proton-j/src/main/java/org/apache/qpid/proton/codec/AbstractDescribedType.java

/*
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.qpid.proton.codec;

import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import org.apache.qpid.proton.amqp.UnsignedLong;

abstract public class AbstractDescribedType<T,M> implements AMQPType<T>
{
    private final DecoderImpl _decoder;
    private final EncoderImpl _encoder;
    private final Map<TypeEncoding<M>, TypeEncoding<T>> _encodings = new HashMap<TypeEncoding<M>, TypeEncoding<T>>();

    public AbstractDescribedType(EncoderImpl encoder)
    {
        _encoder = encoder;
        _decoder = encoder.getDecoder();
    }

    abstract protected UnsignedLong getDescriptor();

    public EncoderImpl getEncoder()
    {
        return _encoder;
    }

    public DecoderImpl getDecoder()
    {
        return _decoder;
    }

    public TypeEncoding<T> getEncoding(final T val)
    {
        M asUnderlying = wrap(val);
        TypeEncoding<M> underlyingEncoding = _encoder.getType(asUnderlying).getEncoding(asUnderlying);
        TypeEncoding<T> encoding = _encodings.get(underlyingEncoding);
        if(encoding == null)
        {
            encoding = new DynamicDescribedTypeEncoding(underlyingEncoding);
            _encodings.put(underlyingEncoding, encoding);
        }

        return encoding;
    }

    abstract protected M wrap(T val);

    public TypeEncoding<T> getCanonicalEncoding()
    {
        return null;
    }

    public Collection<TypeEncoding<T>> getAllEncodings()
    {
        Collection values = _encodings.values();
        Collection unmodifiable = Collections.unmodifiableCollection(values);
        return (Collection<TypeEncoding<T>>) unmodifiable;
    }

    public void write(final T val)
    {
        TypeEncoding<T> encoding = getEncoding(val);
        encoding.writeConstructor();
        encoding.writeValue(val);
    }

    private class DynamicDescribedTypeEncoding implements TypeEncoding<T>
    {
        private final TypeEncoding<M> _underlyingEncoding;
        private final TypeEncoding<UnsignedLong> _descriptorType;
        private final int _constructorSize;


        public DynamicDescribedTypeEncoding(final TypeEncoding<M> underlyingEncoding)
        {
            _underlyingEncoding = underlyingEncoding;
            _descriptorType = _encoder.getType(getDescriptor()).getEncoding(getDescriptor());
            _constructorSize = 1 + _descriptorType.getConstructorSize()
                               + _descriptorType.getValueSize(getDescriptor())
                               + _underlyingEncoding.getConstructorSize();
        }

        public AMQPType<T> getType()
        {
            return AbstractDescribedType.this;
        }

        public void writeConstructor()
        {
            _encoder.writeRaw(EncodingCodes.DESCRIBED_TYPE_INDICATOR);
            _descriptorType.writeConstructor();
            _descriptorType.writeValue(getDescriptor());
            _underlyingEncoding.writeConstructor();
        }

        public int getConstructorSize()
        {
            return _constructorSize;
        }

        public void writeValue(final T val)
        {
            _underlyingEncoding.writeValue(wrap(val));
        }

        public int getValueSize(final T val)
        {
            return _underlyingEncoding.getValueSize(wrap(val));
        }

        public boolean isFixedSizeVal()
        {
            return _underlyingEncoding.isFixedSizeVal();
        }

        public boolean encodesSuperset(final TypeEncoding<T> encoding)
        {
            return (getType() == encoding.getType())
                   && (_underlyingEncoding.encodesSuperset(((DynamicDescribedTypeEncoding)encoding)
                                                                   ._underlyingEncoding));
        }

        @Override
        public boolean encodesJavaPrimitive()
        {
            return false;
        }

    }
}