Initial revision

From-SVN: r102074

libjava/classpath/gnu/java/beans/decoder/Context.java

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+/* gnu.java.beans.decoder.Context
+   Copyright (C) 2004 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+ 
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+package gnu.java.beans.decoder;
+
+/** A Context is the environment for an object which is being assembler. If there
+ * are no errors each handler creates one Context.
+ * <p>Depending on the result of isStatement() a Context can be statement or an
+ * expression. An expression returns a value to the Context of its parent handler,
+ * a statement does not. Whenever a Context is a statement the parent handler's
+ * Context is informed about that through the {@link notifyStatement}-method.</p>
+ *
+ * @author Robert Schuster
+ */
+interface Context
+{
+  /** Adds a parameter object to the context. This method is used when
+   * sub-Contexts return their result.
+   *
+   * Some Contexts do not accept more than a certain amount of objects
+   * and throw an AssemblerException if the amount is exceeded.
+   *
+   * @param o The object added to this context.
+   */
+  void addParameterObject(Object o) throws AssemblyException;
+
+  /** Notifies that the next element is a statement. This can mean
+   * that an argument list is complete to be called.
+   *
+   */
+  void notifyStatement(Context outerContext) throws AssemblyException;
+
+  /** Notifies that the context ends and the returns the appropriate result
+   * object.
+   *
+   * @param outerContext
+   * @return
+   */
+  Object endContext(Context outerContext) throws AssemblyException;
+
+  /** Notifies that the assembly of a subcontext failed and returns
+   * whether this Context is affected in a way that it fails too.
+   *
+   * @return Whether the failure of a subcontext lets this context fail, too.
+   */
+  boolean subContextFailed();
+
+  /** Calls an appropriate indexed set method if it is available or
+   * throws an AssemblerException if that is not allowed on this Context.
+   *
+   * The behaviour of this method is equal to List.set(int, Object).
+   *
+   * @param index Index position to be set.
+   * @param o Object to be set at the given index position.
+   * @throws AssemblerException Indexed set is not allowed or otherwise failed.
+   */
+  void set(int index, Object o) throws AssemblyException;
+
+  /** Calls an appropriate indexed get method if it is available or
+   * throws an AssemblerException if that is not allowed on this Context.
+   *
+   * The behaviour of this method is equal to List.get(int).
+   *
+   * @param index Index position of the object return.
+   * @throws AssemblerException Indexed get is not allowed or otherwise failed.
+   */
+  Object get(int index) throws AssemblyException;
+
+  /** Returns the result which was calculated by calling endContext() or reportStatement().
+   * Its the handler's responsibility to care that any of these two methods was called.
+   *
+   * This is used by sub-Contexts to access this Context's result.
+   *
+   * @return
+   */
+  Object getResult();
+
+  /** Gives this Context a unique id. For convenience the id may be null which means
+   * that no id exists at all.
+   *
+   * @param id
+   */
+  void setId(String id);
+
+  /** Returns this Context's unique id or null if does not have such an id.
+   *
+   * @return This Context's id or null.
+   */
+  String getId();
+
+  /** Returns whether this Context is a statement (not returning result back
+   * to parent handler's Context) or not (= expression).
+   *
+   * @return
+   */
+  boolean isStatement();
+
+  /** Sets whether this Context is a statement or not.
+   *
+   * @param b
+   */
+  void setStatement(boolean b);
+}