/***********************************************************************************************************************
 * Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
 *
 * Licensed 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.
 **********************************************************************************************************************/
package eu.stratosphere.runtime.io.serialization.types;

import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Random;

public class Util {

	private static final long SEED = 64871654635745873L;

	private static Random random = new Random(SEED);

	public static SerializationTestType randomRecord(SerializationTestTypeFactory type) {
		return type.factory().getRandom(Util.random);
	}

	public static MockRecords randomRecords(final int numElements, final SerializationTestTypeFactory type) {

		return new MockRecords(numElements) {
			@Override
			protected SerializationTestType getRecord() {
				return type.factory().getRandom(Util.random);
			}
		};
	}

	public static MockRecords randomRecords(final int numElements) {

		return new MockRecords(numElements) {
			@Override
			protected SerializationTestType getRecord() {
				// select random test type factory
				SerializationTestTypeFactory[] types = SerializationTestTypeFactory.values();
				int i = Util.random.nextInt(types.length);

				return types[i].factory().getRandom(Util.random);
			}
		};
	}

	// -----------------------------------------------------------------------------------------------------------------
	public abstract static class MockRecords implements Iterable<SerializationTestType> {

		private int numRecords;

		public MockRecords(int numRecords) {
			this.numRecords = numRecords;
		}

		@Override
		public Iterator<SerializationTestType> iterator() {
			return new Iterator<SerializationTestType>() {
				@Override
				public boolean hasNext() {
					return numRecords > 0;
				}

				@Override
				public SerializationTestType next() {
					if (numRecords > 0) {
						numRecords--;

						return getRecord();
					}

					throw new NoSuchElementException();
				}

				@Override
				public void remove() {
					throw new UnsupportedOperationException();
				}
			};
		}

		abstract protected SerializationTestType getRecord();
	}
}