Sequence.java

package jetbrains.mps.internal.collections.runtime;

/*Generated by MPS */

import jetbrains.mps.internal.collections.runtime.impl.NullSetSequence;
import jetbrains.mps.internal.collections.runtime.impl.NullSequence;
import jetbrains.mps.internal.collections.runtime.impl.BasicSequence;
import java.util.Arrays;
import jetbrains.mps.baseLanguage.closures.runtime.AdapterClass;
import jetbrains.mps.baseLanguage.closures.runtime._FunctionTypes;
import java.util.Collections;

public abstract class Sequence<T> extends AbstractSequence<T> implements ISequence<T>, Iterable<T> {
  public static final boolean USE_NULL_SEQUENCE = true;
  public static final boolean IGNORE_NULL_VALUES = false;
  public static final boolean NULL_WHEN_EMPTY = true;
  public static final boolean NULL_ARRAY_IS_SINGLETON = true;
  protected static final Object[] ARRAY_WITH_NULL = new Object[]{null};
  public Sequence() {
  }
  @Override
  public String toString() {
    Iterable<T> iterable = toIterable();
    if (iterable == null) {
      return "null";
    }
    StringBuilder sb = new StringBuilder("[");
    String sep = "";
    for (T t : iterable) {
      sb.append(sep).append(String.valueOf(t));
      sep = ", ";
    }
    sb.append("]");
    return sb.toString();
  }
  @SuppressWarnings(value = "unchecked")
  protected static <U> U[] nullSingletonArray() {
    return (U[]) ARRAY_WITH_NULL;
  }
  public static <U> ISequence<U> emptySequence() {
    return NullSetSequence.instance();
  }
  public static <U> ISequence<U> fromArray(U... array) {
    if (USE_NULL_SEQUENCE) {
      if (array == null) {
        return NullSequence.instance();
      }
    }
    return new BasicSequence<U>(Arrays.asList(array));
  }
  public static <U> ISequence<U> fromClosure(@AdapterClass(value = "ISequenceClosure") _FunctionTypes._return_P0_E0<? extends Iterable<U>> cls) {
    return Sequence.fromIterable(cls.invoke());
  }
  public static <U> ISequence<U> fromIterable(Iterable<U> iterable) {
    if (USE_NULL_SEQUENCE) {
      if (iterable == null) {
        return NullSequence.instance();
      }
    }
    if (iterable instanceof ISequence) {
      return (ISequence<U>) iterable;
    }
    return new BasicSequence<U>(iterable);
  }
  public static <U> ISequence<U> singleton(U value) {
    if (IGNORE_NULL_VALUES) {
      if (value == null) {
        return NullSequence.instance();
      }
    }
    return new BasicSequence<U>(Collections.singleton(value));
  }
}