com.xmlmind.xml.xpath

Class XPathUtil

java.lang.Object

com.xmlmind.xml.xpath.XPathUtil

public final class XPathUtil
extends Object

A collection of convenience methods for James Clark's full XPath 1.0 implementation.

Method Summary

Modifier and Type	Method and Description
static boolean	evalAsBoolean(String expr, PrefixEntry[] prefixes, XNode node, Object[] variables) Evaluates specified expression in the context of specified node.
static boolean	evalAsBoolean(String expr, XNode node) Equivalent to evalAsBoolean(expr, null, node, null).
static XNode[]	evalAsNodeSet(String expr, PrefixEntry[] prefixes, XNode node, Object[] variables) Evaluates specified expression in the context of specified node.
static XNode[]	evalAsNodeSet(String expr, XNode node) Equivalent to evalAsNodeSet(expr, null, node, null).
static double	evalAsNumber(String expr, PrefixEntry[] prefixes, XNode node, Object[] variables) Evaluates specified expression in the context of specified node.
static double	evalAsNumber(String expr, XNode node) Equivalent to evalAsNumber(expr, null, node, null).
static String	evalAsString(String expr, PrefixEntry[] prefixes, XNode node, Object[] variables) Evaluates specified expression in the context of specified node.
static String	evalAsString(String expr, XNode node) Equivalent to evalAsString(expr, null, node, null).
static Variant	evalAsVariant(String expr, PrefixEntry[] prefixes, XNode node, Object[] variables) Evaluates specified expression in the context of specified node.
static Variant	evalAsVariant(String expr, XNode node) Equivalent to evalAsVariant(expr, null, node, null).
static boolean	matches(XNode node, String pattern) Equivalent to matches(node, pattern, null, null).
static boolean	matches(XNode node, String pattern, PrefixEntry[] prefixes, Object[] variables) Matches specified node with specified pattern.
static Element	toElement(NodeIterator iter) Returns the first node iterated by specified iterator if this node is an element; null otherwise.

Methods inherited from class java.lang.Object

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

Method Detail

evalAsString

public static String evalAsString(String expr,
                                  XNode node)
                           throws ParseException,
                                  EvalException

Equivalent to evalAsString(expr, null, node, null).

Throws:

ParseException

EvalException

evalAsString

public static String evalAsString(String expr,
                                  PrefixEntry[] prefixes,
                                  XNode node,
                                  Object[] variables)
                           throws ParseException,
                                  EvalException

Evaluates specified expression in the context of specified node.

Parameters:

expr - XPath expression to be evaluated

prefixes - used to map prefixes to namespaces when parsing expr.

May be null. If null, it is node which is used during the parsing of expression expr to map prefixes to namespaces.

node - context of the evaluation

variables - specifies the values of the variables possibly referenced in the expression. May be null.

This array contains variable name/variable value pairs.

A variable name may be a Name or a plain string. A string, which is an NCName, is automatically converted to a Name having no namespace.

A variable value may be a Variant or an Object. An Object is automatically converted to a Variant using VariantBase.create(java.lang.Object).

Returns:

the result of the evaluation converted to a String (using XPath semantics)

Throws:

ParseException - if expression cannot be parsed

EvalException - if parsed expression cannot be evaluated

evalAsNumber

public static double evalAsNumber(String expr,
                                  XNode node)
                           throws ParseException,
                                  EvalException

Equivalent to evalAsNumber(expr, null, node, null).

Throws:

ParseException

EvalException

evalAsNumber

public static double evalAsNumber(String expr,
                                  PrefixEntry[] prefixes,
                                  XNode node,
                                  Object[] variables)
                           throws ParseException,
                                  EvalException

Evaluates specified expression in the context of specified node.

Parameters:

expr - XPath expression to be evaluated

prefixes - used to map prefixes to namespaces when parsing expr.

May be null. If null, it is node which is used during the parsing of expression expr to map prefixes to namespaces.

node - context of the evaluation

variables - specifies the values of the variables possibly referenced in the expression. May be null.

Returns:

the result of the evaluation converted to a number (using XPath semantics)

Throws:

ParseException - if expression cannot be parsed

EvalException - if parsed expression cannot be evaluated

evalAsBoolean

public static boolean evalAsBoolean(String expr,
                                    XNode node)
                             throws ParseException,
                                    EvalException

Equivalent to evalAsBoolean(expr, null, node, null).

Throws:

ParseException

EvalException

evalAsBoolean

public static boolean evalAsBoolean(String expr,
                                    PrefixEntry[] prefixes,
                                    XNode node,
                                    Object[] variables)
                             throws ParseException,
                                    EvalException

Evaluates specified expression in the context of specified node.

Parameters:

expr - XPath expression to be evaluated

prefixes - used to map prefixes to namespaces when parsing expr.

May be null. If null, it is node which is used during the parsing of expression expr to map prefixes to namespaces.

node - context of the evaluation

variables - specifies the values of the variables possibly referenced in the expression. May be null.

Returns:

the result of the evaluation converted to a boolean (using XPath semantics)

Throws:

ParseException - if expression cannot be parsed

EvalException - if parsed expression cannot be evaluated

evalAsNodeSet

public static XNode[] evalAsNodeSet(String expr,
                                    XNode node)
                             throws ParseException,
                                    EvalException

Equivalent to evalAsNodeSet(expr, null, node, null).

Throws:

ParseException

EvalException

evalAsNodeSet

public static XNode[] evalAsNodeSet(String expr,
                                    PrefixEntry[] prefixes,
                                    XNode node,
                                    Object[] variables)
                             throws ParseException,
                                    EvalException

Evaluates specified expression in the context of specified node.

Parameters:

expr - XPath expression to be evaluated

prefixes - used to map prefixes to namespaces when parsing expr.

May be null. If null, it is node which is used during the parsing of expression expr to map prefixes to namespaces.

node - context of the evaluation

variables - specifies the values of the variables possibly referenced in the expression. May be null.

Returns:

the node-set which is the result of the evaluation

Throws:

ParseException - if expression cannot be parsed

EvalException - if parsed expression cannot be evaluated

evalAsVariant

public static Variant evalAsVariant(String expr,
                                    XNode node)
                             throws ParseException,
                                    EvalException

Equivalent to evalAsVariant(expr, null, node, null).

Throws:

ParseException

EvalException

evalAsVariant

public static Variant evalAsVariant(String expr,
                                    PrefixEntry[] prefixes,
                                    XNode node,
                                    Object[] variables)
                             throws ParseException,
                                    EvalException

Evaluates specified expression in the context of specified node.

Parameters:

expr - XPath expression to be evaluated

prefixes - used to map prefixes to namespaces when parsing expr.

May be null. If null, it is node which is used during the parsing of expression expr to map prefixes to namespaces.

node - context of the evaluation

variables - specifies the values of the variables possibly referenced in the expression. May be null.

Returns:

the result of the evaluation wrapped in a Variant

Throws:

ParseException - if expression cannot be parsed

EvalException - if parsed expression cannot be evaluated

matches

public static boolean matches(XNode node,
                              String pattern)
                       throws ParseException,
                              EvalException

Equivalent to matches(node, pattern, null, null).

Throws:

ParseException

EvalException

matches

public static boolean matches(XNode node,
                              String pattern,
                              PrefixEntry[] prefixes,
                              Object[] variables)
                       throws ParseException,
                              EvalException

Matches specified node with specified pattern.

Parameters:

node - node to be matched

pattern - XPath pattern (subset of XPath expressions; see XSLT) used to match node node

prefixes - used to map prefixes to namespaces when parsing pattern.

May be null. If null, it is node which is used during the parsing of pattern pattern to map prefixes to namespaces.

variables - specifies the values of the variables possibly referenced in the pattern. May be null.

Returns:

true if node matches; false otherwise

Throws:

ParseException - if pattern cannot be parsed

EvalException - if an XPath problem occurs during the operation

toElement

public static Element toElement(NodeIterator iter)

Returns the first node iterated by specified iterator if this node is an element; null otherwise.

This utility method is useful to write XPath extension functions.