessibleObject.setAccessibleto gain access to private fields. This means that it will throw a security exception if run under a security manager, if the permissions are not set up correctly. It is also not as efficient as testing explicitly.Transient members will be not be included, as they are likely derived. Static fields will not be included. Superclass fields will be appended.
- Parameters:
object- the Object to be output- Returns:
- the String result
- Throws:
IllegalArgumentException- if the Object isnull- See Also:
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toString
Builds atoStringvalue through reflection.It uses
AccessibleObject.setAccessibleto gain access to private fields. This means that it will throw a security exception if run under a security manager, if the permissions are not set up correctly. It is also not as efficient as testing explicitly.Transient members will be not be included, as they are likely derived. Static fields will not be included. Superclass fields will be appended.
If the style is
null, the defaultToStringStyleis used.- Parameters:
object- the Object to be outputstyle- the style of thetoStringto create, may benull- Returns:
- the String result
- Throws:
IllegalArgumentException- if the Object orToStringStyleisnull- See Also:
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toString
Builds atoStringvalue through reflection.It uses
AccessibleObject.setAccessibleto gain access to private fields. This means that it will throw a security exception if run under a security manager, if the permissions are not set up correctly. It is also not as efficient as testing explicitly.If the
outputTransientsistrue, transient members will be output, otherwise they are ignored, as they are likely derived fields, and not part of the value of the Object.Static fields will not be included. Superclass fields will be appended.
If the style is
null, the defaultToStringStyleis used.- Parameters:
object- the Object to be outputstyle- the style of thetoStringto create, may benulloutputTransients- whether to include transient fields- Returns:
- the String result
- Throws:
IllegalArgumentException- if the Object isnull- See Also:
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toString
public static String toString(Object object, ToStringStyle style, boolean outputTransients, boolean outputStatics) Builds atoStringvalue through reflection.It uses
AccessibleObject.setAccessibleto gain access to private fields. This means that it will throw a security exception if run under a security manager, if the permissions are not set up correctly. It is also not as efficient as testing explicitly.If the
outputTransientsistrue, transient fields will be output, otherwise they are ignored, as they are likely derived fields, and not part of the value of the Object.If the
outputStaticsistrue, static fields will be output, otherwise they are ignored.Static fields will not be included. Superclass fields will be appended.
If the style is
null, the defaultToStringStyleis used.- Parameters:
object- the Object to be outputstyle- the style of thetoStringto create, may benulloutputTransients- whether to include transient fieldsoutputStatics- whether to include static fields- Returns:
- the String result
- Throws:
IllegalArgumentException- if the Object isnull- Since:
- 2.1
- See Also:
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toString
public static <T> String toString(T object, ToStringStyle style, boolean outputTransients, boolean outputStatics, boolean excludeNullValues, Class<? super T> reflectUpToClass) Builds atoStringvalue through reflection.It uses
AccessibleObject.setAccessibleto gain access to private fields. This means that it will throw a security exception if run under a security manager, if the permissions are not set up correctly. It is also not as efficient as testing explicitly.If the
outputTransientsistrue, transient fields will be output, otherwise they are ignored, as they are likely derived fields, and not part of the value of the Object.If the
outputStaticsistrue, static fields will be output, otherwise they are ignored.Superclass fields will be appended up to and including the specified superclass. A null superclass is treated as
Object.If the style is
null, the defaultToStringStyleis used.- Type Parameters:
T- the type of the object- Parameters:
object- the Object to be outputstyle- the style of thetoStringto create, may benulloutputTransients- whether to include transient fieldsoutputStatics- whether to include static fieldsexcludeNullValues- whether to exclude fields whose values are nullreflectUpToClass- the superclass to reflect up to (inclusive), may benull- Returns:
- the String result
- Throws:
IllegalArgumentException- if the Object isnull- Since:
- 3.6
- See Also:
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toString
public static <T> String toString(T object, ToStringStyle style, boolean outputTransients, boolean outputStatics, Class<? super T> reflectUpToClass) Builds atoStringvalue through reflection.It uses
AccessibleObject.setAccessibleto gain access to private fields. This means that it will throw a security exception if run under a security manager, if the permissions are not set up correctly. It is also not as efficient as testing explicitly.If the
outputTransientsistrue, transient fields will be output, otherwise they are ignored, as they are likely derived fields, and not part of the value of the Object.If the
outputStaticsistrue, static fields will be output, otherwise they are ignored.Superclass fields will be appended up to and including the specified superclass. A null superclass is treated as
Object.If the style is
null, the defaultToStringStyleis used.- Type Parameters:
T- the type of the object- Parameters:
object- the Object to be outputstyle- the style of thetoStringto create, may benulloutputTransients- whether to include transient fieldsoutputStatics- whether to include static fieldsreflectUpToClass- the superclass to reflect up to (inclusive), may benull- Returns:
- the String result
- Throws:
IllegalArgumentException- if the Object isnull- Since:
- 2.1
- See Also:
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toStringExclude
Builds a String for a toString method excluding the given field names.- Parameters:
object- The object to "toString".excludeFieldNames- The field names to exclude. Null excludes nothing.- Returns:
- The toString value.
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toStringExclude
Builds a String for a toString method excluding the given field names.- Parameters:
object- The object to "toString".excludeFieldNames- The field names to exclude- Returns:
- The toString value.
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toStringInclude
Builds a String for a toString method including the given field names.- Parameters:
object- The object to "toString".includeFieldNames-nullor empty means all fields are included. All fields are included by default. This method will override the default behavior.- Returns:
- The toString value.
- Since:
- 3.13.0
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toStringInclude
Builds a String for a toString method including the given field names.- Parameters:
object- The object to "toString".includeFieldNames- The field names to include.nullor empty means all fields are included. All fields are included by default. This method will override the default behavior.- Returns:
- The toString value.
- Since:
- 3.13.0
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accept
Returns whether or not to append the givenField.- Transient fields are appended only if
isAppendTransients()returnstrue. - Static fields are appended only if
isAppendStatics()returnstrue. - Inner class fields are not appended.
- Parameters:
field- The Field to test.- Returns:
- Whether or not to append the given
Field.
- Transient fields are appended only if
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appendFieldsIn
Appends the fields and values defined by the given object of the given Class.If a cycle is detected as an object is "toString()'ed", such an object is rendered as if
Object.toString()had been called and not implemented by the object.- Parameters:
clazz- The class of object parameter
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getExcludeFieldNames
Gets the excludeFieldNames.- Returns:
- the excludeFieldNames.
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getIncludeFieldNames
Gets the includeFieldNames- Returns:
- the includeFieldNames.
- Since:
- 3.13.0
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getUpToClass
Gets the last super class to stop appending fields for.- Returns:
- The last super class to stop appending fields for.
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getValue
Callsjava.lang.reflect.Field.get(Object).- Parameters:
field- The Field to query.- Returns:
- The Object from the given Field.
- Throws:
IllegalArgumentException- seeField.get(Object)IllegalAccessException- seeField.get(Object)- See Also:
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isAppendStatics
Gets whether or not to append static fields.- Returns:
- Whether or not to append static fields.
- Since:
- 2.1
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isAppendTransients
Gets whether or not to append transient fields.- Returns:
- Whether or not to append transient fields.
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isExcludeNullValues
Gets whether or not to append fields whose values are null.- Returns:
- Whether or not to append fields whose values are null.
- Since:
- 3.6
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reflectionAppendArray
Appends to thetoStringanObjectarray.- Parameters:
array- the array to add to thetoString- Returns:
thisinstance.
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setAppendStatics
Sets whether or not to append static fields.- Parameters:
appendStatics- Whether or not to append static fields.- Since:
- 2.1
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setAppendTransients
Sets whether or not to append transient fields.- Parameters:
appendTransients- Whether or not to append transient fields.
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setExcludeFieldNames
Sets the field names to exclude.- Parameters:
excludeFieldNamesParam- The excludeFieldNames to excluding from toString ornull.- Returns:
this
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setExcludeNullValues
Sets whether or not to append fields whose values are null.- Parameters:
excludeNullValues- Whether or not to append fields whose values are null.- Since:
- 3.6
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setIncludeFieldNames
Sets the field names to include.nullor empty means all fields are included. All fields are included by default. This method will override the default behavior.- Parameters:
includeFieldNamesParam- The includeFieldNames that must be on toString ornull.- Returns:
this- Since:
- 3.13.0
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setUpToClass
Sets the last super class to stop appending fields for.- Parameters:
clazz- The last super class to stop appending fields for.
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toString
Gets the String built by this builder.- Overrides:
toStringin classToStringBuilder- Returns:
- the built string
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