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1   /*
2    * Copyright 2007 the original author or authors.
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package org.springframework.xml.xpath;
18  
19  import java.util.Properties;
20  
21  import org.springframework.beans.factory.FactoryBean;
22  import org.springframework.beans.factory.InitializingBean;
23  import org.springframework.util.Assert;
24  
25  /**
26   * Spring {@link FactoryBean} for {@link XPathExpression} object. Facilitates injection of XPath expressions into
27   * endpoint beans.
28   * <p/>
29   * Uses {@link XPathExpressionFactory} underneath, so support is provided for JAXP 1.3, and Jaxen XPaths.
30   *
31   * @author Arjen Poutsma
32   * @see #setExpression(String)
33   * @since 1.0.0
34   */
35  public class XPathExpressionFactoryBean implements FactoryBean, InitializingBean {
36  
37      private Properties namespaces;
38  
39      private String expressionString;
40  
41      private XPathExpression expression;
42  
43      /** Sets the XPath expression. Setting this property is required. */
44      public void setExpression(String expression) {
45          expressionString = expression;
46      }
47  
48      /** Sets the namespaces for the expressions. The given properties binds string prefixes to string namespaces. */
49      public void setNamespaces(Properties namespaces) {
50          this.namespaces = namespaces;
51      }
52  
53      public void afterPropertiesSet() throws IllegalStateException, XPathParseException {
54          Assert.notNull(expressionString, "expression is required");
55          if (namespaces == null || namespaces.isEmpty()) {
56              expression = XPathExpressionFactory.createXPathExpression(expressionString);
57          }
58          else {
59              expression = XPathExpressionFactory.createXPathExpression(expressionString, namespaces);
60          }
61      }
62  
63      public Object getObject() throws Exception {
64          return expression;
65      }
66  
67      public Class getObjectType() {
68          return XPathExpression.class;
69      }
70  
71      public boolean isSingleton() {
72          return true;
73      }
74  }