Java DebugPrinter
Diese Klasse erzeugt eine Debugausgabe eines Objektes, Arrays, Liste oder Map ähnlich der print_r oder var_dump Funktion in PHP. Es wird nicht überprüft ob die Struktur rekursiv ist, stattdessen muss die maximale Tiefe angegeben werden bis zu der verzweigt wird.
Das Ausgabeformat orientiert sich an der JavaScript Object Notation.
package de.planetxml.tools;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.reflect.Array;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Collection;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.beans.Introspector;
/**
* Diese Klasse erzeugt eine Debugausgabe eines Objektes, Arrays, Liste oder
* Map ähnlich der print_r oder var_dump Funktion in PHP. Es wird nicht
* überprüft ob die Struktur rekursiv ist, stattdessen muss die maximale Tiefe
* angegeben werden bis zu der verzweigt wird.
*
* Das Ausgabeformat orientiert sich an der
* <a href="http://www.json.org/">JavaScript Object Notation</a>.
*
* @version $Revision$
* @author Jörn Horstmann <joern_h@gmx.net>, http://blog.planetxml.de/
*/
public class DebugPrinter {
private Object object;
private int maxLevel;
private HashSet visited;
public DebugPrinter(Object o, int maxLevel) {
this.object = o;
this.maxLevel = maxLevel;
this.visited = new HashSet();
}
public DebugPrinter(Object o) {
this(o, 3);
}
private static String escapeString(String str) {
return escapeString(str, '"');
}
private static String escapeString(String str, char quote) {
// create a StringBuffer that is a bit bigger than str
StringBuffer sb = new StringBuffer(str.length() + str.length() / 8 + 2);
int len = str.length();
sb.append(quote);
for (int i=0; i<len; i++) {
char ch = str.charAt(i);
if (ch == '\\') {
sb.append("\\\\");
}
else if (ch == '\n') {
sb.append("\\n");
}
else if (ch == '\r') {
sb.append("\\r");
}
else if (ch == '\t') {
sb.append("\\t");
}
else if (ch == '\b') {
sb.append("\\b");
}
else if (ch == '\f') {
sb.append("\\f");
}
else if (ch == quote) {
sb.append('\\');
sb.append(quote);
}
else if (ch < 16) {
sb.append("\\u000");
sb.append(Integer.toHexString(ch));
}
else if (ch < 32) {
sb.append("\\u00");
sb.append(Integer.toHexString(ch));
}
else if (ch < 127) { // 127 is a control character
sb.append(ch);
}
else if (ch < 256) {
sb.append("\\u00");
sb.append(Integer.toHexString(ch));
}
else if (ch < 4096) {
sb.append("\\u0");
sb.append(Integer.toHexString(ch));
}
else {
sb.append("\\u");
sb.append(Integer.toHexString(ch));
}
}
sb.append(quote);
return sb.toString();
}
public void print(PrintWriter out) {
printProperties(object, out, 0);
out.flush();
}
public String dump() {
StringWriter w = new StringWriter(512);
print(new PrintWriter(w));
return w.toString();
}
private static void indent(PrintWriter pw, int level) {
for (int i=0; i<level; i++) {
pw.print(" ");
}
}
private static String getPropertyName(Method m) {
Class type = m.getReturnType();
String name = m.getName();
String property = null;
if (type != Void.TYPE && type != Class.class && m.getParameterTypes().length == 0 && Modifier.isPublic(m.getModifiers())) {
if (type == Boolean.TYPE && name.length() > 2 && name.startsWith("is")) {
property = name.substring(2);
}
else if (name.length() > 3 && name.startsWith("get")) {
property = name.substring(3);
}
if (property != null) {
property = Introspector.decapitalize(property);
}
}
return property;
}
private void printProperties(Object o, PrintWriter pw, int level) {
if (o == null) {
pw.print("null");
}
else if (o instanceof Boolean || o instanceof Byte || o instanceof Short || o instanceof Character || o instanceof Integer || o instanceof Long || o instanceof Float || o instanceof Double) {
pw.print(o);
}
else if (o instanceof String) {
pw.print(escapeString((String)o));
}
else {
if (level > maxLevel) {
pw.print("...");
return;
}
else if (o.getClass().isArray()) {
pw.println('[');
int len = Array.getLength(o);
for (int i=0; i<len; i++) {
indent(pw, level+1);
pw.print(i > 0 ? ", " : " ");
printProperties(Array.get(o, i), pw, level+1);
pw.println();
}
indent(pw, level);
pw.print(']');
}
else if (o instanceof Collection) {
pw.println('[');
Collection col = (Collection)o;
int c = 0;
for (Iterator it=col.iterator(); it.hasNext(); ) {
indent(pw, level+1);
pw.print(c > 0 ? ", " : " ");
printProperties(it.next(), pw, level+1);
pw.println();
c++;
}
indent(pw, level);
pw.print(']');
}
else if (o instanceof Iterator) {
pw.println('[');
int c = 0;
for (Iterator it=(Iterator)o; it.hasNext(); ) {
indent(pw, level+1);
pw.print(c > 0 ? ", " : " ");
printProperties(it.next(), pw, level+1);
pw.println();
c++;
}
indent(pw, level);
pw.print(']');
}
else if (o instanceof Enumeration) {
pw.println('[');
int c = 0;
for (Enumeration e=(Enumeration)o; e.hasMoreElements(); ) {
indent(pw, level+1);
pw.print(c > 0 ? ", " : " ");
printProperties(e.nextElement(), pw, level+1);
pw.println();
c++;
}
indent(pw, level);
pw.print(']');
}
else if (o instanceof Map) {
pw.println('{');
Map map = (Map)o;
int c = 0;
for (Iterator it=map.entrySet().iterator(); it.hasNext(); ) {
Map.Entry me = (Map.Entry)it.next();
indent(pw, level+1);
pw.print(c > 0 ? ", " : " ");
pw.print(escapeString(me.getKey().toString()));
pw.print(": ");
printProperties(me.getValue(), pw, level+1);
pw.println();
c++;
}
indent(pw, level);
pw.print('}');
}
else {
Method[] m = o.getClass().getMethods();
int c = 0;
pw.println('{');
for (int i=0; i<m.length; i++) {
String property = getPropertyName(m[i]);
if (property != null) {
indent(pw, level+1);
pw.print(c > 0 ? ", " : " ");
pw.print(escapeString(property));
pw.print(": ");
try {
printProperties(m[i].invoke(o, null), pw, level+1);
c++;
}
catch (Exception e) {
}
pw.println();
}
}
indent(pw, level);
pw.print('}');
}
}
}
}