Refactored AndroidXPathFactory into sdklib.

tools/sdkmanager/libs/sdklib/src/com/android/sdklib/xml/AndroidXPathFactory.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.sdklib.xml;
+
+import com.android.sdklib.SdkConstants;
+
+import java.util.Iterator;
+
+import javax.xml.XMLConstants;
+import javax.xml.namespace.NamespaceContext;
+import javax.xml.xpath.XPath;
+import javax.xml.xpath.XPathFactory;
+
+/**
+ * XPath factory with automatic support for the android name space.
+ */
+public class AndroidXPathFactory {
+    /** Default prefix for android name space: 'android' */
+    public final static String DEFAULT_NS_PREFIX = "android"; //$NON-NLS-1$
+
+    private final static XPathFactory sFactory = XPathFactory.newInstance();
+
+    /** Name space context for Android resource XML files. */
+    private static class AndroidNamespaceContext implements NamespaceContext {
+        private final static AndroidNamespaceContext sThis = new AndroidNamespaceContext(
+                DEFAULT_NS_PREFIX);
+
+        private String mAndroidPrefix;
+
+        /**
+         * Returns the default {@link AndroidNamespaceContext}.
+         */
+        private static AndroidNamespaceContext getDefault() {
+            return sThis;
+        }
+
+        /**
+         * Construct the context with the prefix associated with the android namespace.
+         * @param androidPrefix the Prefix
+         */
+        public AndroidNamespaceContext(String androidPrefix) {
+            mAndroidPrefix = androidPrefix;
+        }
+
+        public String getNamespaceURI(String prefix) {
+            if (prefix != null) {
+                if (prefix.equals(mAndroidPrefix)) {
+                    return SdkConstants.NS_RESOURCES;
+                }
+            }
+
+            return XMLConstants.NULL_NS_URI;
+        }
+
+        public String getPrefix(String namespaceURI) {
+            // This isn't necessary for our use.
+            assert false;
+            return null;
+        }
+
+        public Iterator<?> getPrefixes(String namespaceURI) {
+            // This isn't necessary for our use.
+            assert false;
+            return null;
+        }
+    }
+
+    /**
+     * Creates a new XPath object, specifying which prefix in the query is used for the
+     * android namespace.
+     * @param androidPrefix The namespace prefix.
+     */
+    public static XPath newXPath(String androidPrefix) {
+        XPath xpath = sFactory.newXPath();
+        xpath.setNamespaceContext(new AndroidNamespaceContext(androidPrefix));
+        return xpath;
+    }
+
+    /**
+     * Creates a new XPath object using the default prefix for the android namespace.
+     * @see #DEFAULT_NS_PREFIX
+     */
+    public static XPath newXPath() {
+        XPath xpath = sFactory.newXPath();
+        xpath.setNamespaceContext(AndroidNamespaceContext.getDefault());
+        return xpath;
+    }
+}