[GROOVY-8517] Add ASTNode.getNodeMetaData overload that supports computation of missing value (like Map.computeIfAbsent)

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha-1
• Fix Version/s: 3.0.0-rc-3
• Assignee: Eric Milles
• Reporter: Eric Milles
• Created: 22/Mar/18 20:59
• Updated: 27/Jan/20 00:44
• Resolved: 31/Oct/19 14:01

Description

org.codehaus.groovy.ast.ASTNode currently provides 2 versions of the getNodeMetaData method. I'd like to see a 3rd option that provides a Java 8 computeIfAbsent-like API, since the method that returns the whole Map returns an immutable view.

    /**
     * ...
     */
    public <T> T getNodeMetaData(Object key, Function<?, ? extends T> valFn) {
        if (key == null) throw new GroovyBugError("Tried to get/set meta data with null key on " + this + ".");
        if (metaDataMap == null) {
            metaDataMap = new ListHashMap();
        }
        return metaDataMap.computeIfAbsent(key, valFn);
    }

    /**
     * Gets the node meta data. 
     * 
     * @param key - the meta data key
     * @return the node meta data value for this key
     */
    public <T> T getNodeMetaData(Object key) {
        if (metaDataMap == null) {
            return (T) null;
        }
        return (T) metaDataMap.get(key);
    }

    /**
     * Returns an unmodifiable view of the current node metadata.
     * @return the node metadata. Always not null.
     */
    public Map<?,?> getNodeMetaData() {
        if (metaDataMap==null) {
            return Collections.emptyMap();
        }
        return Collections.unmodifiableMap(metaDataMap);
    }