| /* |
| * Copyright 2005 The Apache Software Foundation. |
| * |
| * Licensed 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.jdo.impl.fostore; |
| |
| import java.io.DataInput; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| |
| /** |
| * Process GetExtent requests. |
| * |
| * @author Dave Bristor |
| */ |
| // This is server-side code. It does not need to live in the client. |
| class GetExtentHandler extends RequestHandler { |
| |
| private GetExtentHandler(Reply reply, int length, |
| FOStoreServerConnection con) { |
| |
| super(reply, length, con); |
| } |
| |
| public static final HandlerFactory factory = |
| new HandlerFactory() { |
| public RequestHandler getHandler(Reply reply, int length, |
| FOStoreServerConnection con) { |
| return new GetExtentHandler(reply, length, con); |
| }}; |
| |
| /** |
| * The desired extent's class can be specified either by CLID (i.e., the |
| * class's CLID was already loaded from store to the client) or classname |
| * and FSUID (in case the CLID wasn't known). In the latter case, look |
| * up the CLID. |
| * <br> |
| * With the CLID, get the set of extents: it will be only one if |
| * subclasses is false, an aribtrary number otherwise. |
| * <br> |
| * Iterate over the extents, writing the items into the reply. |
| * @see RequestHandler#handleRequest |
| * @see GetExtentRequest#doRequestBody |
| */ |
| RequestFinisher handleRequest() |
| throws IOException, FOStoreDatabaseException { |
| |
| FOStoreInput in = con.getInputFromClient(); |
| FOStoreDatabase db = con.getDatabase(); |
| HashSet dbExtents = null; |
| |
| // true => resulting extent to include subclasses of indicated class. |
| boolean subclasses; |
| |
| int maxInstances = in.readInt(); |
| |
| // By CLID or by classname/fsuid? |
| boolean isCLID = in.readBoolean(); |
| |
| CLID clid = null; |
| if (isCLID) { |
| clid = CLID.read(in); |
| subclasses = in.readBoolean(); |
| |
| } else { |
| // Find the clid for the given name/fsuid. |
| |
| String name = in.readUTF(); |
| FOStoreSchemaUID fsuid = FOStoreSchemaUID.read(in); |
| subclasses = in.readBoolean(); |
| |
| if (logger.isDebugEnabled()) { |
| logger.debug( |
| "GetExtentHandler for name=" + name); // NOI18N |
| } |
| |
| for (Iterator i = db.getDBInfo().getDBClasses(); i.hasNext();) { |
| DBClass dbClass = (DBClass)i.next(); |
| if (fsuid.equals(dbClass.getFSUID()) && |
| name.equals(dbClass.getName())) { |
| clid = dbClass.getCLID(); |
| // break because there can be only one match. |
| break; |
| } |
| } |
| } |
| |
| // Get the set of CLIDs of extents |
| if (null != clid) { |
| dbExtents = getDBExtents(clid, subclasses, db); |
| } |
| |
| if (logger.isDebugEnabled()) { |
| if (null == dbExtents) { |
| logger.debug("GetExtentHandler.hr: no extents"); // NOI18N |
| } else { |
| for (Iterator i = dbExtents.iterator(); i.hasNext();) { |
| logger.debug( |
| "GetExtentHandler.hr: extent=" + i.next()); // NOI18N |
| } |
| } |
| } |
| |
| Status status = null; |
| int extentSize = 0; |
| int numInstances = 0; |
| int numOIDs = 0; |
| |
| // Write instances into the reply |
| if (null == dbExtents) { |
| reply.writeInt(0); |
| reply.writeInt(0); |
| reply.writeInt(0); |
| status = Status.OK; |
| |
| } else { |
| // Save space for writing various counts in the reply. |
| int extentSizePos = reply.beginStash(); |
| int numInstancesPos = reply.beginStash(); |
| int numOIDsPos = reply.beginStash(); |
| |
| for (Iterator i = dbExtents.iterator(); i.hasNext();) { |
| DBExtent extent = (DBExtent)i.next(); |
| |
| if (null != extent && extent.size() > 0) { |
| |
| // Fetch some of the instances from the store. |
| // If we fail to get an object, continue, but set status |
| // to WARN. |
| for (Iterator j = extent.iterator(); j.hasNext();) { |
| OID oid = (OID)j.next(); |
| try { |
| reply.writeOID(oid); |
| if (logger.isDebugEnabled()) { |
| logger.debug( |
| "GetExtentHandler.hR/2: " + // NOI18N |
| oid + " " + // NOI18N |
| Tester.toHex(oid.oid, 16)); |
| } |
| |
| if (numInstances < maxInstances) { |
| Block block = (Block)db.get(oid); |
| if (logger.isTraceEnabled()) { |
| block.dump(); |
| } |
| |
| byte data[] = block.getData(); |
| reply.writeInt(data.length); |
| reply.write(data); |
| numInstances++; |
| } else { |
| numOIDs++; |
| } |
| extentSize++; |
| } catch (FOStoreDatabaseException ex) { |
| status = Status.WARN; |
| } |
| } |
| } |
| } |
| |
| // Write counts. |
| reply.endStash(extentSize, extentSizePos); |
| reply.endStash(numInstances, numInstancesPos); |
| reply.endStash(numOIDs, numOIDsPos); |
| |
| if (null == status) { |
| status = Status.OK; |
| } |
| } |
| reply.setStatus(status); |
| |
| if (logger.isDebugEnabled()) { |
| logger.debug( |
| "GetExtentHandler.hR/3: " + // NOI18N |
| "extentSize=" + extentSize + // NOI18N |
| ", numInstances=" + numInstances + // NOI18N |
| ", numOIDs=" + numOIDs + " " + status); // NOI18N |
| } |
| return null; |
| } |
| |
| /** |
| * Get a set of CLIDs of extents for the given clid. The set will have at |
| * most one element if subclasses is false, or an arbitrary number |
| * otherwise. |
| * @param clid The CLID of the class whose extent is wanted. |
| * @param subclasses If true, then include extents for all subclasses of |
| * the class corresponding to CLID. |
| * @param db Database in which to find extents. |
| * @return Set of extents of clid (and possibly its subclasses). |
| * @throws FOStoreDatabaseException if a database error occurs. |
| */ |
| HashSet getDBExtents(CLID clid, boolean subclasses, FOStoreDatabase db) |
| throws FOStoreDatabaseException { |
| |
| HashSet rc = null; |
| |
| if (logger.isDebugEnabled()) { |
| logger.debug( |
| "GetExtentHandler.getExtents: for " + clid); // NOI18N |
| } |
| OID oid = db.getDBInfo().getExtentOID(clid); |
| DBExtent extent = (DBExtent)db.getIfExists(oid); |
| if (null != extent) { |
| rc = new HashSet(); |
| rc.add(extent); |
| } |
| |
| if (logger.isDebugEnabled()) { |
| logger.debug( |
| "GetExtentHandler.getExtents: got " + extent); // NOI18N |
| } |
| |
| if (subclasses) { |
| OID ssOID = DBInfo.getSubclassSetOID(clid); |
| SubclassSet ss = (SubclassSet)db.getIfExists(ssOID); |
| if (null != ss) { |
| for (Iterator i = ss.iterator(); i.hasNext();) { |
| CLID subCLID = (CLID)i.next(); |
| OID subExtentOID = DBInfo.getExtentOID(subCLID); |
| DBExtent subExtent = |
| (DBExtent)db.getIfExists(subExtentOID); |
| if (null != subExtent) { |
| if (logger.isDebugEnabled()) { |
| logger.debug( |
| "GetExtentHandler.getExtents: "+ // NOI18N |
| "subclass " + subExtent); // NOI18N |
| } |
| if (null == rc) { |
| rc = new HashSet(); |
| } |
| rc.add(subExtent); |
| } |
| } |
| } |
| } |
| return rc; |
| } |
| } |
