DebugUtil.java

package org.neo4j.kernel.impl.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringReader;
import java.io.StringWriter;

public class DebugUtil
{
    public static void printShortStackTrace( Throwable cause, int maxNumberOfStackLines )
    {
        StringWriter stringWriter = new StringWriter();
        PrintWriter writer = new PrintWriter( stringWriter );
        cause.printStackTrace( writer );
        writer.close();
        String string = stringWriter.getBuffer().toString();
        System.out.println( firstLinesOf( string, maxNumberOfStackLines+1 ) );
    }

    public static String firstLinesOf( String string, int maxNumberOfLines )
    {
        // Totally verbose implementation of this functionality :)
        StringWriter stringWriter = new StringWriter();
        PrintWriter writer = new PrintWriter( stringWriter );
        try
        {
            BufferedReader reader = new BufferedReader( new StringReader( string ) );
            String line = null;
            for ( int count = 0; ( line = reader.readLine() ) != null && count < maxNumberOfLines;
                    count++ )
            {
                writer.println( line );
            }
            writer.close();
            return stringWriter.getBuffer().toString();
        }
        catch ( IOException e )
        {
            throw new RuntimeException( "Can't happen", e );
        }
    }
}