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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      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 package com.android.cts;
     17 
     18 import java.io.File;
     19 import java.io.FileNotFoundException;
     20 import java.io.FileOutputStream;
     21 import java.io.IOException;
     22 
     23 import javax.xml.transform.Transformer;
     24 import javax.xml.transform.TransformerException;
     25 import javax.xml.transform.TransformerFactory;
     26 import javax.xml.transform.TransformerFactoryConfigurationError;
     27 import javax.xml.transform.dom.DOMSource;
     28 import javax.xml.transform.stream.StreamResult;
     29 
     30 import org.w3c.dom.Attr;
     31 import org.w3c.dom.Document;
     32 import org.w3c.dom.Node;
     33 import org.w3c.dom.NodeList;
     34 
     35 /**
     36  * An abstract class to deal with the XML information using DOM.
     37  */
     38 public abstract class XMLResourceHandler {
     39 
     40     protected String getElementContent(Node elem) {
     41         return elem.getChildNodes().item(0).getNodeValue().trim();
     42     }
     43 
     44     /**
     45      * Get string from DOM node by attribute name.
     46      *
     47      * @param elem a node from DOM tree.
     48      * @param attrName the attribute name.
     49      * @return string value of the attribute name from the DOM node.
     50      */
     51     static public String getStringAttributeValue(Node elem, String attrName) {
     52         Node node = elem.getAttributes().getNamedItem(attrName);
     53         if (node == null) {
     54             return null;
     55         }
     56         return node.getNodeValue().trim();
     57     }
     58 
     59     /**
     60      * Get integer attribute value.
     61      *
     62      * @param elem The element node.
     63      * @param attrName The attribute name.
     64      * @return The attribute value in integer.
     65      */
     66     protected int getAttributeValue(Node elem, String attrName) {
     67         return Integer.parseInt(getStringAttributeValue(elem, attrName));
     68     }
     69 
     70     /**
     71      * Get child by attribute.
     72      *
     73      * @param parent The parent node.
     74      * @param attrName The attribute name.
     75      * @param attrValue The attribute value.
     76      * @return The child node.
     77      */
     78     protected Node getChildByAttribute(Node parent, String attrName, String attrValue) {
     79         if (parent == null || attrName == null || attrValue == null) {
     80             return null;
     81         }
     82         NodeList children = parent.getChildNodes();
     83         for (int i = 0; i < children.getLength(); i++) {
     84             Node child = children.item(i);
     85             if (child.getNodeType() == Node.ELEMENT_NODE) {
     86                 if (attrValue.equals(getStringAttributeValue(child, attrName))) {
     87                     return child;
     88                 }
     89             }
     90         }
     91 
     92         return null;
     93     }
     94 
     95     /**
     96      * Set the attribute value.
     97      *
     98      * @param doc The document.
     99      * @param elem The element node.
    100      * @param name The attribute name.
    101      * @param value The attribute value in integer.
    102      */
    103     protected void setAttribute(Document doc, Node elem, String name, int value) {
    104         setAttribute(doc, elem, name, Integer.toString(value));
    105     }
    106 
    107     /**
    108      * Set the attribute value.
    109      *
    110      * @param doc The document.
    111      * @param elem The element node.
    112      * @param name The attribute name.
    113      * @param value The attribute value in string.
    114      */
    115     protected void setAttribute(Document doc, Node elem, String name, String value) {
    116         Attr attrNode = doc.createAttribute(name);
    117         attrNode.setNodeValue(value);
    118 
    119         elem.getAttributes().setNamedItem(attrNode);
    120     }
    121 
    122     /**
    123      * Write a DOM Document object into a file.
    124      *
    125      * @param file XML file to be written
    126      * @param doc DOM Document
    127      */
    128     protected static void writeToFile(File file, Document doc) throws FileNotFoundException,
    129             IOException, TransformerFactoryConfigurationError, TransformerException {
    130         Transformer t = TransformerFactory.newInstance().newTransformer();
    131         // enable indent in result file
    132         t.setOutputProperty("indent", "yes");
    133         FileOutputStream fos = new FileOutputStream(file);
    134         try {
    135             StreamResult sr = new StreamResult(fos);
    136             t.transform(new DOMSource(doc), sr);
    137         } finally {
    138             fos.close();
    139         }
    140     }
    141 }
    142