Java tutorial
/* * 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 com.invalidcodeexception.experiment.langstringbuilder.lang3; import org.apache.commons.lang3.builder.Builder; /** * <p>Assists in implementing {@link Object#toString()} methods.</p> * * <p>This class enables a good and consistent <code>toString()</code> to be built for any * class or object. This class aims to simplify the process by:</p> * <ul> * <li>allowing field names</li> * <li>handling all types consistently</li> * <li>handling nulls consistently</li> * <li>outputting arrays and multi-dimensional arrays</li> * <li>enabling the detail level to be controlled for Objects and Collections</li> * <li>handling class hierarchies</li> * </ul> * * <p>To use this class write code as follows:</p> * * <pre> * 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(); * } * } * </pre> * * <p>This will produce a toString of the format: * <code>Person@7f54[name=Stephen,age=29,smoker=false]</code></p> * * <p>To add the superclass <code>toString</code>, use {@link #appendSuper}. * To append the <code>toString</code> from an object that is delegated * to (or any other object), use {@link #appendToString}.</p> * * <p>Alternatively, there is a method that uses reflection to determine * the fields to test. Because these fields are usually private, the method, * <code>reflectionToString</code>, uses <code>AccessibleObject.setAccessible</code> 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.</p> * * <p>A typical invocation for this method would look like:</p> * * <pre> * public String toString() { * return ToStringBuilder.reflectionToString(this); * } * </pre> * * <p>You can also use the builder to debug 3rd party objects:</p> * * <pre> * System.out.println("An object: " + ToStringBuilder.reflectionToString(anObject)); * </pre> * * <p>The exact format of the <code>toString</code> is determined by * the {@link UnsafeToStringStyle} passed into the constructor.</p> * * @since 1.0 * @version $Id: ToStringBuilder.java 1088899 2011-04-05 05:31:27Z bayard $ */ public class UnsafeToStringBuilder implements Builder<String> { /** * The default style of output to use, not null. */ private static volatile UnsafeToStringStyle defaultStyle = UnsafeToStringStyle.DEFAULT_STYLE; //---------------------------------------------------------------------------- /** * <p>Gets the default <code>UnsafeToStringStyle</code> to use.</p> * * <p>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 <code>UnsafeToStringStyle</code> to the constructor instead * of using this global default.</p> * * <p>This method can be used from multiple threads. * Internally, a <code>volatile</code> 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.</p> * * <p>One reason for changing the default could be to have a verbose style during * development and a compact style in production.</p> * * @return the default <code>UnsafeToStringStyle</code>, never null */ public static UnsafeToStringStyle getDefaultStyle() { return defaultStyle; } /** * <p>Sets the default <code>UnsafeToStringStyle</code> to use.</p> * * <p>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 <code>UnsafeToStringStyle</code> to the constructor instead * of changing this global default.</p> * * <p>This method is not intended for use from multiple threads. * Internally, a <code>volatile</code> variable is used to provide the guarantee * that the latest value set is the value returned from {@link #getDefaultStyle}.</p> * * @param style the default <code>UnsafeToStringStyle</code> * @throws IllegalArgumentException if the style is <code>null</code> */ public static void setDefaultStyle(UnsafeToStringStyle style) { if (style == null) { throw new IllegalArgumentException("The style must not be null"); } defaultStyle = style; } //---------------------------------------------------------------------------- /** * Current toString buffer, not null. */ private final StringBuilder buffer; /** * The object being output, may be null. */ private final Object object; /** * The style of output to use, not null. */ private final UnsafeToStringStyle style; /** * <p>Constructs a builder for the specified object using the default output style.</p> * * <p>This default style is obtained from {@link #getDefaultStyle()}.</p> * * @param object the Object to build a <code>toString</code> for, not recommended to be null */ public UnsafeToStringBuilder(Object object) { this(object, null, null); } /** * <p>Constructs a builder for the specified object using the a defined output style.</p> * * <p>If the style is <code>null</code>, the default style is used.</p> * * @param object the Object to build a <code>toString</code> for, not recommended to be null * @param style the style of the <code>toString</code> to create, null uses the default style */ public UnsafeToStringBuilder(Object object, UnsafeToStringStyle style) { this(object, style, null); } /** * <p>Constructs a builder for the specified object.</p> * * <p>If the style is <code>null</code>, the default style is used.</p> * * <p>If the buffer is <code>null</code>, a new one is created.</p> * * @param object the Object to build a <code>toString</code> for, not recommended to be null * @param style the style of the <code>toString</code> to create, null uses the default style * @param buffer the <code>StringBuffer</code> to populate, may be null */ public UnsafeToStringBuilder(Object object, UnsafeToStringStyle style, StringBuilder buffer) { if (style == null) { style = getDefaultStyle(); } if (buffer == null) { buffer = new StringBuilder(512); } this.buffer = buffer; this.style = style; this.object = object; style.appendStart(buffer, object); } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>boolean</code> * value.</p> * * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(boolean value) { style.append(buffer, null, value); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>boolean</code> * array.</p> * * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(boolean[] array) { style.append(buffer, null, array, null); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>byte</code> * value.</p> * * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(byte value) { style.append(buffer, null, value); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>byte</code> * array.</p> * * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(byte[] array) { style.append(buffer, null, array, null); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>char</code> * value.</p> * * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(char value) { style.append(buffer, null, value); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>char</code> * array.</p> * * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(char[] array) { style.append(buffer, null, array, null); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>double</code> * value.</p> * * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(double value) { style.append(buffer, null, value); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>double</code> * array.</p> * * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(double[] array) { style.append(buffer, null, array, null); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>float</code> * value.</p> * * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(float value) { style.append(buffer, null, value); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>float</code> * array.</p> * * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(float[] array) { style.append(buffer, null, array, null); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> an <code>int</code> * value.</p> * * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(int value) { style.append(buffer, null, value); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> an <code>int</code> * array.</p> * * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(int[] array) { style.append(buffer, null, array, null); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>long</code> * value.</p> * * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(long value) { style.append(buffer, null, value); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>long</code> * array.</p> * * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(long[] array) { style.append(buffer, null, array, null); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> an <code>Object</code> * value.</p> * * @param obj the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(Object obj) { style.append(buffer, null, obj, null); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> an <code>Object</code> * array.</p> * * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(Object[] array) { style.append(buffer, null, array, null); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>short</code> * value.</p> * * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(short value) { style.append(buffer, null, value); return this; } //---------------------------------------------------------------------------- /** * <p>Append to the <code>toString</code> a <code>short</code> * array.</p> * * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(short[] array) { style.append(buffer, null, array, null); return this; } /** * <p>Append to the <code>toString</code> a <code>boolean</code> * value.</p> * * @param fieldName the field name * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, boolean value) { style.append(buffer, fieldName, value); return this; } /** * <p>Append to the <code>toString</code> a <code>boolean</code> * array.</p> * * @param fieldName the field name * @param array the array to add to the <code>hashCode</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, boolean[] array) { style.append(buffer, fieldName, array, null); return this; } /** * <p>Append to the <code>toString</code> a <code>boolean</code> * array.</p> * * <p>A boolean parameter controls the level of detail to show. * Setting <code>true</code> will output the array in full. Setting * <code>false</code> will output a summary, typically the size of * the array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @param fullDetail <code>true</code> for detail, <code>false</code> * for summary info * @return this */ public UnsafeToStringBuilder append(String fieldName, boolean[] array, boolean fullDetail) { style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail)); return this; } /** * <p>Append to the <code>toString</code> an <code>byte</code> * value.</p> * * @param fieldName the field name * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, byte value) { style.append(buffer, fieldName, value); return this; } /** * <p>Append to the <code>toString</code> a <code>byte</code> array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, byte[] array) { style.append(buffer, fieldName, array, null); return this; } /** * <p>Append to the <code>toString</code> a <code>byte</code> * array.</p> * * <p>A boolean parameter controls the level of detail to show. * Setting <code>true</code> will output the array in full. Setting * <code>false</code> will output a summary, typically the size of * the array. * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @param fullDetail <code>true</code> for detail, <code>false</code> * for summary info * @return this */ public UnsafeToStringBuilder append(String fieldName, byte[] array, boolean fullDetail) { style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail)); return this; } /** * <p>Append to the <code>toString</code> a <code>char</code> * value.</p> * * @param fieldName the field name * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, char value) { style.append(buffer, fieldName, value); return this; } /** * <p>Append to the <code>toString</code> a <code>char</code> * array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, char[] array) { style.append(buffer, fieldName, array, null); return this; } /** * <p>Append to the <code>toString</code> a <code>char</code> * array.</p> * * <p>A boolean parameter controls the level of detail to show. * Setting <code>true</code> will output the array in full. Setting * <code>false</code> will output a summary, typically the size of * the array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @param fullDetail <code>true</code> for detail, <code>false</code> * for summary info * @return this */ public UnsafeToStringBuilder append(String fieldName, char[] array, boolean fullDetail) { style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail)); return this; } /** * <p>Append to the <code>toString</code> a <code>double</code> * value.</p> * * @param fieldName the field name * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, double value) { style.append(buffer, fieldName, value); return this; } /** * <p>Append to the <code>toString</code> a <code>double</code> * array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, double[] array) { style.append(buffer, fieldName, array, null); return this; } /** * <p>Append to the <code>toString</code> a <code>double</code> * array.</p> * * <p>A boolean parameter controls the level of detail to show. * Setting <code>true</code> will output the array in full. Setting * <code>false</code> will output a summary, typically the size of * the array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @param fullDetail <code>true</code> for detail, <code>false</code> * for summary info * @return this */ public UnsafeToStringBuilder append(String fieldName, double[] array, boolean fullDetail) { style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail)); return this; } /** * <p>Append to the <code>toString</code> an <code>float</code> * value.</p> * * @param fieldName the field name * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, float value) { style.append(buffer, fieldName, value); return this; } /** * <p>Append to the <code>toString</code> a <code>float</code> * array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, float[] array) { style.append(buffer, fieldName, array, null); return this; } /** * <p>Append to the <code>toString</code> a <code>float</code> * array.</p> * * <p>A boolean parameter controls the level of detail to show. * Setting <code>true</code> will output the array in full. Setting * <code>false</code> will output a summary, typically the size of * the array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @param fullDetail <code>true</code> for detail, <code>false</code> * for summary info * @return this */ public UnsafeToStringBuilder append(String fieldName, float[] array, boolean fullDetail) { style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail)); return this; } /** * <p>Append to the <code>toString</code> an <code>int</code> * value.</p> * * @param fieldName the field name * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, int value) { style.append(buffer, fieldName, value); return this; } /** * <p>Append to the <code>toString</code> an <code>int</code> * array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, int[] array) { style.append(buffer, fieldName, array, null); return this; } /** * <p>Append to the <code>toString</code> an <code>int</code> * array.</p> * * <p>A boolean parameter controls the level of detail to show. * Setting <code>true</code> will output the array in full. Setting * <code>false</code> will output a summary, typically the size of * the array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @param fullDetail <code>true</code> for detail, <code>false</code> * for summary info * @return this */ public UnsafeToStringBuilder append(String fieldName, int[] array, boolean fullDetail) { style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail)); return this; } /** * <p>Append to the <code>toString</code> a <code>long</code> * value.</p> * * @param fieldName the field name * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, long value) { style.append(buffer, fieldName, value); return this; } /** * <p>Append to the <code>toString</code> a <code>long</code> * array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, long[] array) { style.append(buffer, fieldName, array, null); return this; } /** * <p>Append to the <code>toString</code> a <code>long</code> * array.</p> * * <p>A boolean parameter controls the level of detail to show. * Setting <code>true</code> will output the array in full. Setting * <code>false</code> will output a summary, typically the size of * the array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @param fullDetail <code>true</code> for detail, <code>false</code> * for summary info * @return this */ public UnsafeToStringBuilder append(String fieldName, long[] array, boolean fullDetail) { style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail)); return this; } /** * <p>Append to the <code>toString</code> an <code>Object</code> * value.</p> * * @param fieldName the field name * @param obj the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, Object obj) { style.append(buffer, fieldName, obj, null); return this; } /** * <p>Append to the <code>toString</code> an <code>Object</code> * value.</p> * * @param fieldName the field name * @param obj the value to add to the <code>toString</code> * @param fullDetail <code>true</code> for detail, * <code>false</code> for summary info * @return this */ public UnsafeToStringBuilder append(String fieldName, Object obj, boolean fullDetail) { style.append(buffer, fieldName, obj, Boolean.valueOf(fullDetail)); return this; } /** * <p>Append to the <code>toString</code> an <code>Object</code> * array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, Object[] array) { style.append(buffer, fieldName, array, null); return this; } /** * <p>Append to the <code>toString</code> an <code>Object</code> * array.</p> * * <p>A boolean parameter controls the level of detail to show. * Setting <code>true</code> will output the array in full. Setting * <code>false</code> will output a summary, typically the size of * the array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @param fullDetail <code>true</code> for detail, <code>false</code> * for summary info * @return this */ public UnsafeToStringBuilder append(String fieldName, Object[] array, boolean fullDetail) { style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail)); return this; } /** * <p>Append to the <code>toString</code> an <code>short</code> * value.</p> * * @param fieldName the field name * @param value the value to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, short value) { style.append(buffer, fieldName, value); return this; } /** * <p>Append to the <code>toString</code> a <code>short</code> * array.</p> * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @return this */ public UnsafeToStringBuilder append(String fieldName, short[] array) { style.append(buffer, fieldName, array, null); return this; } /** * <p>Append to the <code>toString</code> a <code>short</code> * array.</p> * * <p>A boolean parameter controls the level of detail to show. * Setting <code>true</code> will output the array in full. Setting * <code>false</code> will output a summary, typically the size of * the array. * * @param fieldName the field name * @param array the array to add to the <code>toString</code> * @param fullDetail <code>true</code> for detail, <code>false</code> * for summary info * @return this */ public UnsafeToStringBuilder append(String fieldName, short[] array, boolean fullDetail) { style.append(buffer, fieldName, array, Boolean.valueOf(fullDetail)); return this; } /** * <p>Appends with the same format as the default <code>Object toString() * </code> method. Appends the class name followed by * {@link System#identityHashCode(java.lang.Object)}.</p> * * @param object the <code>Object</code> whose class name and id to output * @return this * @since 2.0 */ public UnsafeToStringBuilder appendAsObjectToString(Object object) { if (object == null) { throw new NullPointerException("Cannot get the toString of a null identity"); } buffer.append(object.getClass().getName()).append('@') .append(Integer.toHexString(System.identityHashCode(object))); return this; } //---------------------------------------------------------------------------- /** * <p>Append the <code>toString</code> from the superclass.</p> * * <p>This method assumes that the superclass uses the same <code>UnsafeToStringStyle</code> * as this one.</p> * * <p>If <code>superToString</code> is <code>null</code>, no change is made.</p> * * @param superToString the result of <code>super.toString()</code> * @return this * @since 2.0 */ public UnsafeToStringBuilder appendSuper(String superToString) { if (superToString != null) { style.appendSuper(buffer, superToString); } return this; } /** * <p>Append the <code>toString</code> from another object.</p> * * <p>This method is useful where a class delegates most of the implementation of * its properties to another class. You can then call <code>toString()</code> on * the other class and pass the result into this method.</p> * * <pre> * private AnotherObject delegate; * private String fieldInThisClass; * * public String toString() { * return new ToStringBuilder(this). * appendToString(delegate.toString()). * append(fieldInThisClass). * toString(); * }</pre> * * <p>This method assumes that the other object uses the same <code>UnsafeToStringStyle</code> * as this one.</p> * * <p>If the <code>toString</code> is <code>null</code>, no change is made.</p> * * @param toString the result of <code>toString()</code> on another object * @return this * @since 2.0 */ public UnsafeToStringBuilder appendToString(String toString) { if (toString != null) { style.appendToString(buffer, toString); } return this; } /** * <p>Returns the <code>Object</code> being output.</p> * * @return The object being output. * @since 2.0 */ public Object getObject() { return object; } /** * <p>Gets the <code>StringBuffer</code> being populated.</p> * * @return the <code>StringBuffer</code> being populated */ public StringBuilder getStringBuffer() { return buffer; } //---------------------------------------------------------------------------- /** * <p>Gets the <code>UnsafeToStringStyle</code> being used.</p> * * @return the <code>UnsafeToStringStyle</code> being used * @since 2.0 */ public UnsafeToStringStyle getStyle() { return style; } /** * <p>Returns the built <code>toString</code>.</p> * * <p>This method appends the end of data indicator, and can only be called once. * Use {@link #getStringBuffer} to get the current string state.</p> * * <p>If the object is <code>null</code>, return the style's <code>nullText</code></p> * * @return the String <code>toString</code> */ @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 <code>toString</code> * * @see #toString() * * @since 3.0 */ public String build() { return toString(); } }