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package com.unboundid.directory.sdk.examples;
import java.util.Arrays;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import com.unboundid.directory.sdk.common.types.Entry;
import com.unboundid.directory.sdk.common.types.OperationContext;
import com.unboundid.directory.sdk.ds.api.VirtualAttributeProvider;
import com.unboundid.directory.sdk.ds.config.VirtualAttributeProviderConfig;
import com.unboundid.directory.sdk.ds.types.DirectoryServerContext;
import com.unboundid.ldap.sdk.Attribute;
import com.unboundid.ldap.sdk.LDAPException;
import com.unboundid.ldap.sdk.ResultCode;
import com.unboundid.util.args.ArgumentException;
import com.unboundid.util.args.ArgumentParser;
import com.unboundid.util.args.StringArgument;
/**
* This class provides a simple example of a virtual attribute provider that
* will generate a virtual attribute whose value will be the reverse of another
* attribute in the same entry. It takes a single configuration argument:
* <UL>
* <LI>source-attribute -- The name of the attribute in the entry whose value
* will be reversed to obtain the values for the virtual attribute.</LI>
* </UL>
*/
public final class ExampleVirtualAttributeProvider
extends VirtualAttributeProvider
{
/**
* The name of the argument that will be used for the argument used to specify
* the attribute whose values should be reversed.
*/
private static final String ARG_NAME_ATTR = "source-attribute";
// The server context for the server in which this extension is running.
private DirectoryServerContext serverContext;
// The source attribute from which to obtain the data for the virtual
// attribute.
private volatile String sourceAttribute;
/**
* Creates a new instance of this virtual attribute provider. All virtual
* attribute provider implementations must include a default constructor, but
* any initialization should generally be done in the
* {@code initializeVirtualAttributeProvider} method.
*/
public ExampleVirtualAttributeProvider()
{
// 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 Virtual Attribute Provider";
}
/**
* 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 virtual attribute provider serves as an example that may be used " +
"to demonstrate the process for creating a third-party virtual " +
"attribute provider. It will generate an attribute whose values " +
"are the same as the values of another attribute in the same " +
"entry but with the characters of those values in reverse order."
};
}
/**
* Updates the provided argument parser to define any configuration arguments
* which may be used by this virtual attribute provider. 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 virtual attribute
* provider.
*
* @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 source attribute name.
Character shortIdentifier = null;
String longIdentifier = ARG_NAME_ATTR;
boolean required = true;
int maxOccurrences = 1;
String placeholder = "{attr}";
String description = "The name of the attribute whose values " +
"should be reversed to generate the values for the virtual attribute.";
parser.addArgument(new StringArgument(shortIdentifier, longIdentifier,
required, maxOccurrences, placeholder, description));
}
/**
* Initializes this virtual attribute provider.
*
* @param serverContext A handle to the server context for the server in
* which this extension is running.
* @param config The general configuration for this virtual attribute
* provider.
* @param parser The argument parser which has been initialized from
* the configuration for this virtual attribute
* provider.
*
* @throws LDAPException If a problem occurs while initializing this virtual
* attribute provider.
*/
@Override()
public void initializeVirtualAttributeProvider(
final DirectoryServerContext serverContext,
final VirtualAttributeProviderConfig config,
final ArgumentParser parser)
throws LDAPException
{
this.serverContext = serverContext;
// Get the source attribute name.
final StringArgument arg =
(StringArgument) parser.getNamedArgument(ARG_NAME_ATTR);
sourceAttribute = arg.getValue();
}
/**
* Indicates whether the configuration contained in the provided argument
* parser represents a valid configuration for this extension.
*
* @param config The general configuration for this virtual
* attribute provider.
* @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 VirtualAttributeProviderConfig config,
final ArgumentParser parser,
final List<String> unacceptableReasons)
{
// The argument parser will handle all of the necessary validation, so
// we don't need to do anything here.
return true;
}
/**
* Attempts to apply the configuration contained in the provided argument
* parser.
*
* @param config The general configuration for this virtual
* attribute provider.
* @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 VirtualAttributeProviderConfig config,
final ArgumentParser parser,
final List<String> adminActionsRequired,
final List<String> messages)
{
// Get the new source attribute name.
final StringArgument arg =
(StringArgument) parser.getNamedArgument(ARG_NAME_ATTR);
sourceAttribute = arg.getValue();
return ResultCode.SUCCESS;
}
/**
* Performs any cleanup which may be necessary when this virtual attribute
* provider is to be taken out of service.
*/
@Override()
public void finalizeVirtualAttributeProvider()
{
// No implementation required.
}
/**
* Indicates whether the server may cache values generated by this virtual
* attribute provider for reuse against the same entry in the course of
* processing the same operation.
*
* @return {@code true} if the server may cache the value generated by this
* virtual attribute provider for reuse with the same entry in the
* same operation, or {@code false} if not.
*/
@Override()
public boolean mayCacheInOperation()
{
// The values of this virtual attribute are safe to cache.
return true;
}
/**
* Indicates whether this virtual attribute provider may generate attributes
* with multiple values.
*
* @return {@code true} if this virtual attribute provider may generate
* attributes with multiple values, or {@code false} if it will only
* generate single-valued attributes.
*/
@Override()
public boolean isMultiValued()
{
// If the source attribute is multi-valued, then the virtual attribute will
// also be multi-valued.
return true;
}
/**
* Generates an attribute for inclusion in the provided entry.
*
* @param operationContext The operation context for the operation in
* progress, if any. It may be {@code null} if no
* operation is available.
* @param entry The entry for which the attribute is to be
* generated.
* @param attributeName The name of the attribute to be generated.
*
* @return The generated attribute, or {@code null} if no attribute should be
* generated.
*/
@Override()
public Attribute generateAttribute(final OperationContext operationContext,
final Entry entry,
final String attributeName)
{
final List<Attribute> attrList = entry.getAttribute(sourceAttribute);
if ((attrList == null) || attrList.isEmpty())
{
// The source attribute doesn't exist, so we can't generate a virtual
// attribute.
if (serverContext.debugEnabled())
{
serverContext.debugInfo("Returning null because attribute " +
sourceAttribute + " does not exist in entry " + entry.getDN());
}
return null;
}
final LinkedHashSet<String> values = new LinkedHashSet<String>();
for (final Attribute a : attrList)
{
for (final String s : a.getValues())
{
values.add(new StringBuilder(s).reverse().toString());
}
}
if (values.isEmpty())
{
if (serverContext.debugEnabled())
{
serverContext.debugInfo("Returning null because attribute " +
sourceAttribute + " does not have any values in entry " +
entry.getDN());
}
return null;
}
else
{
final Attribute va = new Attribute(attributeName, values);
if (serverContext.debugEnabled())
{
serverContext.debugInfo("Generated virtual attribute " + va);
}
return va;
}
}
/**
* 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_ATTR + "=cn"),
"Generate a virtual attribute whose values will be the reverse of " +
"the values of the cn attribute in the same entry.");
return exampleMap;
}
}
