| /* |
| * Copyright (c) 2008, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package com.sun.beans.decoder; |
| |
| /** |
| * The base class for element handlers. |
| * |
| * @since 1.7 |
| * |
| * @author Sergey A. Malenkov |
| * |
| * @see DocumentHandler |
| */ |
| public abstract class ElementHandler { |
| private DocumentHandler owner; |
| private ElementHandler parent; |
| |
| private String id; |
| |
| /** |
| * Returns the document handler that creates this element handler. |
| * |
| * @return the owner document handler |
| */ |
| public final DocumentHandler getOwner() { |
| return this.owner; |
| } |
| |
| /** |
| * Sets the document handler that creates this element handler. |
| * The owner document handler should be set after instantiation. |
| * Such approach is used to simplify the extensibility. |
| * |
| * @param owner the owner document handler |
| * @see DocumentHandler#startElement |
| */ |
| final void setOwner(DocumentHandler owner) { |
| if (owner == null) { |
| throw new IllegalArgumentException("Every element should have owner"); |
| } |
| this.owner = owner; |
| } |
| |
| /** |
| * Returns the element handler that contains this one. |
| * |
| * @return the parent element handler |
| */ |
| public final ElementHandler getParent() { |
| return this.parent; |
| } |
| |
| /** |
| * Sets the element handler that contains this one. |
| * The parent element handler should be set after instantiation. |
| * Such approach is used to simplify the extensibility. |
| * |
| * @param parent the parent element handler |
| * @see DocumentHandler#startElement |
| */ |
| final void setParent(ElementHandler parent) { |
| this.parent = parent; |
| } |
| |
| /** |
| * Returns the value of the variable with specified identifier. |
| * |
| * @param id the identifier |
| * @return the value of the variable |
| */ |
| protected final Object getVariable(String id) { |
| if (id.equals(this.id)) { |
| ValueObject value = getValueObject(); |
| if (value.isVoid()) { |
| throw new IllegalStateException("The element does not return value"); |
| } |
| return value.getValue(); |
| } |
| return (this.parent != null) |
| ? this.parent.getVariable(id) |
| : this.owner.getVariable(id); |
| } |
| |
| /** |
| * Returns the value of the parent element. |
| * |
| * @return the value of the parent element |
| */ |
| protected Object getContextBean() { |
| if (this.parent != null) { |
| ValueObject value = this.parent.getValueObject(); |
| if (!value.isVoid()) { |
| return value.getValue(); |
| } |
| throw new IllegalStateException("The outer element does not return value"); |
| } else { |
| Object value = this.owner.getOwner(); |
| if (value != null) { |
| return value; |
| } |
| throw new IllegalStateException("The topmost element does not have context"); |
| } |
| } |
| |
| /** |
| * Parses attributes of the element. |
| * By default, the following atribute is supported: |
| * <dl> |
| * <dt>id |
| * <dd>the identifier of the variable that is intended to store the result |
| * </dl> |
| * |
| * @param name the attribute name |
| * @param value the attribute value |
| */ |
| public void addAttribute(String name, String value) { |
| if (name.equals("id")) { // NON-NLS: the attribute name |
| this.id = value; |
| } else { |
| throw new IllegalArgumentException("Unsupported attribute: " + name); |
| } |
| } |
| |
| /** |
| * This method is called before parsing of the element's body. |
| * All attributes are parsed at this point. |
| * By default, do nothing. |
| */ |
| public void startElement() { |
| } |
| |
| /** |
| * This method is called after parsing of the element's body. |
| * By default, it calculates the value of this element. |
| * The following tasks are executing for any non-void value: |
| * <ol> |
| * <li>If the {@code id} attribute is set |
| * the value of the variable with the specified identifier |
| * is set to the value of this element.</li> |
| * <li>This element is used as an argument of parent element if it is possible.</li> |
| * </ol> |
| * |
| * @see #isArgument |
| */ |
| public void endElement() { |
| // do nothing if no value returned |
| ValueObject value = getValueObject(); |
| if (!value.isVoid()) { |
| if (this.id != null) { |
| this.owner.setVariable(this.id, value.getValue()); |
| } |
| if (isArgument()) { |
| if (this.parent != null) { |
| this.parent.addArgument(value.getValue()); |
| } else { |
| this.owner.addObject(value.getValue()); |
| } |
| } |
| } |
| } |
| |
| /** |
| * Adds the character that contained in this element. |
| * By default, only whitespaces are acceptable. |
| * |
| * @param ch the character |
| */ |
| public void addCharacter(char ch) { |
| if ((ch != ' ') && (ch != '\n') && (ch != '\t') && (ch != '\r')) { |
| throw new IllegalStateException("Illegal character with code " + (int) ch); |
| } |
| } |
| |
| /** |
| * Adds the argument that is used to calculate the value of this element. |
| * By default, no arguments are acceptable. |
| * |
| * @param argument the value of the element that contained in this one |
| */ |
| protected void addArgument(Object argument) { |
| throw new IllegalStateException("Could not add argument to simple element"); |
| } |
| |
| /** |
| * Tests whether the value of this element can be used |
| * as an argument of the element that contained in this one. |
| * |
| * @return {@code true} if the value of this element can be used |
| * as an argument of the element that contained in this one, |
| * {@code false} otherwise |
| */ |
| protected boolean isArgument() { |
| return this.id == null; |
| } |
| |
| /** |
| * Returns the value of this element. |
| * |
| * @return the value of this element |
| */ |
| protected abstract ValueObject getValueObject(); |
| } |