Package org.apache.uima.cas.impl

Class FeatureValuePathImpl

  • All Implemented Interfaces:
    FeatureValuePath
    public class FeatureValuePathImpl
extends java.lang.Object
implements FeatureValuePath
    Contains CAS Type and Feature objects to represent a feature path of the form feature1/.../featureN. Each part that is enclosed within / is referred to as "path snippet" below. Also contains the necessary evaluation logic to yield the value of the feature path. For leaf snippets, the following "special features" are defined:
    • coveredText() can be accessed using evaluateAsString
    • typeName() can be accessed using evaluateAsString
    • fsId() can be accessed using evaluateAsInt. Its result can be used to retrieve an FS from the current LowLevel-CAS.
    • uniqueId() can be accessed using evaluateAsInt. Its result can be used to uniquely identify an FS for a document (even if the document is split over several CAS chunks)
    Handling of Arrays
    • A feature path may contain 0 or more features of type FSArray, but not as the last path snippet. The next path snippet must contain the fully qualified type name, example: family/members[0]/somepackage.Person:name
    • A feature path may also contain 0 or 1 feature of type IntArray, StringArray, FloatArray, but only as the last path snippet.
    For array-valued features, the following access operators are defined:
    • [index] returns the array entry at index
    • [last] returns the last entry of the array
    • [] returns an array of values. [] is only allowed 0 or 1 time in a feature path. If it is used, getValueType will return one of the following: CAS.TYPE_NAME_STRING_ARRAY ,CAS.TYPE_NAME_INTEGER_ARRAY,CAS.TYPE_NAME_FLOAT_ARRAY.
    If the feature path is defined directly for an FSArray, an actual feature name can be omitted, and only the array access operator can be used. Examples: 
                            
                         
                          
                           
                            
                             
                              
                               
                                
                                 
                                                                            []/somepackage.Person:coveredText()
                                                                             [last]/somepackage.Person:fsId()

    Usage
    • To create the feature path, use FeaturePath.getFeaturePath. Note that the client code needs to keep track of the "start type" of the feature path, that is, the type that contains the attribute used in the first snippet of the path.
    • At typeSystemInit of your component (CAS consumer or TAE), call typeSystemInit of the feature path.
    • Call getValueType to find out whether the feature path evaluates to a String, and int, a float, or their array counterparts.
    • Depending on the leaf type, call the appropriate evaluateAs methods

    • Field Detail

      • CONTAINER_TO_ELEMENTYPE_MAP

        private static final java.util.Map<java.lang.String,​java.lang.String> CONTAINER_TO_ELEMENTYPE_MAP

      • LIST_TO_ARRAYTYPE_MAP

        private static final java.util.Map<java.lang.String,​java.lang.String> LIST_TO_ARRAYTYPE_MAP

      • EMPTY_LIST_TYPE_NAMES

        private static final java.lang.String[] EMPTY_LIST_TYPE_NAMES

      • LAST_ARRAY_ENTRY_MARKER

        private static final java.lang.String LAST_ARRAY_ENTRY_MARKER
        See Also:
        Constant Field Values

      • LIST_TYPE_NAMES

        private static final java.lang.String[] LIST_TYPE_NAMES

      • SIMPLE_VAL_TYPES

        private static final java.lang.String[] SIMPLE_VAL_TYPES

      • TYPE_CLASS_INTEGERLIST

        private static final int TYPE_CLASS_INTEGERLIST
        See Also:
        Constant Field Values

      • arrayIndex

        private int arrayIndex

      • emptyListTypes

        private Type[] emptyListTypes

      • featureCode

        private int featureCode

      • featureName

        private java.lang.String featureName

      • featureRangeType

        private int featureRangeType

      • headFeature

        private int headFeature

      • isArrayOrList

        private boolean isArrayOrList

      • isArrayType

        private boolean isArrayType

      • isBracketsOnly

        private boolean isBracketsOnly

      • isCoveredTextFeature

        private boolean isCoveredTextFeature

      • isFsIdFeature

        private boolean isFsIdFeature

      • isListType

        private boolean isListType

      • isSimpleRangeType

        private boolean isSimpleRangeType

      • isTypeNameFeature

        private boolean isTypeNameFeature

      • isUniqueIdFeature

        private boolean isUniqueIdFeature

      • listType

        private int listType

      • tailFeature

        private int tailFeature

      • typeCode

        private int typeCode

      • typeNameInSnippet

        private final java.lang.String typeNameInSnippet

      • valueTypeName

        private java.lang.String valueTypeName

    • Constructor Detail

    • Method Detail

      • evaluateAsString

        public java.lang.String evaluateAsString​(int currentFS,
                                         LowLevelCAS cas)
        Evaluates each snippet of the feature path. Returns a String representation of the leaf value of the path. Returns null if some feature within the path is not set. If the leaf snippet is COVERED_TEXT, returns the covered text of currentFS.
        Specified by:
        evaluateAsString in interface FeatureValuePath
        Parameters:
        currentFS - the current Feature Structure
        cas - CAS
        Returns:
        A string representation of the leaf value.

      • getFSType

        public int getFSType()
        Returns the type for which the last feature in the feature path is defined. Assumes that typeSystemInit has been called prior to this method.
        • For a feature path feature1/.../featureN-1/featureN, returns the type of featureN.
        • For a feature path feature1/.../featureN-1/typeN:featureN, returns the type code for typeN. (For example, if the range type of featureN-1 is FSList or FSArray)
        • For a feature path feature1, where feature1 is simple-valued, returns the type that was used in typeSystemInit
        Specified by:
        getFSType in interface FeatureValuePath
        Returns:
        the type for which the last feature in the feature path is defined.

      • getValueType

        public java.lang.String getValueType()
        Returns the type that this feature path will evaluate to. Can be used to select the correct "evaluateAs" method.
        Specified by:
        getValueType in interface FeatureValuePath
        Returns:
        String the type that this feature path will evaluate to. Will be one of the following:
        • CAS.TYPE_NAME_STRING
        • CAS.TYPE_NAME_STRING_ARRAY
        • CAS.TYPE_NAME_INTEGER
        • CAS.TYPE_NAME_INTEGER_ARRAY
        • CAS.TYPE_NAME_FLOAT
        • CAS.TYPE_NAME_FLOAT_ARRAY

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • isBuiltInFeature

        private boolean isBuiltInFeature()

      • determineArray

        private final void determineArray()
                           throws CASRuntimeException
        Checks whether the feature snippet denotes array access (i.e., has [..] attached to it). If so, determines the arrayIndex to use within evaluation, which can be a number, the special element "last" or simple [], which means "all elements"
        Throws:
        CASRuntimeException - If the closing ] is missing, or the number is not an integer

      • getArrayIndex

        private int getArrayIndex​(int arraySize)

      • getFeatureInSnippet

        private final java.lang.String getFeatureInSnippet​(java.lang.String pathSnippet)

      • getFsAtIndex

        private int getFsAtIndex​(int currentFS,
                         LowLevelCAS cas,
                         int arraySize)

      • getFsAtListIndex

        private int getFsAtListIndex​(LowLevelCAS cas,
                             int listFS)
        Assumes that arrayIndex!=USE_ALL_ENTRIES, and that the listType is TYPE_CLASS_FSLIST
        Parameters:
        cas - the low level CAS
        the - list feature structure
        Returns:
        int A reference to the fs given in arrayIndex, or 0 if the list does not contain an entry for that index.

      • getHeadValue

        private java.lang.Object getHeadValue​(LowLevelCAS cas,
                                      int listFS)

      • getTypeInSnippet

        private final java.lang.String getTypeInSnippet​(java.lang.String pathSnippet)

      • getValueAtIndexRec

        private java.lang.Object getValueAtIndexRec​(LowLevelCAS cas,
                                            int listFS,
                                            java.util.ArrayList list,
                                            int count)

      • getValueAtListIndex

        private java.lang.Object getValueAtListIndex​(LowLevelCAS cas,
                                             int listFS)
        Parameters:
        cas - CAS
        listFS - the list Feature Structure
        Returns:
        Object If arrayIndex = USE_ALL_ENTRIES, returns an ArrayList containing all entries. Otherwise, returns a String, Integer, or Float. Returns null if the list does not contain an entry for arrayIndex, or is empty.

      • isBracketsOnly

        private boolean isBracketsOnly()

      • isEmptyList

        private boolean isEmptyList​(LowLevelCAS cas,
                            int type)