Add Builder/Creator/Updater for GHLabel

src/main/java/org/kohsuke/github/AbstractBuilder.java

@@ -0,0 +1,165 @@
+package org.kohsuke.github;
+
+import java.io.IOException;
+
+import javax.annotation.CheckForNull;
+import javax.annotation.Nonnull;
+
+/**
+ * An abstract data object builder/updater.
+ *
+ * This class can be use to make a Builder that supports both batch and single property changes.
+ * <p>
+ * Batching looks like this:
+ * 
+ * <pre>
+ * update().someName(value).otherName(value).done()
+ * </pre>
+ * </p>
+ * <p>
+ * Single changes look like this:
+ * 
+ * <pre>
+ * set().someName(value);
+ * set().otherName(value);
+ * </pre>
+ * </p>
+ * <p>
+ * If {@link S} is the same as {@link R}, {@link #with(String, Object)} will commit changes after the first value change
+ * and return a {@link R} from {@link #done()}.
+ * </p>
+ * <p>
+ * If {@link S} is not the same as {@link R}, {@link #with(String, Object)} will batch together multiple changes and let
+ * the user call {@link #done()} when they are ready.
+ *
+ * @param <R>
+ *            Final return type built by this builder returned when {@link #done()}} is called.
+ * @param <S>
+ *            Intermediate return type for this builder returned by calls to {@link #with(String, Object)}. If {@link S}
+ *            the same as {@link R}, this builder will commit changes after each call to {@link #with(String, Object)}.
+ */
+abstract class AbstractBuilder<R, S> {
+
+    @Nonnull
+    private final Class<R> returnType;
+
+    private final boolean commitChangesImmediately;
+
+    @CheckForNull
+    private final R baseInstance;
+
+    @Nonnull
+    protected final Requester requester;
+
+    // TODO: Not sure how update-in-place behavior should be controlled
+    // However, it certainly can be controlled dynamically down to the instance level or inherited for all children of
+    // some
+    // connection.
+    protected boolean updateInPlace;
+
+    /**
+     * Creates a builder.
+     *
+     * @param root
+     *            the GitHub instance to connect to.
+     * @param intermediateReturnType
+     *            the intermediate return type of type {@link S} returned by calls to {@link #with(String, Object)}.
+     *            Must either be equal to {@code builtReturnType} or this instance must be castable to this class. If
+     *            not, the constructor will throw {@link IllegalArgumentException}.
+     * @param finalReturnType
+     *            the final return type for built by this builder returned when {@link #done()}} is called.
+     * @param baseInstance
+     *            optional instance on which to base this builder.
+     */
+    protected AbstractBuilder(@Nonnull Class<R> finalReturnType,
+            @Nonnull Class<S> intermediateReturnType,
+            @Nonnull GitHub root,
+            @CheckForNull R baseInstance) {
+        this.requester = root.createRequest();
+        this.returnType = finalReturnType;
+        this.commitChangesImmediately = returnType.equals(intermediateReturnType);
+        if (!commitChangesImmediately && !intermediateReturnType.isInstance(this)) {
+            throw new IllegalArgumentException(
+                    "Argument \"intermediateReturnType\": This instance must be castable to intermediateReturnType or finalReturnType must be equal to intermediateReturnType.");
+        }
+
+        this.baseInstance = baseInstance;
+        this.updateInPlace = false;
+    }
+
+    /**
+     * Finishes an update, committing changes.
+     *
+     * This method may update-in-place or not. Either way it returns the resulting instance.
+     *
+     * @return an instance with updated current data
+     * @throws IOException
+     *             if there is an I/O Exception
+     */
+    @Nonnull
+    @Preview
+    @Deprecated
+    public R done() throws IOException {
+        R result;
+        if (updateInPlace && baseInstance != null) {
+            result = requester.fetchInto(baseInstance);
+        } else {
+            result = requester.fetch(returnType);
+        }
+        return result;
+    }
+
+    /**
+     * Applies a value to a name for this builder.
+     *
+     * If {@link S} is the same as {@link R}, this method will commit changes after the first value change and return a
+     * {@link R} from {@link #done()}.
+     *
+     * If {@link S} is not the same as {@link R}, this method will return an {@link S} and letting the caller batch
+     * together multiple changes and call {@link #done()} when they are ready.
+     *
+     * @param name
+     *            the name of the field
+     * @param value
+     *            the value of the field
+     * @return either a continuing builder or an updated data record
+     * @throws IOException
+     *             if an I/O error occurs
+     */
+    @Nonnull
+    @Preview
+    @Deprecated
+    protected S with(@Nonnull String name, Object value) throws IOException {
+        requester.with(name, value);
+        return continueOrDone();
+    }
+
+    /**
+     * Chooses whether to return a continuing builder or an updated data record
+     *
+     * If {@link S} is the same as {@link R}, this method will commit changes after the first value change and return a
+     * {@link R} from {@link #done()}.
+     *
+     * If {@link S} is not the same as {@link R}, this method will return an {@link S} and letting the caller batch
+     * together multiple changes and call {@link #done()} when they are ready.
+     *
+     * @return either a continuing builder or an updated data record
+     * @throws IOException
+     *             if an I/O error occurs
+     */
+    @Nonnull
+    @Preview
+    @Deprecated
+    protected S continueOrDone() throws IOException {
+        // This little bit of roughness in this base class means all inheriting builders get to create Updater and
+        // Setter classes from almost identical code. Creator can often be implemented with significant code reuse as
+        // well.
+        if (commitChangesImmediately) {
+            // These casts look strange and risky, but they they're actually guaranteed safe due to the return path
+            // being based on the previous comparison of class instances passed to the constructor.
+            return (S) done();
+        } else {
+            return (S) this;
+        }
+    }
+}