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The Checker Framework enhances Java's type system to make it more powerful and useful. This lets software developers detect and prevent errors in their Java programs. The Checker Framework includes compiler plug-ins ("checkers") that find bugs or verify their absence. It also permits you to write your own compiler plug-ins.
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package org.checkerframework.dataflow.analysis;

import java.util.Map;
import java.util.StringJoiner;
import javax.lang.model.type.TypeMirror;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.plumelib.util.StringsPlume;

/**
 * Implementation of a {@link TransferResult} with just one non-exceptional store. The result of
 * {@code getThenStore} and {@code getElseStore} is equal to the only underlying store.
 *
 * @param  type of the abstract value that is tracked
 * @param  the store type used in the analysis
 */
public class RegularTransferResult, S extends Store>
    extends TransferResult {

  /** The regular result store. */
  protected final S store;

  /**
   * Whether the store changed; see {@link
   * org.checkerframework.dataflow.analysis.TransferResult#storeChanged}.
   */
  private final boolean storeChanged;

  /**
   * Create a new {@link #RegularTransferResult(AbstractValue, Store, Map, boolean)}, using {@code
   * null} for {@link org.checkerframework.dataflow.analysis.TransferResult#exceptionalStores}.
   *
   * Exceptions: If the corresponding {@link
   * org.checkerframework.dataflow.cfg.node.Node} throws an exception, then it is assumed that no
   * special handling is necessary and the store before the corresponding {@link
   * org.checkerframework.dataflow.cfg.node.Node} will be passed along any exceptional edge.
   *
   * 
Aliasing: {@code resultStore} is not allowed to be used anywhere outside of this
   * class (including use through aliases). Complete control over the object is transferred to this
   * class.
   *
   * @param value the abstract value produced by the transfer function
   * @param resultStore regular result store
   * @param storeChanged whether the store changed; see {@link
   *     org.checkerframework.dataflow.analysis.TransferResult#storeChanged}
   * @see #RegularTransferResult(AbstractValue, Store, Map, boolean)
   */
  public RegularTransferResult(@Nullable V value, S resultStore, boolean storeChanged) {
    this(value, resultStore, null, storeChanged);
  }

  /**
   * Create a new {@link #RegularTransferResult(AbstractValue, Store, Map, boolean)}, using {@code
   * null} for {@link org.checkerframework.dataflow.analysis.TransferResult#exceptionalStores} and
   * {@code false} for {@link org.checkerframework.dataflow.analysis.TransferResult#storeChanged}.
   *
   * @param value the abstract value produced by the transfer function
   * @param resultStore regular result store
   * @see #RegularTransferResult(AbstractValue, Store, Map, boolean)
   */
  public RegularTransferResult(@Nullable V value, S resultStore) {
    this(value, resultStore, false);
  }

  /**
   * Create a new {@link #RegularTransferResult(AbstractValue, Store, Map, boolean)}, using {@code
   * false} for {@link org.checkerframework.dataflow.analysis.TransferResult#storeChanged}.
   *
   * @param value the abstract value produced by the transfer function
   * @param resultStore the regular result store
   * @param exceptionalStores the stores in case the basic block throws an exception, or null if the
   *     basic block does not throw any exceptions
   * @see #RegularTransferResult(AbstractValue, Store, Map, boolean)
   */
  public RegularTransferResult(
      @Nullable V value, S resultStore, Map exceptionalStores) {
    this(value, resultStore, exceptionalStores, false);
  }

  /**
   * Create a {@code TransferResult} with {@code resultStore} as the resulting store. If the
   * corresponding {@link org.checkerframework.dataflow.cfg.node.Node} is a boolean node, then
   * {@code resultStore} is used for both the 'then' and 'else' edge.
   *
   * 
Exceptions: If the corresponding {@link
   * org.checkerframework.dataflow.cfg.node.Node} throws an exception, then the corresponding store
   * in {@code exceptionalStores} is used. If no exception is found in {@code exceptionalStores},
   * then it is assumed that no special handling is necessary and the store before the corresponding
   * {@link org.checkerframework.dataflow.cfg.node.Node} will be passed along any exceptional edge.
   *
   * Aliasing: {@code resultStore} and any store in {@code exceptionalStores} are not
   * allowed to be used anywhere outside of this class (including use through aliases). Complete
   * control over the objects is transferred to this class.
   *
   * @param value the abstract value produced by the transfer function
   * @param resultStore the regular result store
   * @param exceptionalStores the stores in case the basic block throws an exception, or null if the
   *     basic block does not throw any exceptions
   * @param storeChanged see {@link
   *     org.checkerframework.dataflow.analysis.TransferResult#storeChanged}
   */
  public RegularTransferResult(
      @Nullable V value,
      S resultStore,
      @Nullable Map exceptionalStores,
      boolean storeChanged) {
    super(value, exceptionalStores);
    this.store = resultStore;
    this.storeChanged = storeChanged;
  }

  /** The regular result store. */
  @Override
  public S getRegularStore() {
    return store;
  }

  @Override
  public S getThenStore() {
    return store;
  }

  @Override
  public S getElseStore() {
    // copy the store such that it is the same as the result of getThenStore
    // (that is, identical according to equals), but two different objects.
    return store.copy();
  }

  @Override
  public boolean containsTwoStores() {
    return false;
  }

  @Override
  public String toString() {
    StringJoiner result = new StringJoiner(System.lineSeparator());
    result.add("RegularTransferResult(");
    result.add("  resultValue = " + StringsPlume.indentLinesExceptFirst(2, resultValue));
    // "toString().trim()" works around bug where toString ends with a newline.
    result.add(
        "  store = " + StringsPlume.indentLinesExceptFirst(2, store.toString().trim()) + ")");
    return result.toString();
  }

  /**
   * See {@link org.checkerframework.dataflow.analysis.TransferResult#storeChanged()}.
   *
   * @see org.checkerframework.dataflow.analysis.TransferResult#storeChanged()
   */
  @Override
  public boolean storeChanged() {
    return storeChanged;
  }
}