Add interface based constructor for LargeText

core/src/main/java/org/kohsuke/stapler/framework/io/LargeText.java

@@ -63,11 +63,24 @@ public class LargeText {
     /**
      * Represents the data source of this text.
      */
-    private interface Source {
+    public interface Source {
+        /**
+         * Open a Source for reading.
+         * @return Opened Session for reading.
+         * @throws IOException if an error occurs.
+         */
         Session open() throws IOException;
 
+        /**
+         * Size of the Source.
+         * @return Number of bytes in the Source.
+         */
         long length();
 
+        /**
+         * Check existence of the Source.
+         * @return true if it exists, otherwise false.
+         */
         boolean exists();
     }
 
@@ -170,6 +183,12 @@ public boolean exists() {
         this.completed = completed;
     }
 
+    public LargeText(Source source, Charset charset, boolean completed) {
+        this.charset = charset;
+        this.source = source;
+        this.completed = completed;
+    }
+
     public void markAsComplete() {
         completed = true;
     }
@@ -509,11 +528,31 @@ public boolean isFull() {
      * Represents the read session of the {@link Source}.
      * Methods follow the contracts of {@link InputStream}.
      */
-    private interface Session extends Closeable {
-        long skip(long start) throws IOException;
+    public interface Session extends Closeable {
+        /**
+         * See also {@link InputStream#skip(long)}.
+         * @param n Number of bytes to skip ahead.
+         * @return Number of bytes that were skipped.
+         * @throws IOException if an error occurs. Skipping less than n bytes does not need to throw.
+         */
+        long skip(long n) throws IOException;
 
+        /**
+         * See also {@link InputStream#read(byte[])}.
+         * @param buf Buffer to fill.
+         * @return Number of bytes that were filled.
+         * @throws IOException if an error occurs.
+         */
         int read(byte[] buf) throws IOException;
 
+        /**
+         * See also {@link InputStream#read(byte[], int, int)}.
+         * @param buf Buffer to fill.
+         * @param offset Number of bytes to skip in buf.
+         * @param length Number of bytes to read at most.
+         * @return Number of bytes that were read.
+         * @throws IOException if an error occurs.
+         */
         int read(byte[] buf, int offset, int length) throws IOException;
     }
 
@@ -536,10 +575,10 @@ public void close() throws IOException {
          * Like {@link RandomAccessFile#skipBytes} but with long instead of int.
          */
         @Override
-        public long skip(long start) throws IOException {
-            if (start <= 0) return 0;
+        public long skip(long n) throws IOException {
+            if (n <= 0) return 0;
             long pos = file.getFilePointer();
-            long newPos = Math.min(file.length(), pos + start);
+            long newPos = Math.min(file.length(), pos + n);
             file.seek(newPos);
             return newPos - pos;
         }
@@ -575,8 +614,8 @@ public void close() throws IOException {
         }
 
         @Override
-        public long skip(long start) throws IOException {
-            return gz.skip(start);
+        public long skip(long n) throws IOException {
+            return gz.skip(n);
         }
 
         @Override
@@ -657,8 +696,8 @@ public void close() throws IOException {
         }
 
         @Override
-        public long skip(long start) throws IOException {
-            return in.skip(start);
+        public long skip(long n) throws IOException {
+            return in.skip(n);
         }
 
         @Override

core/src/test/java/org/kohsuke/stapler/framework/io/LargeTextTest.java

@@ -30,6 +30,7 @@
 import static org.junit.Assert.fail;
 import static org.mockito.Mockito.when;
 
+import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.EOFException;
 import java.io.FileOutputStream;
@@ -62,6 +63,11 @@ public void writeLogToFromByteBuffer() throws Exception {
         writeLogToWith(byteBuffer());
     }
 
+    @Test
+    public void writeLogToFromInterface() throws Exception {
+        writeLogToWith(interfaceBased());
+    }
+
     @Test
     public void writeLogToFromFile() throws Exception {
         writeLogToWith(file());
@@ -115,6 +121,10 @@ BuildLargeText gzFile() {
         return new FromGzFile();
     }
 
+    BuildLargeText interfaceBased() {
+        return new FromInterface();
+    }
+
     static class FromByteBuffer implements BuildLargeText {
         public LargeText build(String text) throws IOException {
             ByteBuffer bb = new ByteBuffer();
@@ -125,6 +135,35 @@ public LargeText build(String text) throws IOException {
         public void close() {}
     }
 
+    static class FromInterface implements BuildLargeText {
+        public LargeText build(String text) throws IOException {
+            LargeText.Source src = new LargeText.Source() {
+                private final byte[] textBytes = text.getBytes(StandardCharsets.UTF_8);
+
+                class BytesSession extends ByteArrayInputStream implements LargeText.Session {
+                    BytesSession() {
+                        super(textBytes);
+                    }
+                }
+
+                public LargeText.Session open() {
+                    return new BytesSession();
+                }
+
+                public long length() {
+                    return textBytes.length;
+                }
+
+                public boolean exists() {
+                    return true;
+                }
+            };
+            return new LargeText(src, StandardCharsets.UTF_8, true);
+        }
+
+        public void close() {}
+    }
+
     static class FromFile implements BuildLargeText {
         private Path path;
         final boolean detectGzip;