/**
* 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();
}
/**
* 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;
}
}