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package net.sf.saxon.pattern;
import net.sf.saxon.Configuration;
import net.sf.saxon.om.Item;
import net.sf.saxon.om.NodeInfo;
import net.sf.saxon.tinytree.TinyTree;
import net.sf.saxon.type.ItemType;
import net.sf.saxon.type.Type;

/**
  * NodeTest is an interface that enables a test of whether a node has a particular
  * name and type. An EmptySequenceTest matches no nodes or atomic values: it corresponds to the
  * type empty-sequence().
  *
  * @author Michael H. Kay
  */

public final class EmptySequenceTest extends NodeTest {

    private static EmptySequenceTest THE_INSTANCE = new EmptySequenceTest();

    /**
    * Get a NoNodeTest instance
    */

    public static EmptySequenceTest getInstance() {
        return THE_INSTANCE;
    }

    /**
     * Private constructor
     */ 

    private EmptySequenceTest() {}

	public final int getPrimitiveType() {
		return Type.EMPTY;
	}

    /**
     * Get the primitive item type corresponding to this item type. For item(),
     * this is Type.ITEM. For node(), it is Type.NODE. For specific node kinds,
     * it is the value representing the node kind, for example Type.ELEMENT.
     * For anyAtomicValue it is Type.ATOMIC_VALUE. For numeric it is Type.NUMBER.
     * For other atomic types it is the primitive type as defined in XML Schema,
     * except that INTEGER is considered to be a primitive type.
     */

    public ItemType getPrimitiveItemType() {
        return this;
    }

    /**
     * Test whether a given item conforms to this type
     * @param item The item to be tested
     * @param allowURIPromotion
     * @param config
     * @return true if the item is an instance of this type; false otherwise
    */

    public boolean matchesItem(Item item, boolean allowURIPromotion, Configuration config) {
        return false;
    }


    /**
    * Test whether this node test is satisfied by a given node
    * @param nodeType The type of node to be matched
     * @param fingerprint identifies the expanded name of the node to be matched
     */

    public boolean matches(int nodeType, int fingerprint, int annotation) {
        return false;
    }

    /**
     * Test whether this node test is satisfied by a given node on a TinyTree. The node
     * must be a document, element, text, comment, or processing instruction node.
     * This method is provided
     * so that when navigating a TinyTree a node can be rejected without
     * actually instantiating a NodeInfo object.
     *
     * @param tree   the TinyTree containing the node
     * @param nodeNr the number of the node within the TinyTree
     * @return true if the node matches the NodeTest, otherwise false
     */

    public boolean matches(TinyTree tree, int nodeNr) {
        return false;
    }

    /**
     * Test whether this node test is satisfied by a given node. This alternative
     * method is used in the case of nodes where calculating the fingerprint is expensive,
     * for example DOM or JDOM nodes.
     * @param node the node to be matched
     */

    public boolean matches(NodeInfo node) {
        return false;
    }


    /**
    * Determine the default priority of this node test when used on its own as a Pattern
    */

    public final double getDefaultPriority() {
    	return -0.5;
    }

    /**
     * Get a mask indicating which kinds of nodes this NodeTest can match. This is a combination
     * of bits: 1<