Ejemplo n.º 1
0
 /**
  * Checks if the specified XQuery string is a library module.
  *
  * @param qu query string
  * @return result of check
  */
 public static boolean isLibrary(final String qu) {
   return LIBMOD_PATTERN.matcher(removeComments(qu, 80)).matches();
 }
Ejemplo n.º 2
0
/**
 * This class is an entry point for evaluating XQuery strings.
 *
 * @author BaseX Team 2005-16, BSD License
 * @author Christian Gruen
 */
public final class QueryProcessor extends Job implements Closeable {
  /** Pattern for detecting library modules. */
  private static final Pattern LIBMOD_PATTERN =
      Pattern.compile(
          "^(xquery( version ['\"].*?['\"])?( encoding ['\"].*?['\"])? ?; ?)?module namespace.*");

  /** Static context. */
  public final StaticContext sc;
  /** Expression context. */
  public final QueryContext qc;
  /** Query. */
  private final String query;
  /** Parsed flag. */
  private boolean parsed;

  /**
   * Default constructor.
   *
   * @param query query string
   * @param ctx database context
   */
  public QueryProcessor(final String query, final Context ctx) {
    this(query, null, ctx);
  }

  /**
   * Default constructor.
   *
   * @param query query string
   * @param uri base uri (can be {@code null})
   * @param ctx database context
   */
  public QueryProcessor(final String query, final String uri, final Context ctx) {
    this.query = query;
    qc = pushJob(new QueryContext(ctx));
    sc = new StaticContext(qc);
    sc.baseURI(uri);
  }

  /**
   * Parses the query.
   *
   * @throws QueryException query exception
   */
  public void parse() throws QueryException {
    if (parsed) return;
    try {
      qc.parseMain(query, null, sc);
    } finally {
      parsed = true;
      updating = qc.updating;
    }
  }

  /**
   * Compiles the query.
   *
   * @throws QueryException query exception
   */
  public void compile() throws QueryException {
    parse();
    qc.compile();
  }

  /**
   * Returns a memory-efficient result iterator. In most cases, the query will only be fully
   * evaluated if all items of this iterator are requested.
   *
   * @return result iterator
   * @throws QueryException query exception
   */
  public Iter iter() throws QueryException {
    parse();
    return qc.iter();
  }

  /**
   * Evaluates the query and returns the resulting value.
   *
   * @return result value
   * @throws QueryException query exception
   */
  public Value value() throws QueryException {
    parse();
    return qc.iter().value();
  }

  /**
   * This function is called by the GUI; use {@link #iter()} or {@link #value()} instead. Caches and
   * returns the result of the specified query. If all nodes are of the same database instance, the
   * returned value will be of type {@link DBNodes}.
   *
   * @param max maximum number of results to cache (negative: return all values)
   * @return result of query
   * @throws QueryException query exception
   */
  public Value cache(final int max) throws QueryException {
    parse();
    return qc.cache(max);
  }

  /**
   * Binds a value with the specified type to a global variable. If the value is an {@link Expr}
   * instance, it is directly assigned. Otherwise, it is first cast to the appropriate XQuery type.
   * If {@code "json"} is specified as type, the value is interpreted according to the rules
   * specified in {@link JsonMapConverter}.
   *
   * @param name name of variable
   * @param value value to be bound
   * @param type type (may be {@code null})
   * @return self reference
   * @throws QueryException query exception
   */
  public QueryProcessor bind(final String name, final Object value, final String type)
      throws QueryException {
    qc.bind(name, value, type, sc);
    return this;
  }

  /**
   * Binds a value to a global variable.
   *
   * @param name name of variable
   * @param value value to be bound
   * @return self reference
   * @throws QueryException query exception
   */
  public QueryProcessor bind(final String name, final Object value) throws QueryException {
    return bind(name, value, null);
  }

  /**
   * Binds an XQuery value to a global variable.
   *
   * @param name name of variable
   * @param value value to be bound
   * @return self reference
   * @throws QueryException query exception
   */
  public QueryProcessor bind(final String name, final Value value) throws QueryException {
    qc.bind(name, value, sc);
    return this;
  }

  /**
   * Binds the context value.
   *
   * @param value value to be bound
   * @return self reference
   * @throws QueryException query exception
   */
  public QueryProcessor context(final Object value) throws QueryException {
    return context(value, null);
  }

  /**
   * Binds the context value.
   *
   * @param value XQuery value to be bound
   * @return self reference
   */
  public QueryProcessor context(final Value value) {
    qc.context(value, sc);
    return this;
  }

  /**
   * Binds the HTTP context to the query processor.
   *
   * @param value HTTP context
   * @return self reference
   */
  public QueryProcessor http(final Object value) {
    qc.http(value);
    return this;
  }

  /**
   * Binds the context value with a specified type, using the same rules as for {@link #bind binding
   * variables}.
   *
   * @param value value to be bound
   * @param type type (may be {@code null})
   * @return self reference
   * @throws QueryException query exception
   */
  public QueryProcessor context(final Object value, final String type) throws QueryException {
    qc.context(value, type, sc);
    return this;
  }

  /**
   * Declares a namespace. A namespace is undeclared if the {@code uri} is an empty string. The
   * default element namespaces is set if the {@code prefix} is empty.
   *
   * @param prefix namespace prefix
   * @param uri namespace uri
   * @return self reference
   * @throws QueryException query exception
   */
  public QueryProcessor namespace(final String prefix, final String uri) throws QueryException {
    sc.namespace(prefix, uri);
    return this;
  }

  /**
   * Assigns a URI resolver.
   *
   * @param resolver resolver
   * @return self reference
   */
  public QueryProcessor uriResolver(final UriResolver resolver) {
    sc.resolver = resolver;
    return this;
  }

  /**
   * Returns a serializer for the given output stream. Optional output declarations within the query
   * will be included in the serializer instance.
   *
   * @param os output stream
   * @return serializer instance
   * @throws IOException query exception
   * @throws QueryException query exception
   */
  public Serializer getSerializer(final OutputStream os) throws IOException, QueryException {
    compile();
    try {
      return Serializer.get(os, qc.serParams()).sc(sc);
    } catch (final QueryIOException ex) {
      throw ex.getCause();
    }
  }

  /**
   * Adds a module reference. Only called from the test APIs.
   *
   * @param uri module uri
   * @param file file name
   */
  public void module(final String uri, final String file) {
    qc.modDeclared.put(uri, file);
  }

  /**
   * Returns the query string.
   *
   * @return query
   */
  public String query() {
    return query;
  }

  @Override
  public void close() {
    qc.close();
  }

  @Override
  public void databases(final LockResult lr) {
    qc.databases(lr);
  }

  /**
   * Returns the number of performed updates after query execution, or {@code 0}.
   *
   * @return number of updates
   */
  public int updates() {
    return updating ? qc.updates().size() : 0;
  }

  /**
   * Returns query information.
   *
   * @return query information
   */
  public String info() {
    return qc.info();
  }

  /**
   * Checks if the specified XQuery string is a library module.
   *
   * @param qu query string
   * @return result of check
   */
  public static boolean isLibrary(final String qu) {
    return LIBMOD_PATTERN.matcher(removeComments(qu, 80)).matches();
  }

  /**
   * Removes comments from the specified string and returns the first characters of a query.
   *
   * @param qu query string
   * @param max maximum length of string to return
   * @return result
   */
  public static String removeComments(final String qu, final int max) {
    final StringBuilder sb = new StringBuilder();
    int m = 0;
    boolean s = false;
    final int cl = qu.length();
    for (int c = 0; c < cl && sb.length() < max; ++c) {
      final char ch = qu.charAt(c);
      if (ch == 0x0d) continue;
      if (ch == '(' && c + 1 < cl && qu.charAt(c + 1) == ':') {
        if (m == 0 && !s) {
          sb.append(' ');
          s = true;
        }
        ++m;
        ++c;
      } else if (m != 0 && ch == ':' && c + 1 < cl && qu.charAt(c + 1) == ')') {
        --m;
        ++c;
      } else if (m == 0) {
        if (ch > ' ') sb.append(ch);
        else if (!s) sb.append(' ');
        s = ch <= ' ';
      }
    }
    if (sb.length() >= max) sb.append("...");
    return sb.toString().trim();
  }

  /**
   * Returns a tree representation of the query plan.
   *
   * @return root node
   */
  public FDoc plan() {
    return new FDoc().add(qc.plan());
  }

  @Override
  public String shortInfo() {
    return PLEASE_WAIT_D;
  }

  @Override
  public String detailedInfo() {
    return PLEASE_WAIT_D;
  }

  @Override
  public String toString() {
    return query;
  }
}