org.exist.xquery
Class BasicFunction

java.lang.Object
  extended by org.exist.xquery.AbstractExpression
      extended by org.exist.xquery.PathExpr
          extended by org.exist.xquery.Function
              extended by org.exist.xquery.BasicFunction
All Implemented Interfaces:
CompiledXQuery, Expression, RewritableExpression, CompiledExpression
Direct Known Subclasses:
AccountManagementFunction, AccountStatusFunction, Base64Functions, BaseConversionFunctions, BaseConverter, BinaryDoc, BinaryToString, BuiltinFunctions, Clear, Collations, CollectionName, Compile, CountInstances, Create, DeepCopyFunction, DocumentNameOrId, EncodeURL, Eval, Expand, FilterNested, FindGroupFunction, FindLastModifiedSince, FindUserFunction, FnExport, FnFormatDates, FnFormatNumbers, FnImport, FunAdjustTimezone, FunAnalyzeString, FunBaseURI, FunCodepointEqual, FunCodepointsToString, FunctionAvailable, FunctionFunction, FunctionTrace, FunDateTime, FunDefaultCollation, FunEnvironment, FunError, FunEscapeURI, FunGenerateId, FunGetDateComponent, FunGetDurationComponent, FunHeadTail, FunHigherOrderFun, FunIndexOf, FunInScopePrefixes, FunNamespaceURIForPrefix, FunNilled, FunOnFunctions, FunQName, FunResolveQName, FunSerialize, FunStringJoin, FunStringToCodepoints, FunTrace, FunTrueOrFalse, FunUnEscapeURI, FuzzyIndexTerms, GetAttributeNames, GetBuild, GetContextPath, GetCookieNames, GetCookieValue, GetData, GetExistHome, GetExists, GetExists, GetExists, GetHeader, GetHeaderNames, GetHostname, GetIndexStatistics, GetMemory, GetMethod, GetModuleLoadPath, GetNodeById, GetParameter, GetParameterNames, GetPathInfo, GetPrincipalMetadataFunction, GetQueryString, GetRemoteAddr, GetRemoteHost, GetRemotePort, GetRequestAttribute, GetRevision, GetRunningJobs, GetRunningXQueries, GetScheduledJobs, GetScheme, GetSequenceType, GetServerName, GetServerPort, GetUploadedFile, GetUploadedFileName, GetUploadedFileSize, GetUptime, GetURI, GetURL, GetVersion, GrammarTooling, GroupManagementFunction, GroupMembershipFunctions, Hash, HighlightMatches, IndexKeyDocuments, IndexKeyOccurrences, IndexKeys, IndexTerms, IndexType, InspectFunction, InspectModule, Invalidate, IsExternallyAuthenticated, IsMultiPartContent, Jaxp, Jaxv, Jing, KillRunningXQuery, KWICDisplay, LibFunction, ListBackups, LogFunction, MapFunction, MatchCount, ModuleFunctions, ModuleInfo, NodeId, NoParamFunctions, OneParamFunctions, Parse, PermissionsFunctions, Profile, PrologFunctions, QNameFunctions, RandomFunction, RedirectTo, RegexpFilter, Restore, RetrieveBackup, Serialize, SetCurrentUser, SetPrincipalMetadataFunction, Shutdown, Stream, StreamBinary, SystemProperty, TextRank, Tokenize, Transform, TriggerSystemTask, TwoParamFunctions, UMaskFunction, UpdateStatistics, UUID, Validation, Wait, XMLDBAbstractCollectionManipulator, XMLDBAddUserToGroup, XMLDBAuthenticate, XMLDBChangeUser, XMLDBCreateGroup, XMLDBCreateUser, XMLDBDefragment, XMLDBDeleteUser, XMLDBGetCurrentUser, XMLDBGetCurrentUserAttribute, XMLDBGetCurrentUserAttributeNames, XMLDBGetMimeType, XMLDBGetUsers, XMLDBGroupExists, XMLDBIsAdmin, XMLDBIsAuthenticated, XMLDBMatchCollection, XMLDBPermissionsToString, XMLDBRegisterDatabase, XMLDBRemoveUserFromGroup, XMLDBSetMimeType, XMLDBURIFunctions, XMLDBUserAccess

public abstract class BasicFunction
extends Function

Abstract base class for simple functions. Subclasses should overwrite method eval(Sequence[], Sequence).

Author:
Wolfgang Meier (wolfgang@exist-db.org)

Nested Class Summary
 
Nested classes/interfaces inherited from class org.exist.xquery.Function
Function.Placeholder
 
Field Summary
 
Fields inherited from class org.exist.xquery.Function
BUILTIN_FUNCTION_NS
 
Fields inherited from interface org.exist.xquery.Expression
DOT_TEST, EXPRESSION_ID_INVALID, IGNORE_CONTEXT, IN_NODE_CONSTRUCTOR, IN_PREDICATE, IN_UPDATE, IN_WHERE_CLAUSE, NEED_INDEX_INFO, NO_CONTEXT_ID, NON_STREAMABLE, POSITIONAL_PREDICATE, SINGLE_STEP_EXECUTION, UNORDERED, USE_TREE_TRAVERSAL
 
Constructor Summary
BasicFunction(XQueryContext context, FunctionSignature signature)
           
 
Method Summary
abstract  Sequence eval(Sequence[] args, Sequence contextSequence)
          Process the function.
 Sequence eval(Sequence contextSequence, Item contextItem)
          Evaluate the expression represented by this object.
 
Methods inherited from class org.exist.xquery.Function
accept, analyze, createFunction, dump, getArgument, getArgumentCount, getArguments, getCardinality, getDependencies, getName, getParent, getSignature, isCalledAs, returnsType, setArguments, setParent, setPrimaryAxis, simplify, toString
 
Methods inherited from class org.exist.xquery.PathExpr
add, add, addPath, addPredicate, allowMixedNodesInReturn, dump, getColumn, getContext, getDocumentSet, getExpression, getFirst, getLastExpression, getLength, getLine, getLiteralValue, getPrevious, getPrimaryAxis, getSubExpression, getSubExpressionCount, isValid, remove, replace, replaceLastExpression, reset, resetState, setContext, setUseStaticContext
 
Methods inherited from class org.exist.xquery.AbstractExpression
eval, getContextDocSet, getContextId, getExpressionId, getSource, match, needsReset, setASTNode, setContextDocSet, setContextId, setLocation
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.exist.xquery.CompiledXQuery
eval, getSource
 

Constructor Detail

BasicFunction

public BasicFunction(XQueryContext context,
                     FunctionSignature signature)
Method Detail

eval

public Sequence eval(Sequence contextSequence,
                     Item contextItem)
              throws XPathException
Description copied from interface: Expression
Evaluate the expression represented by this object. Depending on the context in which this expression is executed, either the context sequence, the context item or both of them may be set. An implementing class should know how to handle this. The general contract is as follows: if the Dependency.CONTEXT_ITEM bit is set in the bit field returned by Expression.getDependencies(), the eval method will be called once for every item in the context sequence. The contextItem parameter will be set to the current item. Otherwise, the eval method will only be called once for the whole context sequence and contextItem will be null. eXist tries to process the entire context set in one, single step whenever possible. Thus, most classes only expect context to contain a list of nodes which represents the current context of the expression. The position() function in XPath is an example for an expression, which requires both, context sequence and context item to be set. The context sequence might be a node set, a sequence of atomic values or a single node or atomic value.

Specified by:
eval in interface Expression
Specified by:
eval in class Function
Parameters:
contextSequence - the current context sequence.
contextItem - a single item, taken from context. This defines the item, the expression should work on.
Throws:
XPathException

eval

public abstract Sequence eval(Sequence[] args,
                              Sequence contextSequence)
                       throws XPathException
Process the function. All arguments are passed in the array args. The number of arguments, their type and cardinality have already been checked to match the function signature.

Parameters:
args -
contextSequence -
Throws:
XPathException


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