Merge "Add bean configurator"

2 files changed, 626 insertions, 0 deletions

diff --git a/utils/src/main/java/org/onap/policy/common/utils/properties/BeanConfigurator.java b/utils/src/main/java/org/onap/policy/common/utils/properties/BeanConfigurator.java
new file mode 100644
index 00000000..9d02819a
--- /dev/null
+++ b/utils/src/main/java/org/onap/policy/common/utils/properties/BeanConfigurator.java
@@ -0,0 +1,567 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP - Common Modules
+ * ================================================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.utils.properties;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.Properties;
+import org.apache.commons.lang3.StringUtils;
+import org.onap.policy.common.utils.properties.exception.PropertyAccessException;
+import org.onap.policy.common.utils.properties.exception.PropertyException;
+import org.onap.policy.common.utils.properties.exception.PropertyInvalidException;
+import org.onap.policy.common.utils.properties.exception.PropertyMissingException;
+
+/**
+ * Configurator for beans whose fields are initialized by reading from a set of
+ * {@link Properties}, as directed by the {@link Property} annotations that appear on
+ * fields within the bean. The values of the fields are set via <i>setXxx()</i> methods.
+ * As a result, if a field is annotated and there is no corresponding <i>setXxx()</i>
+ * method, then an exception will be thrown.
+ *
+ * <p>It is possible that an invalid <i>defaultValue</i> is specified via the
+ * {@link Property} annotation. This could remain undetected until an optional property is
+ * left out of the {@link Properties}. Consequently, this class will always validate a
+ * {@link Property}'s default value, if the <i>defaultValue</i> is not empty or if
+ * <i>accept</i> includes the "empty" option.
+ */
+public class BeanConfigurator {
+
+    /**
+     * The "empty" option that may appear within the {@link Property}'s <i>accept</i>
+     * attribute.
+     */
+    public static final String ACCEPT_EMPTY = "empty";
+
+    /**
+     * Walks the class hierarchy of the bean, populating fields defined in each class,
+     * using values extracted from the given property set.
+     *
+     * @param bean bean whose fields are to be configured from the properties
+     * @param props properties from which to extract the values
+     * @throws PropertyException if an error occurs
+     */
+    public <T> T configureFromProperties(T bean, Properties props) throws PropertyException {
+        Class<?> clazz = bean.getClass();
+
+        while (clazz != Object.class) {
+            for (Field field : clazz.getDeclaredFields()) {
+                setValue(bean, field, props);
+            }
+
+            clazz = clazz.getSuperclass();
+        }
+
+        return bean;
+    }
+
+    /**
+     * Sets a field's value, within an object, based on what's in the properties.
+     *
+     * @param bean bean whose fields are to be configured from the properties
+     * @param field field whose value is to be set
+     * @param props properties from which to get the value
+     * @return {@code true} if the property's value was set, {@code false} otherwise
+     * @throws PropertyException if an error occurs
+     */
+    protected boolean setValue(Object bean, Field field, Properties props) throws PropertyException {
+        Property prop = field.getAnnotation(Property.class);
+        if (prop == null) {
+            return false;
+        }
+
+        checkModifiable(field, prop);
+
+        Method setter = getSetter(field, prop);
+        checkMethod(setter, prop);
+
+        if (setValue(bean, setter, field, props, prop)) {
+            return true;
+        }
+
+        throw new PropertyAccessException(prop.name(), field.getName(), "unsupported field type");
+    }
+
+    /**
+     * Sets a field's value from a particular property.
+     *
+     * @param bean bean whose fields are to be configured from the properties
+     * @param setter method to be used to set the field's value
+     * @param field field whose value is to be set
+     * @param props properties from which to get the value
+     * @param prop property of interest
+     * @return {@code true} if the property's value was set, {@code false} otherwise
+     * @throws PropertyException if an error occurs
+     */
+    protected boolean setValue(Object bean, Method setter, Field field, Properties props, Property prop)
+                    throws PropertyException {
+
+        try {
+            Object val = getValue(field, props, prop);
+            if (val == null) {
+                return false;
+
+            } else {
+                setter.invoke(bean, val);
+                return true;
+            }
+
+        } catch (IllegalArgumentException e) {
+            throw new PropertyInvalidException(prop.name(), field.getName(), e);
+
+        } catch (IllegalAccessException | InvocationTargetException e) {
+            throw new PropertyAccessException(prop.name(), setter.getName(), e);
+        }
+    }
+
+    /**
+     * Get the setter.
+     *
+     * @param field field whose value is to be set
+     * @param prop property of interest
+     * @return the method to be used to set the field's value
+     * @throws PropertyAccessException if a "set" method cannot be identified
+     */
+    private Method getSetter(Field field, Property prop) throws PropertyAccessException {
+        String nm = "set" + StringUtils.capitalize(field.getName());
+
+        try {
+            return field.getDeclaringClass().getMethod(nm, field.getType());
+
+        } catch (NoSuchMethodException | SecurityException e) {
+            throw new PropertyAccessException(prop.name(), nm, e);
+        }
+    }
+
+    /**
+     * Gets a property value, coercing it to the field's type.
+     *
+     * @param field field whose value is to be set
+     * @param props properties from which to get the value
+     * @param prop property of interest
+     * @return the value extracted from the property, or {@code null} if the field type is
+     *         not supported
+     * @throws PropertyException if an error occurs
+     */
+    protected Object getValue(Field field, Properties props, Property prop) throws PropertyException {
+
+        Class<?> clazz = field.getType();
+        String fieldName = field.getName();
+
+        // can still add support for short, float, double, enum
+
+        if (clazz == String.class) {
+            return getStringValue(fieldName, props, prop);
+
+        } else if (clazz == Boolean.class || clazz == boolean.class) {
+            return getBooleanValue(fieldName, props, prop);
+
+        } else if (clazz == Integer.class || clazz == int.class) {
+            return getIntegerValue(fieldName, props, prop);
+
+        } else if (clazz == Long.class || clazz == long.class) {
+            return getLongValue(fieldName, props, prop);
+
+        } else {
+            return null;
+        }
+    }
+
+    /**
+     * Verifies that the field can be modified, i.e., it's neither <i>static</i>, nor
+     * <i>final</i>.
+     *
+     * @param field field whose value is to be set
+     * @param prop property of interest
+     * @throws PropertyAccessException if the field is not modifiable
+     */
+    protected void checkModifiable(Field field, Property prop) throws PropertyAccessException {
+        int mod = field.getModifiers();
+
+        if (Modifier.isStatic(mod)) {
+            throw new PropertyAccessException(prop.name(), field.getName(), "'static' variable cannot be modified");
+        }
+
+        if (Modifier.isFinal(mod)) {
+            throw new PropertyAccessException(prop.name(), field.getName(), "'final' variable cannot be modified");
+        }
+    }
+
+    /**
+     * Verifies that the method is not <i>static</i>.
+     *
+     * @param method method to be checked
+     * @param prop property of interest
+     * @throws PropertyAccessException if the method is static
+     */
+    private void checkMethod(Method method, Property prop) throws PropertyAccessException {
+        int mod = method.getModifiers();
+
+        if (Modifier.isStatic(mod)) {
+            throw new PropertyAccessException(prop.name(), method.getName(), "method is 'static'");
+        }
+    }
+
+    /**
+     * Gets a property value, coercing it to a String.
+     *
+     * @param fieldName field whose value is to be set
+     * @param props properties from which to get the value
+     * @param prop property of interest
+     * @return the value extracted from the property
+     * @throws PropertyException if an error occurs
+     */
+    protected String getStringValue(String fieldName, Properties props, Property prop) throws PropertyException {
+
+        /*
+         * Note: the default value for a String type is always valid, thus no need to
+         * check it.
+         */
+
+        return getPropValue(fieldName, props, prop);
+    }
+
+    /**
+     * Gets a property value, coercing it to a Boolean.
+     *
+     * @param fieldName field whose value is to be set
+     * @param props properties from which to get the value
+     * @param prop property of interest
+     * @return the value extracted from the property
+     * @throws PropertyException if an error occurs
+     */
+    protected Boolean getBooleanValue(String fieldName, Properties props, Property prop) throws PropertyException {
+        // validate the default value
+        checkDefaultValue(fieldName, prop, () -> makeBoolean(fieldName, prop, prop.defaultValue()));
+
+        return makeBoolean(fieldName, prop, getPropValue(fieldName, props, prop));
+    }
+
+    /**
+     * Gets a property value, coercing it to an Integer.
+     *
+     * @param fieldName field whose value is to be set
+     * @param props properties from which to get the value
+     * @param prop property of interest
+     * @return the value extracted from the property
+     * @throws PropertyException if an error occurs
+     */
+    protected Integer getIntegerValue(String fieldName, Properties props, Property prop) throws PropertyException {
+        // validate the default value
+        checkDefaultValue(fieldName, prop, () -> makeInteger(fieldName, prop, prop.defaultValue()));
+
+        return makeInteger(fieldName, prop, getPropValue(fieldName, props, prop));
+    }
+
+    /**
+     * Gets a property value, coercing it to a Long.
+     *
+     * @param fieldName field whose value is to be set
+     * @param props properties from which to get the value
+     * @param prop property of interest
+     * @return the value extracted from the property
+     * @throws PropertyException if an error occurs
+     */
+    protected Long getLongValue(String fieldName, Properties props, Property prop) throws PropertyException {
+        // validate the default value
+        checkDefaultValue(fieldName, prop, () -> makeLong(fieldName, prop, prop.defaultValue()));
+
+        return makeLong(fieldName, prop, getPropValue(fieldName, props, prop));
+    }
+
+    /**
+     * Gets a value from the property set.
+     *
+     * @param fieldName field whose value is to be set
+     * @param props properties from which to get the value
+     * @param prop property of interest
+     * @return the value extracted from the property, or the <i>defaultValue</i> if the
+     *         value does not exist
+     * @throws PropertyMissingException if the property does not exist and the
+     *         <i>defaultValue</i> is empty and <i>emptyOk</i> is {@code false}
+     */
+    protected String getPropValue(String fieldName, Properties props, Property prop) throws PropertyMissingException {
+        String propnm = prop.name();
+
+        String val = props.getProperty(propnm);
+        if (val != null && isEmptyOk(prop, val)) {
+            return val;
+        }
+
+        val = prop.defaultValue();
+        if (val != null && isEmptyOk(prop, val)) {
+            return val;
+        }
+
+        throw new PropertyMissingException(prop.name(), fieldName);
+    }
+
+    /**
+     * Coerces a String value into a Boolean.
+     *
+     * @param fieldName field whose value is to be set
+     * @param prop property of interest
+     * @param value value to be coerced
+     * @return the Boolean value represented by the String value
+     * @throws PropertyInvalidException if the value does not represent a valid Boolean
+     */
+    private Boolean makeBoolean(String fieldName, Property prop, String value) throws PropertyInvalidException {
+        if ("true".equalsIgnoreCase(value)) {
+            return Boolean.TRUE;
+
+        } else if ("false".equalsIgnoreCase(value)) {
+            return Boolean.FALSE;
+
+        } else {
+            throw new PropertyInvalidException(prop.name(), fieldName, "expecting 'true' or 'false'");
+        }
+    }
+
+    /**
+     * Coerces a String value into an Integer.
+     *
+     * @param fieldName field whose value is to be set
+     * @param prop property of interest
+     * @param value value to be coerced
+     * @return the Integer value represented by the String value
+     * @throws PropertyInvalidException if the value does not represent a valid Integer
+     */
+    private Integer makeInteger(String fieldName, Property prop, String value) throws PropertyInvalidException {
+        try {
+            return Integer.valueOf(value);
+
+        } catch (NumberFormatException e) {
+            throw new PropertyInvalidException(prop.name(), fieldName, e);
+        }
+    }
+
+    /**
+     * Coerces a String value into a Long.
+     *
+     * @param fieldName field whose value is to be set
+     * @param prop property of interest
+     * @param value value to be coerced
+     * @return the Long value represented by the String value
+     * @throws PropertyInvalidException if the value does not represent a valid Long
+     */
+    private Long makeLong(String fieldName, Property prop, String value) throws PropertyInvalidException {
+        try {
+            return Long.valueOf(value);
+
+        } catch (NumberFormatException e) {
+            throw new PropertyInvalidException(prop.name(), fieldName, e);
+        }
+    }
+
+    /**
+     * Applies a function to check a property's default value. If the function throws an
+     * exception about an invalid property, then it's re-thrown as an exception about an
+     * invalid <i>defaultValue</i>.
+     *
+     * @param fieldName name of the field being checked
+     * @param prop property of interest
+     * @param func function to invoke to check the default value
+     */
+    private void checkDefaultValue(String fieldName, Property prop, CheckDefaultValueFunction func)
+                    throws PropertyInvalidException {
+
+        if (isEmptyOk(prop, prop.defaultValue())) {
+            try {
+                func.apply();
+
+            } catch (PropertyInvalidException ex) {
+                throw new PropertyInvalidException(ex.getPropertyName(), fieldName, "defaultValue is invalid", ex);
+            }
+        }
+    }
+
+    /**
+     * Determines if a value is OK, even if it's empty.
+     *
+     * @param prop property specifying what's acceptable
+     * @param value value to be checked
+     * @return {@code true} if the value is not empty or empty is allowed, {@code false}
+     *         otherwise
+     */
+    protected boolean isEmptyOk(Property prop, String value) {
+        return !value.isEmpty() || isEmptyOk(prop);
+    }
+
+    /**
+     * Determines if a {@link Property}'s <i>accept</i> attribute includes the "empty"
+     * option.
+     *
+     * @param prop property whose <i>accept</i> attribute is to be examined
+     * @return {@code true} if the <i>accept</i> attribute includes "empty"
+     */
+    protected boolean isEmptyOk(Property prop) {
+        for (String option : prop.accept().split(",")) {
+            if (ACCEPT_EMPTY.equals(option)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Copies the field values to a set of properties.
+     *
+     * @param bean bean whose fields are to be exported to the properties
+     * @param props properties into which the values should be added
+     * @param origPrefix prefix of the property names as they appear within the Property
+     *        annotations
+     * @param finalPrefix prefix to use instead, when adding to the set of properties
+     * @throws PropertyException if an error occurs
+     */
+    public void addToProperties(Object bean, Properties props, String origPrefix, String finalPrefix)
+                    throws PropertyException {
+
+        Class<?> clazz = bean.getClass();
+
+        String dottedOrig = (origPrefix.isEmpty() || origPrefix.endsWith(".") ? origPrefix : origPrefix + ".");
+        String dottedFinal = (finalPrefix.isEmpty() || finalPrefix.endsWith(".") ? finalPrefix : finalPrefix + ".");
+
+        while (clazz != Object.class) {
+            for (Field field : clazz.getDeclaredFields()) {
+                putProperty(bean, field, props, dottedOrig, dottedFinal);
+            }
+
+            clazz = clazz.getSuperclass();
+        }
+    }
+
+    /**
+     * Copies the field values to a set of properties.
+     *
+     * @param bean bean whose fields are to be exported to the properties
+     * @param field field whose value is to be copied
+     * @param props properties into which the values should be added
+     * @param origPrefix prefix of the property names as they appear within the Property
+     *        annotations. Includes a trailing "." (if non-empty)
+     * @param finalPrefix prefix to use instead, when adding to the set of properties.
+     *        Includes a trailing "." (if non-empty)
+     * @throws PropertyAccessException if an error occurs
+     */
+    private void putProperty(Object bean, Field field, Properties props, String origPrefix, String finalPrefix)
+                    throws PropertyAccessException {
+
+        Property prop = field.getAnnotation(Property.class);
+        if (prop == null) {
+            return;
+        }
+
+        Method getter = getGetter(field, prop);
+        checkMethod(getter, prop);
+
+        Object value = getBeanValue(bean, field, getter, prop);
+        if (value == null) {
+            return;
+        }
+
+        String name = prop.name();
+        if (name.startsWith(origPrefix)) {
+            name = finalPrefix + name.substring(origPrefix.length());
+        }
+
+        props.setProperty(name, value.toString());
+    }
+
+    /**
+     * Get the getter.
+     *
+     * @param field field whose value is to be gotten
+     * @param prop property of interest
+     * @return the method to be used to get the field's value
+     * @throws PropertyAccessException if a "get" method cannot be identified
+     */
+    private Method getGetter(Field field, Property prop) throws PropertyAccessException {
+        String capnm = StringUtils.capitalize(field.getName());
+
+        try {
+            return getGetter(field, "get" + capnm);
+
+        } catch (NoSuchMethodException e) {
+            if (field.getType() == Boolean.class || field.getType() == boolean.class) {
+                // boolean - check for "isXxx" method, too
+                try {
+                    return getGetter(field, "is" + capnm);
+
+                } catch (NoSuchMethodException | SecurityException e2) {
+                    throw new PropertyAccessException(prop.name(), "is" + capnm, e2);
+                }
+            }
+
+            throw new PropertyAccessException(prop.name(), "get" + capnm, e);
+
+        } catch (SecurityException e) {
+            // problem with "get" method
+            throw new PropertyAccessException(prop.name(), "get" + capnm, e);
+        }
+    }
+
+    /**
+     * Get the getter.  This may be overridden by junit tests.
+     *
+     * @param field field whose value is to be gotten
+     * @param methodName name of the method to return
+     * @return the method to be used to get the field's value
+     * @throws NoSuchMethodException if the method does not exist
+     * @throws SecurityException if the method cannot be accessed
+     */
+    protected Method getGetter(Field field, String methodName) throws NoSuchMethodException, SecurityException {
+        return field.getDeclaringClass().getMethod(methodName);
+    }
+
+    /**
+     * Gets a field's value for a particular property.
+     *
+     * @param bean bean whose fields are to be configured from the properties
+     * @param getter method to be used to get the field's value
+     * @param field field whose value is to be gotten
+     * @param prop property of interest
+     * @throws PropertyAccessException if an error occurs
+     */
+    private Object getBeanValue(Object bean, Field field, Method getter, Property prop)
+                    throws PropertyAccessException {
+        try {
+            return getter.invoke(bean);
+
+        } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
+            throw new PropertyAccessException(prop.name(), field.getName(), e);
+        }
+    }
+
+    /**
+     * Functions to check a default value.
+     */
+    @FunctionalInterface
+    private static interface CheckDefaultValueFunction {
+
+        /**
+         * Checks the default value.
+         *
+         * @throws PropertyInvalidException if an error occurs
+         */
+        public void apply() throws PropertyInvalidException;
+    }
+}
diff --git a/utils/src/main/java/org/onap/policy/common/utils/properties/Property.java b/utils/src/main/java/org/onap/policy/common/utils/properties/Property.java
new file mode 100644
index 00000000..bacedef9
--- /dev/null
+++ b/utils/src/main/java/org/onap/policy/common/utils/properties/Property.java
@@ -0,0 +1,59 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.utils.properties;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.util.Properties;
+
+
+/**
+ * Annotation that declares a variable to be configured via {@link Properties}.
+ */
+@Target(ElementType.FIELD)
+@Retention(RetentionPolicy.RUNTIME)
+
+public @interface Property {
+
+    /**
+     * Name of the property.
+     *
+     * @return the property name
+     */
+    public String name();
+
+    /**
+     * Default value, used when the property does not exist.
+     *
+     * @return the default value
+     */
+    public String defaultValue() default "";
+
+    /**
+     * Comma-separated options identifying what's acceptable. The word, "empty",
+     * indicates that an empty string, "", is an acceptable value.
+     *
+     * @return options identifying what's acceptable
+     */
+    public String accept() default "";
+}