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//================================================================================
//Copyright (c) 2012, David Yu
//All rights reserved.
//--------------------------------------------------------------------------------
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// 1. Redistributions of source code must retain the above copyright notice,
//    this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
// 3. Neither the name of protostuff nor the names of its contributors may be used
//    to endorse or promote products derived from this software without
//    specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//================================================================================


package com.dyuproject.protostuff.runtime;

import static com.dyuproject.protostuff.runtime.RuntimeFieldFactory.ID_THROWABLE;
import static com.dyuproject.protostuff.runtime.RuntimeFieldFactory.STR_THROWABLE;

import java.io.IOException;

import com.dyuproject.protostuff.GraphInput;
import com.dyuproject.protostuff.Input;
import com.dyuproject.protostuff.Output;
import com.dyuproject.protostuff.Pipe;
import com.dyuproject.protostuff.ProtostuffException;
import com.dyuproject.protostuff.Schema;
import com.dyuproject.protostuff.StatefulOutput;

/**
 * Used when the type is assignable from {@link java.lang.Throwable}.
 *
 * @author David Yu
 * @created May 2, 2012
 */
public abstract class PolymorphicThrowableSchema extends PolymorphicSchema
{
    
    static final java.lang.reflect.Field __cause;
    
    static
    {
        java.lang.reflect.Field cause = null;
        try
        {
            cause = Throwable.class.getDeclaredField("cause");
            cause.setAccessible(true);
        }
        catch (Exception e)
        {
            cause = null;
        }
        
        __cause = cause;
    }
    
    static String name(int number)
    {
        return number == ID_THROWABLE ? STR_THROWABLE : null;
    }
    
    static int number(String name)
    {
        return name.length() == 1 && name.charAt(0) == 'Z' ? ID_THROWABLE : 0;
    }
    
    protected final Pipe.Schema pipeSchema = new Pipe.Schema(this)
    {
        protected void transfer(Pipe pipe, Input input, Output output) throws IOException
        {
            transferObject(this, pipe, input, output, strategy);
        }
    };
    
    public PolymorphicThrowableSchema(IdStrategy strategy)
    {
        super(strategy);
    }
    
    public Pipe.Schema getPipeSchema()
    {
        return pipeSchema;
    }
    
    public String getFieldName(int number)
    {
        return name(number);
    }

    public int getFieldNumber(String name)
    {
        return number(name);
    }

    public String messageFullName()
    {
        return Throwable.class.getName();
    }

    public String messageName()
    {
        return Throwable.class.getSimpleName();
    }

    public void mergeFrom(Input input, Object owner) throws IOException
    {
        setValue(readObjectFrom(input, this, owner, strategy), owner);
    }

    public void writeTo(Output output, Object value) throws IOException
    {
        writeObjectTo(output, value, this, strategy);
    }
    
    @SuppressWarnings("unchecked")
    static void writeObjectTo(Output output, Object value, Schema currentSchema, 
            IdStrategy strategy) throws IOException
    {
        final Schema schema = strategy.writePojoIdTo(output, ID_THROWABLE, 
                (Class)value.getClass());
        
        if(output instanceof StatefulOutput)
        {
            // update using the derived schema.
            ((StatefulOutput)output).updateLast(schema, currentSchema);
        }
        
        if(tryWriteWithoutCause(output, value, schema))
            return;

        schema.writeTo(output, value);
    }
    
    static boolean tryWriteWithoutCause(Output output, Object value, 
            Schema schema) throws IOException
    {
        if(schema instanceof MappedSchema && __cause != null)
        {
            // ignore the field "cause" if its references itself (cyclic)
            final MappedSchema ms = (MappedSchema)schema;
            if(ms.fields.length > 1 && ms.fields[1].name.equals("cause"))
            {
                final Object cause;
                try
                {
                    cause = __cause.get(value);
                }
                catch (IllegalArgumentException e)
                {
                    throw new RuntimeException(e);
                }
                catch (IllegalAccessException e)
                {
                    throw new RuntimeException(e);
                }
                
                if(cause == value)
                {
                    // its cyclic, skip the second field "cause"
                    ms.fields[0].writeTo(output, value);
                    
                    for(int i = 2, len = ms.fields.length; i < len; i++)
                        ms.fields[i].writeTo(output, value);
                    
                    return true;
                }
            }
        }
        
        return false;
    }
    
    static Object readObjectFrom(Input input, Schema schema, Object owner, 
            IdStrategy strategy) throws IOException
    {
        final int number = input.readFieldNumber(schema);
        if(number != ID_THROWABLE)
            throw new ProtostuffException("Corrupt input.");
        
        return readObjectFrom(input, schema, owner, strategy, number);
    }
            
    
    static Object readObjectFrom(Input input,  Schema schema, Object owner, 
            IdStrategy strategy, int number) throws IOException
    {
        final Schema derivedSchema = strategy.resolvePojoFrom(
                input, number).getSchema();
        
        final Object pojo = derivedSchema.newMessage();
        
        if(input instanceof GraphInput)
        {
            // update the actual reference.
            ((GraphInput)input).updateLast(pojo, owner);
        }
        
        if(__cause != null)
        {
            final Object cause;
            try
            {
                cause = __cause.get(pojo);
            }
            catch (IllegalArgumentException e)
            {
                throw new RuntimeException(e);
            }
            catch (IllegalAccessException e)
            {
                throw new RuntimeException(e);
            }
            
            if(cause == null)
            {
                // was not written because it was cyclic
                // so we set it here manually for correctness
                try
                {
                    __cause.set(pojo, cause);
                }
                catch (IllegalArgumentException e)
                {
                    throw new RuntimeException(e);
                }
                catch (IllegalAccessException e)
                {
                    throw new RuntimeException(e);
                }
            }
        }
        
        derivedSchema.mergeFrom(input, pojo);
        return pojo;
    }
    
    static void transferObject(Pipe.Schema pipeSchema, Pipe pipe, 
            Input input, Output output, IdStrategy strategy) throws IOException
    {
        final int number = input.readFieldNumber(pipeSchema.wrappedSchema);
        if(number != ID_THROWABLE)
            throw new ProtostuffException("Corrupt input.");
        
        transferObject(pipeSchema, pipe, input, output, strategy, number);
    }
    
    static void transferObject(Pipe.Schema pipeSchema, Pipe pipe, 
            Input input, Output output, IdStrategy strategy, int number) throws IOException
    {
        final Pipe.Schema derivedPipeSchema = strategy.transferPojoId(
                input, output, number).getPipeSchema();
        
        if(output instanceof StatefulOutput)
        {
            // update using the derived schema.
            ((StatefulOutput)output).updateLast(derivedPipeSchema, pipeSchema);
        }
        
        Pipe.transferDirect(derivedPipeSchema, pipe, input, output);
    }

}
    

    

    

            

    

            



    
    






    
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