Java: Add Herb Java JNI Bindings

[marcoroth]

This pull request adds Java bindings for Herb using the JNI (Java Native Interface), allowing Java applications to parse and analyze ERB templates with the same implementation as the native C, Ruby C-Extension, C++ Emscripten WASM and the C++ Node.js NAPI bindings.

Building the Java bindings requires Java and a C compiler:

cd java
make

Once built, you can use the herb-java CLI tool:

herb-java version

herb java v0.7.5, libprism v1.6.0, libherb v0.7.5 (Java JNI)

herb-java lex examples/test.html.erb

#<Herb::Token type="TOKEN_HTML_TAG_START" value="<" range=[0, 1] start=(1:0) end=(1:1)>
#<Herb::Token type="TOKEN_IDENTIFIER" value="h1" range=[1, 3] start=(1:1) end=(1:3)>
#<Herb::Token type="TOKEN_WHITESPACE" value=" " range=[3, 4] start=(1:3) end=(1:4)>
#<Herb::Token type="TOKEN_IDENTIFIER" value="class" range=[4, 9] start=(1:4) end=(1:9)>
#<Herb::Token type="TOKEN_EQUALS" value="=" range=[9, 10] start=(1:9) end=(1:10)>
#<Herb::Token type="TOKEN_QUOTE" value="\"" range=[10, 11] start=(1:10) end=(1:11)>
#<Herb::Token type="TOKEN_IDENTIFIER" value="title" range=[11, 16] start=(1:11) end=(1:16)>
#<Herb::Token type="TOKEN_QUOTE" value="\"" range=[16, 17] start=(1:16) end=(1:17)>
#<Herb::Token type="TOKEN_HTML_TAG_END" value=">" range=[17, 18] start=(1:17) end=(1:18)>
#<Herb::Token type="TOKEN_ERB_START" value="<%=" range=[18, 21] start=(1:18) end=(1:21)>
#<Herb::Token type="TOKEN_ERB_CONTENT" value=" content " range=[21, 30] start=(1:21) end=(1:30)>
#<Herb::Token type="TOKEN_ERB_END" value="%>" range=[30, 32] start=(1:30) end=(1:32)>
#<Herb::Token type="TOKEN_HTML_TAG_START_CLOSE" value="</" range=[32, 34] start=(1:32) end=(1:34)>
#<Herb::Token type="TOKEN_IDENTIFIER" value="h1" range=[34, 36] start=(1:34) end=(1:36)>
#<Herb::Token type="TOKEN_HTML_TAG_END" value=">" range=[36, 37] start=(1:36) end=(1:37)>
#<Herb::Token type="TOKEN_NEWLINE" value="\n" range=[37, 38] start=(1:37) end=(2:0)>
#<Herb::Token type="TOKEN_EOF" value="<EOF>" range=[38, 38] start=(2:0) end=(2:0)>

herb-java parse examples/test.html.erb

@ DocumentNode (location: (1:0)-(2:0))
└── children: (2 items)
    ├── @ HTMLElementNode (location: (1:0)-(1:37))
    │   ├── open_tag:
    │   │   └── @ HTMLOpenTagNode (location: (1:0)-(1:18))
    │   │       ├── tag_opening: "<" (location: (1:0)-(1:1))
    │   │       ├── tag_name: "h1" (location: (1:1)-(1:3))
    │   │       ├── tag_closing: ">" (location: (1:17)-(1:18))
    │   │       ├── children: (1 item)
    │   │       │   └── @ HTMLAttributeNode (location: (1:4)-(1:17))
    │   │       │       ├── name:
    │   │       │       │   └── @ HTMLAttributeNameNode (location: (1:4)-(1:9))
    │   │       │       │       └── children: (1 item)
    │   │       │       │           └── @ LiteralNode (location: (1:4)-(1:9))
    │   │       │       │               └── content: "class"
    │   │       │       │
    │   │       │       ├── equals: "=" (location: (1:9)-(1:10))
    │   │       │       └── value:
    │   │       │           └── @ HTMLAttributeValueNode (location: (1:10)-(1:17))
    │   │       │               ├── open_quote: "\"" (location: (1:10)-(1:11))
    │   │       │               ├── children: (1 item)
    │   │       │               │   └── @ LiteralNode (location: (1:11)-(1:16))
    │   │       │               │       └── content: "title"
    │   │       │               ├── close_quote: "\"" (location: (1:16)-(1:17))
    │   │       │               └── quoted: true
    │   │       └── is_void: false
    │   │
    │   ├── tag_name: "h1" (location: (1:1)-(1:3))
    │   ├── body: (1 item)
    │   │   └── @ ERBContentNode (location: (1:18)-(1:32))
    │   │       ├── tag_opening: "<%=" (location: (1:18)-(1:21))
    │   │       ├── content: " content " (location: (1:21)-(1:30))
    │   │       ├── tag_closing: "%>" (location: (1:30)-(1:32))
    │   │       ├── parsed: true
    │   │       └── valid: true
    │   ├── close_tag:
    │   │   └── @ HTMLCloseTagNode (location: (1:32)-(1:37))
    │   │       ├── tag_opening: "</" (location: (1:32)-(1:34))
    │   │       ├── tag_name: "h1" (location: (1:34)-(1:36))
    │   │       ├── children: []
    │   │       └── tag_closing: ">" (location: (1:36)-(1:37))
    │   │
    │   ├── is_void: false
    │   └── source: ""
    │
    └── @ HTMLTextNode (location: (1:37)-(2:0))
        └── content: "\n"

Resolves #648