Assertion class for DAO code

This class is used by the DAO model code being moved from
the APEX PDP to policy-models for generic DAO handling in the
Policy Framework

Issue-ID: POLICY-1264
Change-Id: I67cca540d9357f9ab16532090cb2edf397b332be
Signed-off-by: liamfallon <liam.fallon@est.tech>

1 files changed, 190 insertions, 0 deletions

diff --git a/utils/src/main/java/org/onap/policy/common/utils/validation/Assertions.java b/utils/src/main/java/org/onap/policy/common/utils/validation/Assertions.java
new file mode 100644
index 00000000..19a25295
--- /dev/null
+++ b/utils/src/main/java/org/onap/policy/common/utils/validation/Assertions.java
@@ -0,0 +1,190 @@
+/*
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2016-2018 Ericsson. All rights reserved.
+ *  Modifications Copyright (C) 2019 Nordix 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.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.utils.validation;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * The Class Assertions is a static class that is used as a shorthand for assertions in the source code.
+ * It throws runtime exceptions on assertion fails.
+ */
+public final class Assertions {
+    // Logger for this class
+    private static final Logger LOGGER = LoggerFactory.getLogger(Assertions.class);
+
+    /**
+     * Private constructor used to prevent sub class instantiation.
+     */
+    private Assertions() {
+    }
+
+    /**
+     * Gets the validation message for a string parameter.
+     *
+     * @param parameterName the string parameter name
+     * @param parameterValue the string parameter value
+     * @param pattern The regular expression
+     * @return null if the parameter is valid, the validation message otherwise
+     */
+    public static String getStringParameterValidationMessage(final String parameterName, final String parameterValue,
+                    final String pattern) {
+        try {
+            validateStringParameter(parameterName, parameterValue, pattern);
+        } catch (IllegalArgumentException e) {
+            String message = "parameter " + parameterName + " with value " + parameterValue
+                            + " does not match regular expression " + pattern;
+            if (LOGGER.isTraceEnabled()) {
+                LOGGER.trace(message, e);
+            }
+
+            return message;
+        }
+
+        return null;
+    }
+
+    /**
+     * Checks if a string parameter matches a regular expression.
+     *
+     * @param parameterName the string parameter name
+     * @param parameterValue the string parameter value
+     * @param pattern The regular expression
+     * @return the trimmed string
+     */
+    public static String validateStringParameter(final String parameterName, final String parameterValue,
+                    final String pattern) {
+        argumentNotNull(parameterName, "parameter name is null");
+        argumentNotNull(parameterValue, "parameter \"" + parameterName + "\" is null");
+        argumentNotNull(pattern, "parameter pattern is null");
+
+        final String trimmedValue = parameterValue.trim();
+        if (trimmedValue.matches(pattern)) {
+            return trimmedValue;
+        } else {
+            throw new IllegalArgumentException("parameter \"" + parameterName + "\": value \"" + parameterValue
+                            + "\", does not match regular expression \"" + pattern + "\"");
+        }
+    }
+
+    /**
+     * Used as a shorthand to check that method arguments are not null, throws IllegalArgumentException on error.
+     *
+     * @param <T> the generic type of the argument to check
+     * @param value the value of the type
+     * @param message the error message to issue
+     */
+    public static <T> void argumentNotNull(final T value, final String message) {
+        if (value == null) {
+            throw new IllegalArgumentException(message);
+        }
+    }
+
+    /**
+     * Used as a shorthand to check that method arguments are not false, throws IllegalArgumentException on error.
+     *
+     * @param value the value to check if false
+     * @param message the error message to issue
+     */
+    public static void argumentNotFalse(final boolean value, final String message) {
+        if (!value) {
+            throw new IllegalArgumentException(message);
+        }
+    }
+
+    /**
+     * Used as a shorthand to check that method arguments are not null, throws an exception of the specified type on
+     * error.
+     *
+     * @param <T> the generic type of the argument to check
+     * @param <E> the exception to throw if incoming value is null
+     * @param value the value of the type
+     * @param exceptionClass the class of exception to return an instance of
+     * @param message the error message to issue
+     * @throws E an instance of the passed Exception Class
+     */
+    public static <T, E extends Exception> void argumentOfClassNotNull(final T value, final Class<E> exceptionClass,
+                    final String message) throws E {
+        if (value == null) {
+            // Instantiate the exception and throw it
+            try {
+                throw exceptionClass.getConstructor(String.class).newInstance(message);
+            } catch (final Exception errorException) {
+                throw new IllegalArgumentException(message, errorException);
+            }
+        }
+    }
+
+    /**
+     * Used as a shorthand to check that method argument is not false, throws an exception of the specified type on
+     * error.
+     *
+     * @param <E> the exception to throw if incoming value is false
+     * @param value the value to check if false
+     * @param exceptionClass the class of exception to return an instance of
+     * @param message the error message to issue
+     * @throws E an instance of the passed Exception Class
+     */
+    public static <E extends Exception> void argumentOfClassNotFalse(final boolean value, final Class<E> exceptionClass,
+                    final String message) throws E {
+        if (!value) {
+            // Instantiate the exception and throw it
+            try {
+                throw exceptionClass.getConstructor(String.class).newInstance(message);
+            } catch (final Exception errorException) {
+                throw new IllegalArgumentException(message, errorException);
+            }
+        }
+    }
+
+    /**
+     * Used as a shorthand to check that an object is an instance of a given class, throws IllegalArgumentException on
+     * error.
+     *
+     * @param <T> the generic type of the argument to check
+     * @param objectInstance the object instance for which to check the class
+     * @param requiredClass the class that the object should be an instance of
+     * @throws IllegalArgumentException if the incoming object is not an instance of requiredClass
+     */
+    public static <T> void instanceOf(final Object objectInstance, final Class<T> requiredClass) {
+        if (!requiredClass.isAssignableFrom(objectInstance.getClass())) {
+            throw new IllegalArgumentException(objectInstance.getClass().getCanonicalName() + " is not an instance of "
+                            + requiredClass.getCanonicalName());
+        }
+    }
+
+    /**
+     * Used as a shorthand to check that an instance of a class can be an instance of a given class, throws
+     * IllegalArgumentException on error.
+     *
+     * @param <T> the generic type of the argument to check
+     * @param checkClass the class to check
+     * @param requiredClass the class that the object should be an instance of
+     * @throws IllegalArgumentException if the incoming object is not an instance of requiredClass
+     */
+    public static <T> void assignableFrom(final Class<?> checkClass, final Class<T> requiredClass) {
+        if (!requiredClass.isAssignableFrom(checkClass)) {
+            throw new IllegalArgumentException(checkClass.getCanonicalName() + " is not an instance of "
+                            + requiredClass.getCanonicalName());
+        }
+    }
+}