netkit.graph.io
Class NodeReader

java.lang.Object
  netkit.graph.io.NodeReader

public final class NodeReader
extends java.lang.Object

This class reads Node instance data from a Reader object. The input format is line oriented and organized into columns corresponding to Node instance data fields. Column delimiters are commas, and no decorative whitespace is allowed in between values and the delimiters. Each line represents the instance data for one Node. The order of the values must match the order of the fields in the Attributes container of the node type. Data is always converted into java double types. The conversion for CONTINUOUS and DISCRETE values is straightforward, except that DISCRETE values must be a valid integer type before conversion to double. CATEGORICAL types are first converted into int values coresponding to the order they appear defined in the TokenSet of the AttributeCategorical they are from. The KEY field additionally gets inserted into the name field for each Node and must be unique across each node type with a single Graph. Lines may contain comments, which are lines where a '%' or '#' is the first character. Comments are terminated by the end-of-line.

Author:

Kaveh R. Ghazi

See Also:

SchemaReader, SchemaWriter, NodeWriter, Attributes, Node, Graph, TokenSet, AttributeCategorical

Constructor Summary

NodeReader()

Method Summary

static void

readNodes(Graph graph, java.lang.String nodeType, java.io.Reader reader, boolean skipFirstLine) This static method does the work of reading input data for the class.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NodeReader

public NodeReader()

Method Detail

readNodes

public static void readNodes(Graph graph,
                             java.lang.String nodeType,
                             java.io.Reader reader,
                             boolean skipFirstLine)

This static method does the work of reading input data for the class. Given a Graph object, a node type name and an input Reader object, it will read in the Node data and instantiate Nodes as part of the supplied Graph with the appropriate node type Attributes container. This assumes that the graph object contains an appropraite Attributes object with a corresponding nodeType. The Attributes object must contain a key Attribute.

Parameters:

graph - the Graph object to insert Nodes into.

nodeType - the node type name for these Nodes.

reader - the Reader object to read instance data from; the Reader will be closed when this method completes.

skipFirstLine - true if the reader should skip the first line of input; appropriate if the first line contains column headers as in GDA files.

Throws:

java.lang.RuntimeException - if any of the input format constraints are violated or the input cannot be read.