org.hsqldb.types.JavaObjectData Maven / Gradle / Ivy
Show all versions of hsqldb Show documentation
/* Copyright (c) 2001-2019, The HSQL Development Group
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 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.
*
* Neither the name of the HSQL Development Group 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 HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
* 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 org.hsqldb.types;
import java.io.Serializable;
import org.hsqldb.error.Error;
import org.hsqldb.error.ErrorCode;
import org.hsqldb.lib.InOutUtil;
/**
* Represents of an instance of an OTHER field value.
*
* Prior to 1.7.0 there were problems storing Objects of normal column types
* in columns of the type OTHER. In 1.7.0 changes were made to allow this,
* but as all the conversion took place inside the engine, it introduced a
* requirement for all classes for objects stored in OTHER columns to be
* available on the runtime class path of the engine.
*
* In 1.7.2, the introduction of real prepared statement support allows us
* revert to the pre 1.7.0 behaviour without the artificial limitations.
*
* The classes for stored objects need not be available to open and operate
* the database in general. The classes need to be available only if a
* conversion from one of these objects to another type is performed inside
* the engine while operating the database.
*
* The current limitation is that in SQL statements, values of type String
* (CHARACTER and related SQL types) cannot be stored in columns of type
* OTHER. This limitation does not exist for String values assigned to
* PreparedStatement variables.
*
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 2.3.4
* @since 1.7.2
*/
public class JavaObjectData {
private byte[] data;
JavaObjectData() {}
/**
* Constructor used inside the engine when an already serialized
* Object is read from a file (.log, .script, .data or text table source).
*/
public JavaObjectData(byte[] data) {
this.data = data;
}
/**
* Constructor used inside the engine to convert an Object into an
* object of type OTHER.
* Used also with JDBC setParameter().
* If parameter serialize is true, the Object is serialized for storage.
*/
public JavaObjectData(Serializable o) {
try {
data = InOutUtil.serialize(o);
} catch (Exception e) {
throw Error.error(ErrorCode.X_22521, e.toString());
}
}
public byte[] getBytes() {
return data;
}
public int getBytesLength() {
return data.length;
}
/**
* This method is called from classes implementing the JDBC
* interfaces. Inside the engine it is used for conversion from a value of
* type OTHER to another type. It will throw if the OTHER is an instance
* of a class that is not available.
*/
public Object getObject() {
try {
return InOutUtil.deserialize(data);
} catch (Exception e) {
throw Error.error(ErrorCode.X_22521, e.toString());
}
}
/**
* Returns String representation of this object.
*
* @return a String representation of this object.
*/
public String toString() {
return super.toString();
}
public boolean equals(Object other) {
return other instanceof JavaObjectData;
}
public int hashCode() {
return 1;
}
}