001: /*
002: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
003: *
004: * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
005: *
006: * The contents of this file are subject to the terms of either the GNU
007: * General Public License Version 2 only ("GPL") or the Common
008: * Development and Distribution License("CDDL") (collectively, the
009: * "License"). You may not use this file except in compliance with the
010: * License. You can obtain a copy of the License at
011: * http://www.netbeans.org/cddl-gplv2.html
012: * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
013: * specific language governing permissions and limitations under the
014: * License. When distributing the software, include this License Header
015: * Notice in each file and include the License file at
016: * nbbuild/licenses/CDDL-GPL-2-CP. Sun designates this
017: * particular file as subject to the "Classpath" exception as provided
018: * by Sun in the GPL Version 2 section of the License file that
019: * accompanied this code. If applicable, add the following below the
020: * License Header, with the fields enclosed by brackets [] replaced by
021: * your own identifying information:
022: * "Portions Copyrighted [year] [name of copyright owner]"
023: *
024: * Contributor(s):
025: *
026: * The Original Software is NetBeans. The Initial Developer of the Original
027: * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
028: * Microsystems, Inc. All Rights Reserved.
029: *
030: * If you wish your version of this file to be governed by only the CDDL
031: * or only the GPL Version 2, indicate your decision by adding
032: * "[Contributor] elects to include this software in this distribution
033: * under the [CDDL or GPL Version 2] license." If you do not indicate a
034: * single choice of license, a recipient has the option to distribute
035: * your version of this file under either the CDDL, the GPL Version 2 or
036: * to extend the choice of license to its licensees as provided above.
037: * However, if you add GPL Version 2 code and therefore, elected the GPL
038: * Version 2 license, then the option applies only if the new code is
039: * made subject to such option by the copyright holder.
040: */
041:
042: package org.openide.util;
043:
044: /**
045: * Utilities for checking the values of method parameters.
046: *
047: * Methods in this class generally take the name of
048: * the parameter to check and its value and throw exceptions
049: * with messages according to the method name or just return. For example,
050: * if you have a <code>myMethod()</code> method taking a <code>myParam</code>
051: * parameter whose value must be a Java identifier, you usually check that
052: * by doing:
053: *
054: * <pre>
055: * public void myMethod(String myParam) {
056: * if (!Utilities.isJavaIdentifier(myParam)) {
057: * throw new IllegalArgumentException("The myParam parameter is not a valid Java identifier");
058: * }
059: * }
060: * </pre>
061: *
062: * Using this class you can do the same in a simpler way:
063: *
064: * <pre>
065: * public void myMethod(String myParam) {
066: * Parameters.javaIdentifier("myParam", myParam);
067: * }
068: * </pre>
069: *
070: * @author Andrei Badea
071: * @since org.openide.util 7.6
072: */
073: public class Parameters {
074:
075: private Parameters() {
076: }
077:
078: /**
079: * Asserts the parameter value is not <code>null</code>.
080: *
081: * @param name the parameter name.
082: * @param value the parameter value.
083: * @throws NullPointerException if the parameter value is <code>null</code>.
084: */
085: public static void notNull(CharSequence name, Object value) {
086: if (value == null) {
087: throw new NullPointerException("The " + name
088: + " parameter cannot be null"); // NOI18N
089: }
090: }
091:
092: /**
093: * Asserts the parameter value is neither <code>null</code> nor an empty
094: * character sequence.
095: *
096: * @param name the parameter name.
097: * @param value the parameter value.
098: * @throws NullPointerException if the parameter value is <code>null</code>.
099: * @throws IllegalArgumentException if the parameter value is an empty
100: * character sequence.
101: */
102: public static void notEmpty(CharSequence name, CharSequence value) {
103: notNull(name, value);
104: if (value.length() == 0) {
105: throw new IllegalArgumentException(
106: "The "
107: + name
108: + " parameter cannot be an empty character sequence"); // NOI18N
109: }
110: }
111:
112: /**
113: * Asserts the parameter value is not <code>null</code> and it contains
114: * at least one non-whitespace character. Whitespace is defined as by
115: * {@link String#trim}.
116: *
117: * @param name the parameter name.
118: * @param value the parameter value.
119: * @throws NullPointerException if the parameter value is <code>null</code>.
120: * @throws IllegalArgumentException if the parameter value does not
121: * contain at least one non-whitespace character.
122: */
123: public static void notWhitespace(CharSequence name,
124: CharSequence value) {
125: notNull(name, value);
126: if (value.toString().trim().length() == 0) {
127: throw new IllegalArgumentException(
128: "The "
129: + name
130: + " parameter must contain at least one non-whitespace character"); // NOI18N
131: }
132: }
133:
134: /**
135: * Asserts the parameter value is not <code>null</code> and it is
136: * a Java identifier.
137: *
138: * @param name the parameter name.
139: * @param value the parameter value.
140: * @throws NullPointerException if the parameter value is <code>null</code>.
141: * @throws IllegalArgumentException if the parameter value is not
142: * a Java identifier.
143: */
144: public static void javaIdentifier(CharSequence name,
145: CharSequence value) {
146: notNull(name, value);
147: javaIdentifierOrNull(name, value);
148: }
149:
150: /**
151: * Asserts the parameter value is either <code>null</code> or a Java
152: * identifier.
153: *
154: * @param name the parameter name.
155: * @param value the parameter value.
156: * @throws IllegalArgumentException if the parameter value is neither
157: * <code>null</code> nor a Java identifier.
158: */
159: public static void javaIdentifierOrNull(CharSequence name,
160: CharSequence value) {
161: if (value != null
162: && !Utilities.isJavaIdentifier(value.toString())) {
163: throw new IllegalArgumentException("The " + name
164: + " parameter ('" + value
165: + "') is not a valid Java identifier"); // NOI18N
166: }
167: }
168: }
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