| /* |
| * Copyright 1999-2004 The Apache Software Foundation. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.cocoon.woody.formmodel; |
| |
| import org.outerj.expression.ExpressionContext; |
| |
| import java.math.BigDecimal; |
| |
| /** |
| * Implementation of the ExpressionContext required for the evaluation of |
| * expressions by xReporter expression interpreter. |
| * |
| * @version $Id: ExpressionContextImpl.java,v 1.6 2004/03/05 13:02:31 bdelacretaz Exp $ |
| */ |
| public class ExpressionContextImpl implements ExpressionContext { |
| private Widget widget; |
| private boolean referenceChildren; |
| |
| public ExpressionContextImpl(Widget widget) { |
| this.widget = widget; |
| this.referenceChildren = false; |
| } |
| |
| /** |
| * @param referenceChildren if true, variables will be resolved among the children of the given |
| * container widget, rather than among the siblings of the widget. |
| */ |
| public ExpressionContextImpl(Widget widget, boolean referenceChildren) { |
| this.widget = widget; |
| this.referenceChildren = referenceChildren; |
| } |
| |
| /** |
| * Variables refer to other widgets. |
| * |
| * <p>The current implementation only allows access to sibling widgets. |
| * |
| * <p>In case the value of a widget is null but the widget is required, then a special |
| * exception will be thrown, the {@link CannotYetResolveWarning}. This is because in |
| * that case, you'll probably want to re-evaluate the expression at a later time (since |
| * the widget is required, it will eventually get a value). |
| * |
| * <p>In case the value of the widget is null but the field is not required, then simply |
| * null is returned. (TODO: a function IsNull() will provided in the expression library |
| * so that expression writers can check for the likely condition where a non-required field |
| * is null). |
| * |
| * <p>If the variable name does not refer to an existing widget, null is returned (TODO: this |
| * behaviour will probably change in the future) |
| */ |
| public Object resolveVariable(String name) { |
| // TODO allow to access other widgets instead of only siblings (allow going up with ../ notation or something) |
| Widget widget; |
| if (!referenceChildren) |
| widget = this.widget.getParent().getWidget(name); |
| else |
| widget = this.widget.getWidget(name); |
| if (widget != null) { |
| Object value = widget.getValue(); |
| |
| if (value == null && widget.isRequired()) { |
| // the widget currently has not yet a value, but since it is required, it will get a value sooner |
| // or later. Therefore, we throw an exception here indicating that this expression can currenlty |
| // not yet be evaluated, but will be at a later time. |
| throw new CannotYetResolveWarning(); |
| } |
| |
| // do some type conversions: |
| // * the expression library only knows about BigDecimals as being numbers, so convert Longs first to BigDecimals |
| // * ... |
| if (value instanceof Long) |
| return new BigDecimal(((Long)value).longValue()); |
| else if (value instanceof Integer) |
| return new BigDecimal(((Integer)value).intValue()); |
| else |
| return value; |
| } |
| return null; |
| } |
| |
| public Object get(String s) { |
| return null; |
| } |
| |
| } |