xpath.java

java1.6众多例子参考

    private NodeTest parseNodeTest( int typeToken, Tokens xtokens, NamespaceContext context )
        throws XPathException {
        switch(typeToken) {
        case XPath.Tokens.EXPRTOKEN_NAMETEST_ANY:
            return new NodeTest(NodeTest.WILDCARD);
            
        case XPath.Tokens.EXPRTOKEN_NAMETEST_NAMESPACE:
        case XPath.Tokens.EXPRTOKEN_NAMETEST_QNAME:
            // consume QName token
            String prefix = xtokens.nextTokenAsString();
            String uri = null;
            if (context != null && prefix != XMLSymbols.EMPTY_STRING) {
                uri = context.getURI(prefix);
            }
            if (prefix != XMLSymbols.EMPTY_STRING && context != null && uri == null) {
                throw new XPathException("c-general-xpath-ns");
            }
    
            if (typeToken==XPath.Tokens.EXPRTOKEN_NAMETEST_NAMESPACE)
                return new NodeTest(prefix,uri);
    
            String localpart = xtokens.nextTokenAsString();
            String rawname = prefix != XMLSymbols.EMPTY_STRING
            ? fSymbolTable.addSymbol(prefix+':'+localpart)
            : localpart;
    
            return new NodeTest(new QName(prefix, localpart, rawname, uri));
        
        default:
            // assertion error
            throw new XPathException("c-general-xpath");
            
        }
    }
    
    
    //
    // Classes
    //

    // location path information

    /**
     * A location path representation for an XPath expression.
     * 
     * @xerces.internal
     *
     * @author Andy Clark, IBM
     */
    public static class LocationPath
        implements Cloneable {

        //
        // Data
        //

        /** List of steps. */
        public Step[] steps;

        //
        // Constructors
        //

        /** Creates a location path from a series of steps. */
        public LocationPath(Step[] steps) {
            this.steps = steps;
        } // <init>(Step[])

        /** Copy constructor. */
        protected LocationPath(LocationPath path) {
            steps = new Step[path.steps.length];
            for (int i = 0; i < steps.length; i++) {
                steps[i] = (Step)path.steps[i].clone();
            }
        } // <init>(LocationPath)

        //
        // Object methods
        //

        /** Returns a string representation of this object. */
        public String toString() {
            StringBuffer str = new StringBuffer();
            for (int i = 0; i < steps.length; i++) {
                if (i > 0	&& (steps[i-1].axis.type!=Axis.DESCENDANT
                    && steps[i].axis.type!=Axis.DESCENDANT) ){
                    str.append('/');
                }
                str.append(steps[i].toString());
            }
            // DEBUG: This code is just for debugging and should *not*
            //        be left in because it will mess up hashcodes of
            //        serialized versions of this object. -Ac
            if (false) {
                str.append('[');
                String s = super.toString();
                str.append(s.substring(s.indexOf('@')));
                str.append(']');
            }
            return str.toString();
        } // toString():String

        /** Returns a clone of this object. */
        public Object clone() {
            return new LocationPath(this);
        } // clone():Object

    } // class locationPath

    /**
     * A location path step comprised of an axis and node test.
     * 
     * @xerces.internal
     *
     * @author Andy Clark, IBM
     */
    public static class Step
        implements Cloneable {

        //
        // Data
        //

        /** Axis. */
        public Axis axis;

        /** Node test. */
        public NodeTest nodeTest;

        //
        // Constructors
        //

        /** Constructs a step from an axis and node test. */
        public Step(Axis axis, NodeTest nodeTest) {
            this.axis = axis;
            this.nodeTest = nodeTest;
        } // <init>(Axis,NodeTest)

        /** Copy constructor. */
        protected Step(Step step) {
            axis = (Axis)step.axis.clone();
            nodeTest = (NodeTest)step.nodeTest.clone();
        } // <init>(Step)

        //
        // Object methods
        //

        /** Returns a string representation of this object. */
        public String toString() {
            if (axis.type == Axis.SELF) {
                return ".";
            }
            if (axis.type == Axis.ATTRIBUTE) {
                return "@" + nodeTest.toString();
            }
            if (axis.type == Axis.CHILD) {
                return nodeTest.toString();
            }
            if (axis.type == Axis.DESCENDANT) {
                return "//";
            }
            return "??? ("+axis.type+')';
        } // toString():String

        /** Returns a clone of this object. */
        public Object clone() {
            return new Step(this);
        } // clone():Object

    } // class Step

    /**
     * Axis.
     * 
     * @xerces.internal
     *
     * @author Andy Clark, IBM
     */
    public static class Axis
        implements Cloneable {

        //
        // Constants
        //

        /** Type: child. */
        public static final short CHILD = 1;

        /** Type: attribute. */
        public static final short ATTRIBUTE = 2;

        /** Type: self. */
        public static final short SELF = 3;


        /** Type: descendant. */
        public static final short DESCENDANT = 4;
        //
        // Data
        //

        /** Axis type. */
        public short type;

        //
        // Constructors
        //

        /** Constructs an axis with the specified type. */
        public Axis(short type) {
            this.type = type;
        } // <init>(short)

        /** Copy constructor. */
        protected Axis(Axis axis) {
            type = axis.type;
        } // <init>(Axis)

        //
        // Object methods
        //

        /** Returns a string representation of this object. */
        public String toString() {
            switch (type) {
                case CHILD: return "child";
                case ATTRIBUTE: return "attribute";
                case SELF: return "self";
                case DESCENDANT: return "descendant";
            }
            return "???";
        } // toString():String

        /** Returns a clone of this object. */
        public Object clone() {
            return new Axis(this);
        } // clone():Object

    } // class Axis

    /**
     * Node test.
     * 
     * @xerces.internal
     *
     * @author Andy Clark, IBM
     */
    public static class NodeTest
        implements Cloneable {

        //
        // Constants
        //

        /** Type: qualified name. */
        public static final short QNAME = 1;

        /** Type: wildcard. */
        public static final short WILDCARD = 2;

        /** Type: node. */
        public static final short NODE = 3;

        /** Type: namespace */
        public static final short NAMESPACE= 4;

        //
        // Data
        //

        /** Node test type. */
        public short type;

        /** Node qualified name. */
        public final QName name = new QName();

        //
        // Constructors
        //

        /** Constructs a node test of type WILDCARD or NODE. */
        public NodeTest(short type) {
            this.type = type;
        } // <init>(int)

        /** Constructs a node test of type QName. */
        public NodeTest(QName name) {
            this.type = QNAME;
            this.name.setValues(name);
        } // <init>(QName)
        /** Constructs a node test of type Namespace. */
        public NodeTest(String prefix, String uri) {
            this.type = NAMESPACE;
            this.name.setValues(prefix, null, null, uri);
        } // <init>(String,String)

        /** Copy constructor. */
        public NodeTest(NodeTest nodeTest) {
            type = nodeTest.type;
            name.setValues(nodeTest.name);
        } // <init>(NodeTest)

        //
        // Object methods
        //

        /** Returns a string representation of this object. */
        public String toString() {

            switch (type) {
                case QNAME: {
                    if (name.prefix.length() !=0) {
                        if (name.uri != null) {
                            return name.prefix+':'+name.localpart;
                        }
                        return "{"+name.uri+'}'+name.prefix+':'+name.localpart;
                    }