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package com.sun.xml.internal.xsom;

import com.sun.xml.internal.xsom.impl.scd.Iterators;
import com.sun.xml.internal.xsom.impl.scd.ParseException;
import com.sun.xml.internal.xsom.impl.scd.SCDImpl;
import com.sun.xml.internal.xsom.impl.scd.SCDParser;
import com.sun.xml.internal.xsom.impl.scd.Step;
import com.sun.xml.internal.xsom.impl.scd.TokenMgrError;
import com.sun.xml.internal.xsom.util.DeferedCollection;

import javax.xml.namespace.NamespaceContext;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

Schema Component Designator (SCD).

SCD for schema is what XPath is for XML. SCD allows you to select a schema component(s)
from a schema component(s).

See XML Schema: Component Designators.
This implementation is based on 03/29/2005 working draft.
Author:
Kohsuke Kawaguchi/**
 * Schema Component Designator (SCD).
 *
 * <p>
 * SCD for schema is what XPath is for XML. SCD allows you to select a schema component(s)
 * from a schema component(s).
 *
 * <p>
 * See <a href="http://www.w3.org/TR/2005/WD-xmlschema-ref-20050329/">XML Schema: Component Designators</a>.
 * This implementation is based on 03/29/2005 working draft.
 *
 * @author Kohsuke Kawaguchi
 */
public abstract class SCD {

    
Parses the string representation of SCD.

This method involves parsing the path expression and preparing the in-memory
structure, so this is useful when you plan to use the same SCD against
different context node multiple times.
 If you want to evaluate SCD just once, use XSComponent.select methods. 
Params:
path – 
     the string representation of SCD, such as "/foo/bar".
nsContext –  Its NamespaceContext.getNamespaceURI(String) is used to resolve prefixes in the SCD to the namespace URI./**
     * Parses the string representation of SCD.
     *
     * <p>
     * This method involves parsing the path expression and preparing the in-memory
     * structure, so this is useful when you plan to use the same SCD against
     * different context node multiple times.
     *
     * <p>
     * If you want to evaluate SCD just once, use {@link XSComponent#select} methods.
     *
     * @param path
     *      the string representation of SCD, such as "/foo/bar".
     * @param nsContext
     *      Its {@link NamespaceContext#getNamespaceURI(String)} is used
     *      to resolve prefixes in the SCD to the namespace URI.
     */
    public static SCD create(String path, NamespaceContext nsContext) throws java.text.ParseException {
        try {
            SCDParser p = new SCDParser(path,nsContext);
            List<?> list = p.RelativeSchemaComponentPath();
            return new SCDImpl(path,list.toArray(new Step[list.size()]));
        } catch (TokenMgrError e) {
            throw setCause(new java.text.ParseException(e.getMessage(), -1 ),e);
        } catch (ParseException e) {
            throw setCause(new java.text.ParseException(e.getMessage(), e.currentToken.beginColumn ),e);
        }
    }

    private static java.text.ParseException setCause(java.text.ParseException e, Throwable x) {
        e.initCause(x);
        return e;
    }

    
Evaluates the SCD against the given context node and
returns the matched nodes.
Returns:

     could be empty but never be null./**
     * Evaluates the SCD against the given context node and
     * returns the matched nodes.
     *
     * @return
     *      could be empty but never be null.
     */
    public final Collection<XSComponent> select(XSComponent contextNode) {
        return new DeferedCollection<XSComponent>(select(Iterators.singleton(contextNode)));
    }

    
Evaluates the SCD against the whole schema and
returns the matched nodes.
 This method is here because XSSchemaSet doesn't implement XSComponent. 
Returns:

     could be empty but never be null./**
     * Evaluates the SCD against the whole schema and
     * returns the matched nodes.
     *
     * <p>
     * This method is here because {@link XSSchemaSet}
     * doesn't implement {@link XSComponent}.
     *
     * @return
     *      could be empty but never be null.
     */
    public final Collection<XSComponent> select(XSSchemaSet contextNode) {
        return select(contextNode.getSchemas());
    }

    
Evaluates the SCD against the given context node and
returns the matched node.
Returns:

     null if the SCD didn't match anything. If the SCD matched more than one node,
     the first one will be returned./**
     * Evaluates the SCD against the given context node and
     * returns the matched node.
     *
     * @return
     *      null if the SCD didn't match anything. If the SCD matched more than one node,
     *      the first one will be returned.
     */
    public final XSComponent selectSingle(XSComponent contextNode) {
        Iterator<XSComponent> r = select(Iterators.singleton(contextNode));
        if(r.hasNext())     return r.next();
        return null;
    }

    
Evaluates the SCD against the whole schema set and
returns the matched node.
Returns:

     null if the SCD didn't match anything. If the SCD matched more than one node,
     the first one will be returned./**
     * Evaluates the SCD against the whole schema set and
     * returns the matched node.
     *
     * @return
     *      null if the SCD didn't match anything. If the SCD matched more than one node,
     *      the first one will be returned.
     */
    public final XSComponent selectSingle(XSSchemaSet contextNode) {
        Iterator<XSComponent> r = select(contextNode.iterateSchema());
        if(r.hasNext())     return r.next();
        return null;
    }

    
Evaluates the SCD against the given set of context nodes and
returns the matched nodes.
Params:
contextNodes –  XSComponents that represent the context node against which SCD is evaluated.
Returns:

     could be empty but never be null./**
     * Evaluates the SCD against the given set of context nodes and
     * returns the matched nodes.
     *
     * @param contextNodes
     *      {@link XSComponent}s that represent the context node against
     *      which {@link SCD} is evaluated.
     *
     * @return
     *      could be empty but never be null.
     */
    public abstract Iterator<XSComponent> select(Iterator<? extends XSComponent> contextNodes);

    
Evaluates the SCD against the given set of context nodes and
returns the matched nodes.
Params:
contextNodes –  XSComponents that represent the context node against which SCD is evaluated.
Returns:

     could be empty but never be null./**
     * Evaluates the SCD against the given set of context nodes and
     * returns the matched nodes.
     *
     * @param contextNodes
     *      {@link XSComponent}s that represent the context node against
     *      which {@link SCD} is evaluated.
     *
     * @return
     *      could be empty but never be null.
     */
    public final Collection<XSComponent> select(Collection<? extends XSComponent> contextNodes) {
        return new DeferedCollection<XSComponent>(select(contextNodes.iterator()));
    }

    
Returns the textual SCD representation as given to create(String, NamespaceContext). /**
     * Returns the textual SCD representation as given to {@link SCD#create(String, NamespaceContext)}.
     */
    public abstract String toString();
}