1 package org.apache.commons.digester3;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import static java.lang.String.format;
23
24 import org.xml.sax.Attributes;
25
26 /**
27 * <p>
28 * Rule implementation that saves a parameter for use by a surrounding <code>CallMethodRule<code>.
29 * </p>
30 * <p>
31 * This parameter may be:
32 * <ul>
33 * <li>an arbitrary Object defined programatically, assigned when the element pattern associated with the Rule is
34 * matched. See {@link #ObjectParamRule(int paramIndex, Object param)}.
35 * <li>an arbitrary Object defined programatically, assigned if the element pattern AND specified attribute name are
36 * matched. See {@link #ObjectParamRule(int paramIndex, String attributeName, Object param)}.
37 * </ul>
38 * </p>
39 *
40 * @since 1.4
41 */
42 public class ObjectParamRule
43 extends Rule
44 {
45 // ----------------------------------------------------------- Constructors
46 /**
47 * Construct a "call parameter" rule that will save the given Object as the parameter value.
48 *
49 * @param paramIndex The zero-relative parameter number
50 * @param param the parameter to pass along
51 */
52 public ObjectParamRule( int paramIndex, Object param )
53 {
54 this( paramIndex, null, param );
55 }
56
57 /**
58 * Construct a "call parameter" rule that will save the given Object as the parameter value, provided that the
59 * specified attribute exists.
60 *
61 * @param paramIndex The zero-relative parameter number
62 * @param attributeName The name of the attribute to match
63 * @param param the parameter to pass along
64 */
65 public ObjectParamRule( int paramIndex, String attributeName, Object param )
66 {
67 this.paramIndex = paramIndex;
68 this.attributeName = attributeName;
69 this.param = param;
70 }
71
72 // ----------------------------------------------------- Instance Variables
73
74 /**
75 * The attribute which we are attempting to match
76 */
77 protected String attributeName = null;
78
79 /**
80 * The zero-relative index of the parameter we are saving.
81 */
82 protected int paramIndex = 0;
83
84 /**
85 * The parameter we wish to pass to the method call
86 */
87 protected Object param = null;
88
89 // --------------------------------------------------------- Public Methods
90
91 /**
92 * {@inheritDoc}
93 */
94 @Override
95 public void begin( String namespace, String name, Attributes attributes )
96 throws Exception
97 {
98 Object anAttribute = null;
99 Object parameters[] = getDigester().peekParams();
100
101 if ( attributeName != null )
102 {
103 anAttribute = attributes.getValue( attributeName );
104 if ( anAttribute != null )
105 {
106 parameters[paramIndex] = param;
107 }
108 // note -- if attributeName != null and anAttribute == null, this rule
109 // will pass null as its parameter!
110 }
111 else
112 {
113 parameters[paramIndex] = param;
114 }
115 }
116
117 /**
118 * {@inheritDoc}
119 */
120 @Override
121 public String toString()
122 {
123 return format( "ObjectParamRule[paramIndex=%s, attributeName=%s, param=%s]", paramIndex, attributeName, param );
124 }
125
126 }