001 package edu.nrao.sss.validation;
002
003 import java.util.ArrayList;
004 import java.util.HashMap;
005 import java.util.List;
006 import java.util.Map;
007
008 /**
009 * Partial implementation of a {@link Validator}.
010 * <p>
011 * <b>Version Info:</b>
012 * <table style="margin-left:2em">
013 * <tr><td>$Revision: 1511 $</td></tr>
014 * <tr><td>$Date: 2008-08-19 11:43:17 -0600 (Tue, 19 Aug 2008) $</td></tr>
015 * <tr><td>$Author: dharland $</td></tr>
016 * </table></p>
017 *
018 * @author David M. Harland
019 * @since 2007-02-05
020 */
021 public abstract class AbstractValidator<T>
022 implements Validator
023 {
024 private String name;
025 private Class<? extends T> expectedClass;
026
027 private Map<ValidationPurpose, List<Validation<T>>> validationMap;
028
029 /**
030 * The object most recently subject to validation by this validator.
031 * This variable is initially null.
032 */
033 protected T target;
034
035 /**
036 * The purpose for which this validator was most recently run.
037 * This variable is initially ValidationPurpose.CERTIFY_READY_TO_USE.
038 */
039 protected ValidationPurpose purpose;
040
041 /**
042 * List of all validation failures.
043 * This list is never null, but may be empty.
044 */
045 protected List<ValidationFailure> failures;
046
047 /**
048 * The manager for which this validator is performing its duties.
049 * This variable is initially null.
050 */
051 protected ValidationManager manager;
052
053 /**
054 * When true, validate() stops running tests after first failure.
055 * This variable is initially false.
056 */
057 protected boolean failFast;
058
059 /** Helps create a new instance. */
060 protected AbstractValidator(String validatorName, Class<? extends T> targetClass)
061 {
062 //TODO null handling?
063
064 name = validatorName;
065 expectedClass = targetClass;
066
067 target = null;
068 purpose = ValidationPurpose.CERTIFY_READY_TO_USE;
069 failFast = false;
070 failures = new ArrayList<ValidationFailure>();
071 manager = null;
072
073 validationMap = new HashMap<ValidationPurpose, List<Validation<T>>>();
074 }
075
076 //============================================================================
077 // IMPLEMENTATION OF INTERFACE Validator
078 //============================================================================
079
080 /* (non-Javadoc)
081 * @see edu.nrao.sss.validation.Validator#getName()
082 */
083 public String getName() { return name; }
084
085 /* (non-Javadoc)
086 * @see edu.nrao.sss.validation.Validator#getTarget()
087 */
088 public T getTarget() { return target; }
089
090 /* (non-Javadoc)
091 * @see edu.nrao.sss.validation.Validator#getPurpose()
092 */
093 public ValidationPurpose getPurpose() { return purpose; }
094
095 /* (non-Javadoc)
096 * @see edu.nrao.sss.validation.Validator#setManager(ValidationManager)
097 */
098 public void setManager(ValidationManager newManager)
099 {
100 manager = newManager;
101 }
102
103 /**
104 * Tells this validator whether it should run all validations or stop
105 * after the first validation that fails. The concrete implementations
106 * of this abstract are free to override this default implementation,
107 * whic is to run all validations.
108 *
109 * @param stop if <i>true</i> this validator will stop running its
110 * validations after the first one fails.
111 */
112 public void stopTestingAfterFirstFailure(boolean stop)
113 {
114 failFast = stop;
115 }
116
117
118 /* (non-Javadoc)
119 * @see Validator#validate(Object, ValidationPurpose)
120 */
121 @SuppressWarnings("unchecked")
122 public List<ValidationFailure> validate(Object target,
123 ValidationPurpose purpose)
124 {
125 failures.clear();
126
127 if (expectedClass.isInstance(target))
128 {
129 this.target = (T)target;
130 this.purpose = purpose;
131
132 validate();
133 }
134 else //target is wrong class
135 {
136 failures.add(ValidationFailure.wrongObjectType(name, target,
137 expectedClass.getName()));
138 }
139
140 return failures;
141 }
142
143 //============================================================================
144 //
145 //============================================================================
146
147 /**
148 * Runs each of the individual validations.
149 * <p>
150 * Subclasses may use this default implementation or override it.
151 * Subclasses that contain collections of component objects will typically
152 * override this method, call {@code super.validate()}, and then invoke
153 * other validators on the elements of the collections.</p>
154 */
155 protected void validate()
156 {
157 if (failFast)
158 validateUntilFailure();
159 else
160 validateAll();
161 }
162
163 /** Runs all validations. */
164 private void validateAll()
165 {
166 for (Validation<T> test : getValidations())
167 test.run(failures);
168 }
169
170 /** Runs validations until one fails. */
171 private void validateUntilFailure()
172 {
173 for (Validation<T> test : getValidations())
174 if (!test.run(failures))
175 break;
176 }
177
178 /**
179 * Returns the list of validations to be used for this validator's
180 * current purpose.
181 *
182 * @return the list of validations for the current purpose.
183 */
184 private List<Validation<T>> getValidations()
185 {
186 List<Validation<T>> validations = validationMap.get(purpose);
187
188 //Just-in-time creation
189 if (validations == null)
190 {
191 validations = makeValidationList(purpose);
192 validationMap.put(purpose, validations);
193 }
194
195 return validations;
196 }
197
198 //============================================================================
199 // OBLIGATIONS OF SUBCLASSES
200 //============================================================================
201
202 /**
203 * Creates and returns a list of validations to be performed for the given
204 * {@code purpose}.
205 *
206 * @param purpose the reason for which a validation is performed.
207 *
208 * @return a list of validations to be used for {@code purpose}.
209 */
210 abstract
211 protected List<Validation<T>> makeValidationList(ValidationPurpose purpose);
212 }