This utility provide ability to write objects to string. Example says everything:
Then we call:
and output is:
Utility implementation:
public class Person {
private PersonName name;
private Integer age;
public static class PersonName {
private String firstName;
private String lastName;
public PersonName(String firstName, String lastName) {
this.firstName = firstName;
this.lastName = lastName;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}
public Person(PersonName name, Integer age) {
this.name = name;
this.age = age;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public PersonName getName() {
return name;
}
public void setName(PersonName name) {
this.name = name;
}
@Override
public String toString() {
return StringUtils.objectToString("person", this);
}
}
Then we call:
public static void main(String[] args) {
System.out.println(new Person(new PersonName("Astar", "Sheran"), 2009));
}
and output is:
person.age = 2009 person.name = new Person$PersonName() person.name.firstName = Astar person.name.lastName = Sheran
Utility implementation:
import java.beans.BeanInfo;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
*
* @author Michal Hlavac
*/
public class StringUtils {
private static final Logger log = Logger.getLogger(StringUtils.class.getName());
private static final void toString(String alias, Object obj, StringBuffer sb, List<Object> objects) {
if (obj == null) {
return;
}
if (objects.contains(obj)) {
return;
}
objects.add(obj);
try {
BeanInfo info = Introspector.getBeanInfo(obj.getClass());
PropertyDescriptor[] descriptors = info.getPropertyDescriptors();
for (int i = 0; i < descriptors.length; i++) {
PropertyDescriptor descriptor = descriptors[i];
if (descriptor.getReadMethod().getDeclaringClass().equals(Object.class)) {
log.fine("property defined on Object class: skipping: " + descriptor.getName());
continue;
}
Object value = null;
try {
value = descriptor.getReadMethod().invoke(obj, (Object[]) null);
} catch (Throwable ex) {
log.fine("Can't read value of attribute " + obj.getClass().getName() + "." + descriptor.getName());
}
if (value == null) {
log.fine("property value is null: skipping: " + descriptor.getName());
continue;
}
Class<?> returnType = descriptor.getReadMethod().getReturnType();
if (!returnType.isPrimitive() && !returnType.isArray() && !returnType.getName().startsWith("java.") &&
!returnType.isEnum()) {
log.fine("property is unknown type or not primitive [" + returnType.getName() + "]");
String simpleName = value.getClass().getName().substring(returnType.getName().lastIndexOf('.') + 1);
sb.append(alias).append(".").append(descriptor.getName()).append(" = new ").append(simpleName).append("()\n");
toString(alias + "." + descriptor.getName(), value, sb, objects);
continue;
}
if (value instanceof java.util.Collection<?>) {
try {
Iterator<?> iter = ((Collection<?>) value).iterator(); int num = 0;
while (iter.hasNext()) {
Object item = iter.next();
toString(alias + "." + descriptor.getName() + "[" + num + "]", item, sb, objects);
num++;
}
} catch (Throwable t) {
log.fine("Can't read value of attribute: " + alias + "." + descriptor.getName());
}
continue;
} else if (value.getClass().isArray()) {
try {
Object[] valueArray = (Object[]) value;
for (int idx = 0; idx < valueArray.length; idx++) {
toString(alias + "." + descriptor.getName() + "[" + idx + "]", valueArray[idx], sb, objects);
}
} catch (Throwable t) {
log.fine("Can't read value of attribute: " + alias + "." + descriptor.getName());
}
continue;
}
sb.append(alias).append(".").append(descriptor.getName()).append(" = ").append(value.toString()).append('\n');
}
} catch (Exception e) {
log.log(Level.SEVERE, "hql example criterion building error", e);
}
}
public static final String objectToString(String alias, Object obj) {
StringBuffer buff = new StringBuffer();
toString(alias, obj, buff, new ArrayList<Object>());
return buff.toString();
}
public static final String collectionToString(String alias, Collection<?> collection) {
StringBuffer buff = new StringBuffer();
int idx = 0;
for (Object obj : collection) {
toString(alias + "[" + idx++ + "]", obj, buff, new ArrayList<Object>());
}
return buff.toString();
}
public static final String toStringLine(Object obj) {
if (obj == null) {
return "";
}
String clazz = obj.getClass().getName();
String simpleClazz = clazz.substring(clazz.lastIndexOf('.') + 1);
StringBuffer sb = new StringBuffer(simpleClazz).append("[");
try {
BeanInfo info = Introspector.getBeanInfo(obj.getClass());
PropertyDescriptor[] descriptors = info.getPropertyDescriptors();
for (int i = 0; i < descriptors.length; i++) {
PropertyDescriptor descriptor = descriptors[i];
if (descriptor.getPropertyType() == null ||
Collection.class.isAssignableFrom(descriptor.getPropertyType())) {
log.fine("collection handling not supported: skipping property: " + descriptor.getName());
continue;
}
if (descriptor.getReadMethod().getDeclaringClass().equals(Object.class)) {
log.fine("property defined on Object class: skipping: " + descriptor.getName());
continue;
}
Object value = descriptor.getReadMethod().invoke(obj, (Object[]) null);
if (value == null) {
log.fine("property value is null: skipping: " + descriptor.getName());
continue;
}
Class<?> returnType = descriptor.getReadMethod().getReturnType();
if (!returnType.isPrimitive() && !returnType.getName().startsWith("java.") && !returnType.isEnum()) {
log.fine("property is unknown type or not primitive [" + returnType.getName() + "]");
continue;
}
sb.append(descriptor.getName()).append(" = ").append(value).append(" | ");
}
} catch (Exception e) {
log.log(Level.SEVERE, "hql example criterion building error", e);
return null;
}
sb.append("]");
return sb.toString();
}
}
