Add XPath version maker

pmd-core/src/main/java/net/sourceforge/pmd/lang/XPathHandler.java

@@ -6,6 +6,7 @@ package net.sourceforge.pmd.lang;
 
 import org.jaxen.Navigator;
 
+import net.sourceforge.pmd.Rule;
 import net.sourceforge.pmd.annotation.InternalApi;
 import net.sourceforge.pmd.lang.xpath.Initializer;
 
@@ -36,16 +37,24 @@ public interface XPathHandler {
         }
     };
 
+    Rule newXPathRule()
+
     /**
      * Initialize. This is intended to be called by {@link Initializer} to
      * perform Language specific initialization.
+     *
+     * @deprecated Jaxen support will be removed in 7.0.0
      */
+    @Deprecated
     void initialize();
 
     /**
      * Initialize. This is intended to be called by {@link Initializer} to
      * perform Language specific initialization for Saxon.
+     *
+     * @deprecated Internal API
      */
+    @Deprecated
     void initialize(IndependentContext context);
 
     /**

pmd-core/src/main/java/net/sourceforge/pmd/lang/rule/xpath/XPathVersion.java

@@ -0,0 +1,77 @@
+/*
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+
+package net.sourceforge.pmd.lang.rule.xpath;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Constants for XPath language version used in XPath queries.
+ */
+public enum XPathVersion {
+    /**
+     * XPath 1.0.
+     *
+     * @deprecated not supported anymore
+     */
+    @Deprecated
+    XPATH_1_0("1.0"),
+    /**
+     * XPath 1.0 compatibility mode.
+     *
+     * @deprecated Not supported any more.
+     */
+    @Deprecated
+    XPATH_1_0_COMPATIBILITY("1.0 compatibility"),
+
+    /** XPath 2.0. */
+    XPATH_2_0("2.0"),
+    /** XPath 3.1. */
+    XPATH_3_1("3.1");
+
+    private static final Map<String, XPathVersion> BY_NAME = new HashMap<>();
+    private final String version;
+
+
+    static {
+        for (XPathVersion value : values()) {
+            BY_NAME.put(value.getXmlName(), value);
+        }
+    }
+
+
+    XPathVersion(String version) {
+        this.version = version;
+    }
+
+
+    /**
+     * Returns the string used to represent the version in the XML.
+     *
+     * @return A string representation
+     */
+    public String getXmlName() {
+        return version;
+    }
+
+
+    /**
+     * Gets an XPath version from the string used to represent
+     * it in the XML.
+     *
+     * @param version A version string
+     *
+     * @return An XPath version
+     *
+     * @throws IllegalArgumentException If the argument doesn't match any known version
+     */
+    public static XPathVersion fromString(String version) {
+        XPathVersion v = BY_NAME.get(version);
+        if (v == null) {
+            throw new IllegalArgumentException("Version '" + version + "' is not a valid XPath version");
+        }
+        return v;
+    }
+}