Source code: org/apache/hivemind/schema/Translator.java
1 // Copyright 2004, 2005 The Apache Software Foundation
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 package org.apache.hivemind.schema;
16
17 import org.apache.hivemind.Location;
18 import org.apache.hivemind.internal.Module;
19
20 /**
21 * Object which can translate a string into an object value. This is used to
22 * translate attribute values (or element content) from strings into
23 * numbers, booleans or other constructs before assigning the final value
24 * to a propery. Translation occurs after symbol substitution.
25 *
26 * <p>
27 * Translator classes should have a public constructor that takes no
28 * arguments. They may optionally have a second constructor
29 * that takes a single string as a parameter. When the
30 * {@link org.apache.hivemind.parse.DescriptorParser} encounters
31 * a <code>translator</code> of the form
32 * "<code><i>translator-id</i>,<i>initialization-string</i></code>"
33 * (example: "int,min=0") it will use the second constructor, passing
34 * the initialization string.
35 *
36 * <p>
37 * Generally, initializion strings are of the form
38 * <code><i>key</i>=<i>value</i>[,<i>key</i>=<i>value</i>]*</code>.
39 * Each initializer has a set of keys it recognizes, other keys are simply
40 * ignored.
41 *
42 * @author Howard Lewis Ship
43 */
44 public interface Translator
45 {
46 /**
47 * Invoked by a {@link org.apache.hivemind.schema.Rule}
48 * to translate an inputValue into an appropriate object.
49 * Substitution symbols will already have been expanded before this method is
50 * invoked.
51 *
52 * @param contributingModule the module from which the input value originates
53 * @param propertyType the type of the property to be assigned by this translator; smart translators may
54 * be able to automatically convert from string to the correct type
55 * @param inputValue the value to be translated, either an attribute value or the content of the element
56 * @param location the location of the inputValue; used to set the location of created objects,
57 * or when reporting errors
58 */
59 public Object translate(
60 Module contributingModule,
61 Class propertyType,
62 String inputValue,
63 Location location);
64 }