- /* ====================================================================
- * The Apache Software License, Version 1.1
- *
- * Copyright (c) 2002-2003 The Apache Software Foundation. All rights
- * reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * 3. The end-user documentation included with the redistribution, if
- * any, must include the following acknowledgement:
- * "This product includes software developed by the
- * Apache Software Foundation (http://www.apache.org/)."
- * Alternately, this acknowledgement may appear in the software itself,
- * if and wherever such third-party acknowledgements normally appear.
- *
- * 4. The names "The Jakarta Project", "Commons", and "Apache Software
- * Foundation" must not be used to endorse or promote products derived
- * from this software without prior written permission. For written
- * permission, please contact apache@apache.org.
- *
- * 5. Products derived from this software may not be called "Apache"
- * nor may "Apache" appear in their names without prior written
- * permission of the Apache Software Foundation.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of the Apache Software Foundation. For more
- * information on the Apache Software Foundation, please see
- * <http://www.apache.org/>.
- */
- package org.apache.commons.lang.builder;
-
- import java.lang.reflect.AccessibleObject;
- import java.lang.reflect.Field;
- import java.lang.reflect.Modifier;
- import java.util.HashSet;
- import java.util.Set;
-
- import org.apache.commons.lang.ClassUtils;
-
- /**
- * <p>Assists in implementing {@link Object#toString()} methods using reflection.</p>
- *
- * <p>This class uses reflection to determine the fields to append.
- * Because these fields are usually private, the class
- * 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.</p>
- *
- * <p>A typical invocation for this method would look like:</p>
- * <pre>
- * public String toString() {
- * return ReflectionToStringBuilder.toString(this);
- * }</pre>
- *
- * <p>You can also use the builder to debug 3rd party objects:</p>
- * <pre>
- * System.out.println("An object: " + ReflectionToStringBuilder.toString(anObject));</pre>
- *
- * <p>A subclass can control field output by overriding the methods:
- * <ul>
- * <li>{@link #accept(java.lang.reflect.Field)}</li>
- * <li>{@link #getValue(java.lang.reflect.Field)}</li>
- * </ul>
- * </p>
- * <p>For example, this method does <i>not</i> include the <code>password</code> field in the returned
- * <code>String</code>:</p>
- * <pre>
- * public String toString() {
- * return (new ReflectionToStringBuilder(this) {
- * protected boolean accept(Field f) {
- * return super.accept(f) && !f.getName().equals("password");
- * }
- * }).toString();
- * }</pre>
- *
- * <p>The exact format of the <code>toString</code> is determined by
- * the {@link ToStringStyle} passed into the constructor.</p>
- *
- * @author Gary Gregory
- * @author Stephen Colebourne
- * @author Pete Gieser
- * @since 2.0
- * @version $Id: ReflectionToStringBuilder.java,v 1.10 2003/08/23 00:21:49 ggregory Exp $
- */
- public class ReflectionToStringBuilder extends ToStringBuilder {
-
- /**
- * <p>A registry of objects used by <code>reflectionToString</code> methods
- * to detect cyclical object references and avoid infinite loops.</p>
- */
- private static ThreadLocal registry = new ThreadLocal() {
- protected synchronized Object initialValue() {
- // The HashSet implementation is not synchronized,
- // which is just what we need here.
- return new HashSet();
- }
- };
-
- /**
- * <p>Returns the registry of objects being traversed by the
- * <code>reflectionToString</code> methods in the current thread.</p>
- *
- * @return Set the registry of objects being traversed
- */
- static Set getRegistry() {
- return (Set) registry.get();
- }
-
- /**
- * <p>Returns <code>true</code> if the registry contains the given object.
- * Used by the reflection methods to avoid infinite loops.</p>
- *
- * @param value The object to lookup in the registry.
- * @return boolean <code>true</code> if the registry contains the given object.
- */
- static boolean isRegistered(Object value) {
- return getRegistry().contains(value);
- }
-
- /**
- * <p>Registers the given object.
- * Used by the reflection methods to avoid infinite loops.</p>
- *
- * @param value The object to register.
- */
- static void register(Object value) {
- getRegistry().add(value);
- }
-
- /**
- * <p>This method uses reflection to build a suitable
- * <code>toString</code> using the default <code>ToStringStyle</code>.
- *
- * <p>It uses <code>AccessibleObject.setAccessible</code> 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.</p>
- *
- * <p>Transient members will be not be included, as they are likely derived.
- * Static fields will not be included. Superclass fields will be appended.</p>
- *
- * @param object the Object to be output
- * @return the String result
- * @throws IllegalArgumentException if the Object is <code>null</code>
- */
- public static String toString(Object object) {
- return toString(object, null, false, null);
- }
-
- /**
- * <p>This method uses reflection to build a suitable
- * <code>toString</code>.</p>
- *
- * <p>It uses <code>AccessibleObject.setAccessible</code> 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.</p>
- *
- * <p>Transient members will be not be included, as they are likely derived.
- * Static fields will not be included. Superclass fields will be appended.</p>
- *
- * <p>If the style is <code>null</code>, the default
- * <code>ToStringStyle</code> is used.</p>
- *
- * @param object the Object to be output
- * @param style the style of the <code>toString</code> to create,
- * may be <code>null</code>
- * @return the String result
- * @throws IllegalArgumentException if the Object or
- * <code>ToStringStyle</code> is <code>null</code>
- */
- public static String toString(Object object, ToStringStyle style) {
- return toString(object, style, false, null);
- }
-
- /**
- * <p>This method uses reflection to build a suitable
- * <code>toString</code>.</p>
- *
- * <p>It uses <code>AccessibleObject.setAccessible</code> 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. </p>
- *
- * <p>If the <code>outputTransients</code> is <code>true</code>,
- * transient members will be output, otherwise they are ignored,
- * as they are likely derived fields, and not part of the value of the
- * Object.</p>
- *
- * <p>Static fields will not be included. Superclass fields will be appended.</p>
- *
- * <p>If the style is <code>null</code>, the default
- * <code>ToStringStyle</code> is used.</p>
- *
- * @param object the Object to be output
- * @param style the style of the <code>toString</code> to create,
- * may be <code>null</code>
- * @param outputTransients whether to include transient fields
- * @return the String result
- * @throws IllegalArgumentException if the Object is <code>null</code>
- */
- public static String toString(Object object, ToStringStyle style, boolean outputTransients) {
- return toString(object, style, outputTransients, null);
- }
-
- /**
- * <p>This method uses reflection to build a suitable
- * <code>toString</code>.</p>
- *
- * <p>It uses <code>AccessibleObject.setAccessible</code> 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. </p>
- *
- * <p>If the <code>outputTransients</code> is <code>true</code>,
- * transient members will be output, otherwise they are ignored,
- * as they are likely derived fields, and not part of the value of the
- * Object.</p>
- *
- * <p>Static fields will not be included. Superclass fields will be appended
- * up to and including the specified superclass. A null superclass is treated
- * as <code>java.lang.Object</code>.</p>
- *
- * <p>If the style is <code>null</code>, the default
- * <code>ToStringStyle</code> is used.</p>
- *
- * @param object the Object to be output
- * @param style the style of the <code>toString</code> to create,
- * may be <code>null</code>
- * @param outputTransients whether to include transient fields
- * @param reflectUpToClass the superclass to reflect up to (inclusive),
- * may be <code>null</code>
- * @return the String result
- * @throws IllegalArgumentException if the Object is <code>null</code>
- */
- public static String toString(
- Object object,
- ToStringStyle style,
- boolean outputTransients,
- Class reflectUpToClass) {
- return new ReflectionToStringBuilder(object, style, null, reflectUpToClass, outputTransients).toString();
- }
-
- /**
- * <p>Unregisters the given object.</p>
- *
- * <p>Used by the reflection methods to avoid infinite loops.</p>
- *
- * @param value The object to unregister.
- */
- static void unregister(Object value) {
- getRegistry().remove(value);
- }
-
- /**
- * Whether or not to append transient fields.
- */
- private boolean appendTransients = false;
-
- /**
- * The last super class to stop appending fields for.
- */
- private Class upToClass = null;
-
- /**
- * <p>Constructor.</p>
- *
- * <p>This constructor outputs using the default style set with
- * <code>setDefaultStyle</code>.</p>
- *
- * @param object the Object to build a <code>toString</code> for,
- * must not be <code>null</code>
- * @throws IllegalArgumentException if the Object passed in is
- * <code>null</code>
- */
- public ReflectionToStringBuilder(Object object) {
- super(object);
- }
-
- /**
- * <p>Constructor.</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,
- * must not be <code>null</code>
- * @param style the style of the <code>toString</code> to create,
- * may be <code>null</code>
- * @throws IllegalArgumentException if the Object passed in is
- * <code>null</code>
- */
- public ReflectionToStringBuilder(Object object, ToStringStyle style) {
- super(object, style);
- }
-
- /**
- * <p>Constructor.</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,
- * must not be <code>null</code>
- * @param style the style of the <code>toString</code> to create,
- * may be <code>null</code>
- * @param buffer the <code>StringBuffer</code> to populate, may be
- * <code>null</code>
- * @throws IllegalArgumentException if the Object passed in is
- * <code>null</code>
- */
- public ReflectionToStringBuilder(Object object, ToStringStyle style, StringBuffer buffer) {
- super(object, style, buffer);
- }
-
- /**
- * Constructor.
- *
- * @param object the Object to build a <code>toString</code> for,
- * must not be <code>null</code>
- * @param style the style of the <code>toString</code> to create,
- * may be <code>null</code>
- * @param buffer the <code>StringBuffer</code> to populate, may be
- * <code>null</code>
- * @param reflectUpToClass the superclass to reflect up to (inclusive),
- * may be <code>null</code>
- * @param outputTransients whether to include transient fields
- */
- public ReflectionToStringBuilder(
- Object object,
- ToStringStyle style,
- StringBuffer buffer,
- Class reflectUpToClass,
- boolean outputTransients) {
- super(object, style, buffer);
- this.setUpToClass(reflectUpToClass);
- this.setAppendTransients(outputTransients);
- }
-
- /**
- * Returns whether or not to append the given <code>Field</code>.
- * <ul>
- * <li>Static fields are not appended.</li>
- * <li>Transient fields are appended only if {@link #isAppendTransients()} returns <code>true</code>.
- * <li>Inner class fields are not appened.</li>
- * </ul>
- * @param field The Field to test.
- * @return Whether or not to append the given <code>Field</code>.
- */
- protected boolean accept(Field field) {
- String fieldName = field.getName();
- return (fieldName.indexOf(ClassUtils.INNER_CLASS_SEPARATOR_CHAR) == -1)
- && (this.isAppendTransients() || !Modifier.isTransient(field.getModifiers()))
- && (!Modifier.isStatic(field.getModifiers()));
- }
-
- /**
- * <p>Appends the fields and values defined by the given object of the
- * given Class.</p>
- *
- * <p>If a cycle is detected as an object is "toString()'ed",
- * such an object is rendered as if <code>Object.toString()</code>
- * had been called and not implemented by the object.</p>
- *
- * @param clazz The class of object parameter
- */
- protected void appendFieldsIn(Class clazz) {
- if (isRegistered(this.getObject())) {
- // The object has already been appended, therefore we have an object cycle.
- // Append a simple Object.toString style string. The field name is already appended at this point.
- this.appendAsObjectToString(this.getObject());
- return;
- }
- try {
- this.registerObject();
- if (clazz.isArray()) {
- this.reflectionAppendArray(this.getObject());
- return;
- }
- Field[] fields = clazz.getDeclaredFields();
- AccessibleObject.setAccessible(fields, true);
- for (int i = 0; i < fields.length; i++) {
- Field field = fields[i];
- String fieldName = field.getName();
- if (this.accept(field)) {
- try {
- // Warning: Field.get(Object) creates wrappers objects for primitive types.
- Object fieldValue = this.getValue(field);
- if (isRegistered(fieldValue) && !field.getType().isPrimitive()) {
- // A known field value has already been appended, therefore we have an object cycle,
- // append a simple Object.toString style string.
- this.getStyle().appendFieldStart(this.getStringBuffer(), fieldName);
- this.appendAsObjectToString(fieldValue);
- // The recursion out of
- // builder.append(fieldName, fieldValue);
- // below will append the field
- // end marker.
- } else {
- try {
- this.registerObject();
- this.append(fieldName, fieldValue);
- } finally {
- this.unregisterObject();
- }
- }
- } catch (IllegalAccessException ex) {
- //this can't happen. Would get a Security exception instead
- //throw a runtime exception in case the impossible happens.
- throw new InternalError("Unexpected IllegalAccessException: " + ex.getMessage());
- }
- }
- }
- } finally {
- this.unregisterObject();
- }
- }
-
- /**
- * <p>Gets the last super class to stop appending fields for.</p>
- *
- * @return The last super class to stop appending fields for.
- */
- public Class getUpToClass() {
- return this.upToClass;
- }
-
- /**
- * <p>Calls <code>java.lang.reflect.Field.get(Object)</code>.</p>
- *
- * @see java.lang.reflect.Field#get(Object)
- * @throws IllegalArgumentException
- * @throws IllegalAccessException
- */
- protected Object getValue(Field field) throws IllegalArgumentException, IllegalAccessException {
- return field.get(this.getObject());
- }
-
- /**
- * <p>Gets whether or not to append transient fields.</p>
- *
- * @return Whether or not to append transient fields.
- */
- public boolean isAppendTransients() {
- return this.appendTransients;
- }
-
- /**
- * <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 ToStringBuilder reflectionAppendArray(Object array) {
- this.getStyle().reflectionAppendArrayDetail(this.getStringBuffer(), null, array);
- return this;
- }
-
- /**
- * <p>Registers this builder's source object to avoid infinite
- * loops when processing circular object references.</p>
- */
- void registerObject() {
- register(this.getObject());
- }
-
- /**
- * <p>Sets whether or not to append transient fields.</p>
- *
- * @param appendTransients Whether or not to append transient fields.
- */
- public void setAppendTransients(boolean appendTransients) {
- this.appendTransients = appendTransients;
- }
-
- /**
- * <p>Sets the last super class to stop appending fields for.</p>
- *
- * @param clazz The last super class to stop appending fields for.
- */
- public void setUpToClass(Class clazz) {
- this.upToClass = clazz;
- }
-
- /**
- * <p>Gets the String built by this builder.</p>
- *
- * @return the built string
- */
- public String toString() {
- if (this.getObject() == null) {
- return this.getStyle().getNullText();
- }
- Class clazz = this.getObject().getClass();
- this.appendFieldsIn(clazz);
- while (clazz.getSuperclass() != null && clazz != this.getUpToClass()) {
- clazz = clazz.getSuperclass();
- this.appendFieldsIn(clazz);
- }
- return super.toString();
- }
-
- /**
- * <p>Unegisters this builder's source object to avoid infinite
- * loops when processing circular object references.</p>
- */
- void unregisterObject() {
- unregister(this.getObject());
- }
-
- }