Module for Jackson3

handlebars-jackson3/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+
+  <parent>
+    <groupId>com.github.jknack</groupId>
+    <artifactId>handlebars.java</artifactId>
+    <version>4.5.4</version>
+  </parent>
+
+  <modelVersion>4.0.0</modelVersion>
+  <artifactId>handlebars-jackson3</artifactId>
+
+  <name>JSON Jackson helpers</name>
+
+  <dependencies>
+    <dependency>
+      <groupId>com.github.jknack</groupId>
+      <artifactId>handlebars</artifactId>
+      <version>${project.version}</version>
+    </dependency>
+
+    <dependency>
+      <groupId>tools.jackson.core</groupId>
+      <artifactId>jackson-databind</artifactId>
+    </dependency>
+
+    <!-- Test dependencies -->
+    <dependency>
+      <groupId>com.github.jknack</groupId>
+      <artifactId>handlebars</artifactId>
+      <version>${project.version}</version>
+      <scope>test</scope>
+      <classifier>tests</classifier>
+    </dependency>
+
+    <dependency>
+      <groupId>ch.qos.logback</groupId>
+      <artifactId>logback-classic</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.hamcrest</groupId>
+      <artifactId>hamcrest</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+</project>

handlebars-jackson3/src/main/java/com/github/jknack/handlebars/jackson/JacksonHelper.java

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+/*
+ * Handlebars.java: https://github.com/jknack/handlebars.java
+ * Apache License Version 2.0 http://www.apache.org/licenses/LICENSE-2.0
+ * Copyright (c) 2012 Edgar Espina
+ */
+package com.github.jknack.handlebars.jackson;
+
+import com.github.jknack.handlebars.Handlebars;
+import com.github.jknack.handlebars.Helper;
+import com.github.jknack.handlebars.Options;
+import tools.jackson.core.SerializableString;
+import tools.jackson.core.io.CharacterEscapes;
+import tools.jackson.databind.ObjectMapper;
+import tools.jackson.databind.ObjectWriter;
+import tools.jackson.databind.json.JsonMapper;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static java.util.Objects.requireNonNull;
+
+/**
+ * A Jackson 3.x helper.
+ *
+ * <p>Basic usage:
+ *
+ * <pre>
+ *  Handlebars hbs = new Handlebars();
+ *
+ *  hbs.registerHelper("json", JacksonHelper.INSTANCE);
+ *
+ *  ...
+ *
+ *  {{json model}}
+ * </pre>
+ *
+ * <p>If <code>model</code> is null an empty string is returned.
+ *
+ * <p>You can change this using the <code>default</code> option:
+ *
+ * <pre>
+ *  {{json model default="{}"}}
+ * </pre>
+ *
+ * <p>Using a view class:
+ *
+ * <pre>
+ *  {{json model view="foo.MyView"}}
+ * </pre>
+ *
+ * <p>Using alias for views:
+ *
+ * <pre>
+ *  {{json model view="myView"}}
+ * </pre>
+ *
+ * <p>Escape HTML chars:
+ *
+ * <pre>
+ *  {{json model escapeHTML=true}}
+ * </pre>
+ *
+ * <p>Pretty printer:
+ *
+ * <pre>
+ *  {{json model pretty=true}}
+ * </pre>
+ *
+ * @author edgar.espina, jolarsen
+ * @since 4.5.5
+ */
+public class JacksonHelper implements Helper<Object> {
+
+  /**
+   * Escape HTML chars from JSON content. See
+   * http://www.cowtowncoder.com/blog/archives/2012/08/entry_476.html
+   *
+   * @author edgar.espina, jolarsen
+   * @since 4.5.5
+   */
+  @SuppressWarnings("serial")
+  private static class HtmlEscapes extends CharacterEscapes {
+
+    /** The escape table. */
+    private final int[] escapeTable;
+
+    {
+      // Start with set of characters known to require escaping (double-quote,
+      // backslash etc)
+      escapeTable = CharacterEscapes.standardAsciiEscapesForJSON();
+      // and force escaping of a few others:
+      escapeTable['<'] = CharacterEscapes.ESCAPE_STANDARD;
+      escapeTable['>'] = CharacterEscapes.ESCAPE_STANDARD;
+      escapeTable['&'] = CharacterEscapes.ESCAPE_STANDARD;
+      escapeTable['\''] = CharacterEscapes.ESCAPE_STANDARD;
+    }
+
+    @Override
+    public int[] getEscapeCodesForAscii() {
+      return escapeTable;
+    }
+
+    @Override
+    public SerializableString getEscapeSequence(final int ch) {
+      return null;
+    }
+  }
+
+  /** A singleton version of {@link JacksonHelper}. */
+  public static final Helper<Object> INSTANCE = new JacksonHelper();
+
+  /** The JSON parser. */
+  private final ObjectMapper mapper;
+
+  /** Class alias registry. */
+  private final Map<String, Class<?>> alias = new HashMap<String, Class<?>>();
+
+  /**
+   * Creates a new {@link JacksonHelper}.
+   *
+   * @param objectMapper The object's mapper. Required.
+   */
+  public JacksonHelper(final ObjectMapper objectMapper) {
+    mapper = requireNonNull(objectMapper, "The object mapper is required.");
+  }
+
+  /** Creates a new {@link JacksonHelper}. */
+  private JacksonHelper() {
+    this(JsonMapper.builder().build());
+  }
+
+  @Override
+  public Object apply(final Object context, final Options options) {
+    if (context == null) {
+      return options.hash("default", "");
+    }
+
+    final String viewName = options.hash("view", "");
+    try {
+      final Class<?> viewClass = alias.get(viewName);
+      final ObjectWriter viewWriter = Handlebars.Utils.isEmpty(viewName)
+              ? mapper.writer()
+              : mapper.writerWithView(viewClass != null
+                                      ? viewClass
+                                      : getClass().getClassLoader().loadClass(viewName));
+
+      final boolean escapeHtml = options.hash("escapeHTML", false);
+      final boolean pretty = options.hash("pretty", false);
+
+      final ObjectWriter writer = pretty
+              ? viewWriter.withDefaultPrettyPrinter()
+              : viewWriter;
+
+      final ObjectWriter configuredWriter = escapeHtml
+              ? writer.with(new HtmlEscapes())
+              : writer;
+
+      return new Handlebars.SafeString(configuredWriter.writeValueAsString(context));
+    } catch (ClassNotFoundException|NoClassDefFoundError ex) {
+      throw new IllegalArgumentException(viewName, ex);
+    }
+  }
+
+  /**
+   * Add an alias for the given view class.
+   *
+   * @param alias The view alias. Required.
+   * @param viewClass The view class. Required.
+   * @return This helper.
+   */
+  public JacksonHelper viewAlias(final String alias, final Class<?> viewClass) {
+    this.alias.put(
+        requireNonNull(alias, "A view alias is required."),
+        requireNonNull(viewClass, "A view class is required."));
+    return this;
+  }
+}

handlebars-jackson3/src/main/java/com/github/jknack/handlebars/jackson/JsonNodeValueResolver.java

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+/*
+ * Handlebars.java: https://github.com/jknack/handlebars.java
+ * Apache License Version 2.0 http://www.apache.org/licenses/LICENSE-2.0
+ * Copyright (c) 2012 Edgar Espina
+ */
+package com.github.jknack.handlebars.jackson;
+
+import com.github.jknack.handlebars.ValueResolver;
+import tools.jackson.databind.JsonNode;
+import tools.jackson.databind.node.ArrayNode;
+import tools.jackson.databind.node.BigIntegerNode;
+import tools.jackson.databind.node.BinaryNode;
+import tools.jackson.databind.node.BooleanNode;
+import tools.jackson.databind.node.DecimalNode;
+import tools.jackson.databind.node.DoubleNode;
+import tools.jackson.databind.node.IntNode;
+import tools.jackson.databind.node.LongNode;
+import tools.jackson.databind.node.NullNode;
+import tools.jackson.databind.node.ObjectNode;
+import tools.jackson.databind.node.POJONode;
+import tools.jackson.databind.node.StringNode;
+
+import java.util.AbstractMap;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+/**
+ * Resolve a context stack value from {@link JsonNode}.
+ *
+ * @author edgar.espina, jolarsen
+ * @since 4.5.5
+ */
+public enum JsonNodeValueResolver implements ValueResolver {
+
+  /** The singleton instance. */
+  INSTANCE;
+
+  @Override
+  public Object resolve(final Object context, final String name) {
+    Object value = null;
+    if (context instanceof ArrayNode arrayNode) {
+      try {
+        if (name.equals("length")) {
+          return arrayNode.size();
+        }
+        value = resolve(arrayNode.get(Integer.parseInt(name)));
+      } catch (NumberFormatException ex) {
+        // ignore undefined key and move on, see
+        // https://github.com/jknack/handlebars.java/pull/280
+      }
+    } else if (context instanceof JsonNode jsonNode) {
+      value = resolve(jsonNode.get(name));
+    }
+    return value == null ? UNRESOLVED : value;
+  }
+
+  @Override
+  public Object resolve(final Object context) {
+    if (context instanceof JsonNode jsonNode) {
+      return resolve(jsonNode);
+    }
+    return UNRESOLVED;
+  }
+
+  /**
+   * Resolve a {@link JsonNode} object to a primitive value.
+   *
+   * @param node A {@link JsonNode} object.
+   * @return A primitive value, json object, json array or null.
+   */
+  private static Object resolve(final JsonNode node) {
+    // binary node
+    if (node instanceof BinaryNode binaryNode) {
+      return binaryNode.binaryValue();
+    }
+    // boolean node
+    if (node instanceof BooleanNode booleanNode) {
+      return booleanNode.booleanValue();
+    }
+    // null node
+    if (node instanceof NullNode) {
+      return null;
+    }
+    // numeric nodes
+    if (node instanceof BigIntegerNode bigIntegerNode) {
+      return bigIntegerNode.bigIntegerValue();
+    }
+    if (node instanceof DecimalNode decimalNode) {
+      return decimalNode.decimalValue();
+    }
+    if (node instanceof DoubleNode doubleNode) {
+      return doubleNode.doubleValue();
+    }
+    if (node instanceof IntNode intNode) {
+      return intNode.intValue();
+    }
+    if (node instanceof LongNode longNode) {
+      return longNode.longValue();
+    }
+    // pojo
+    if (node instanceof POJONode pojoNode) {
+      return pojoNode.getPojo();
+    }
+    // string
+    if (node instanceof StringNode stringNode) {
+      return stringNode.stringValue();
+    }
+    // object node to map
+    if (node instanceof ObjectNode objectNode) {
+      return toMap(objectNode);
+    }
+    // container, array or null
+    return node;
+  }
+
+  /**
+   * @param node A json node.
+   * @return A map from a json node.
+   */
+  private static Map<String, Object> toMap(final ObjectNode node) {
+    return new AbstractMap<String, Object>() {
+      @Override
+      public Object get(final Object key) {
+        return resolve(node.get((String) key));
+      }
+
+      @Override
+      public int size() {
+        return node.size();
+      }
+
+      @SuppressWarnings({"unchecked", "rawtypes"})
+      @Override
+      public Set<Entry<String, Object>> entrySet() {
+        Set set = new LinkedHashSet<Map.Entry<String, Object>>();
+        node.propertyStream().forEach(set::add);
+        return set;
+      }
+    };
+  }
+
+  @Override
+  public Set<Entry<String, Object>> propertySet(final Object context) {
+    if (context instanceof ObjectNode node) {
+      Map<String, Object> result = new LinkedHashMap<>();
+      node.propertyNames().forEach(name -> result.put(name, resolve(node.get(name))));
+      return result.entrySet();
+    }
+    return Collections.emptySet();
+  }
+}