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1 /*
2  * $Id: PropertyInfo.java,v 1.2.2.1 2003/02/25 12:56:58 jeremias Exp $
3  * ============================================================================
4  * The Apache Software License, Version 1.1
5  * ============================================================================
6  *
7  * Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without modifica-
10  * tion, are permitted provided that the following conditions are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright notice,
13  * this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright notice,
16  * this list of conditions and the following disclaimer in the documentation
17  * and/or other materials provided with the distribution.
18  *
19  * 3. The end-user documentation included with the redistribution, if any, must
20  * include the following acknowledgment: "This product includes software
21  * developed by the Apache Software Foundation (http://www.apache.org/)."
22  * Alternately, this acknowledgment may appear in the software itself, if
23  * and wherever such third-party acknowledgments normally appear.
24  *
25  * 4. The names "FOP" and "Apache Software Foundation" must not be used to
26  * endorse or promote products derived from this software without prior
27  * written permission. For written permission, please contact
28  * apache@apache.org.
29  *
30  * 5. Products derived from this software may not be called "Apache", nor may
31  * "Apache" appear in their name, without prior written permission of the
32  * Apache Software Foundation.
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34  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
35  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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37  * APACHE SOFTWARE FOUNDATION OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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39  * DING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
40  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
41  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
42  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
43  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
44  * ============================================================================
45  *
46  * This software consists of voluntary contributions made by many individuals
47  * on behalf of the Apache Software Foundation and was originally created by
48  * James Tauber <jtauber@jtauber.com>. For more information on the Apache
49  * Software Foundation, please see <http://www.apache.org/>.
50  */
51 package org.apache.fop.fo.expr;
52
53 import java.util.Stack JavaDoc;
54
55 import org.apache.fop.fo.Property;
56 import org.apache.fop.fo.PropertyList;
57 import org.apache.fop.fo.FObj;
58 import org.apache.fop.datatypes.PercentBase;
59
60
61 /**
62  * This class holds context information needed during property expression
63  * evaluation.
64  * It holds the Maker object for the property, the PropertyList being
65  * built, and the FObj parent of the FObj for which the property is being set.
66  */
67 public class PropertyInfo {
68     private Property.Maker maker;
69     private PropertyList plist;
70     private FObj fo;
71     private Stack JavaDoc stkFunction; // Stack of functions being evaluated
72
73     public PropertyInfo(Property.Maker maker, PropertyList plist, FObj fo) {
74         this.maker = maker;
75         this.plist = plist;
76         this.fo = fo;
77     }
78
79     /**
80      * Return whether this property inherits specified values.
81      * Propagates to the Maker.
82      * @return true if the property inherits specified values, false if it
83      * inherits computed values.
84      */
85     public boolean inheritsSpecified() {
86         return maker.inheritsSpecified();
87     }
88
89     /**
90      * Return the PercentBase object used to calculate the absolute value from
91      * a percent specification.
92      * Propagates to the Maker.
93      * @return The PercentBase object or null if percentLengthOK()=false.
94      */
95     public PercentBase getPercentBase() {
96         PercentBase pcbase = getFunctionPercentBase();
97         return (pcbase != null) ? pcbase : maker.getPercentBase(fo, plist);
98     }
99
100     /**
101      * Return the current font-size value as base units (milli-points).
102      */
103     public int currentFontSize() {
104         return plist.get("font-size").getLength().mvalue();
105     }
106
107     public FObj getFO() {
108         return fo;
109     }
110
111     public PropertyList getPropertyList() {
112         return plist;
113     }
114
115     public void pushFunction(Function func) {
116         if (stkFunction == null) {
117             stkFunction = new Stack JavaDoc();
118         }
119         stkFunction.push(func);
120     }
121
122     public void popFunction() {
123         if (stkFunction != null)
124             stkFunction.pop();
125     }
126
127     private PercentBase getFunctionPercentBase() {
128         if (stkFunction != null) {
129             Function f = (Function)stkFunction.peek();
130             if (f != null) {
131                 return f.getPercentBase();
132             }
133         }
134         return null;
135     }
136
137 }
138
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