org.simpleframework.xml.stream.InputStack Maven / Gradle / Ivy
/*
* InputStack.java July 2006
*
* Copyright (C) 2006, Niall Gallagher
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307 USA
*/
package org.simpleframework.xml.stream;
import java.util.ArrayList;
/**
* The InputStack is used to keep track of the nodes
* that have been read from the document. This ensures that when
* nodes are read from the source document that the reader can tell
* whether a child node for a given InputNode can be
* created. Each created node is pushed, and popped when ended.
*
* @author Niall Gallagher
*
* @see org.simpleframework.xml.stream.InputNode
*/
class InputStack extends ArrayList {
/**
* Constructor for the InputStack object. This is
* used to create a stack that can be used to keep track of the
* elements that have been read from the source XML document.
*/
public InputStack() {
super(6);
}
/**
* This is used to remove the InputNode from the
* top of the input stack. This is used when an element has been
* ended and the input reader wants to block child creation.
*
* @return this returns the node from the top of the stack
*/
public InputNode pop() {
int size = size();
if(size <= 0) {
return null;
}
return remove(size - 1);
}
/**
* This is used to acquired the InputNode from the
* top of the input stack. This is used when the reader wants to
* determine the current element read from the XML document.
*
* @return this returns the node from the top of the stack
*/
public InputNode top() {
int size = size();
if(size <= 0) {
return null;
}
return get(size - 1);
}
/**
* This is used to acquire the InputNode from the
* bottom of the input stack. This is used when the reader wants
* to determine the root element for the read XML document.
*
* @return this returns the node from the bottom of the stack
*/
public InputNode bottom() {
int size = size();
if(size <= 0) {
return null;
}
return get(0);
}
/**
* This method is used to add an InputNode to the
* top of the stack. This is used when an element has been read
* from XML document, and allows the reader to determine if a
* child node can be added from a given input node.
*
* @param value this is the input node to add to the stack
*/
public InputNode push(InputNode value) {
add(value);
return value;
}
/**
* This is used to determine if the specified node is relevant
* with respect to the state of the input stack. This returns
* true if there are no elements in the stack, which accounts
* for a new root node. Also this returns true if the specified
* node exists within the stack and is thus an active node.
*
* @param value this is the input node value to be checked
*
* @return returns true if the node is relevant in the stack
*/
public boolean isRelevant(InputNode value) {
return contains(value) || isEmpty();
}
}