Class ReflectionToStringBuilder


  • public class ReflectionToStringBuilder
    extends ToStringBuilder

    Assists in implementing 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.

    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();
     }

    The exact format of the toString is determined by the ToStringStyle passed into the constructor.

    Since:
    2.0
    Version:
    $Id: ReflectionToStringBuilder.java 905636 2010-02-02 14:03:32Z niallp $
    • Constructor Detail

      • ReflectionToStringBuilder

        public ReflectionToStringBuilder​(Object object)

        Constructor.

        This constructor outputs using the default style set with setDefaultStyle.

        Parameters:
        object - the Object to build a toString for, must not be null
        Throws:
        IllegalArgumentException - if the Object passed in is null
      • ReflectionToStringBuilder

        public ReflectionToStringBuilder​(Object object,
                                         ToStringStyle style)

        Constructor.

        If the style is null, the default style is used.

        Parameters:
        object - the Object to build a toString for, must not be null
        style - the style of the toString to create, may be null
        Throws:
        IllegalArgumentException - if the Object passed in is null
      • ReflectionToStringBuilder

        public ReflectionToStringBuilder​(Object object,
                                         ToStringStyle style,
                                         StringBuffer buffer)

        Constructor.

        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 a toString for
        style - the style of the toString to create, may be null
        buffer - the StringBuffer to populate, may be null
        Throws:
        IllegalArgumentException - if the Object passed in is null
      • ReflectionToStringBuilder

        public ReflectionToStringBuilder​(Object object,
                                         ToStringStyle style,
                                         StringBuffer buffer,
                                         Class reflectUpToClass,
                                         boolean outputTransients,
                                         boolean outputStatics)
        Constructor.
        Parameters:
        object - the Object to build a toString for
        style - the style of the toString to create, may be null
        buffer - the StringBuffer to populate, may be null
        reflectUpToClass - the superclass to reflect up to (inclusive), may be null
        outputTransients - whether to include transient fields
        outputStatics - whether to include static fields
        Since:
        2.1
    • Method Detail

      • toString

        public static String toString​(Object object)

        Builds a toString value using the default ToStringStyle through reflection.

        It uses AccessibleObject.setAccessible to 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 is null
      • toString

        public static String toString​(Object object,
                                      ToStringStyle style)

        Builds a toString value through reflection.

        It uses AccessibleObject.setAccessible to 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 default ToStringStyle is used.

        Parameters:
        object - the Object to be output
        style - the style of the toString to create, may be null
        Returns:
        the String result
        Throws:
        IllegalArgumentException - if the Object or ToStringStyle is null
      • toString

        public static String toString​(Object object,
                                      ToStringStyle style,
                                      boolean outputTransients)

        Builds a toString value through reflection.

        It uses AccessibleObject.setAccessible to 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 outputTransients is true, 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 default ToStringStyle is used.

        Parameters:
        object - the Object to be output
        style - the style of the toString to create, may be null
        outputTransients - whether to include transient fields
        Returns:
        the String result
        Throws:
        IllegalArgumentException - if the Object is null
      • toString

        public static String toString​(Object object,
                                      ToStringStyle style,
                                      boolean outputTransients,
                                      boolean outputStatics)

        Builds a toString value through reflection.

        It uses AccessibleObject.setAccessible to 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 outputTransients is true, 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 outputStatics is true, 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 default ToStringStyle is used.

        Parameters:
        object - the Object to be output
        style - the style of the toString to create, may be null
        outputTransients - whether to include transient fields
        outputStatics - whether to include transient fields
        Returns:
        the String result
        Throws:
        IllegalArgumentException - if the Object is null
        Since:
        2.1
      • toString

        public static String toString​(Object object,
                                      ToStringStyle style,
                                      boolean outputTransients,
                                      boolean outputStatics,
                                      Class reflectUpToClass)

        Builds a toString value through reflection.

        It uses AccessibleObject.setAccessible to 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 outputTransients is true, 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 outputStatics is true, 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 java.lang.Object.

        If the style is null, the default ToStringStyle is used.

        Parameters:
        object - the Object to be output
        style - the style of the toString to create, may be null
        outputTransients - whether to include transient fields
        outputStatics - whether to include static fields
        reflectUpToClass - the superclass to reflect up to (inclusive), may be null
        Returns:
        the String result
        Throws:
        IllegalArgumentException - if the Object is null
        Since:
        2.1
      • toString

        public static String toString​(Object object,
                                      ToStringStyle style,
                                      boolean outputTransients,
                                      Class reflectUpToClass)

        Builds a toString value through reflection.

        It uses AccessibleObject.setAccessible to 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 outputTransients is true, 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 up to and including the specified superclass. A null superclass is treated as java.lang.Object.

        If the style is null, the default ToStringStyle is used.

        Parameters:
        object - the Object to be output
        style - the style of the toString to create, may be null
        outputTransients - whether to include transient fields
        reflectUpToClass - the superclass to reflect up to (inclusive), may be null
        Returns:
        the String result
        Throws:
        IllegalArgumentException - if the Object is null
        Since:
        2.0
      • toStringExclude

        public static String toStringExclude​(Object object,
                                             String excludeFieldName)
        Builds a String for a toString method excluding the given field name.
        Parameters:
        object - The object to "toString".
        excludeFieldName - The field name to exclude
        Returns:
        The toString value.
      • toStringExclude

        public static String toStringExclude​(Object object,
                                             Collection excludeFieldNames)
        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.
      • toStringExclude

        public static String toStringExclude​(Object object,
                                             String[] excludeFieldNames)
        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.
      • accept

        protected boolean accept​(Field field)
        Returns whether or not to append the given Field.
        Parameters:
        field - The Field to test.
        Returns:
        Whether or not to append the given Field.
      • appendFieldsIn

        protected void appendFieldsIn​(Class clazz)

        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
      • getExcludeFieldNames

        public String[] getExcludeFieldNames()
        Returns:
        Returns the excludeFieldNames.
      • getUpToClass

        public Class getUpToClass()

        Gets the last super class to stop appending fields for.

        Returns:
        The last super class to stop appending fields for.
      • isAppendStatics

        public boolean isAppendStatics()

        Gets whether or not to append static fields.

        Returns:
        Whether or not to append static fields.
        Since:
        2.1
      • isAppendTransients

        public boolean isAppendTransients()

        Gets whether or not to append transient fields.

        Returns:
        Whether or not to append transient fields.
      • reflectionAppendArray

        public ToStringBuilder reflectionAppendArray​(Object array)

        Append to the toString an Object array.

        Parameters:
        array - the array to add to the toString
        Returns:
        this
      • setAppendStatics

        public void setAppendStatics​(boolean appendStatics)

        Sets whether or not to append static fields.

        Parameters:
        appendStatics - Whether or not to append static fields.
        Since:
        2.1
      • setAppendTransients

        public void setAppendTransients​(boolean appendTransients)

        Sets whether or not to append transient fields.

        Parameters:
        appendTransients - Whether or not to append transient fields.
      • setExcludeFieldNames

        public ReflectionToStringBuilder setExcludeFieldNames​(String[] excludeFieldNamesParam)
        Sets the field names to exclude.
        Parameters:
        excludeFieldNamesParam - The excludeFieldNames to excluding from toString or null.
        Returns:
        this
      • setUpToClass

        public void setUpToClass​(Class clazz)

        Sets the last super class to stop appending fields for.

        Parameters:
        clazz - The last super class to stop appending fields for.
      • toString

        public String toString()

        Gets the String built by this builder.

        Overrides:
        toString in class ToStringBuilder
        Returns:
        the built string