ObjectPrinter.java

package org.jekamax.utils;

import java.lang.reflect.Field;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;
import java.util.TreeSet;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *Print Contents of deep Hierarchies of objects
 * To be printed object must implement ObjectPrinter.Printable
 * (its just a marker, no real methods to implement)
 * Printer is protected from recursion by tracing already printed objects
 * @author jekamax
 */
public class ObjectPrinter
{
    public static interface Printable
    {
        
    }
    public static String makeIndent(int indent)
    {
        StringBuilder stBuilder = new StringBuilder();
        for (int i = 0; i < indent; ++i)
        {
            stBuilder.append("    ");
        }
        return stBuilder.toString();
    }
    public static String indentStr(int indent, String str)
    {
        String sep = System.getProperty("line.separator");
        String indentStr = makeIndent(indent);
        String[] split = str.split("\\r?\\n");
        StringBuilder stBuilder = new StringBuilder();
        for (String st : split)
        {
            stBuilder.append(indentStr);
            stBuilder.append(st);
            stBuilder.append(sep);
        }
        return stBuilder.toString();
    }
    public static String printObject(Object obj)
    {
        return printObject(obj, 0, null, false);
    }
    public static String printObject(Object obj, int preIndent, Set<Object> AlreadyPrinted, boolean inline)
    {

        StringBuilder stBuilder = new StringBuilder();
        String objStr="null";
        if(obj!=null)
        {
            objStr=obj.toString();
        }
        if (inline)
        {
            stBuilder.append("["+objStr+"] ");
            if(obj!=null)
            {
                stBuilder.append(obj.getClass().getSimpleName());
            }
        } else
        {
            stBuilder.append(indentStr(preIndent, objStr));
        }
        if (AlreadyPrinted == null)
        {
            AlreadyPrinted = new HashSet<Object>();
        }
        if (obj!=null && (obj instanceof ObjectPrinter.Printable || obj instanceof Collection<?>))
        {
            if (!AlreadyPrinted.contains(obj))
            {
                AlreadyPrinted.add(obj);
                if(inline)
                {
                    stBuilder.append("\n");
                }
                stBuilder.append(indentStr(preIndent, String.format("{")));
                
                int indent = preIndent + 1;
                if (obj instanceof Collection<?>)
                {
                    Collection<?> coll = (Collection<?>) obj;
                    for (Object o : coll)
                    {
                        stBuilder.append(printObject(o, indent , AlreadyPrinted, false));
                    }
                } else
                {
                    for (Field field : obj.getClass().getDeclaredFields())
                    {
                        try
                        {
                            field.setAccessible(true);
                            String name = field.getName();
                            java.lang.Object value = field.get(obj);
                            stBuilder.append(indentStr(indent, String.format("%s: %s", name, printObject(value, preIndent, AlreadyPrinted, true))));

                        }
                        catch (IllegalArgumentException ex)
                        {
                            Logger.getLogger(OBJ_Object.class.getName()).log(Level.SEVERE, null, ex);
                        }
                        catch (IllegalAccessException ex)
                        {
                            Logger.getLogger(OBJ_Object.class.getName()).log(Level.SEVERE, null, ex);
                        }
                    }
                }
               stBuilder.append(indentStr(preIndent, String.format("}")));
            } else
            {
                stBuilder.append(" (already printed)");
            }
        }
        return stBuilder.toString();

    }
}