001: /*
002: The contents of this file are subject to the Common Public Attribution License
003: Version 1.0 (the "License"); you may not use this file except in compliance with
004: the License. You may obtain a copy of the License at
005: http://www.projity.com/license . The License is based on the Mozilla Public
006: License Version 1.1 but Sections 14 and 15 have been added to cover use of
007: software over a computer network and provide for limited attribution for the
008: Original Developer. In addition, Exhibit A has been modified to be consistent
009: with Exhibit B.
010:
011: Software distributed under the License is distributed on an "AS IS" basis,
012: WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the
013: specific language governing rights and limitations under the License. The
014: Original Code is OpenProj. The Original Developer is the Initial Developer and
015: is Projity, Inc. All portions of the code written by Projity are Copyright (c)
016: 2006, 2007. All Rights Reserved. Contributors Projity, Inc.
017:
018: Alternatively, the contents of this file may be used under the terms of the
019: Projity End-User License Agreeement (the Projity License), in which case the
020: provisions of the Projity License are applicable instead of those above. If you
021: wish to allow use of your version of this file only under the terms of the
022: Projity License and not to allow others to use your version of this file under
023: the CPAL, indicate your decision by deleting the provisions above and replace
024: them with the notice and other provisions required by the Projity License. If
025: you do not delete the provisions above, a recipient may use your version of this
026: file under either the CPAL or the Projity License.
027:
028: [NOTE: The text of this license may differ slightly from the text of the notices
029: in Exhibits A and B of the license at http://www.projity.com/license. You should
030: use the latest text at http://www.projity.com/license for your modifications.
031: You may not remove this license text from the source files.]
032:
033: Attribution Information: Attribution Copyright Notice: Copyright © 2006, 2007
034: Projity, Inc. Attribution Phrase (not exceeding 10 words): Powered by OpenProj,
035: an open source solution from Projity. Attribution URL: http://www.projity.com
036: Graphic Image as provided in the Covered Code as file: openproj_logo.png with
037: alternatives listed on http://www.projity.com/logo
038:
039: Display of Attribution Information is required in Larger Works which are defined
040: in the CPAL as a work which combines Covered Code or portions thereof with code
041: not governed by the terms of the CPAL. However, in addition to the other notice
042: obligations, all copies of the Covered Code in Executable and Source Code form
043: distributed must, as a form of attribution of the original author, include on
044: each user interface screen the "OpenProj" logo visible to all users. The
045: OpenProj logo should be located horizontally aligned with the menu bar and left
046: justified on the top left of the screen adjacent to the File menu. The logo
047: must be at least 100 x 25 pixels. When users click on the "OpenProj" logo it
048: must direct them back to http://www.projity.com.
049: */
050: package com.projity.algorithm;
051:
052: /**
053: * A calculation visitor that performs a subtraction
054: */
055: public class ValueDifference implements CalculationVisitor, DoubleValue {
056: double value = 0.0;
057: DoubleValue first;
058: DoubleValue second;
059:
060: /**
061: *
062: */
063: private ValueDifference(DoubleValue first, DoubleValue second) {
064: super ();
065: this .first = first;
066: this .second = second;
067:
068: }
069:
070: /**
071: * Factory method
072: * @param first
073: * @param second
074: * @return
075: */
076: public static ValueDifference getInstance(DoubleValue first,
077: DoubleValue second) {
078: return new ValueDifference(first, second);
079: }
080:
081: /* (non-Javadoc)
082: * @see com.projity.algorithm.CalculationVisitor#reset()
083: */
084: public void initialize() {
085: value = 0.0;
086:
087: }
088:
089: /* (non-Javadoc)
090: * @see org.apache.commons.collections.Closure#execute(java.lang.Object)
091: */
092: public void execute(Object arg0) {
093: value = first.getValue() - second.getValue();
094:
095: }
096:
097: /**
098: * @return Returns the value.
099: */
100: public double getValue() {
101: return value;
102: }
103:
104: public String toString() {
105: return Double.toString(value);
106: }
107:
108: /* (non-Javadoc)
109: * @see com.projity.algorithm.CalculationVisitor#isCumulative()
110: */
111: public boolean isCumulative() {
112: return false;
113: }
114:
115: /* (non-Javadoc)
116: * @see com.projity.algorithm.CalculationVisitor#reset()
117: */
118: public void reset() {
119: initialize();
120: }
121:
122: }
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