org.apache.commons.lang3.builder.ToStringBuilder Maven / Gradle / Ivy
Show all versions of commons-lang3 Show documentation
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3.builder;
import org.apache.commons.lang3.ObjectUtils;
import org.apache.commons.lang3.Validate;
/**
* Assists in implementing {@link Object#toString()} methods.
*
* This class enables a good and consistent toString() to be built for any
* class or object. This class aims to simplify the process by:
*
* - allowing field names
* - handling all types consistently
* - handling nulls consistently
* - outputting arrays and multi-dimensional arrays
* - enabling the detail level to be controlled for Objects and Collections
* - handling class hierarchies
*
*
* To use this class write code as follows:
*
*
* public class Person {
* String name;
* int age;
* boolean smoker;
*
* ...
*
* public String toString() {
* return new ToStringBuilder(this).
* append("name", name).
* append("age", age).
* append("smoker", smoker).
* toString();
* }
* }
*
*
* This will produce a toString of the format:
* Person@7f54[name=Stephen,age=29,smoker=false]
*
* To add the superclass toString, use {@link #appendSuper}.
* To append the toString from an object that is delegated
* to (or any other object), use {@link #appendToString}.
*
* Alternatively, there is a method that uses reflection to determine
* the fields to test. Because these fields are usually private, the method,
* reflectionToString, uses AccessibleObject.setAccessible to
* change the visibility of the fields. This will fail under a security manager,
* unless the appropriate permissions are set up correctly. It is also
* slower than testing explicitly.
*
* A typical invocation for this method would look like:
*
*
* public String toString() {
* return ToStringBuilder.reflectionToString(this);
* }
*
*
* You can also use the builder to debug 3rd party objects:
*
*
* System.out.println("An object: " + ToStringBuilder.reflectionToString(anObject));
*
*
* The exact format of the toString is determined by
* the {@link ToStringStyle} passed into the constructor.
*
* @since 1.0
*/
public class ToStringBuilder implements Builder {
/**
* The default style of output to use, not null.
*/
private static volatile ToStringStyle defaultStyle = ToStringStyle.DEFAULT_STYLE;
//----------------------------------------------------------------------------
/**
* Gets the default ToStringStyle to use.
*
* This method gets a singleton default value, typically for the whole JVM.
* Changing this default should generally only be done during application startup.
* It is recommended to pass a ToStringStyle to the constructor instead
* of using this global default.
*
* This method can be used from multiple threads.
* Internally, a volatile variable is used to provide the guarantee
* that the latest value set using {@link #setDefaultStyle} is the value returned.
* It is strongly recommended that the default style is only changed during application startup.
*
* One reason for changing the default could be to have a verbose style during
* development and a compact style in production.
*
* @return the default ToStringStyle, never null
*/
public static ToStringStyle getDefaultStyle() {
return defaultStyle;
}
/**
* Sets the default ToStringStyle to use.
*
* This method sets a singleton default value, typically for the whole JVM.
* Changing this default should generally only be done during application startup.
* It is recommended to pass a ToStringStyle to the constructor instead
* of changing this global default.
*
* This method is not intended for use from multiple threads.
* Internally, a volatile variable is used to provide the guarantee
* that the latest value set is the value returned from {@link #getDefaultStyle}.
*
* @param style the default ToStringStyle
* @throws IllegalArgumentException if the style is null
*/
public static void setDefaultStyle(final ToStringStyle style) {
Validate.isTrue(style != null, "The style must not be null");
defaultStyle = style;
}
//----------------------------------------------------------------------------
/**
* Uses ReflectionToStringBuilder to generate a
* toString for the specified object.
*
* @param object the Object to be output
* @return the String result
* @see ReflectionToStringBuilder#toString(Object)
*/
public static String reflectionToString(final Object object) {
return ReflectionToStringBuilder.toString(object);
}
/**
* Uses ReflectionToStringBuilder to generate a
* toString for the specified object.
*
* @param object the Object to be output
* @param style the style of the toString to create, may be null
* @return the String result
* @see ReflectionToStringBuilder#toString(Object,ToStringStyle)
*/
public static String reflectionToString(final Object object, final ToStringStyle style) {
return ReflectionToStringBuilder.toString(object, style);
}
/**
* Uses ReflectionToStringBuilder to generate a
* toString for the specified object.
*
* @param object the Object to be output
* @param style the style of the toString to create, may be null
* @param outputTransients whether to include transient fields
* @return the String result
* @see ReflectionToStringBuilder#toString(Object,ToStringStyle,boolean)
*/
public static String reflectionToString(final Object object, final ToStringStyle style, final boolean outputTransients) {
return ReflectionToStringBuilder.toString(object, style, outputTransients, false, null);
}
/**
* Uses ReflectionToStringBuilder to generate a
* toString for the specified object.
*
* @param the type of the object
* @param object the Object to be output
* @param style the style of the toString to create, may be null
* @param outputTransients whether to include transient fields
* @param reflectUpToClass the superclass to reflect up to (inclusive), may be null
* @return the String result
* @see ReflectionToStringBuilder#toString(Object,ToStringStyle,boolean,boolean,Class)
* @since 2.0
*/
public static String reflectionToString(
final T object,
final ToStringStyle style,
final boolean outputTransients,
final Class reflectUpToClass) {
return ReflectionToStringBuilder.toString(object, style, outputTransients, false, reflectUpToClass);
}
//----------------------------------------------------------------------------
/**
* Current toString buffer, not null.
*/
private final StringBuffer buffer;
/**
* The object being output, may be null.
*/
private final Object object;
/**
* The style of output to use, not null.
*/
private final ToStringStyle style;
/**
* Constructs a builder for the specified object using the default output style.
*
* This default style is obtained from {@link #getDefaultStyle()}.
*
* @param object the Object to build a toString for, not recommended to be null
*/
public ToStringBuilder(final Object object) {
this(object, null, null);
}
/**
* Constructs a builder for the specified object using the defined output style.
*
* If the style is null, the default style is used.
*
* @param object the Object to build a toString for, not recommended to be null
* @param style the style of the toString to create, null uses the default style
*/
public ToStringBuilder(final Object object, final ToStringStyle style) {
this(object, style, null);
}
/**
* Constructs a builder for the specified object.
*
* If the style is null, the default style is used.
*
* If the buffer is null, a new one is created.
*
* @param object the Object to build a toString for, not recommended to be null
* @param style the style of the toString to create, null uses the default style
* @param buffer the StringBuffer to populate, may be null
*/
public ToStringBuilder(final Object object, ToStringStyle style, StringBuffer buffer) {
if (style == null) {
style = getDefaultStyle();
}
if (buffer == null) {
buffer = new StringBuffer(512);
}
this.buffer = buffer;
this.style = style;
this.object = object;
style.appendStart(buffer, object);
}
//----------------------------------------------------------------------------
/**
* Append to the toString a boolean
* value.
*
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final boolean value) {
style.append(buffer, null, value);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a boolean
* array.
*
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final boolean[] array) {
style.append(buffer, null, array, null);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a byte
* value.
*
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final byte value) {
style.append(buffer, null, value);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a byte
* array.
*
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final byte[] array) {
style.append(buffer, null, array, null);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a char
* value.
*
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final char value) {
style.append(buffer, null, value);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a char
* array.
*
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final char[] array) {
style.append(buffer, null, array, null);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a double
* value.
*
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final double value) {
style.append(buffer, null, value);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a double
* array.
*
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final double[] array) {
style.append(buffer, null, array, null);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a float
* value.
*
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final float value) {
style.append(buffer, null, value);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a float
* array.
*
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final float[] array) {
style.append(buffer, null, array, null);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString an int
* value.
*
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final int value) {
style.append(buffer, null, value);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString an int
* array.
*
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final int[] array) {
style.append(buffer, null, array, null);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a long
* value.
*
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final long value) {
style.append(buffer, null, value);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a long
* array.
*
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final long[] array) {
style.append(buffer, null, array, null);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString an Object
* value.
*
* @param obj the value to add to the toString
* @return this
*/
public ToStringBuilder append(final Object obj) {
style.append(buffer, null, obj, null);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString an Object
* array.
*
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final Object[] array) {
style.append(buffer, null, array, null);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a short
* value.
*
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final short value) {
style.append(buffer, null, value);
return this;
}
//----------------------------------------------------------------------------
/**
* Append to the toString a short
* array.
*
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final short[] array) {
style.append(buffer, null, array, null);
return this;
}
/**
* Append to the toString a boolean
* value.
*
* @param fieldName the field name
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final boolean value) {
style.append(buffer, fieldName, value);
return this;
}
/**
* Append to the toString a boolean
* array.
*
* @param fieldName the field name
* @param array the array to add to the hashCode
* @return this
*/
public ToStringBuilder append(final String fieldName, final boolean[] array) {
style.append(buffer, fieldName, array, null);
return this;
}
/**
* Append to the toString a boolean
* array.
*
* A boolean parameter controls the level of detail to show.
* Setting true will output the array in full. Setting
* false will output a summary, typically the size of
* the array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @param fullDetail true for detail, false
* for summary info
* @return this
*/
public ToStringBuilder append(final String fieldName, final boolean[] array, final boolean fullDetail) {
style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail));
return this;
}
/**
* Append to the toString an byte
* value.
*
* @param fieldName the field name
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final byte value) {
style.append(buffer, fieldName, value);
return this;
}
/**
* Append to the toString a byte array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final byte[] array) {
style.append(buffer, fieldName, array, null);
return this;
}
/**
* Append to the toString a byte
* array.
*
* A boolean parameter controls the level of detail to show.
* Setting true will output the array in full. Setting
* false will output a summary, typically the size of
* the array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @param fullDetail true for detail, false
* for summary info
* @return this
*/
public ToStringBuilder append(final String fieldName, final byte[] array, final boolean fullDetail) {
style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail));
return this;
}
/**
*
Append to the toString a char
* value.
*
* @param fieldName the field name
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final char value) {
style.append(buffer, fieldName, value);
return this;
}
/**
* Append to the toString a char
* array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final char[] array) {
style.append(buffer, fieldName, array, null);
return this;
}
/**
* Append to the toString a char
* array.
*
* A boolean parameter controls the level of detail to show.
* Setting true will output the array in full. Setting
* false will output a summary, typically the size of
* the array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @param fullDetail true for detail, false
* for summary info
* @return this
*/
public ToStringBuilder append(final String fieldName, final char[] array, final boolean fullDetail) {
style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail));
return this;
}
/**
* Append to the toString a double
* value.
*
* @param fieldName the field name
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final double value) {
style.append(buffer, fieldName, value);
return this;
}
/**
* Append to the toString a double
* array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final double[] array) {
style.append(buffer, fieldName, array, null);
return this;
}
/**
* Append to the toString a double
* array.
*
* A boolean parameter controls the level of detail to show.
* Setting true will output the array in full. Setting
* false will output a summary, typically the size of
* the array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @param fullDetail true for detail, false
* for summary info
* @return this
*/
public ToStringBuilder append(final String fieldName, final double[] array, final boolean fullDetail) {
style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail));
return this;
}
/**
* Append to the toString an float
* value.
*
* @param fieldName the field name
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final float value) {
style.append(buffer, fieldName, value);
return this;
}
/**
* Append to the toString a float
* array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final float[] array) {
style.append(buffer, fieldName, array, null);
return this;
}
/**
* Append to the toString a float
* array.
*
* A boolean parameter controls the level of detail to show.
* Setting true will output the array in full. Setting
* false will output a summary, typically the size of
* the array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @param fullDetail true for detail, false
* for summary info
* @return this
*/
public ToStringBuilder append(final String fieldName, final float[] array, final boolean fullDetail) {
style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail));
return this;
}
/**
* Append to the toString an int
* value.
*
* @param fieldName the field name
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final int value) {
style.append(buffer, fieldName, value);
return this;
}
/**
* Append to the toString an int
* array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final int[] array) {
style.append(buffer, fieldName, array, null);
return this;
}
/**
* Append to the toString an int
* array.
*
* A boolean parameter controls the level of detail to show.
* Setting true will output the array in full. Setting
* false will output a summary, typically the size of
* the array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @param fullDetail true for detail, false
* for summary info
* @return this
*/
public ToStringBuilder append(final String fieldName, final int[] array, final boolean fullDetail) {
style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail));
return this;
}
/**
* Append to the toString a long
* value.
*
* @param fieldName the field name
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final long value) {
style.append(buffer, fieldName, value);
return this;
}
/**
* Append to the toString a long
* array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final long[] array) {
style.append(buffer, fieldName, array, null);
return this;
}
/**
* Append to the toString a long
* array.
*
* A boolean parameter controls the level of detail to show.
* Setting true will output the array in full. Setting
* false will output a summary, typically the size of
* the array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @param fullDetail true for detail, false
* for summary info
* @return this
*/
public ToStringBuilder append(final String fieldName, final long[] array, final boolean fullDetail) {
style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail));
return this;
}
/**
* Append to the toString an Object
* value.
*
* @param fieldName the field name
* @param obj the value to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final Object obj) {
style.append(buffer, fieldName, obj, null);
return this;
}
/**
* Append to the toString an Object
* value.
*
* @param fieldName the field name
* @param obj the value to add to the toString
* @param fullDetail true for detail,
* false for summary info
* @return this
*/
public ToStringBuilder append(final String fieldName, final Object obj, final boolean fullDetail) {
style.append(buffer, fieldName, obj, Boolean.valueOf(fullDetail));
return this;
}
/**
* Append to the toString an Object
* array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final Object[] array) {
style.append(buffer, fieldName, array, null);
return this;
}
/**
* Append to the toString an Object
* array.
*
* A boolean parameter controls the level of detail to show.
* Setting true will output the array in full. Setting
* false will output a summary, typically the size of
* the array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @param fullDetail true for detail, false
* for summary info
* @return this
*/
public ToStringBuilder append(final String fieldName, final Object[] array, final boolean fullDetail) {
style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail));
return this;
}
/**
* Append to the toString an short
* value.
*
* @param fieldName the field name
* @param value the value to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final short value) {
style.append(buffer, fieldName, value);
return this;
}
/**
* Append to the toString a short
* array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @return this
*/
public ToStringBuilder append(final String fieldName, final short[] array) {
style.append(buffer, fieldName, array, null);
return this;
}
/**
* Append to the toString a short
* array.
*
* A boolean parameter controls the level of detail to show.
* Setting true will output the array in full. Setting
* false will output a summary, typically the size of
* the array.
*
* @param fieldName the field name
* @param array the array to add to the toString
* @param fullDetail true for detail, false
* for summary info
* @return this
*/
public ToStringBuilder append(final String fieldName, final short[] array, final boolean fullDetail) {
style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail));
return this;
}
/**
*
Appends with the same format as the default Object toString()
* method. Appends the class name followed by
* {@link System#identityHashCode(java.lang.Object)}.
*
* @param srcObject the Object whose class name and id to output
* @return this
* @since 2.0
*/
public ToStringBuilder appendAsObjectToString(final Object srcObject) {
ObjectUtils.identityToString(this.getStringBuffer(), srcObject);
return this;
}
//----------------------------------------------------------------------------
/**
* Append the toString from the superclass.
*
* This method assumes that the superclass uses the same ToStringStyle
* as this one.
*
* If superToString is null, no change is made.
*
* @param superToString the result of super.toString()
* @return this
* @since 2.0
*/
public ToStringBuilder appendSuper(final String superToString) {
if (superToString != null) {
style.appendSuper(buffer, superToString);
}
return this;
}
/**
* Append the toString from another object.
*
* This method is useful where a class delegates most of the implementation of
* its properties to another class. You can then call toString() on
* the other class and pass the result into this method.
*
*
* private AnotherObject delegate;
* private String fieldInThisClass;
*
* public String toString() {
* return new ToStringBuilder(this).
* appendToString(delegate.toString()).
* append(fieldInThisClass).
* toString();
* }
*
* This method assumes that the other object uses the same ToStringStyle
* as this one.
*
* If the toString is null, no change is made.
*
* @param toString the result of toString() on another object
* @return this
* @since 2.0
*/
public ToStringBuilder appendToString(final String toString) {
if (toString != null) {
style.appendToString(buffer, toString);
}
return this;
}
/**
* Returns the Object being output.
*
* @return The object being output.
* @since 2.0
*/
public Object getObject() {
return object;
}
/**
* Gets the StringBuffer being populated.
*
* @return the StringBuffer being populated
*/
public StringBuffer getStringBuffer() {
return buffer;
}
//----------------------------------------------------------------------------
/**
* Gets the ToStringStyle being used.
*
* @return the ToStringStyle being used
* @since 2.0
*/
public ToStringStyle getStyle() {
return style;
}
/**
* Returns the built toString.
*
* This method appends the end of data indicator, and can only be called once.
* Use {@link #getStringBuffer} to get the current string state.
*
* If the object is null, return the style's nullText
*
* @return the String toString
*/
@Override
public String toString() {
if (this.getObject() == null) {
this.getStringBuffer().append(this.getStyle().getNullText());
} else {
style.appendEnd(this.getStringBuffer(), this.getObject());
}
return this.getStringBuffer().toString();
}
/**
* Returns the String that was build as an object representation. The
* default implementation utilizes the {@link #toString()} implementation.
*
* @return the String toString
*
* @see #toString()
*
* @since 3.0
*/
@Override
public String build() {
return toString();
}
}