org.opencastproject.util.data.Arrays Maven / Gradle / Ivy
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* Licensed to The Apereo Foundation under one or more contributor license
* agreements. See the NOTICE file distributed with this work for additional
* information regarding copyright ownership.
*
*
* The Apereo Foundation licenses this file to you under the Educational
* Community 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://opensource.org/licenses/ecl2.txt
*
* 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 org.opencastproject.util.data;
import java.lang.reflect.Array;
public final class Arrays {
private Arrays() {
}
/** Create a new array by prepending a to as: [a, as0, as1, .. asn] */
public static A[] cons(Class type, A a, A[] as) {
@SuppressWarnings("unchecked")
final A[] x = (A[]) Array.newInstance(type, as.length + 1);
x[0] = a;
System.arraycopy(as, 0, x, 1, as.length);
return x;
}
/** Create a new array by appending a to as: [as0, as1, .. asn, a]. */
public static A[] append(Class type, A[] as, A a) {
@SuppressWarnings("unchecked")
final A[] x = (A[]) Array.newInstance(type, as.length + 1);
System.arraycopy(as, 0, x, 0, as.length);
x[as.length] = a;
return x;
}
/** Create an array from the vararg parameter list. */
public static A[] array(A... as) {
return as;
}
/** Turn a value into a single element array. */
public static Function singleton(final Class type) {
return new Function() {
@Override
public A[] apply(A a) {
@SuppressWarnings("unchecked")
final A[] as = (A[]) Array.newInstance(type, 1);
as[0] = a;
return as;
}
};
}
/** Make a string from a collection separating each element by sep. */
public static String mkString(A[] as, String sep) {
final StringBuilder b = new StringBuilder();
for (Object a : as) b.append(a).append(sep);
return b.substring(0, Math.max(b.length() - sep.length(), 0));
}
}