/*
* Copyright (c) 2012, Eric Coolman, Codename One and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Codename One designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Codename One through http://www.codenameone.com/ if you
* need additional information or have any questions.
*/
package com.codename1.processing;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import java.util.Vector;
/**
* Internal class, do not use.
*
* This evaluator handles expressions that involve the index. Example:
*
* <code>
*
* Get the name of the second player
*
* /tournament/player[2]/name
*
* Get the name of the last player
*
* /tournament/player[last()]/name
*
* Get the name of the second last player
*
* //player[last()-1]/name
*
* Get players 4 and greater
*
* //player[position() > 3]/name
*
* Get players 0 to 4
*
* //player[position() < 5]/name
* </code>
*
* @author Eric Coolman
*
*/
class IndexEvaluator extends AbstractEvaluator {
static String FUNC_LAST = "last()";
static String FUNC_POSITION = "position()";
/**
* Construct with a full predicate expression.
*
* @param expr a full predicate expression
*/
public IndexEvaluator(String expr) {
super(expr);
}
/**
* Select all elements from the array with an index less than the given
* value.
*
* Example:
*
* <code>
* [position() < 5]
* </code>
*
* @param elements array of StructuredContent elements
* @param rvalue index value
* @return an array of matching elements.
*/
private List _getByPositionLess(List elements, int rvalue) {
if (rvalue > elements.size()) {
return elements;
}
if (rvalue < 0) {
return null;
}
List array;
if (elements instanceof Vector) {
array = new Vector();
} else {
array = new ArrayList();
}
for (int i = 0; i < rvalue; i++) {
array.add(elements.get(i));
}
return array;
}
/**
* Select all elements from the array with an index greater than the given
* value.
*
* Example:
*
* <code>
* [position() > 5]
* </code>
*
* @param elements array of StructuredContent elements
* @param rvalue index value
* @return an array of matching elements.
*/
private List _getByPositionGreater(List elements, int rvalue) {
if (rvalue >= elements.size()) {
return null;
}
if (rvalue <= 0) {
return elements;
}
List array;
if (elements instanceof Vector) {
array = new Vector();
} else {
array = new ArrayList();
}
for (int i = rvalue; i < elements.size(); i++) {
array.add(elements.get(i));
}
return array;
}
/**
* Select a single element from an array, relative to the last element. Ie.
*
* <code>
* Fifth last element:
*
* [last() - 5]
*
* Last element:
*
* [last()]
*
* </code>
*
* @param elements array of StructuredContent elements
* @param rvalue index value
* @return an array of matching elements.
*/
private StructuredContent _getByLast(List elements, String expr) throws IllegalArgumentException {
int index = expr.indexOf("-");
if (index == -1) {
throw new IllegalArgumentException("Could not handle expression: " + expr);
}
String rvalue = expr.substring(index + 1).trim();
int dim = (elements.size() - 1) - Integer.parseInt(rvalue);
if (dim < 0) {
return null;
}
return (StructuredContent) elements.get(dim);
}
/* (non-Javadoc)
* @see com.codename1.path.impl.AbstractEvaluator#evaluateSingle(java.util.List, java.lang.String)
*/
protected Object evaluateSingle(List elements, String expr) {
if (isNumeric(expr)) {
int dim = Integer.parseInt(expr);
if ((dim < 0) || (dim >= elements.size())) {
return null;
}
return (StructuredContent) elements.get(dim);
} else if (expr.equals(FUNC_LAST)) {
if (elements.size() == 0) {
return null;
}
return (StructuredContent) elements.get(elements.size() - 1);
} else if (expr.indexOf(FUNC_LAST) != -1) {
return _getByLast(elements, expr);
} else if (expr.equals(FUNC_POSITION)) {
return elements;
}
return null;
}
/* (non-Javadoc)
* @see com.codename1.path.impl.AbstractEvaluator#evaluateLeftLessRight(java.util.List, java.lang.String, java.lang.String)
*/
protected Object evaluateLeftLessRight(List elements, String lvalue,
String rvalue) {
if (FUNC_POSITION.equals(lvalue)) {
return _getByPositionLess(elements, Integer.parseInt(rvalue));
}
return null;
}
/* (non-Javadoc)
* @see com.codename1.path.impl.AbstractEvaluator#evaluateLeftGreaterRight(java.util.List, java.lang.String, java.lang.String)
*/
protected Object evaluateLeftGreaterRight(List elements, String lvalue,
String rvalue) {
if (FUNC_POSITION.equals(lvalue)) {
return _getByPositionGreater(elements, Integer.parseInt(rvalue));
}
return null;
}
}