85 lines
2.2 KiB
Java
85 lines
2.2 KiB
Java
import java.lang.reflect.*;
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import java.util.*;
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/**
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* This program uses reflection to spy on objects.
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* @version 1.11 2004-02-21
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* @author Cay Horstmann
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*/
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public class ObjectAnalyzerTest
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{
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public static void main(String[] args)
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{
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ArrayList<Integer> squares = new ArrayList<Integer>();
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for (int i = 1; i <= 5; i++)
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squares.add(i * i);
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System.out.println(new ObjectAnalyzer().toString(squares));
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}
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}
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class ObjectAnalyzer
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{
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/**
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* Converts an object to a string representation that lists all fields.
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* @param obj an object
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* @return a string with the object's class name and all field names and
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* values
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*/
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public String toString(Object obj)
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{
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if (obj == null) return "null";
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if (visited.contains(obj)) return "...";
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visited.add(obj);
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Class cl = obj.getClass();
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if (cl == String.class) return (String) obj;
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if (cl.isArray())
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{
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String r = cl.getComponentType() + "[]{";
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for (int i = 0; i < Array.getLength(obj); i++)
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{
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if (i > 0) r += ",";
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Object val = Array.get(obj, i);
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if (cl.getComponentType().isPrimitive()) r += val;
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else r += toString(val);
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}
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return r + "}";
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}
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String r = cl.getName();
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// inspect the fields of this class and all superclasses
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do
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{
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r += "[";
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Field[] fields = cl.getDeclaredFields();
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AccessibleObject.setAccessible(fields, true);
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// get the names and values of all fields
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for (Field f : fields)
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{
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if (!Modifier.isStatic(f.getModifiers()))
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{
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if (!r.endsWith("[")) r += ",";
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r += f.getName() + "=";
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try
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{
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Class t = f.getType();
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Object val = f.get(obj);
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if (t.isPrimitive()) r += val;
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else r += toString(val);
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}
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catch (Exception e)
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{
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e.printStackTrace();
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}
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}
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}
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r += "]";
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cl = cl.getSuperclass();
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}
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while (cl != null);
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return r;
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}
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private ArrayList<Object> visited = new ArrayList<Object>();
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}
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