ArrayInsertBefore.java

/*
 * SPDX-FileCopyrightText: none
 * SPDX-License-Identifier: CC0-1.0
 */

package gov.nist.secauto.metaschema.core.metapath.function.library;

import gov.nist.secauto.metaschema.core.metapath.DynamicContext;
import gov.nist.secauto.metaschema.core.metapath.ICollectionValue;
import gov.nist.secauto.metaschema.core.metapath.ISequence;
import gov.nist.secauto.metaschema.core.metapath.MetapathConstants;
import gov.nist.secauto.metaschema.core.metapath.function.FunctionUtils;
import gov.nist.secauto.metaschema.core.metapath.function.IArgument;
import gov.nist.secauto.metaschema.core.metapath.function.IFunction;
import gov.nist.secauto.metaschema.core.metapath.item.IItem;
import gov.nist.secauto.metaschema.core.metapath.item.atomic.IIntegerItem;
import gov.nist.secauto.metaschema.core.metapath.item.function.ArrayException;
import gov.nist.secauto.metaschema.core.metapath.item.function.IArrayItem;
import gov.nist.secauto.metaschema.core.util.ObjectUtils;

import java.util.List;

import edu.umd.cs.findbugs.annotations.NonNull;

/**
 * Implements the XPath 3.1 <a href=
 * "https://www.w3.org/TR/xpath-functions-31/#func-array-insert-before">array:insert-before</a>
 * function.
 */
public final class ArrayInsertBefore {
  @NonNull
  private static final String NAME = "insert-before";
  // CPD-OFF
  @NonNull
  static final IFunction SIGNATURE = IFunction.builder()
      .name(NAME)
      .namespace(MetapathConstants.NS_METAPATH_FUNCTIONS_ARRAY)
      .deterministic()
      .contextIndependent()
      .focusIndependent()
      .argument(IArgument.builder()
          .name("array")
          .type(IArrayItem.class)
          .one()
          .build())
      .argument(IArgument.builder()
          .name("position")
          .type(IIntegerItem.class)
          .one()
          .build())
      .argument(IArgument.builder()
          .name("member")
          .type(IItem.class)
          .zeroOrMore()
          .build())
      .returnType(IArrayItem.class)
      .returnOne()
      .functionHandler(ArrayInsertBefore::execute)
      .build();
  // CPD-ON

  private ArrayInsertBefore() {
    // disable construction
  }

  @SuppressWarnings("unused")
  @NonNull
  private static <T extends ICollectionValue> ISequence<IArrayItem<T>> execute(@NonNull IFunction function,
      @NonNull List<ISequence<?>> arguments,
      @NonNull DynamicContext dynamicContext,
      IItem focus) {
    IArrayItem<T> array = FunctionUtils.asType(ObjectUtils.requireNonNull(
        arguments.get(0).getFirstItem(true)));
    IIntegerItem position = FunctionUtils.asType(ObjectUtils.requireNonNull(arguments.get(1).getFirstItem(true)));
    @SuppressWarnings("unchecked")
    T member = (T) ObjectUtils.requireNonNull(arguments.get(2)).toCollectionValue();

    return ISequence.of(insertBefore(array, position, member));
  }

  /**
   * An implementation of XPath 3.1 <a href=
   * "https://www.w3.org/TR/xpath-functions-31/#func-array-insert-before">array:insert-before</a>.
   *
   * @param <T>
   *          the type of items in the given Metapath array
   * @param array
   *          the target Metapath array
   * @param positionItem
   *          the integer position of the item to insert before
   * @param member
   *          the Metapath item to insert into the identified array
   * @return a new array containing the modification
   * @throws ArrayException
   *           if the position is not in the range of 1 to array:size
   */
  @NonNull
  public static <T extends ICollectionValue> IArrayItem<T> insertBefore(
      @NonNull IArrayItem<T> array,
      @NonNull IIntegerItem positionItem,
      @NonNull T member) {
    return insertBefore(array, positionItem.asInteger().intValueExact(), member);
  }

  /**
   * An implementation of XPath 3.1 <a href=
   * "https://www.w3.org/TR/xpath-functions-31/#func-array-insert-before">array:insert-before</a>.
   *
   * @param <T>
   *          the type of items in the given Metapath array
   * @param array
   *          the target Metapath array
   * @param position
   *          the integer position of the item to insert before
   * @param member
   *          the Metapath item to insert into the identified array
   * @return a new array containing the modification
   * @throws ArrayException
   *           if the position is not in the range of 1 to array:size
   */
  @NonNull
  public static <T extends ICollectionValue> IArrayItem<T> insertBefore(
      @NonNull IArrayItem<T> array,
      int position,
      @NonNull T member) {
    return ArrayJoin.join(ObjectUtils.notNull(List.of(
        ArraySubarray.subarray(array, 1, position - 1),
        IArrayItem.of(member),
        ArraySubarray.subarray(array, position))));
  }
}