java.fedora.server.storage.FastBmechReader Maven / Gradle / Ivy
/*
* -----------------------------------------------------------------------------
*
* License and Copyright: The contents of this file are subject to 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.fedora-commons.org/licenses.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
* the specific language governing rights and limitations under the License.
*
* The entire file consists of original code.
* Copyright © 2008 Fedora Commons, Inc.
*
Copyright © 2002-2007 The Rector and Visitors of the University of
* Virginia and Cornell University
* All rights reserved.
*
* -----------------------------------------------------------------------------
*/
package fedora.server.storage;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Date;
import java.util.Enumeration;
import java.util.Vector;
import org.apache.log4j.Logger;
import fedora.server.Context;
import fedora.server.Server;
import fedora.server.errors.GeneralException;
import fedora.server.errors.ServerException;
import fedora.server.storage.types.BMechDSBindSpec;
import fedora.server.storage.types.MethodDef;
import fedora.server.storage.types.MethodDefOperationBind;
import fedora.server.storage.types.MethodParmDef;
/**
* Title: FastBmechReader.java
* Description: BMECH Object Reader that accesses objects located in the
* "Fast" storage area. It mirros the functionality of SimpleBMechReader for
* the "Definitive" storage aread. To enhance performance of disseminations,
* there are two distinct storage areas for digital objects:
*
* -
* "Fast" storage area - The storage area containing a subset of digital
* objects that is optimized for performance. Both the composition of the
* subset of objects and storage area are implementation specific. For Phase 1,
* this object subset consists of a partial replication of the most current
* version of each object and is used as the primary source for resolving
* dissemination requests. The replication is partial since only information
* required to disseminate the object is replicated in the Fast storage area.
* For Phase 1, the Fast storage area is implemented as a relational database
* that is accessed via JDBC. Note that an appropriate definitve reader
* should always be used to obtain the most complete information about a
* specific object. A fast reader is used primarily for dissemination
* requests..
*
* -
* Definitive storage area - The storage area containing complete information on
* all digital objects in the repository. This storage area is used as the
* authoritative source for reading complete information about a digital object.
* This storage area is used as a secondary source for resolving dissemination
* requests when the specified object does not exist in the Fast storage area.
*
*
* This reader is designed to read bmech objects from the "Fast" storage area
* that is implemented as a relational database. If the object cannot be found
* in the relational database, this reader will attempt to read the object
* from the Definitive storage area using the appropriate definitive reader.
* When the object exists in both storage areas, preference is given to the
* Fast storage area since this reader is designed to read primarily from the
* Fast Storage area. A SimpleBMechReader should always be used to
* read the authoritative version of a bmech object.
* Note that versioning is not implemented in Phase 1. Methods in
* FastBmechReader that contain arguments related to versioning
* date such as versDateTime or asOfDate will be
* ignored in Phase 1.
*
* @author [email protected]
* @version $Id: FastBmechReader.java 5218 2006-11-20 05:10:11Z cwilper $
*/
public class FastBmechReader extends FastDOReader implements BMechReader
{
/** Logger for this class. */
private static final Logger LOG = Logger.getLogger(
FastBmechReader.class.getName());
/** Instance of BMechReader */
private BMechReader bMechReader = null;
/** Persistent identifier of behavior mechanism object */
private String bMechPID = null;
/** Label of behavior mechanism object */
private String bMechLabel = null;
/**
* Constructs an instance of FastBmechReader.
*
* Constructs a new FastBmechReader for the specified bmech
* object. If the object is found, this constructor initializes the class
* variables for bMechPID and bMechLabel.
*
* @param context The context of this request.
* @param objectPID The persistent identifier of the bmech object.
* @throws ServerException If any type of error occurred fulfilling the
* request.
*/
public FastBmechReader(Context context, String objectPID) throws ServerException
{
super(context, objectPID);
// Override FastDOReader constructor.
// In FastBmechReader, the object PID is assumed to always be a bmech PID.
try
{
// Attempt to find bmech object in either Fast or Definitive store
this.bMechLabel = locateBmechPID(objectPID);
this.bMechPID = objectPID;
} catch (ServerException se)
{
throw se;
} catch (Throwable th)
{
LOG.error("Unable to construct FastBmechReader", th);
throw new GeneralException("[FastBmechReader] An error has occurred. "
+ "The error was a \"" + th.getClass().getName() + "\" . "
+ "Reason: \"" + th.getMessage() + "\" .");
}
}
/**
*
Gets default mechanism method parameters associated with the specified
* method name. Default method parameters are defined by the Behavior
* Mechanism object as mechanism default parameters and cannot be altered
* by the user.
*
* @param methodName The name of the method.
* @param versDateTime The versioning datetime stamp.
* @return An array of method parameter definitions.
* @throws GeneralException If there was any misc exception that we want to
* catch and re-throw as a Fedora exception. Extends ServerException.
*/
public MethodParmDef[] getServiceMethodParms(String methodName,
Date versDateTime) throws GeneralException
{
MethodParmDef[] methodParms = null;
MethodParmDef methodParm = null;
Vector queryResults = new Vector();
Connection connection = null;
Statement statement = null;
ResultSet rs = null;
if (isFoundInFastStore && versDateTime == null)
{
// Requested object exists in Fast storage area and is NOT versioned;
// query relational database
String query =
"SELECT DISTINCT "
+ "defParmName,"
+ "defParmDefaultValue,"
+ "defParmDomainValues,"
+ "defParmRequiredFlag,"
+ "defParmLabel,"
+ "defParmType "
+ " FROM "
+ "bDef,"
+ "bMech,"
+ "mechImpl,"
+ "method,"
+ "mechDefParm "
+ " WHERE "
+ "bMech.bMechDbID=mechDefParm.bMechDbID AND "
+ "method.methodDbID=mechDefParm.methodDbID AND "
+ "bMech.bDefDbID=method.bDefDbID AND "
+ "mechImpl.methodDbID=method.methodDbID AND "
+ "bMech.bDefDbID=bDef.bDefDbID AND "
+ "bMech.bMechPID='" + bMechPID + "' AND "
+ "method.methodName='" + methodName + "'";
LOG.debug("GetBmechDefaultMethodParmQuery=" + query);
try
{
connection = connectionPool.getConnection();
LOG.debug("connectionPool = " + connectionPool);
statement = connection.createStatement();
rs = statement.executeQuery(query);
ResultSetMetaData rsMeta = rs.getMetaData();
int cols = rsMeta.getColumnCount();
// Note: a row is returned for each method parameter
while (rs.next())
{
methodParm = new MethodParmDef();
String[] results = new String[cols];
for (int i=1; i<=cols; i++)
{
results[i-1] = rs.getString(i);
}
methodParm.parmName = results[0];
methodParm.parmDefaultValue = results[1];
methodParm.parmDomainValues = results[2].split(",");
Boolean B = new Boolean(results[3]);
methodParm.parmRequired = B.booleanValue();
methodParm.parmLabel = results[4];
methodParm.parmType = results[5];
LOG.debug("methodParms: " + methodParm.parmName
+ "\nlabel: " + methodParm.parmLabel
+ "\ndefault: " + methodParm.parmDefaultValue
+ "\nrequired: " + methodParm.parmRequired
+ "\ntype: " + methodParm.parmType);
for (int j=0; jGets all method defintiions associated with the specified Behavior
* Mechanism. Note the PID of the associated Behavior Mechanism object is
* determined via reflection based on the specified PID of the digital object
* and the PID of its Behavior Definition object. This method retrieves the
* list of available methods based on the assocaited Behavior Mechanism
* object and NOT the Behavior Definition object. This is done to insure
* that only methods that have been implemented in the mechanism are returned.
* This distinction is only important when versioning is enabled
* in a later release. When versioning is enabled, it is possible
* that a versioned Behavior Definition may have methods that have not
* yet been implemented by all of its associated Behavior Mechanisms.
* In such a case, only those methods implemented in the mechanism
* will be returned.
*
* @param versDateTime The versioning datetime stamp.
* @return An array of method definitions.
* @throws ServerException If there was any misc exception that we want to
* catch and re-throw as a Fedora exception. Extends ServerException.
*/
public MethodDef[] getServiceMethods(Date versDateTime) throws ServerException
{
MethodDef[] methodDefs = null;
MethodDef methodDef = null;
Vector queryResults = new Vector();
Connection connection = null;
Statement statement = null;
ResultSet rs = null;
if (isFoundInFastStore && versDateTime == null)
{
// Requested object exists in Fast storage area and is NOT versioned;
// query relational database
String query =
"SELECT DISTINCT "
+ "method.methodName,"
+ "method.methodLabel "
+ "FROM "
+ "bDef,"
+ "method,"
+ "bMech,"
+ "mechImpl "
+ "WHERE "
+ "bMech.bMechDbID = mechImpl.bMechDbID AND "
+ "bDef.bDefDbID = mechImpl.bDefDbID AND "
+ "method.methodDbID = mechImpl.methodDbID AND "
+ "method.bDefDbID = bDef.bDefDbID AND "
+ "bMech.bMechPID = \'" + bMechPID + "\'";
LOG.debug("getObjectMethodsQuery: " + query);
String[] results = null;
try
{
connection = connectionPool.getConnection();
statement = connection.createStatement();
rs = statement.executeQuery(query);
ResultSetMetaData rsMeta = rs.getMetaData();
int cols = rsMeta.getColumnCount();
while (rs.next())
{
results = new String[cols];
methodDef = new MethodDef();
for (int i=1; i<=cols; i++)
{
results[i-1] = rs.getString(i);
}
methodDef.methodName = results[0];
methodDef.methodLabel = results[1];
try
{
methodDef.methodParms = getServiceMethodParms(methodDef.methodName,
versDateTime);
} catch (Throwable th)
{
// Failed to get method paramters
throw new GeneralException("[FastBmechReader] An error has occured. The "
+ "underlying error was a \"" + th.getClass().getName()
+ "\" . The message was \"" + th.getMessage() + "\" .");
}
queryResults.add(methodDef);
}
methodDefs = new MethodDef[queryResults.size()];
int rowCount = 0;
for (Enumeration e = queryResults.elements(); e.hasMoreElements();)
{
methodDefs[rowCount] = (MethodDef)e.nextElement();
rowCount++;
}
return methodDefs;
} catch (Throwable th)
{
throw new GeneralException("[FastBmechReader] An error has occured. The "
+ "underlying error was a \"" + th.getClass().getName()
+ "\" . The message was \"" + th.getMessage() + "\" .");
} finally
{
try
{
if (rs != null) rs.close();
if (statement != null) statement.close();
if (connection!=null) connectionPool.free(connection);
} catch (SQLException sqle)
{
throw new GeneralException("[FastBmechReader] Unexpected error "
+ "from SQL database. The error was \"" + sqle.getMessage()
+ "\" .");
} finally {
rs=null;
statement=null;
}
}
} else if (isFoundInDefinitiveStore || versDateTime != null)
{
// Requested object exists in Definitive storage area or is versioned;
// query Definitive storage area.
try
{
if (bMechReader == null)
{
bMechReader = m_manager.getBMechReader(Server.USE_DEFINITIVE_STORE, m_context, PID);
}
return bMechReader.getServiceMethods(versDateTime);
} catch (ServerException se)
{
throw se;
} catch (Throwable th)
{
throw new GeneralException("[FastbMechReader] Definitive bMechReader returned "
+ "error. The underlying error was a \"" + th.getClass().getName()
+ "\" . The message was \"" + th.getMessage() + "\" .");
}
}
return null;
}
public MethodDefOperationBind[] getServiceMethodBindings(Date versDateTime) throws ServerException
{
try
{
if (bMechReader == null)
{
bMechReader = m_manager.getBMechReader(Server.GLOBAL_CHOICE, m_context, PID);
}
return bMechReader.getServiceMethodBindings(versDateTime);
} catch (ServerException se)
{
throw se;
} catch (Throwable th)
{
throw new GeneralException("[FastbMechReader] Definitive bMechReader returned "
+ "error. The underlying error was a \"" + th.getClass().getName()
+ "\" . The message was \"" + th.getMessage() + "\" .");
}
}
/**
* Gets XML containing method definitions. Since the XML representation
* of digital objects is not stored in the Fast storage area, this method
* uses a BMechReader to query the Definitive
* storage area.
*
* @param versDateTime The versioning datetime stamp.
* @return A stream of bytes containing XML-encoded representation of
* method definitions from XML in the Behavior Mechanism
* object.
* @throws ServerException If any type of error occurred fulfilling the
* request.
*/
public InputStream getServiceMethodsXML(Date versDateTime) throws ServerException
{
try
{
if (bMechReader == null)
{
bMechReader = m_manager.getBMechReader(Server.GLOBAL_CHOICE, m_context, PID);
}
return bMechReader.getServiceMethodsXML(versDateTime);
} catch (ServerException se)
{
throw se;
} catch (Throwable th)
{
throw new GeneralException("[FastbMechReader] Definitive bMechReader returned "
+ "error. The underlying error was a \"" + th.getClass().getName()
+ "\" . The message was \"" + th.getMessage() + "\" .");
}
}
public BMechDSBindSpec getServiceDSInputSpec(Date versDateTime) throws ServerException
{
try
{
if (bMechReader == null)
{
bMechReader = m_manager.getBMechReader(Server.USE_DEFINITIVE_STORE, m_context, PID);
}
return bMechReader.getServiceDSInputSpec(versDateTime);
} catch (ServerException se)
{
throw se;
} catch (Throwable th)
{
throw new GeneralException("[FastbMechReader] Definitive bMechReader returned "
+ "error. The underlying error was a \"" + th.getClass().getName()
+ "\" . The message was \"" + th.getMessage() + "\" .");
}
}
/**
* Locates the specified bmech object using its persistent identifier.
* This method will first attempt to locate the object in the Fast storage
* area. If the the object cannot be located there, it will then try to find
* it in the Definitive storage area. If the object is found, the object's
* label is returned. Otherwise, it throws
* GeneralException.
*
* @param bMechPID persistent identifier of the digital object.
* @return String containing label of the specified digital object.
* @throws GeneralException If there was any misc exception that we want to
* catch and re-throw as a Fedora exception. Extends ServerException.
* @throws ServerException If any type of error occurred fulfilling the
* request.
*/
public String locateBmechPID(String bMechPID) throws GeneralException, ServerException
{
Connection connection = null;
Statement statement = null;
ResultSet rs = null;
String query =
"SELECT "
+ "bMech.bMechLabel "
+ "FROM "
+ "bMech "
+ "WHERE "
+ "bMech.bMechPID=\'" + bMechPID + "\'";
LOG.debug("LocateBmechPIDQuery: " + query);
try
{
connection = connectionPool.getConnection();
LOG.debug("LocateBmechPIDConnectionPool: " + connectionPool);
statement = connection.createStatement();
rs = statement.executeQuery(query);
while (rs.next())
{
bMechLabel = rs.getString(1);
}
} catch (Throwable th)
{
LOG.error("Error locating BMech PID", th);
throw new GeneralException("[FastBmechReader] An error has occurred. The "
+ "underlying error was a \"" + th.getClass().getName()
+ "\" . The message was \"" + th.getMessage() + "\" .");
} finally
{
try
{
if (rs != null) rs.close();
if (statement != null) statement.close();
if (connection!=null) connectionPool.free(connection);
} catch (SQLException sqle)
{
throw new GeneralException("[FastBmechReader] Unexpected error "
+ "from SQL database. The error was \"" + sqle.getMessage()
+ "\" .");
} finally {
rs=null;
statement=null;
}
}
if (bMechLabel == null || bMechLabel.equalsIgnoreCase(""))
{
// Empty result means that the bmech object could not be found in the
// relational database. This could be due to incorrectly specified
// parameter for PID OR the object is not in the relational database.
// If not in the relational database, attempt to find the object in the
// Definitive storage area.
try
{
if (definitiveDOReader == null)
{
definitiveDOReader = m_manager.getReader(Server.USE_DEFINITIVE_STORE, m_context, bMechPID);
}
bMechLabel = definitiveDOReader.GetObjectLabel();
isFoundInDefinitiveStore = true;
LOG.debug("BMech found in definitive store: " + bMechPID);
} catch (ServerException se)
{
throw se;
} catch (Throwable th)
{
LOG.error("BMech found in definitive store: " + bMechPID, th);
throw new GeneralException("[FastBmechReader] Definitive doReader "
+ "returned error. The underlying error was a \""
+ th.getClass().getName() + "\" . The message "
+ "was \"" + th.getMessage() + "\" .");
}
} else
{
isFoundInFastStore = true;
LOG.debug("BMech found in fast store: " + bMechPID);
}
return bMechLabel;
}
}