This script acts as a wrapper for the PlantUML jar file, making it easier to call the jar file with the appropriate arguments. It allows specifying the path to the Java binary and the PlantUML jar file via command-line arguments or environment variables, and it validates the existence of these files before execution.

plantuml.sh

#!/usr/bin/env bash

################################################################################
# plantuml.sh - A script to wrap PlantUML jar execution
#
# Author: Firas AlShafei
# Created: 2024.07.20
# Last Modified: 2024.07.20
#
# Description:
# This script acts as a wrapper for the PlantUML jar file, making it easier to
# call the jar file with the appropriate arguments. It allows specifying the
# path to the Java binary and the PlantUML jar file via command-line arguments
# or environment variables, and it validates the existence of these files before
# execution.
#
# Usage:
# ./plantuml.sh [--jar <jar_path>] [--java <java_bin>] [PlantUML options]
#
# Options:
#   --jar   Path to the PlantUML jar file (default: ./plantuml.jar)
#   --java  Path to the Java binary (default: java)
#   --usage Display this help message
#
# Example:
# ./plantuml.sh --jar ./plantuml.jar --java /usr/bin/java -tpng mydiagram.puml
################################################################################

set -euo pipefail

# Default paths
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
DEFAULT_PLANTUML_JAR="$SCRIPT_DIR/plantuml.jar"
DEFAULT_JAVA_BIN="java"

# Allow user to override defaults via environment variables
PLANTUML_JAR="${PLANTUML_JAR_PATH:-$DEFAULT_PLANTUML_JAR}"
JAVA_BIN="${JAVA_BIN_PATH:-$DEFAULT_JAVA_BIN}"

# Function to display usage information
usage() {
    echo "Usage: $0 [--jar <jar_path>] [--java <java_bin>] [PlantUML options]"
    echo "Options:"
    echo "  --jar   Path to the PlantUML jar file (default: $DEFAULT_PLANTUML_JAR)"
    echo "  --java  Path to the Java binary (default: $DEFAULT_JAVA_BIN)"
    echo "  --usage Display this help message"
}

# Function to parse command-line arguments manually
parse_args() {
    while [[ $# -gt 0 ]]; do
        case $1 in
            --jar)
                PLANTUML_JAR="$2"
                shift 2
                ;;
            --java)
                JAVA_BIN="$2"
                shift 2
                ;;
            --usage)
                usage
                exit 0
                ;;
            --)
                shift
                break
                ;;
            *)
                break
                ;;
        esac
    done
    PLANTUML_OPTS=("$@")
}

# Function to validate paths
validate_paths() {
    if ! command -v "$JAVA_BIN" &> /dev/null; then
        echo "Error: Java binary not found at '$JAVA_BIN'. Please install Java or specify the correct path." >&2
        exit 1
    fi

    if [[ ! -f "$PLANTUML_JAR" ]]; then
        echo "Error: PlantUML jar file not found at '$PLANTUML_JAR'. Please specify the correct path." >&2
        exit 1
    fi
}

# Main script execution
main() {
    parse_args "$@"
    validate_paths
    "$JAVA_BIN" -jar "$PLANTUML_JAR" "${PLANTUML_OPTS[@]}"
}

main "$@"