Cure feature envy of DefaultPluginXmlFactory

Author: Vincent Potucek

impl/maven-impl/src/main/java/org/apache/maven/impl/DefaultPluginXmlFactory.java

@@ -18,13 +18,12 @@
  */
 package org.apache.maven.impl;
 
+import javax.xml.stream.XMLStreamException;
+
+import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
-import java.io.Reader;
-import java.io.Writer;
-import java.net.URL;
 import java.nio.file.Files;
-import java.nio.file.Path;
 
 import org.apache.maven.api.annotations.Nonnull;
 import org.apache.maven.api.di.Named;
@@ -38,67 +37,25 @@
 import org.apache.maven.plugin.descriptor.io.PluginDescriptorStaxReader;
 import org.apache.maven.plugin.descriptor.io.PluginDescriptorStaxWriter;
 
-import static org.apache.maven.impl.ImplUtils.nonNull;
 import static org.apache.maven.impl.StaxLocation.getLocation;
 import static org.apache.maven.impl.StaxLocation.getMessage;
 
 @Named
 @Singleton
 public class DefaultPluginXmlFactory implements PluginXmlFactory {
+
+    private static final PluginDescriptorStaxWriter WRITER = new PluginDescriptorStaxWriter();
+    private static final PluginDescriptorStaxReader READER = new PluginDescriptorStaxReader();
+
     @Override
     public PluginDescriptor read(@Nonnull XmlReaderRequest request) throws XmlReaderException {
-        nonNull(request, "request");
-        Path path = request.getPath();
-        URL url = request.getURL();
-        Reader reader = request.getReader();
-        InputStream inputStream = request.getInputStream();
-        if (path == null && url == null && reader == null && inputStream == null) {
-            throw new IllegalArgumentException("path, url, reader or inputStream must be non null");
-        }
-        try {
-            PluginDescriptorStaxReader xml = new PluginDescriptorStaxReader();
-            xml.setAddDefaultEntities(request.isAddDefaultEntities());
-            if (inputStream != null) {
-                return xml.read(inputStream, request.isStrict());
-            } else if (reader != null) {
-                return xml.read(reader, request.isStrict());
-            } else if (path != null) {
-                try (InputStream is = Files.newInputStream(path)) {
-                    return xml.read(is, request.isStrict());
-                }
-            } else {
-                try (InputStream is = url.openStream()) {
-                    return xml.read(is, request.isStrict());
-                }
-            }
-        } catch (Exception e) {
-            throw new XmlReaderException("Unable to read plugin: " + getMessage(e), getLocation(e), e);
-        }
+        READER.setAddDefaultEntities(request.isAddDefaultEntities());
+        return createReadDescriptor(validate(request));
     }
 
     @Override
     public void write(XmlWriterRequest<PluginDescriptor> request) throws XmlWriterException {
-        nonNull(request, "request");
-        PluginDescriptor content = nonNull(request.getContent(), "content");
-        Path path = request.getPath();
-        OutputStream outputStream = request.getOutputStream();
-        Writer writer = request.getWriter();
-        if (writer == null && outputStream == null && path == null) {
-            throw new IllegalArgumentException("writer, outputStream or path must be non null");
-        }
-        try {
-            if (writer != null) {
-                new PluginDescriptorStaxWriter().write(writer, content);
-            } else if (outputStream != null) {
-                new PluginDescriptorStaxWriter().write(outputStream, content);
-            } else {
-                try (OutputStream os = Files.newOutputStream(path)) {
-                    new PluginDescriptorStaxWriter().write(outputStream, content);
-                }
-            }
-        } catch (Exception e) {
-            throw new XmlWriterException("Unable to write plugin: " + getMessage(e), getLocation(e), e);
-        }
+        createWriteDescriptor(validate(request));
     }
 
     /**
@@ -124,4 +81,58 @@ public static PluginDescriptor fromXml(@Nonnull String xml) throws XmlReaderExce
     public static String toXml(@Nonnull PluginDescriptor content) throws XmlWriterException {
         return new DefaultPluginXmlFactory().toXmlString(content);
     }
+
+    private static PluginDescriptor createReadDescriptor(XmlReaderRequest request) {
+        try {
+            if (request.getInputStream() != null) {
+                return READER.read(request.getInputStream(), request.isStrict());
+            } else if (request.getReader() != null) {
+                return READER.read(request.getReader(), request.isStrict());
+            } else if (request.getPath() != null) {
+                try (InputStream is = Files.newInputStream(request.getPath())) {
+                    return READER.read(is, request.isStrict());
+                }
+            }
+            try (InputStream is = request.getURL().openStream()) {
+                return READER.read(is, request.isStrict());
+            }
+        } catch (IOException | XMLStreamException e) {
+            throw new XmlReaderException("Unable to read plugin: " + getMessage(e), getLocation(e), e);
+        }
+    }
+
+    private static XmlReaderRequest validate(XmlReaderRequest request) {
+        if (request.getInputStream() == null
+                && request.getReader() == null
+                && request.getPath() == null
+                && request.getURL() == null) {
+            throw new IllegalArgumentException("writer, outputStream or path must be non null");
+        }
+        return request;
+    }
+
+    private static void createWriteDescriptor(XmlWriterRequest<PluginDescriptor> request) throws XmlWriterException {
+        try {
+            if (request.getWriter() != null) {
+                WRITER.write(request.getWriter(), request.getContent());
+            } else if (request.getOutputStream() != null) {
+                WRITER.write(request.getOutputStream(), request.getContent());
+            } else if (request.getPath() != null) {
+                try (OutputStream os = Files.newOutputStream(request.getPath())) {
+                    WRITER.write(os, request.getContent());
+                }
+            } else {
+                throw new IllegalArgumentException("writer, outputStream or path must be non null");
+            }
+        } catch (XmlWriterException | XMLStreamException | IOException e) {
+            throw new XmlWriterException("Unable to write plugin: " + getMessage(e), getLocation(e), e);
+        }
+    }
+
+    private static XmlWriterRequest<PluginDescriptor> validate(XmlWriterRequest<PluginDescriptor> request) {
+        if (request.getWriter() == null && request.getOutputStream() == null && request.getPath() == null) {
+            throw new IllegalArgumentException("writer, outputStream or path must be non null");
+        }
+        return request;
+    }
 }