Add rule for "const": generate Java constants

jsonschema2pojo-core/src/main/java/org/jsonschema2pojo/rules/ConstRule.java

@@ -0,0 +1,152 @@
+/**
+ * Copyright © 2010-2020 Nokia
+ *
+ * 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.
+ */
+
+package org.jsonschema2pojo.rules;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.util.StdDateFormat;
+import com.sun.codemodel.JDefinedClass;
+import com.sun.codemodel.JExpr;
+import com.sun.codemodel.JExpression;
+import com.sun.codemodel.JFieldVar;
+import com.sun.codemodel.JInvocation;
+import com.sun.codemodel.JMod;
+import com.sun.codemodel.JType;
+import org.joda.time.DateTime;
+import org.joda.time.LocalDate;
+import org.joda.time.LocalTime;
+import org.jsonschema2pojo.Schema;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.net.URI;
+import java.text.ParseException;
+import java.util.Date;
+import java.util.Objects;
+
+import static org.apache.commons.lang3.StringUtils.isNotEmpty;
+import static org.apache.commons.lang3.StringUtils.joinWith;
+import static org.apache.commons.lang3.StringUtils.splitByCharacterTypeCamelCase;
+
+public class ConstRule implements Rule<JFieldVar, JFieldVar> {
+
+    private final RuleFactory ruleFactory;
+    private final JDefinedClass jclass;
+
+    public ConstRule(RuleFactory ruleFactory, JDefinedClass jclass) {
+        this.ruleFactory = ruleFactory;
+        this.jclass = jclass;
+    }
+
+    @Override
+    public JFieldVar apply(String nodeName, JsonNode node, JsonNode parent, JFieldVar field, Schema currentSchema) {
+        boolean constPresent = node != null && isNotEmpty(node.asText());
+        JType propertyType = field.type();
+
+        if (!constPresent) {
+            return field;
+        }
+
+        String constName = joinWith("_", splitByCharacterTypeCamelCase(nodeName)).toUpperCase();
+        JFieldVar myConstant = jclass.field(JMod.PUBLIC | JMod.STATIC | JMod.FINAL,
+                                            propertyType,
+                                            constName,
+                                            getValue(propertyType, node));
+
+        return field;
+    }
+
+    static JExpression getValue(JType type, JsonNode node) {
+        Objects.requireNonNull(node);
+        String fieldType = type.fullName();
+        if (fieldType.startsWith(String.class.getName())) {
+            return getConstValue(type, node);
+        } else {
+            return getConstValue(type, node);
+        }
+    }
+
+    static JExpression getConstValue(JType fieldType, JsonNode node) {
+        return getConstValue(fieldType, node.asText());
+    }
+
+    static JExpression getConstValue(JType fieldType, String value) {
+
+        fieldType = fieldType.unboxify();
+
+        if (fieldType.fullName().equals(String.class.getName())) {
+            return JExpr.lit(value);
+
+        } else if (fieldType.fullName().equals(int.class.getName())) {
+            return JExpr.lit(Integer.parseInt(value));
+
+        } else if (fieldType.fullName().equals(BigInteger.class.getName())) {
+            return JExpr._new(fieldType).arg(JExpr.lit(value));
+
+        } else if (fieldType.fullName().equals(double.class.getName())) {
+            return JExpr.lit(Double.parseDouble(value));
+
+        } else if (fieldType.fullName().equals(BigDecimal.class.getName())) {
+            return JExpr._new(fieldType).arg(JExpr.lit(value));
+
+        } else if (fieldType.fullName().equals(boolean.class.getName())) {
+            return JExpr.lit(Boolean.parseBoolean(value));
+
+        } else if (fieldType.fullName().equals(DateTime.class.getName()) || fieldType.fullName().equals(Date.class.getName())) {
+            long millisecs = parseDateToMillisecs(value);
+
+            JInvocation newDateTime = JExpr._new(fieldType);
+            newDateTime.arg(JExpr.lit(millisecs));
+
+            return newDateTime;
+
+        } else if (fieldType.fullName().equals(LocalDate.class.getName()) || fieldType.fullName().equals(LocalTime.class.getName())) {
+
+            JInvocation stringParseableTypeInstance = JExpr._new(fieldType);
+            stringParseableTypeInstance.arg(JExpr.lit(value));
+            return stringParseableTypeInstance;
+
+        } else if (fieldType.fullName().equals(long.class.getName())) {
+            return JExpr.lit(Long.parseLong(value));
+
+        } else if (fieldType.fullName().equals(float.class.getName())) {
+            return JExpr.lit(Float.parseFloat(value));
+
+        } else if (fieldType.fullName().equals(URI.class.getName())) {
+            JInvocation invokeCreate = fieldType.owner().ref(URI.class).staticInvoke("create");
+            return invokeCreate.arg(JExpr.lit(value));
+        } else {
+            return JExpr._null();
+
+        }
+
+    }
+
+    private static long parseDateToMillisecs(String valueAsText) {
+
+        try {
+            return Long.parseLong(valueAsText);
+        } catch (NumberFormatException nfe) {
+            try {
+                return new StdDateFormat().parse(valueAsText).getTime();
+            } catch (ParseException pe) {
+                throw new IllegalArgumentException("Unable to parse this string as a date: " + valueAsText);
+            }
+        }
+
+    }
+
+}

jsonschema2pojo-core/src/main/java/org/jsonschema2pojo/rules/PropertyRule.java

@@ -119,6 +119,8 @@ public JDefinedClass apply(String nodeName, JsonNode node, JsonNode parent, JDef
             ruleFactory.getPatternRule().apply(nodeName, node.get("pattern"), node, field, schema);
         }
 
+        ruleFactory.getConstRule(jclass).apply(nodeName, node.get("const"), node, field, schema);
+
         ruleFactory.getDefaultRule().apply(nodeName, node.get("default"), node, field, schema);
 
         ruleFactory.getMinimumMaximumRule().apply(nodeName, node, parent, field, schema);

jsonschema2pojo-core/src/main/java/org/jsonschema2pojo/rules/RuleFactory.java

@@ -252,6 +252,11 @@ public Rule<JFieldVar, JFieldVar> getDefaultRule() {
         return new DefaultRule(this);
     }
 
+
+    public Rule<JFieldVar, JFieldVar> getConstRule(JDefinedClass jclass) {
+        return new ConstRule(this, jclass);
+    }
+
     /**
      * Provides a rule instance that should be applied when a property
      * declaration is found in the schema, to assign any minimum/maximum

jsonschema2pojo-integration-tests/src/test/java/org/jsonschema2pojo/integration/DefaultIT.java

@@ -20,8 +20,10 @@
 import static org.jsonschema2pojo.integration.util.CodeGenerationHelper.*;
 import static org.junit.Assert.*;
 
+import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.net.URI;
@@ -37,7 +39,7 @@
 import org.junit.Test;
 
 public class DefaultIT {
-    
+
     @ClassRule public static Jsonschema2PojoRule classSchemaRule = new Jsonschema2PojoRule();
     @Rule public Jsonschema2PojoRule schemaRule = new Jsonschema2PojoRule();
 
@@ -74,6 +76,162 @@ public void stringPropertyHasCorrectDefaultValue() throws NoSuchMethodException,
 
     }
 
+    @Test
+    public void emptyConst()
+            throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException {
+
+        Object instance = classWithDefaults.newInstance();
+
+        assertThrows(NoSuchFieldException.class, () -> classWithDefaults.getField("EMPTY_WITH_CONST"));
+        Method getter = classWithDefaults.getMethod("getEmptyWithConst");
+        assertNull(getter.invoke(instance));
+    }
+
+    @Test
+    public void stringConst()
+            throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException,
+            NoSuchFieldException {
+
+        Object instance = classWithDefaults.newInstance();
+
+        Field field = classWithDefaults.getField("STRING_WITH_CONST");
+        Method getter = classWithDefaults.getMethod("getStringWithConst");
+
+        assertPublicStaticFinal(field);
+
+        Object value = field.get(null);
+        assertEquals("abc", value);
+        assertNull(getter.invoke(instance));
+    }
+
+    @Test
+    public void booleanConst()
+            throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException,
+            NoSuchFieldException {
+
+        Object instance = classWithDefaults.newInstance();
+
+        Field field = classWithDefaults.getField("BOOLEAN_WITH_CONST");
+        Method getter = classWithDefaults.getMethod("getBooleanWithConst");
+
+        assertPublicStaticFinal(field);
+
+        Object value = field.get(null);
+        assertEquals(true, value);
+        assertNull(getter.invoke(instance));
+    }
+
+    @Test
+    public void integerConst()
+            throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException,
+            NoSuchFieldException {
+
+        Object instance = classWithDefaults.newInstance();
+
+        Field field = classWithDefaults.getField("INTEGER_WITH_CONST");
+        Method getter = classWithDefaults.getMethod("getIntegerWithConst");
+
+        assertPublicStaticFinal(field);
+
+        Object value = field.get(null);
+        assertEquals(1, value);
+        assertNull(getter.invoke(instance));
+    }
+
+    @Test
+    public void numberConst()
+            throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException,
+            NoSuchFieldException {
+
+        Object instance = classWithDefaults.newInstance();
+
+        Field field = classWithDefaults.getField("NUMBER_WITH_CONST");
+        Method getter = classWithDefaults.getMethod("getNumberWithConst");
+
+        assertPublicStaticFinal(field);
+
+        Object value = field.get(null);
+        assertEquals(1.1, value);
+        assertNull(getter.invoke(instance));
+    }
+
+    @Test
+    public void numberConstBigDecimal() throws Exception {
+        ClassLoader resultsClassLoader = schemaRule.generateAndCompile("/schema/default/default.json", "com.example", config("useBigDecimals", true));
+        Class<?> c = resultsClassLoader.loadClass("com.example.Default");
+
+        Field field = c.getField("NUMBER_WITH_CONST");
+
+        assertPublicStaticFinal(field);
+        Object value = field.get(null);
+
+        assertThat((BigDecimal) value, is(equalTo(new BigDecimal("1.1"))));
+    }
+
+    @Test
+    public void dateTimeAsMillisecPropertyHasCorrectConstValue()
+            throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException,
+            NoSuchFieldException {
+
+        Field field = classWithDefaults.getField("DATE_TIME_WITH_CONST");
+        Method getter = classWithDefaults.getMethod("getDateTimeWithConst");
+
+        assertPublicStaticFinal(field);
+
+        Object value = field.get(null);
+
+        assertThat((Date) value, is(equalTo(new Date(123456789))));
+    }
+
+    private static void assertPublicStaticFinal(Field field) {
+        int modifiers = field.getModifiers();
+        assertTrue(Modifier.isPublic(modifiers));
+        assertTrue(Modifier.isStatic(modifiers));
+        assertTrue(Modifier.isFinal(modifiers));
+    }
+
+    @Test
+    public void dateTimeAsStringPropertyHasCorrectConstValue()
+            throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException,
+            NoSuchFieldException {
+
+        Field field = classWithDefaults.getField("DATE_TIME_AS_STRING_WITH_CONST");
+        Method getter = classWithDefaults.getMethod("getDateTimeAsStringWithConst");
+
+        assertPublicStaticFinal(field);
+
+        Object value = field.get(null);
+
+        assertThat((Date) value, is(equalTo(new Date(1298539523112L))));
+    }
+
+    @Test
+    public void utcmillisecPropertyHasCorrectConstValue()
+            throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException,
+            NoSuchFieldException {
+
+        Field field = classWithDefaults.getField("UTCMILLISEC_WITH_CONST");
+        Method getter = classWithDefaults.getMethod("getUtcmillisecWithConst");
+
+        assertPublicStaticFinal(field);
+
+        Object value = field.get(null);
+
+        assertThat((Long) value, is(equalTo(123456789L)));
+    }
+
+    @Test
+    public void uriPropertyHasCorrectConstValue() throws Exception {
+        Field field = classWithDefaults.getField("URI_WITH_CONST");
+        Method getter = classWithDefaults.getMethod("getUriWithConst");
+
+        assertPublicStaticFinal(field);
+
+        Object value = field.get(null);
+
+        assertThat((URI) value, is(URI.create("http://example.com")));
+    }
+
     @Test
     public void integerPropertyHasCorrectDefaultValue() throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException {
 
@@ -270,7 +428,7 @@ public void simplePropertyCanHaveNullDefaultValue() throws NoSuchMethodException
         assertThat(getter.invoke(instance), is(nullValue()));
 
     }
-    
+
     @Test
     public void arrayPropertyCanHaveNullDefaultValue() throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException {