1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one or more
3  * contributor license agreements.  See the NOTICE file distributed with
4  * this work for additional information regarding copyright ownership.
5  * The ASF licenses this file to You under the Apache License, Version 2.0
6  * (the "License"); you may not use this file except in compliance with
7  * the License.  You may obtain a copy of the License at
8  *
9  *      http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17 
18 /* $Id: StaticPropertyList.java 985537 2010-08-14 17:17:00Z jeremias $ */
19 
20 package org.apache.fop.fo;
21 
22 import org.apache.fop.fo.expr.PropertyException;
23 import org.apache.fop.fo.properties.Property;
24 
25 /**
26  * A very fast implementation of PropertyList that uses arrays to store
27  * the explicit set properties and another array to store cached values.
28  */
29 public class StaticPropertyList extends PropertyList {
30     private final Property[] explicit;
31     private final Property[] values;
32 
33     /**
34      * Construct a StaticPropertyList.
35      * @param fObjToAttach The FObj object.
36      * @param parentPropertyList The parent property list.
37      */
StaticPropertyList(FObj fObjToAttach, PropertyList parentPropertyList)38     public StaticPropertyList(FObj fObjToAttach, PropertyList parentPropertyList) {
39         super(fObjToAttach, parentPropertyList);
40         explicit = new Property[Constants.PROPERTY_COUNT + 1];
41         values = new Property[Constants.PROPERTY_COUNT + 1];
42     }
43 
44     /**
45      * Return the value explicitly specified on this FO.
46      * @param propId The ID of the property whose value is desired.
47      * @return The value if the property is explicitly set, otherwise null.
48      */
getExplicit(int propId)49     public Property getExplicit(int propId) {
50         return explicit[propId];
51     }
52 
53     /**
54      * Set an value defined explicitly on this FO.
55      * @param propId The ID of the property whose value is desired.
56      * @param value The value of the property to set.
57      */
putExplicit(int propId, Property value)58     public void putExplicit(int propId, Property value) {
59         explicit[propId] = value;
60         if (values[propId] != null) { // if the cached value is set overwrite it
61             values[propId] = value;
62         }
63     }
64 
65     /**
66      * Override PropertyList.get() and provides fast caching of previously
67      * retrieved property values.
68      * {@inheritDoc}
69      */
get(int propId, boolean bTryInherit, boolean bTryDefault)70     public Property get(int propId, boolean bTryInherit, boolean bTryDefault)
71         throws PropertyException {
72         Property p = values[propId];
73         if (p == null) {
74             p = super.get(propId, bTryInherit, bTryDefault);
75             values[propId] = p;
76         }
77         return p;
78     }
79 }
80