AstExternalizble.java
/*
** Module : AstExternalizble.java
** Abstract : Allow serialization for an AST, to database.
**
** Copyright (c) 2020-2023, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description----------------------------------
** 001 CA 20200412 Created initial version, for incremental conversion support.
** 002 CA 20200416 Reduce the memory footprint for incremental conversion.
** 003 CA 20210423 Added 'getAstId'.
** 004 CA 20230127 Performance improvement for incremental conversion.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
** You must preserve all legal notices or author attributions in the covered
** work or Appropriate Legal Notices displayed by works containing the covered
** work. You may not remove from the covered work any author or developer
** credit already included within the covered work.
**
** 1. No License To Use Trademarks.
**
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** name Golden Code, FWD, or the names of any author or contributor, for
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*/
package com.goldencode.p2j.convert.db;
import java.io.*;
import com.goldencode.ast.*;
import com.goldencode.p2j.pattern.*;
/**
* For AST values for a db-backed collection, this allows the serialization to the database.
* <p>
* Only the AST ID will be stored.
*/
public class AstExternalizble
implements CustomExternalizable
{
/**
* The associated AST node. This can be <code>null</code> and resolved by {@link #getValue()},
* if the AST is loaded from disk.
*/
private Aast ast = null;
/** The AST ID. */
private Long astId = null;
/**
* Flag indicating if this serialized instance requires special processing.
* <p>
* WARNING: {@link AstExternalizble} is used only by 'tmpTabNodes', which sets the {@link #special} flag
* only for ASTs with <code>authoritative</code> annotation.
*/
private boolean special = false;
/**
* Default c'tor, for deserialization purposes.
*/
public AstExternalizble()
{
// no-op
}
/**
* Create a new instance and map it to the specified AST.
* <p>
* This c'tor is used via reflection.
*
* @param value
* The AST instance.
*/
public AstExternalizble(Object value)
{
this.astId = ((Aast) value).getId();
AstManager mgr = AstManager.get();
long treeId = mgr.getTreeId(astId);
String treeName = mgr.getTreeName(treeId);
if (treeName == null)
{
this.ast = (Aast) value;
}
else
{
File file = new File(treeName);
if (!(file.exists() && file.isFile()))
{
this.ast = (Aast) value;
}
}
this.special = Boolean.TRUE.equals(((Aast) value).getAnnotation("authoritative"));
}
/**
* Get the {@link #astId}.
*
* @return See above.
*/
public Long getAstId()
{
return astId;
}
/**
* Compact this instance.
*
* @param fileId
* The AST file ID which has finished processing.
*/
@Override
public void compact(long fileId)
{
if (ast == null)
{
return;
}
AstManager mgr = AstManager.get();
long treeId = mgr.getTreeId(astId);
if (treeId == fileId)
{
this.ast = null;
}
}
/**
* Get the value to be stored in a collection, after it was deserialized from the database.
*
* @return See above.
*/
@Override
public Object getValue()
{
if (ast == null)
{
// TODO: if AST doesn't exist, don't initialize... throw exception?
AstSymbolResolver resolver = AstSymbolResolver.getResolver();
ast = resolver.getAst(astId);
if (ast == null)
{
AstManager mgr = AstManager.get();
long treeId = mgr.getTreeId(astId);
Aast tree = mgr.loadTree(mgr.getTreeName(treeId));
// keep a copy of this tree registered
resolver.registerTree(tree.duplicate());
this.ast = resolver.getAst(astId);
}
}
return ast;
}
/**
* Write this instance to stream.
*
* @param out
* The object output stream.
*/
@Override
public void writeExternal(ObjectOutput out) throws IOException
{
out.writeObject(astId);
out.writeByte(special ? 1 : 0);
}
/**
* Restore this instance by re-loading the AST with the given ID.
*
* @param in
* The object input stream.
*/
@Override
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
{
this.astId = (Long) in.readObject();
this.special = in.readByte() == 1;
}
/**
* Get the state of the {@link #special} flag.
*
* @return See above.
*/
public boolean isSpecial()
{
return special;
}
}