Add 'src/be/nikiroo/utils/' from commit '46add0670fdee4bd936a13fe2448c5e20a7ffd0a'

[fanfix.git] / src / be / nikiroo / utils / serial / CustomSerializer.java

diff --git a/src/be/nikiroo/utils/serial/CustomSerializer.java b/src/be/nikiroo/utils/serial/CustomSerializer.java
new file mode 100644 (file)
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+++ b/src/be/nikiroo/utils/serial/CustomSerializer.java
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+package be.nikiroo.utils.serial;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import be.nikiroo.utils.streams.BufferedInputStream;
+import be.nikiroo.utils.streams.ReplaceInputStream;
+import be.nikiroo.utils.streams.ReplaceOutputStream;
+
+/**
+ * A {@link CustomSerializer} supports and generates values in the form:
+ * <ul>
+ * <li><tt>custom^<i>TYPE</i>^<i>ENCODED_VALUE</i></tt></li>
+ * </ul>
+ * <p>
+ * In this scheme, the values are:
+ * <ul>
+ * <li><tt>custom</tt>: a fixed keyword</li>
+ * <li><tt>^</tt>: a fixed separator character (the
+ * <tt><i>ENCODED_VALUE</i></tt> can still use it inside its content, though</li>
+ * <li><tt><i>TYPE</i></tt>: the object type of this value</li>
+ * <li><tt><i>ENCODED_VALUE</i></tt>: the custom encoded value</li>
+ * </ul>
+ * <p>
+ * To create a new {@link CustomSerializer}, you are expected to implement the
+ * abstract methods of this class. The rest should be taken care of bythe
+ * system.
+ * 
+ * @author niki
+ */
+public abstract class CustomSerializer {
+       /**
+        * Generate the custom <tt><i>ENCODED_VALUE</i></tt> from this
+        * <tt>value</tt>.
+        * <p>
+        * The <tt>value</tt> will always be of the supported type.
+        * 
+        * @param out
+        *            the {@link OutputStream} to write the value to
+        * @param value
+        *            the value to serialize
+        * 
+        * @throws IOException
+        *             in case of I/O error
+        */
+       protected abstract void toStream(OutputStream out, Object value)
+                       throws IOException;
+
+       /**
+        * Regenerate the value from the custom <tt><i>ENCODED_VALUE</i></tt>.
+        * <p>
+        * The value in the {@link InputStream} <tt>in</tt> will always be of the
+        * supported type.
+        * 
+        * @param in
+        *            the {@link InputStream} containing the
+        *            <tt><i>ENCODED_VALUE</i></tt>
+        * 
+        * @return the regenerated object
+        * 
+        * @throws IOException
+        *             in case of I/O error
+        */
+       protected abstract Object fromStream(InputStream in) throws IOException;
+
+       /**
+        * Return the supported type name.
+        * <p>
+        * It <b>must</b> be the name returned by {@link Object#getClass()
+        * #getCanonicalName()}.
+        * 
+        * @return the supported class name
+        */
+       protected abstract String getType();
+
+       /**
+        * Encode the object into the given {@link OutputStream}, i.e., generate the
+        * <tt><i>ENCODED_VALUE</i></tt> part.
+        * <p>
+        * Use whatever scheme you wish, the system shall ensure that the content is
+        * correctly encoded and that you will receive the same content at decode
+        * time.
+        * 
+        * @param out
+        *            the builder to append to
+        * @param value
+        *            the object to encode
+        * 
+        * @throws IOException
+        *             in case of I/O error
+        */
+       public void encode(OutputStream out, Object value) throws IOException {
+               ReplaceOutputStream replace = new ReplaceOutputStream(out, //
+                               new String[] { "\\", "\n" }, //
+                               new String[] { "\\\\", "\\n" });
+
+               try {
+                       SerialUtils.write(replace, "custom^");
+                       SerialUtils.write(replace, getType());
+                       SerialUtils.write(replace, "^");
+                       toStream(replace, value);
+               } finally {
+                       replace.close(false);
+               }
+       }
+
+       /**
+        * Decode the value back into the supported object type.
+        * <p>
+        * We do <b>not</b> expect the full content here but only:
+        * <ul>
+        * <li>ENCODED_VALUE
+        * <li>
+        * </ul>
+        * That is, we do not expect the "<tt>custom</tt>^<tt><i>TYPE</i></tt>^"
+        * part.
+        * 
+        * @param in
+        *            the encoded value
+        * 
+        * @return the object
+        * 
+        * @throws IOException
+        *             in case of I/O error
+        */
+       public Object decode(InputStream in) throws IOException {
+               ReplaceInputStream replace = new ReplaceInputStream(in, //
+                               new String[] { "\\\\", "\\n" }, //
+                               new String[] { "\\", "\n" });
+
+               try {
+                       return fromStream(replace);
+               } finally {
+                       replace.close(false);
+               }
+       }
+
+       public static boolean isCustom(BufferedInputStream in) throws IOException {
+               return in.startsWith("custom^");
+       }
+
+       public static String typeOf(String encodedValue) {
+               int pos1 = encodedValue.indexOf('^');
+               int pos2 = encodedValue.indexOf('^', pos1 + 1);
+               String type = encodedValue.substring(pos1 + 1, pos2);
+
+               return type;
+       }
+}