StringConcat.java

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

package gov.nist.secauto.metaschema.core.metapath.cst;

import gov.nist.secauto.metaschema.core.metapath.DynamicContext;
import gov.nist.secauto.metaschema.core.metapath.ISequence;
import gov.nist.secauto.metaschema.core.metapath.function.library.FnData;
import gov.nist.secauto.metaschema.core.metapath.item.atomic.IStringItem;
import gov.nist.secauto.metaschema.core.util.ObjectUtils;

import java.util.List;

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

public class StringConcat
    extends AbstractNAryExpression {

  /**
   * Create a new expression that concatenates the results of evaluating the
   * provided {@code expressions} as strings.
   *
   * @param expressions
   *          the expressions to evaluate
   */
  public StringConcat(@NonNull List<IExpression> expressions) {
    super(expressions);
  }

  @Override
  public Class<IStringItem> getBaseResultType() {
    return IStringItem.class;
  }

  @Override
  public Class<IStringItem> getStaticResultType() {
    return getBaseResultType();
  }

  @Override
  public <RESULT, CONTEXT> RESULT accept(IExpressionVisitor<RESULT, CONTEXT> visitor, CONTEXT context) {
    return visitor.visitStringConcat(this, context);
  }

  @Override
  public ISequence<?> accept(DynamicContext dynamicContext, ISequence<?> focus) {
    // TODO: replace with concat function when implemented
    StringBuilder builder = new StringBuilder();
    for (IExpression child : getChildren()) {
      ISequence<?> result = child.accept(dynamicContext, focus);
      FnData.fnData(result).stream()
          .forEachOrdered(item -> {
            builder.append(item.asString());
          });
    }
    return ISequence.of(IStringItem.valueOf(ObjectUtils.notNull(builder.toString())));
  }
}