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/*
 * Copyright (c) 2003, PostgreSQL Global Development Group
 * See the LICENSE file in the project root for more information.
 */

package org.postgresql.largeobject;

import org.postgresql.core.BaseConnection;
import org.postgresql.fastpath.Fastpath;
import org.postgresql.fastpath.FastpathArg;
import org.postgresql.util.GT;
import org.postgresql.util.PSQLException;
import org.postgresql.util.PSQLState;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;

/**
 * This class implements the large object interface to org.postgresql.
 *
 * 

It provides methods that allow client code to create, open and delete large objects from the * database. When opening an object, an instance of org.postgresql.largeobject.LargeObject is * returned, and its methods then allow access to the object.

* *

This class can only be created by {@link BaseConnection}

* *

To get access to this class, use the following segment of code:

* *
 * import org.postgresql.largeobject.*;
 *
 * Connection  conn;
 * LargeObjectManager lobj;
 *
 * ... code that opens a connection ...
 *
 * lobj = ((org.postgresql.PGConnection)myconn).getLargeObjectAPI();
 * 
* *

Normally, client code would use the getAsciiStream, getBinaryStream, or getUnicodeStream methods * in ResultSet, or setAsciiStream, setBinaryStream, or setUnicodeStream methods in * PreparedStatement to access Large Objects.

* *

However, sometimes lower level access to Large Objects are required, that are not supported by * the JDBC specification.

* *

Refer to org.postgresql.largeobject.LargeObject on how to manipulate the contents of a Large * Object.

* * @see java.sql.ResultSet#getAsciiStream * @see java.sql.ResultSet#getBinaryStream * @see java.sql.ResultSet#getUnicodeStream * @see java.sql.PreparedStatement#setAsciiStream * @see java.sql.PreparedStatement#setBinaryStream * @see java.sql.PreparedStatement#setUnicodeStream */ @SuppressWarnings("deprecation") // support for deprecated Fastpath API public class LargeObjectManager { // the fastpath api for this connection private Fastpath fp; private BaseConnection conn; /** * This mode indicates we want to write to an object. */ public static final int WRITE = 0x00020000; /** * This mode indicates we want to read an object. */ public static final int READ = 0x00040000; /** * This mode is the default. It indicates we want read and write access to a large object. */ public static final int READWRITE = READ | WRITE; /** *

Constructs the LargeObject API.

* *

Important Notice
* This method should only be called by {@link BaseConnection}

* *

There should only be one LargeObjectManager per Connection. The {@link BaseConnection} class * keeps track of the various extension API's and it's advised you use those to gain access, and * not going direct.

* * @param conn connection * @throws SQLException if something wrong happens */ public LargeObjectManager(BaseConnection conn) throws SQLException { this.conn = conn; // We need Fastpath to do anything this.fp = conn.getFastpathAPI(); // Now get the function oid's for the api // // This is an example of Fastpath.addFunctions(); // String sql; if (conn.getMetaData().supportsSchemasInTableDefinitions()) { sql = "SELECT p.proname,p.oid " + " FROM pg_catalog.pg_proc p, pg_catalog.pg_namespace n " + " WHERE p.pronamespace=n.oid AND n.nspname='pg_catalog' AND ("; } else { sql = "SELECT proname,oid FROM pg_proc WHERE "; } sql += " proname = 'lo_open'" + " or proname = 'lo_close'" + " or proname = 'lo_creat'" + " or proname = 'lo_unlink'" + " or proname = 'lo_lseek'" + " or proname = 'lo_lseek64'" + " or proname = 'lo_tell'" + " or proname = 'lo_tell64'" + " or proname = 'loread'" + " or proname = 'lowrite'" + " or proname = 'lo_truncate'" + " or proname = 'lo_truncate64'"; if (conn.getMetaData().supportsSchemasInTableDefinitions()) { sql += ")"; } Statement stmt = conn.createStatement(); ResultSet res = stmt.executeQuery(sql); fp.addFunctions(res); res.close(); stmt.close(); conn.getLogger().log(Level.FINE, "Large Object initialised"); } /** * This opens an existing large object, based on its OID. This method assumes that READ and WRITE * access is required (the default). * * @param oid of large object * @return LargeObject instance providing access to the object * @throws SQLException on error * @deprecated As of 8.3, replaced by {@link #open(long)} */ @Deprecated public LargeObject open(int oid) throws SQLException { return open((long) oid, false); } /** * This opens an existing large object, same as previous method, but commits the transaction on * close if asked. This is useful when the LOB is returned to a caller which won't take care of * transactions by itself. * * @param oid of large object * @param commitOnClose commit the transaction when this LOB will be closed * @return LargeObject instance providing access to the object * @throws SQLException on error */ public LargeObject open(int oid, boolean commitOnClose) throws SQLException { return open((long) oid, commitOnClose); } /** * This opens an existing large object, based on its OID. This method assumes that READ and WRITE * access is required (the default). * * @param oid of large object * @return LargeObject instance providing access to the object * @throws SQLException on error */ public LargeObject open(long oid) throws SQLException { return open(oid, READWRITE, false); } /** * This opens an existing large object, same as previous method, but commits the transaction on * close if asked. * * @param oid of large object * @param commitOnClose commit the transaction when this LOB will be closed * @return LargeObject instance providing access to the object * @throws SQLException on error */ public LargeObject open(long oid, boolean commitOnClose) throws SQLException { return open(oid, READWRITE, commitOnClose); } /** * This opens an existing large object, based on its OID. * * @param oid of large object * @param mode mode of open * @return LargeObject instance providing access to the object * @throws SQLException on error * @deprecated As of 8.3, replaced by {@link #open(long, int)} */ @Deprecated public LargeObject open(int oid, int mode) throws SQLException { return open((long) oid, mode, false); } /** * This opens an existing large object, same as previous method, but commits the transaction on * close if asked. * * @param oid of large object * @param mode mode of open * @param commitOnClose commit the transaction when this LOB will be closed * @return LargeObject instance providing access to the object * @throws SQLException on error */ public LargeObject open(int oid, int mode, boolean commitOnClose) throws SQLException { return open((long) oid, mode, commitOnClose); } /** * This opens an existing large object, based on its OID. * * @param oid of large object * @param mode mode of open * @return LargeObject instance providing access to the object * @throws SQLException on error */ public LargeObject open(long oid, int mode) throws SQLException { return open(oid, mode, false); } /** * This opens an existing large object, based on its OID. * * @param oid of large object * @param mode mode of open * @param commitOnClose commit the transaction when this LOB will be closed * @return LargeObject instance providing access to the object * @throws SQLException on error */ public LargeObject open(long oid, int mode, boolean commitOnClose) throws SQLException { if (conn.getAutoCommit()) { throw new PSQLException(GT.tr("Large Objects may not be used in auto-commit mode."), PSQLState.NO_ACTIVE_SQL_TRANSACTION); } return new LargeObject(fp, oid, mode, conn, commitOnClose); } /** *

This creates a large object, returning its OID.

* *

It defaults to READWRITE for the new object's attributes.

* * @return oid of new object * @throws SQLException on error * @deprecated As of 8.3, replaced by {@link #createLO()} */ @Deprecated public int create() throws SQLException { return create(READWRITE); } /** *

This creates a large object, returning its OID.

* *

It defaults to READWRITE for the new object's attributes.

* * @return oid of new object * @throws SQLException if something wrong happens */ public long createLO() throws SQLException { return createLO(READWRITE); } /** * This creates a large object, returning its OID. * * @param mode a bitmask describing different attributes of the new object * @return oid of new object * @throws SQLException on error */ public long createLO(int mode) throws SQLException { if (conn.getAutoCommit()) { throw new PSQLException(GT.tr("Large Objects may not be used in auto-commit mode."), PSQLState.NO_ACTIVE_SQL_TRANSACTION); } FastpathArg[] args = new FastpathArg[1]; args[0] = new FastpathArg(mode); return fp.getOID("lo_creat", args); } /** * This creates a large object, returning its OID. * * @param mode a bitmask describing different attributes of the new object * @return oid of new object * @throws SQLException on error * @deprecated As of 8.3, replaced by {@link #createLO(int)} */ @Deprecated public int create(int mode) throws SQLException { long oid = createLO(mode); return (int) oid; } /** * This deletes a large object. * * @param oid describing object to delete * @throws SQLException on error */ public void delete(long oid) throws SQLException { FastpathArg[] args = new FastpathArg[1]; args[0] = Fastpath.createOIDArg(oid); fp.fastpath("lo_unlink", args); } /** *

This deletes a large object.

* *

It is identical to the delete method, and is supplied as the C API uses unlink.

* * @param oid describing object to delete * @throws SQLException on error * @deprecated As of 8.3, replaced by {@link #unlink(long)} */ @Deprecated public void unlink(int oid) throws SQLException { delete((long) oid); } /** *

This deletes a large object.

* *

It is identical to the delete method, and is supplied as the C API uses unlink.

* * @param oid describing object to delete * @throws SQLException on error */ public void unlink(long oid) throws SQLException { delete(oid); } /** * This deletes a large object. * * @param oid describing object to delete * @throws SQLException on error * @deprecated As of 8.3, replaced by {@link #delete(long)} */ @Deprecated public void delete(int oid) throws SQLException { delete((long) oid); } }




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