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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2013 Saxonica Limited.
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
package net.sf.saxon.om;
import net.sf.saxon.evpull.PullEvent;
/**
* An Item is an object that can occur as a member of a sequence.
* It corresponds directly to the concept of an item in the XPath 2.0 data model.
* There are two kinds of Item: atomic values, and nodes.
*
* This interface is part of the public Saxon API. As such (starting from Saxon 8.4),
* methods that form part of the stable API are labelled with a JavaDoc "since" tag
* to identify the Saxon release at which they were introduced.
*
* Note: there is no method getItemType(). This is to avoid having to implement it
* on every implementation of NodeInfo. Instead, use the static method Type.getItemType(Item).
*
* @author Michael H. Kay
* @since 8.4
*/
public interface Item extends Sequence, PullEvent {
/**
* Get the value of the item as a string. For nodes, this is the string value of the
* node as defined in the XPath 2.0 data model, except that all nodes are treated as being
* untyped: it is not an error to get the string value of a node with a complex type.
* For atomic values, the method returns the result of casting the atomic value to a string.
*
* If the calling code can handle any CharSequence, the method {@link #getStringValueCS} should
* be used. If the caller requires a string, this method is preferred.
*
* @return the string value of the item
* @throws UnsupportedOperationException if the item is a function item (an unchecked exception
* is used here to avoid introducing exception handling to a large number of paths where it is not
* needed)
* @see #getStringValueCS
* @since 8.4
*/
public String getStringValue();
/**
* Get the string value of the item as a CharSequence. This is in some cases more efficient than
* the version of the method that returns a String. The method satisfies the rule that
* X.getStringValueCS().toString() returns a string that is equal to
* X.getStringValue().
*
* Note that two CharSequence values of different types should not be compared using equals(), and
* for the same reason they should not be used as a key in a hash table.
*
* If the calling code can handle any CharSequence, this method should
* be used. If the caller requires a string, the {@link #getStringValue} method is preferred.
*
* @return the string value of the item
* @throws UnsupportedOperationException if the item is a function item (an unchecked exception
* is used here to avoid introducing exception handling to a large number of paths where it is not
* needed)
* @see #getStringValue
* @since 8.4
*/
public CharSequence getStringValueCS();
}