(enhance) introduce resolving strategy (configurable xml security); introduce API configuration

src/main/java/de/kosit/validationtool/config/XPathBuilder.java

@@ -0,0 +1,83 @@
+package de.kosit.validationtool.config;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.stream.StreamSupport;
+
+import org.apache.commons.lang3.ArrayUtils;
+
+import lombok.AccessLevel;
+import lombok.Data;
+import lombok.Getter;
+import lombok.Setter;
+
+import de.kosit.validationtool.impl.ContentRepository;
+import de.kosit.validationtool.impl.model.Result;
+
+import net.sf.saxon.s9api.XPathExecutable;
+
+/**
+ * Internal class to represent xpath configuration.
+ * 
+ * @author Andreas Penski
+ */
+@Data
+class XPathBuilder implements Builder<XPathExecutable> {
+
+    private static final String[] IGNORED_PREFIXES = new String[] { "xsd" };
+
+    private String xpath;
+
+    private XPathExecutable executable;
+
+    @Setter(AccessLevel.PACKAGE)
+    @Getter(AccessLevel.PACKAGE)
+    private Map<String, String> namespaces;
+
+    /**
+     * Returns the xpath expression.
+     * 
+     * @return xpath expression
+     */
+    public String getXPath() {
+        return this.xpath == null && this.executable != null ? this.executable.getUnderlyingExpression().getInternalExpression().toString()
+                : this.xpath;
+
+    }
+
+    @Override
+    public Result<XPathExecutable, String> build(final ContentRepository repository) {
+        if (this.executable == null && this.xpath == null) {
+            return createError("No configuration for xpath expression found");
+        }
+        if (this.executable == null) {
+            this.executable = repository.createXPath(this.xpath, this.namespaces);
+        } else {
+            this.xpath = extractExpression();
+            this.namespaces = extractNamespaces();
+        }
+        return new Result<>(this.executable);
+    }
+
+    private Map<String, String> extractNamespaces() {
+        final Map<String, String> ns = new HashMap<>();
+        final Iterator<String> iterator = this.executable.getUnderlyingExpression().getInternalExpression().getRetainedStaticContext()
+                .iteratePrefixes();
+        final Iterable<String> iterable = () -> iterator;
+        StreamSupport.stream(iterable.spliterator(), false).filter(e -> !ArrayUtils.contains(IGNORED_PREFIXES, e)).forEach(e -> {
+            ns.put(e,
+                    this.executable.getUnderlyingExpression().getInternalExpression().getRetainedStaticContext().getURIForPrefix(e, false));
+        });
+        return ns;
+    }
+
+    private String extractExpression() {
+        return this.executable.getUnderlyingExpression().getInternalExpression().toString();
+    }
+
+    private static Result<XPathExecutable, String> createError(final String msg) {
+        return new Result<>(null, Collections.singletonList(msg));
+    }
+}