# TraceOnConsoleSideEffect.java

    /*
     * Copyright 2006 Niclas Hedhman.
     *
     * Licensed  under the  Apache License,  Version 2.0  (the "License");
     * you may not use  this file  except in  compliance with the License.
     * You may obtain a copy of the License at
     *
     *   http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed  under the  License is distributed on an "AS IS" BASIS,
     * WITHOUT  WARRANTIES OR CONDITIONS  OF ANY KIND, either  express  or
     * implied.
     *
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    package org.qi4j.logging.trace;

    import java.io.PrintStream;
    import java.lang.reflect.Method;
    import org.qi4j.api.composite.Composite;
    import org.qi4j.api.sideeffect.SideEffectOf;
    import org.qi4j.logging.trace.service.TraceService;

    /**
     * The ConsoleViewSideEffect is just a temporary solution for logging output, until a more
     * robust framework has been designed.
     */
    public abstract class TraceOnConsoleSideEffect extends SideEffectOf<TraceService>
        implements TraceService
    {
        private static PrintStream OUT = System.err;

        @Override
        public void traceSuccess( Class compositeType, Composite object, Method method, Object[] args, Object result, long entryTime, long durationNano )
        {
            StringBuffer buf = new StringBuffer();
            buf.append( durationNano / 1000000 );
            buf.append( " ms: " );
            formatMethod( buf, object, compositeType, method, args );
            OUT.println( buf.toString() );
            OUT.println( result );
        }

        @Override
        public void traceException( Class compositeType, Composite object, Method method, Object[] args, Throwable t, long entryTime, long durationNano )
        {
            StringBuffer buf = new StringBuffer();
            buf.append( "Exception: " );
            buf.append( durationNano / 1000000 );
            buf.append( " ms: " );
            OUT.println( buf.toString() );
            t.printStackTrace( OUT );
        }

        private void formatMethod( StringBuffer buf, Composite object, Class compositeType, Method method, Object[] args )
        {
            buf.append( compositeType.getClass().getName() );
            buf.append( "." );
            buf.append( method.getName() );
            buf.append( "( " );
            if( args != null )
            {
                boolean first = true;
                for( Object arg : args )
                {
                    if( !first )
                    {
                        buf.append( ", " );
                    }
                    first = false;
                    if( arg instanceof String )
                    {
                        buf.append( "\"" );
                    }
                    buf.append( arg );
                    if( arg instanceof String )
                    {
                        buf.append( "\"" );
                    }
                }
            }
            buf.append( " )  [ " );
            if( object == null )
            {
                buf.append( "<null>" );
            }
            else
            {
                buf.append( object.toString() );
            }
            buf.append( " ]" );
        }
    }