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/*
*
* 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.qmf2.common;
// Misc Imports
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Map;
import java.util.UUID;
/**
* Subclass of QmfData
* <p>
* When representing formally defined data, a QmfData instance is assigned a Schema.
* <p>
* The following diagram illustrates the QMF2 Schema class hierarchy.
* <p>
* <img alt="" src="doc-files/Schema.png">
*
* @author Fraser Adams
*/
public class SchemaClass extends QmfData
{
public static final SchemaClass EMPTY_SCHEMA = new SchemaClass();
private SchemaClassId _classId;
/**
* The default constructor, initialises the underlying QmfData base class with an empty Map
*/
protected SchemaClass()
{
}
/**
* The main constructor, taking a java.util.Map as a parameter.
*
* @param m the map used to construct the SchemaClass
*/
public SchemaClass(final Map m)
{
super(m);
_classId = new SchemaClassId((Map)getValue("_schema_id"));
}
/**
* Return the SchemaClassId that identifies this Schema instance.
* @return the SchemaClassId that identifies this Schema instance.
*/
public final SchemaClassId getClassId()
{
if (_classId.getHashString() == null)
{
_classId = new SchemaClassId(_classId.getPackageName(),
_classId.getClassName(),
_classId.getType(),
generateHash());
}
return _classId;
}
/**
* Set the SchemaClassId that identifies this Schema instance.
* @param cid the SchemaClassId that identifies this Schema instance.
*/
public final void setClassId(final SchemaClassId cid)
{
_classId = cid;
}
/**
* Return a hash generated over the body of the schema, and return a representation of the hash
* @return a hash generated over the body of the schema, and return a representation of the hash
*/
public final UUID generateHash()
{
try
{
MessageDigest md5 = MessageDigest.getInstance("MD5");
updateHash(md5);
return UUID.nameUUIDFromBytes(md5.digest());
}
catch (NoSuchAlgorithmException nsae)
{
}
return null;
}
/**
* Generate the partial hash for the schema fields in this base class
* @param md5 the MessageDigest to be updated
*/
protected void updateHash(MessageDigest md5)
{
try
{
md5.update(_classId.getPackageName().getBytes("UTF-8"));
md5.update(_classId.getClassName().getBytes("UTF-8"));
md5.update(_classId.getType().getBytes("UTF-8"));
}
catch (UnsupportedEncodingException uee)
{
}
}
/**
* Helper/debug method to list the QMF Object properties and their type.
*/
@Override
public void listValues()
{
super.listValues();
_classId.listValues();
}
}
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