/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-09 Wolfgang M. Meier
* wolfgang@exist-db.org
* http://exist.sourceforge.net
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id: BuiltinFunctions.java 9598 2009-07-31 05:45:57Z ixitar $
*/
package org.exist.xquery.modules.context;
import java.util.HashMap;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.exist.dom.QName;
import org.exist.xquery.Cardinality;
import org.exist.xquery.Dependency;
import org.exist.xquery.Function;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.Profiler;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.XQueryWatchDog;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.IntegerValue;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
public class ContextAttributes extends Function
{
public final static String ATTRIBUTES_CONTEXTVAR = "_eXist_xquery_context_attributes";
protected static final Logger logger = LogManager.getLogger( ContextAttributes.class );
protected static final FunctionParameterSequenceType ATTRIBUTE_NAME_PARAM = new FunctionParameterSequenceType( "name", Type.STRING, Cardinality.EXACTLY_ONE, "The attribute name" );
protected static final FunctionParameterSequenceType ATTRIBUTE_VALUE_PARAM = new FunctionParameterSequenceType( "value", Type.ITEM, Cardinality.ZERO_OR_MORE, "The value to be stored in the context by attribute name" );
protected static final FunctionParameterSequenceType XQUERY_ID_PARAM = new FunctionParameterSequenceType( "xquery-id", Type.INTEGER, Cardinality.EXACTLY_ONE, "The XQuery ID" );
public final static FunctionSignature signatures[] = {
new FunctionSignature(
new QName( "get-attribute", ContextModule.NAMESPACE_URI, ContextModule.PREFIX ),
"Returns the value associated with the given name, which was stored in the XQuery" +
"context. This function is useful for storing temporary information if you don't have " +
"a servlet request or session, that is you're running an XQuery as a scheduled task.",
new SequenceType[] {
ATTRIBUTE_NAME_PARAM
},
new FunctionReturnSequenceType( Type.ITEM, Cardinality.ZERO_OR_MORE, "The attribute value" )
),
new FunctionSignature(
new QName( "set-attribute", ContextModule.NAMESPACE_URI, ContextModule.PREFIX ),
"Set the value of an XQuery context attribute with the specified name " +
"This function is useful for storing temporary information if you don't have " +
"a servlet request or session, that is you're running an XQuery as a scheduled task.",
new SequenceType[] {
ATTRIBUTE_NAME_PARAM,
ATTRIBUTE_VALUE_PARAM
},
new FunctionReturnSequenceType( Type.ITEM, Cardinality.EMPTY, "Returns an empty sequence" )
),
new FunctionSignature(
new QName( "get-attribute", ContextModule.NAMESPACE_URI, ContextModule.PREFIX ),
"Returns the value associated with the given name, which was stored in the XQuery" +
"context for the XQuery with the provided id. (dba role only). This function can be sued for simple inter-XQuery communication.",
new SequenceType[] {
ATTRIBUTE_NAME_PARAM,
XQUERY_ID_PARAM
},
new FunctionReturnSequenceType( Type.ITEM, Cardinality.ZERO_OR_MORE, "The attribute value" )
),
new FunctionSignature(
new QName( "set-attribute", ContextModule.NAMESPACE_URI, ContextModule.PREFIX ),
"Set the value of an XQuery context attribute with the specified name for the XQuery with the provided id. (dba role only)" +
"This function can be used for simple inter-XQuery communication.",
new SequenceType[] {
ATTRIBUTE_NAME_PARAM,
ATTRIBUTE_VALUE_PARAM,
XQUERY_ID_PARAM
},
new FunctionReturnSequenceType( Type.ITEM, Cardinality.EMPTY, "Returns an empty sequence" )
)
};
public ContextAttributes( XQueryContext context, FunctionSignature signature )
{
super( context, signature );
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#eval(org.exist.dom.persistent.DocumentSet, org.exist.xquery.value.Sequence, org.exist.xquery.value.Item)
*/
public Sequence eval( Sequence contextSequence, Item contextItem ) throws XPathException
{
Sequence ret = Sequence.EMPTY_SEQUENCE;
if( context.getProfiler().isEnabled() ) {
context.getProfiler().start( this );
context.getProfiler().message( this, Profiler.DEPENDENCIES, "DEPENDENCIES", Dependency.getDependenciesName( this.getDependencies() ) );
if( contextSequence != null ) {
context.getProfiler().message( this, Profiler.START_SEQUENCES, "CONTEXT SEQUENCE", contextSequence );
}
if( contextItem != null ) {
context.getProfiler().message( this, Profiler.START_SEQUENCES, "CONTEXT ITEM", contextItem.toSequence() );
}
}
// get attribute name parameter
String attribName = getArgument( 0 ).eval( contextSequence, contextItem ).getStringValue();
if( isCalledAs( "get-attribute" ) ) {
if( getArgumentCount() > 1 ) {
long xqueryID = ((IntegerValue)(getArgument( 1 ).eval( contextSequence, contextItem ).itemAt( 0 ))).getLong();
ret = retrieveAttribute( getForeignContext( xqueryID ), attribName );
} else {
ret = retrieveAttribute( context, attribName );
}
} else {
Sequence attribValue = getArgument( 1 ).eval( contextSequence, contextItem );
if( getArgumentCount() > 2 ) {
long xqueryID = ((IntegerValue)(getArgument( 2 ).eval( contextSequence, contextItem ).itemAt( 0 ))).getLong();
ret = storeAttribute( getForeignContext( xqueryID ), attribName, attribValue );
} else {
ret = storeAttribute( context, attribName, attribValue );
}
}
return( ret );
}
//***************************************************************************
//*
//* Foreign Context Methods
//*
//***************************************************************************/
private XQueryContext getForeignContext( long id ) throws XPathException
{
XQueryContext foreignContext = null;
if( !context.getUser().hasDbaRole() ) {
throw( new XPathException( this, "Permission denied, calling user '" + context.getUser().getName() + "' must be a DBA to access foreign contexts" ) );
}
if( id != 0 ) {
XQueryWatchDog watchdogs[] = getContext().getBroker().getBrokerPool().getProcessMonitor().getRunningXQueries();
for (XQueryWatchDog watchdog : watchdogs) {
XQueryContext ctx = watchdog.getContext();
if (id == ctx.hashCode()) {
if (!watchdog.isTerminating()) {
foreignContext = ctx;
}
break;
}
}
}
if( foreignContext == null ) {
throw( new XPathException( this, "Foreign XQuery with id: " + id + " not found or is terminating" ) );
}
return( foreignContext );
}
//***************************************************************************
//*
//* Context Attribute Methods
//*
//***************************************************************************/
/**
* Retrieves a previously stored Attribute from the Context of an XQuery
*
* @param context The Context of the XQuery containing the attribute
* @param key The key of the attribute to retrieve from the Context of the XQuery
*/
private Sequence retrieveAttribute( XQueryContext context, String key )
{
Sequence attribute = Sequence.EMPTY_SEQUENCE;
synchronized( context ) {
// get the existing attributes map from the context
HashMap<String, Sequence> attributes = (HashMap<String, Sequence>)context.getXQueryContextVar( ATTRIBUTES_CONTEXTVAR );
if( attributes != null ) {
Sequence value = attributes.get( key );
if( value != null ) {
attribute = value;
}
}
}
return attribute;
}
/**
* Stores an attribute in the Context of an XQuery
*
* @param context The Context of the XQuery to store the attribute in
* @param key The key of the attribute to store in the Context of the XQuery
* @param attribute The attribute to store
*
* @return empty sequence
*/
private Sequence storeAttribute( XQueryContext context, String key, Sequence attribute )
{
synchronized( context ) {
// get the existing attributes map from the context
HashMap<String, Sequence> attributes = (HashMap<String, Sequence>)context.getXQueryContextVar( ATTRIBUTES_CONTEXTVAR );
if( attributes == null ) {
// if there is no attributes map, create a new one
attributes = new HashMap<>();
}
// place the attribute in the attributes map
attributes.put( key, attribute );
// store the updated sessions map back in the context
context.setXQueryContextVar( ATTRIBUTES_CONTEXTVAR, attributes );
}
return( Sequence.EMPTY_SEQUENCE );
}
}