Added examples (#29)

Closes #27 

Signed-off-by: Steve Winslow <swinslow@gmail.com>

1 files changed, 77 insertions, 0 deletions

diff --git a/examples/5-report/example_report.go b/examples/5-report/example_report.go
new file mode 100644
index 0000000..5506a68
--- /dev/null
+++ b/examples/5-report/example_report.go
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+
+// Example for: *reporter*, *tvloader*
+
+// This example demonstrates loading an SPDX tag-value file from disk into memory,
+// generating a basic report listing counts of the concluded licenses for its
+// files, and printing the report to standard output.
+
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/swinslow/spdx-go/v0/reporter"
+	"github.com/swinslow/spdx-go/v0/tvloader"
+)
+
+func main() {
+
+	// check that we've received the right number of arguments
+	args := os.Args
+	if len(args) != 2 {
+		fmt.Printf("Usage: %v <spdx-file-in>\n", args[0])
+		fmt.Printf("  Load SPDX 2.1 tag-value file <spdx-file-in>, and\n")
+		fmt.Printf("  generate and print a report of its concluded licenses.\n")
+		return
+	}
+
+	// open the SPDX file
+	filename := args[1]
+	r, err := os.Open(filename)
+	if err != nil {
+		fmt.Printf("Error while opening %v for reading: %v", filename, err)
+		return
+	}
+	defer r.Close()
+
+	// try to load the SPDX file's contents as a tag-value file, version 2.1
+	doc, err := tvloader.Load2_1(r)
+	if err != nil {
+		fmt.Printf("Error while parsing %v: %v", filename, err)
+		return
+	}
+
+	// if we got here, the file is now loaded into memory.
+	fmt.Printf("Successfully loaded %s\n\n", filename)
+
+	// check whether the SPDX file has at least one package
+	if doc.Packages == nil || len(doc.Packages) < 1 {
+		fmt.Printf("No packages found in SPDX document\n")
+		return
+	}
+
+	// it does, so we'll choose the first one
+	pkg := doc.Packages[0]
+
+	// check whether the package had its files analyzed
+	if !pkg.FilesAnalyzed {
+		fmt.Printf("First Package (%s) had FilesAnalyzed: false\n", pkg.PackageName)
+		return
+	}
+
+	// also check whether the package has any files present
+	if pkg.Files == nil || len(pkg.Files) < 1 {
+		fmt.Printf("No Files found in first Package (%s)\n", pkg.PackageName)
+		return
+	}
+
+	// if we got here, there's at least one file
+	// generate and print a report of the Package's Files' LicenseConcluded
+	// values, sorted by # of occurrences
+	err = reporter.Generate(pkg, os.Stdout)
+	if err != nil {
+		fmt.Printf("Error while generating report: %v\n", err)
+	}
+}