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package com.unboundid.directory.sdk.examples;
import java.io.File;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.Date;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import com.unboundid.directory.sdk.common.api.DiskSpaceConsumer;
import com.unboundid.directory.sdk.common.operation.AddRequest;
import com.unboundid.directory.sdk.common.operation.AddResult;
import com.unboundid.directory.sdk.common.operation.DeleteRequest;
import com.unboundid.directory.sdk.common.operation.DeleteResult;
import com.unboundid.directory.sdk.common.operation.ModifyRequest;
import com.unboundid.directory.sdk.common.operation.ModifyResult;
import com.unboundid.directory.sdk.common.operation.ModifyDNRequest;
import com.unboundid.directory.sdk.common.operation.ModifyDNResult;
import com.unboundid.directory.sdk.common.types.AlertSeverity;
import com.unboundid.directory.sdk.common.types.CompletedOperationContext;
import com.unboundid.directory.sdk.common.types.Entry;
import com.unboundid.directory.sdk.common.types.RegisteredDiskSpaceConsumer;
import com.unboundid.directory.sdk.ds.api.ChangeSubscriptionHandler;
import com.unboundid.directory.sdk.ds.config.ChangeSubscriptionHandlerConfig;
import com.unboundid.directory.sdk.ds.types.ChangeSubscription;
import com.unboundid.directory.sdk.ds.types.DirectoryServerContext;
import com.unboundid.ldap.sdk.LDAPException;
import com.unboundid.ldap.sdk.ResultCode;
import com.unboundid.ldif.LDIFChangeRecord;
import com.unboundid.util.StaticUtils;
import com.unboundid.util.args.ArgumentException;
import com.unboundid.util.args.ArgumentParser;
import com.unboundid.util.args.FileArgument;
/**
* This class provides a simple example of a change subscription handler which
* will write information about each matching change to a file in a specified
* directory. The file will be named with the change sequence number. It has
* one configuration argument:
* <UL>
* <LI>log-directory -- The path to the directory in which files will be
* written about matching changes.</LI>
* </UL>
*/
public final class ExampleChangeSubscriptionHandler
extends ChangeSubscriptionHandler
implements DiskSpaceConsumer
{
/**
* The name of the argument that will be used to specify the path to the
* directory in which to write log files.
*/
private static final String ARG_NAME_LOG_DIR = "log-directory";
// The general configuration for this change subscription handler.
private volatile ChangeSubscriptionHandlerConfig config;
// The server context for the server in which this extension is running.
private DirectoryServerContext serverContext;
// The directory in which to write log files.
private volatile File logDirectory;
// The registered disk space consumer for this change subscription handler.
private volatile RegisteredDiskSpaceConsumer registeredConsumer;
/**
* Creates a new instance of this change subscription handler. All change
* subscription handler implementations must include a default constructor,
* but any initialization should generally be done in the
* {@code initializeChangeSubscriptionHandler} method.
*/
public ExampleChangeSubscriptionHandler()
{
// No implementation required.
}
/**
* Retrieves a human-readable name for this extension.
*
* @return A human-readable name for this extension.
*/
@Override()
public String getExtensionName()
{
return "Example Change Subscription Handler";
}
/**
* Retrieves a human-readable description for this extension. Each element
* of the array that is returned will be considered a separate paragraph in
* generated documentation.
*
* @return A human-readable description for this extension, or {@code null}
* or an empty array if no description should be available.
*/
@Override()
public String[] getExtensionDescription()
{
return new String[]
{
"This change subscription handler serves an example that may be used " +
"to demonstrate the process for creating a third-party change " +
"subscription handler. For each change processed in the server, " +
"it will create a file with an LDIF representation of the change, " +
"including comments providing additional information about the " +
"operation that was processed.",
"Because this change subscription handler writes to disk, it also " +
"serves as an example of a disk space consumer so that the server " +
"may track available space on the disk containing the log files " +
"and potentially warn administrators if usable space becomes too " +
"low."
};
}
/**
* Updates the provided argument parser to define any configuration arguments
* which may be used by this change subscription handler. The argument parser
* may also be updated to define relationships between arguments (e.g., to
* specify required, exclusive, or dependent argument sets).
*
* @param parser The argument parser to be updated with the configuration
* arguments which may be used by this change subscription
* handler.
*
* @throws ArgumentException If a problem is encountered while updating the
* provided argument parser.
*/
@Override()
public void defineConfigArguments(final ArgumentParser parser)
throws ArgumentException
{
// Add an argument that allows you to specify the log directory.
Character shortIdentifier = null;
String longIdentifier = ARG_NAME_LOG_DIR;
boolean required = true;
int maxOccurrences = 1;
String placeholder = "{path}";
String description = "The path to the directory in which log " +
"files should be written with information about matching changes. " +
"Relative paths will be relative to the server root.";
boolean fileMustExist = true;
boolean parentMustExist = true;
boolean mustBeFile = false;
boolean mustBeDirectory = true;
parser.addArgument(new FileArgument(shortIdentifier, longIdentifier,
required, maxOccurrences, placeholder, description, fileMustExist,
parentMustExist, mustBeFile, mustBeDirectory));
}
/**
* Initializes this change subscription handler.
*
* @param serverContext A handle to the server context for the server in
* which this extension is running.
* @param config The general configuration for this change
* subscription handler.
* @param parser The argument parser which has been initialized from
* the configuration for this change subscription
* handler.
*
* @throws LDAPException If a problem occurs while initializing this change
* subscription handler.
*/
@Override()
public void initializeChangeSubscriptionHandler(
final DirectoryServerContext serverContext,
final ChangeSubscriptionHandlerConfig config,
final ArgumentParser parser)
throws LDAPException
{
serverContext.debugInfo(
"Beginning change subscription handler initialization");
this.serverContext = serverContext;
this.config = config;
// Get the path to the directory in which the log files should be written.
final FileArgument logDirArg =
(FileArgument) parser.getNamedArgument(ARG_NAME_LOG_DIR);
logDirectory = logDirArg.getValue();
// Register as a disk space consumer since we will be writing to the log
// directory.
registeredConsumer = serverContext.registerDiskSpaceConsumer(this);
}
/**
* Indicates whether the configuration contained in the provided argument
* parser represents a valid configuration for this extension.
*
* @param config The general configuration for this change
* subscription handler.
* @param parser The argument parser which has been initialized
* with the proposed configuration.
* @param unacceptableReasons A list that can be updated with reasons that
* the proposed configuration is not acceptable.
*
* @return {@code true} if the proposed configuration is acceptable, or
* {@code false} if not.
*/
@Override()
public boolean isConfigurationAcceptable(
final ChangeSubscriptionHandlerConfig config,
final ArgumentParser parser,
final List<String> unacceptableReasons)
{
// No special validation is required.
return true;
}
/**
* Attempts to apply the configuration contained in the provided argument
* parser.
*
* @param config The general configuration for this change
* subscription handler.
* @param parser The argument parser which has been
* initialized with the new configuration.
* @param adminActionsRequired A list that can be updated with information
* about any administrative actions that may be
* required before one or more of the
* configuration changes will be applied.
* @param messages A list that can be updated with information
* about the result of applying the new
* configuration.
*
* @return A result code that provides information about the result of
* attempting to apply the configuration change.
*/
@Override()
public ResultCode applyConfiguration(
final ChangeSubscriptionHandlerConfig config,
final ArgumentParser parser,
final List<String> adminActionsRequired,
final List<String> messages)
{
this.config = config;
// Get the new path to the log directory. We don't really care if it's the
// the same as the directory that was already in use.
final FileArgument logDirArg =
(FileArgument) parser.getNamedArgument(ARG_NAME_LOG_DIR);
logDirectory = logDirArg.getValue();
return ResultCode.SUCCESS;
}
/**
* Performs any cleanup which may be necessary when this change subscription
* handler is to be taken out of service.
*/
@Override()
public void finalizeChangeSubscriptionHandler()
{
// Deregister as a disk space consumer.
if (registeredConsumer != null)
{
serverContext.deregisterDiskSpaceConsumer(registeredConsumer);
}
}
/**
* Performs any processing necessary for an add operation matching the
* subscription criteria.
*
* @param operationContext The context for the add operation.
* @param sequenceNumber The sequence number for the change
* subscription notification.
* @param changeSubscriptions The set of change subscriptions whose criteria
* matched the add operation.
* @param addRequest Information about the request for the add
* operation that was processed.
* @param addResult Information about the result for the add
* operation that was processed.
* @param entry The entry that was added to the server.
*/
@Override()
public void addOperationProcessed(
final CompletedOperationContext operationContext,
final BigInteger sequenceNumber,
final Set<ChangeSubscription> changeSubscriptions,
final AddRequest addRequest,
final AddResult addResult, final Entry entry)
{
writeChange(operationContext, sequenceNumber, changeSubscriptions,
addRequest.toLDIFChangeRecord());
}
/**
* Performs any processing necessary for a delete operation matching the
* subscription criteria.
*
* @param operationContext The context for the delete operation.
* @param sequenceNumber The sequence number for the change
* subscription notification.
* @param changeSubscriptions The set of change subscriptions whose criteria
* matched the delete operation.
* @param deleteRequest Information about the request for the delete
* operation that was processed.
* @param deleteResult Information about the result for the delete
* operation that was processed.
* @param entry The entry that was removed from the server.
*/
@Override()
public void deleteOperationProcessed(
final CompletedOperationContext operationContext,
final BigInteger sequenceNumber,
final Set<ChangeSubscription> changeSubscriptions,
final DeleteRequest deleteRequest,
final DeleteResult deleteResult, final Entry entry)
{
writeChange(operationContext, sequenceNumber, changeSubscriptions,
deleteRequest.toLDIFChangeRecord());
}
/**
* Performs any processing necessary for a modify operation matching the
* subscription criteria.
*
* @param operationContext The context for the modify operation.
* @param sequenceNumber The sequence number for the change
* subscription notification.
* @param changeSubscriptions The set of change subscriptions whose criteria
* matched the modify operation.
* @param modifyRequest Information about the request for the modify
* operation that was processed.
* @param modifyResult Information about the result for the modify
* operation that was processed.
* @param oldEntry The entry as it appeared before the changes
* were applied.
* @param newEntry The entry as it appeared immediately after the
* changes were applied.
*/
@Override()
public void modifyOperationProcessed(
final CompletedOperationContext operationContext,
final BigInteger sequenceNumber,
final Set<ChangeSubscription> changeSubscriptions,
final ModifyRequest modifyRequest,
final ModifyResult modifyResult,
final Entry oldEntry, final Entry newEntry)
{
writeChange(operationContext, sequenceNumber, changeSubscriptions,
modifyRequest.toLDIFChangeRecord());
}
/**
* Performs any processing necessary for a modify DN operation matching the
* subscription criteria.
*
* @param operationContext The context for the modify DN operation.
* @param sequenceNumber The sequence number for the change
* subscription notification.
* @param changeSubscriptions The set of change subscriptions whose criteria
* matched the modify DN operation.
* @param modifyDNRequest Information about the request for the modify
* DN operation that was processed.
* @param modifyDNResult Information about the result for the modify DN
* operation that was processed.
* @param oldEntry The entry as it appeared before being renamed.
* @param newEntry The entry as it appeared immediately after
* being renamed.
*/
@Override()
public void modifyDNOperationProcessed(
final CompletedOperationContext operationContext,
final BigInteger sequenceNumber,
final Set<ChangeSubscription> changeSubscriptions,
final ModifyDNRequest modifyDNRequest,
final ModifyDNResult modifyDNResult,
final Entry oldEntry, final Entry newEntry)
{
writeChange(operationContext, sequenceNumber, changeSubscriptions,
modifyDNRequest.toLDIFChangeRecord());
}
/**
* Writes information about the change to a file in the configured log
* directory.
*
* @param operationContext The context for the associated operation.
* @param sequenceNumber The sequence number for the change
* subscription notification.
* @param changeSubscriptions The set of change subscriptions whose criteria
* matched the associated operation.
* @param changeRecord The change record that was processed.
*/
private void writeChange(final CompletedOperationContext operationContext,
final BigInteger sequenceNumber,
final Set<ChangeSubscription> changeSubscriptions,
final LDIFChangeRecord changeRecord)
{
// Determine the file that should be used for the change. It will be named
// based on the sequence number, which is guaranteed to be unique (even
// across restarts).
final File ldifFile =
new File(logDirectory, sequenceNumber.toString() + ".ldif");
// Open the file for writing.
final PrintWriter w;
try
{
w = new PrintWriter(ldifFile);
}
catch (final Exception e)
{
// About the only thing we can do here is to generate an alert to notify
// administrators of the problem.
serverContext.debugCaught(e);
serverContext.sendAlert(AlertSeverity.ERROR,
"Unable to write a record of change " + changeRecord.toString() +
" to file " + ldifFile.getAbsolutePath() + ": " +
StaticUtils.getExceptionMessage(e));
return;
}
// Write the header to the file. Write it using LDIF comments so that the
// change can be parsed using an LDIF reader.
w.println("# Connection ID: " + operationContext.getConnectionID());
w.println("# Operation ID: " + operationContext.getOperationID());
w.println("# Requester DN: " + operationContext.getAuthorizationDN());
w.println("# Request Time: " +
new Date(operationContext.getProcessingStartTime()));
w.println("# Processing Time (ns): " +
new Date(operationContext.getProcessingTimeNanos()));
for (final ChangeSubscription s : changeSubscriptions)
{
w.println("# Matches change subscription: " + s.getName());
}
// Write an LDIF representation of the change and close the file.
w.println(changeRecord.toLDIFString());
w.close();
}
/**
* Retrieves a map containing examples of configurations that may be used for
* this extension. The map key should be a list of sample arguments, and the
* corresponding value should be a description of the behavior that will be
* exhibited by the extension when used with that configuration.
*
* @return A map containing examples of configurations that may be used for
* this extension. It may be {@code null} or empty if there should
* not be any example argument sets.
*/
@Override()
public Map<List<String>,String> getExamplesArgumentSets()
{
final LinkedHashMap<List<String>,String> exampleMap =
new LinkedHashMap<List<String>,String>(1);
exampleMap.put(
Arrays.asList(ARG_NAME_LOG_DIR + "=logs/change-notifications"),
"Write information about any matching changes into the " +
"logs/change-notifications directory below the server root.");
return exampleMap;
}
/**
* Retrieves the name that should be used to identify this disk space
* consumer.
*
* @return The name that should be used to identify this disk space consumer.
*/
public String getDiskSpaceConsumerName()
{
return "Example Change Subscription Handler " +
config.getConfigObjectName();
}
/**
* Retrieves a list of filesystem paths in which this disk space consumer may
* store files which may consume a significant amount of space. It is
* generally recommended that the paths be directories, but they may also be
* individual files.
*
* @return A list of filesystem paths in which this disk space consumer may
* store files which may consume a significant amount of space.
*/
public List<File> getDiskSpaceConsumerPaths()
{
return Arrays.asList(logDirectory);
}
}
