/libformula-1.1.3/source/org/pentaho/reporting/libraries/formula/FormulaContext.java

 1/*
 2 * This program is free software; you can redistribute it and/or modify it under the
 3 * terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
 4 * Foundation.
 5 *
 6 * You should have received a copy of the GNU Lesser General Public License along with this
 7 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
 8 * or from the Free Software Foundation, Inc.,
 9 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
10 *
11 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
12 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
13 * See the GNU Lesser General Public License for more details.
14 *
15 * Copyright (c) 2006 - 2009 Pentaho Corporation and Contributors.  All rights reserved.
16 */
17
18package org.pentaho.reporting.libraries.formula;
19
20import org.pentaho.reporting.libraries.formula.function.FunctionRegistry;
21import org.pentaho.reporting.libraries.formula.operators.OperatorFactory;
22import org.pentaho.reporting.libraries.formula.typing.Type;
23import org.pentaho.reporting.libraries.formula.typing.TypeRegistry;
24import org.pentaho.reporting.libraries.base.config.Configuration;
25
26/**
27 * The formula-context connects the formula functions with the outside world. The context can be used to resolve
28 * external references, to query the configuration or to retrieve information about the formula-evaluation system.
29 *
30 * @author Thomas Morgner
31 */
32public interface FormulaContext
33{
34  /**
35   * Checks whether the external object referenced by <code>name</code> has changed.
36   *
37   * @param name the name that identifies the reference.
38   * @return true, if the reference has changed, false otherwise.
39   * @throws ContextEvaluationException if an error occurs.
40   */
41  public boolean isReferenceDirty(Object name) throws ContextEvaluationException;
42
43  /**
44   * Resolves the given reference. How the name is interpreted by the outside system is an implementation detail.
45   *
46   * @param name the name that identifies the reference.
47   * @return the resolved object.
48   * @throws ContextEvaluationException if an error occurs.
49   */
50  public Object resolveReference(Object name) throws ContextEvaluationException;
51
52  /**
53   * Queries the type of the given reference. How the name is interpreted by the outside system is an implementation
54   * detail. This return a LibFormula type object matching the type of the object that would be returned by
55   * resolveReference.
56   *
57   * @param name the name that identifies the reference.
58   * @return the type of the resolved object.
59   * @throws ContextEvaluationException if an error occurs.
60   */
61  public Type resolveReferenceType(Object name) throws ContextEvaluationException;
62
63  /**
64   * Returns the localization context of this formula. The localization context can be used to query locale specific
65   * configuration settings.
66   *
67   * @return the localization context.
68   */
69  public LocalizationContext getLocalizationContext();
70
71  /**
72   * Returns the local configuration of the formula.
73   *
74   * @return the local configuration.
75   */
76  public Configuration getConfiguration();
77
78  /**
79   * Returns the function registry. The function registry grants access to all formula-function implementations.
80   *
81   * @return the function registry.
82   */
83  public FunctionRegistry getFunctionRegistry();
84
85  /**
86   * Returns the type registry. The type registry contains all type information and allows to convert values between
87   * different types.
88   *
89   * @return the function registry.
90   */
91  public TypeRegistry getTypeRegistry();
92
93  /**
94   * Returns the operator registry. The Operator-registry contains all operator-implementations.
95   *
96   * @return the operator registry.
97   */
98  public OperatorFactory getOperatorFactory();
99}