Migrating maven2-repository to java.nio

1 files changed, 253 insertions, 0 deletions

diff --git a/archiva-modules/archiva-base/archiva-common/src/main/java/org/apache/archiva/common/Try.java b/archiva-modules/archiva-base/archiva-common/src/main/java/org/apache/archiva/common/Try.java
new file mode 100644
index 000000000..f71d45fc7
--- /dev/null
+++ b/archiva-modules/archiva-base/archiva-common/src/main/java/org/apache/archiva/common/Try.java
@@ -0,0 +1,253 @@
+package org.apache.archiva.common;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.util.function.Function;
+
+/**
+ * This is a class that can be used for the Try monad
+ *
+ * The Try monad is able to collect exceptions during processing
+ * of a stream.
+ *
+ *
+ *
+ */
+public abstract class Try<V> {
+
+    private Try() {
+
+    }
+
+    public abstract Boolean isSuccess();
+
+    public abstract Boolean isFailure();
+
+    public abstract void throwException();
+
+    /**
+     * Returns the value if this is a success instance. Otherwise throws
+     * a runtime exception with the stored throwable as cause.
+     *
+     * @return The value
+     */
+    public abstract V get();
+
+    /**
+     * Returns the throwable that is stored in the failure.
+     *
+     * @return The Throwable or null.
+     */
+    public abstract Throwable getError();
+
+
+    /**
+     * A mapping method for mapping the current instance to a new type.
+     *
+     * @param fn
+     * @param <U>
+     * @return
+     */
+    public <U> Try<U> map(Function<? super V, U> fn) {
+        try {
+            return Try.success(fn.apply(get()));
+        } catch (Throwable e) {
+            return Try.failure(e);
+        }
+    }
+
+    /**
+     * This is the bind method.
+     * If this instance is success the function will be applied. If any error occurs
+     * a failure instance will be returned.
+     * If this instance is failure a new failure will be returned.
+     *
+     * @param fn
+     * @param <U>
+     * @return
+     */
+    public <U> Try<U> flatMap(Function<? super V, Try<U>> fn) {
+        try {
+            return fn.apply(get());
+        } catch (Throwable t) {
+            return Try.failure(t);
+        }
+    }
+
+    public static <V> Try<V> failure(String message) {
+
+        return new Failure<>(message);
+
+    }
+
+    public static <V> Try<V> failure(String message, Throwable e) {
+
+        return new Failure<>(message, e);
+
+    }
+
+    /**
+     * If you need type coercion, you should call this method as
+     *  Try.&lt;YOUR_TYPE&gt;failure(e)
+     *
+     *
+     *
+     * @param e The exception that is thrown
+     * @param <V> The generic type this monad keeps
+     * @return A new Try instance that represents a failure.
+     */
+    public static <V> Try<V> failure(Throwable e) {
+
+        return new Failure<>(e);
+
+    }
+
+
+    /**
+     * Returns a instance for the success case.
+     *
+     * @param value The value that should be stored.
+     * @param <V> The return type
+     * @return A new Try instance with the given value
+     */
+    public static <V> Try<V> success(V value) {
+
+        return new Success<>(value);
+
+    }
+
+    private static class Failure<V> extends Try<V> {
+
+        private Throwable exception;
+
+        public Failure(String message) {
+
+            super();
+
+            this.exception = new IllegalStateException(message);
+
+        }
+
+        public Failure(String message, Throwable e) {
+
+            super();
+
+            this.exception = new IllegalStateException(message, e);
+
+        }
+
+        public Failure(Throwable e) {
+
+            super();
+
+            this.exception = new IllegalStateException(e);
+
+        }
+
+        @Override
+
+        public Boolean isSuccess() {
+
+            return false;
+
+        }
+
+        @Override
+
+        public Boolean isFailure() {
+
+            return true;
+
+        }
+
+        @Override
+
+        public void throwException() {
+
+            throw new RuntimeException(this.exception);
+
+        }
+
+        @Override
+        public V get() {
+            throw new RuntimeException(this.exception);
+        }
+
+        @Override
+        public Throwable getError() {
+            return exception;
+        }
+    }
+
+    private static class Success<V> extends Try<V> {
+
+        private V value;
+
+        public Success(V value) {
+
+            super();
+
+            this.value = value;
+
+        }
+
+        @Override
+
+        public Boolean isSuccess() {
+
+            return true;
+
+        }
+
+        @Override
+
+        public Boolean isFailure() {
+
+            return false;
+
+        }
+
+        @Override
+
+        public void throwException() {
+
+            //log.error("Method throwException() called on a Success instance");
+
+        }
+
+        @Override
+        public V get() {
+            return value;
+        }
+
+        @Override
+        public Throwable getError() {
+            return null;
+        }
+    }
+
+    // various method such as map an flatMap
+
+
+    @Override
+    public String toString() {
+        return isSuccess() ? "true: "+get() : "false: "+ getError().getMessage();
+    }
+}