Add a builder for ValidatorChains.

This allows them to be created inline without using type-unsafe
varargs (albeit a bit more verbosely).

new ValidatorChain(v1, v2, ...) becomes

ValidatorChain.builder()
    .addValidator(v1)
    .addValidator(v2)
    ...
    .build();

Change-Id: I6c92142bf294335419fbd16593125416dd33c74e
Reviewed-on: http://gerrit.dmdirc.com/3168
Automatic-Compile: DMDirc Build Manager
Reviewed-by: Greg Holmes <greg@dmdirc.com>

src/com/dmdirc/util/validators/ValidatorChain.java

@@ -19,35 +19,45 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-
 package com.dmdirc.util.validators;
 
-import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 
 /**
  * Allows multiple validators to be chained together.
  *
  * @param <A> The type of class that this chain validates
- * @author chris
  */
 public class ValidatorChain<A> implements Validator<A> {
 
-    /** A list of validators to use. */
-    private final List<Validator<A>> validatorList = new ArrayList<>();
+    /**
+     * A list of validators to use.
+     */
+    private final List<Validator<A>> validatorList;
 
     /**
      * Creates a new validator chain containing the specified validators.
      *
      * @param validators The validators to be used in this chain.
+     * @deprecated Use a builder or pass a list to avoid unchecked warnings.
      */
     @SuppressWarnings({"unchecked", "varargs"})
-    public ValidatorChain(final Validator<A> ... validators) {
-        validatorList.addAll(Arrays.asList(validators));
+    @Deprecated
+    public ValidatorChain(final Validator<A>... validators) {
+        validatorList = Arrays.asList(validators);
+    }
+
+    /**
+     * Creates a new validator chain containing the specified validators.
+     *
+     * @param validators The validators to be used in this chain.
+     */
+    public ValidatorChain(final List<Validator<A>> validators) {
+        validatorList = Collections.unmodifiableList(validators);
     }
 
-    /** {@inheritDoc} */
     @Override
     public ValidationResponse validate(final A object) {
         for (Validator<A> validator : validatorList) {
@@ -61,4 +71,14 @@ public class ValidatorChain<A> implements Validator<A> {
         return new ValidationResponse();
     }
 
+    /**
+     * Creates a builder which can be used to construct a new
+     * {@link ValidatorChain}.
+     *
+     * @param <T> The type of validator that will be in the chain.
+     * @return A builder to use to make a validator.
+     */
+    public static <T> ValidatorChainBuilder<T> builder() {
+        return new ValidatorChainBuilder<>();
+    }
 }

src/com/dmdirc/util/validators/ValidatorChainBuilder.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2006-2014 DMDirc Developers
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.dmdirc.util.validators;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Simple builder to create a {@link ValidatorChain} with a dynamic number of
+ * validators.
+ *
+ * @param <T> The type of validator to build.
+ */
+public final class ValidatorChainBuilder<T> {
+
+    private final List<Validator<T>> validators = new ArrayList<>();
+
+    ValidatorChainBuilder() {
+    }
+
+    public ValidatorChainBuilder<T> addValidator(final Validator<T> validator) {
+        validators.add(validator);
+        return this;
+    }
+
+    public ValidatorChain<T> build() {
+        return new ValidatorChain<>(validators);
+    }
+}