Use the Java7 java.nio.file interfaces, make output atomic.

4 files changed, 115 insertions, 91 deletions

diff --git a/org/madore/damlengine/DamlEngine.java b/org/madore/damlengine/DamlEngine.java
index f708d81..85ebeed 100644
--- a/org/madore/damlengine/DamlEngine.java
+++ b/org/madore/damlengine/DamlEngine.java
@@ -5,14 +5,18 @@ import java.util.regex.Pattern;
 import java.util.regex.Matcher;
 import java.util.Properties;
 import java.io.InputStream;
-import java.io.FileInputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.io.FileOutputStream;
 import java.io.OutputStreamWriter;
 import java.io.BufferedReader;
 import java.io.PrintStream;
-import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
+import java.nio.file.NoSuchFileException;
 import javax.xml.XMLConstants;
 import javax.xml.namespace.NamespaceContext;
 import org.w3c.dom.*;
@@ -151,44 +155,69 @@ public final class DamlEngine {
     }
 
     public static Properties appProps;
-    public static String basePath;
-    public static String templatePath;
+    public static Path basePath;
+    public static Path templatePath;
+
+    private static interface Processor {
+	public void process(OutputStream out) throws Exception;
+    }
+    private static void processWithTemp(Processor p, String outf)
+	throws Exception {
+	Path tempPath = (outf != null) ? Paths.get(outf+".temp") : null;
+	OutputStream out = (tempPath != null)
+	    ? Files.newOutputStream(tempPath)
+	    : System.out;
+	try {
+	    p.process(out);
+	    if ( tempPath != null ) {
+		out.close();
+		Files.move(tempPath, Paths.get(outf),
+			   StandardCopyOption.REPLACE_EXISTING,
+			   StandardCopyOption.ATOMIC_MOVE);
+	    }
+	} finally {
+	    try {
+		if (tempPath != null )
+		    Files.deleteIfExists(tempPath);
+	    } catch ( Exception e ) { }
+	}
+    }
 
     public static void main(String[] args)
 	throws Exception {
 
 	appProps = new Properties();
-	String appPropsFile = null;
+	Path appPropsFile = null;
 	if ( System.getenv("DAMLENGINE_PROPERTIES_PATH") != null )
-	    appPropsFile = System.getenv("DAMLENGINE_PROPERTIES_PATH");
+	    appPropsFile = Paths.get(System.getenv("DAMLENGINE_PROPERTIES_PATH"));
 	if ( appPropsFile == null ) {
 	    if ( System.getProperty("user.home") != null )
-		appPropsFile = System.getProperty("user.home") + "/damlengine.properties";
+		appPropsFile = Paths.get(System.getProperty("user.home"),"damlengine.properties");
 	    else
-		appPropsFile = "damlengine.properties";
+		appPropsFile = Paths.get("damlengine.properties");
 	}
 	try {
-	    appProps.load(new FileInputStream(appPropsFile));
-	} catch (FileNotFoundException e) { }
+	    appProps.load(Files.newInputStream(appPropsFile));
+	} catch (NoSuchFileException e) { }
 
 	basePath = null;
 	if ( System.getenv("DAMLENGINE_BASE_PATH") != null )
-	    basePath = System.getenv("DAMLENGINE_BASE_PATH");
-	if ( basePath == null )
-	    basePath = appProps.getProperty("base_path");
+	    basePath = Paths.get(System.getenv("DAMLENGINE_BASE_PATH"));
+	if ( basePath == null && appProps.getProperty("base_path") != null )
+	    basePath = Paths.get(appProps.getProperty("base_path"));
 	if ( basePath == null ) {
-	    basePath = ".";
+	    basePath = Paths.get(".");
 	    System.err.println("warning: using working directory as base path");
 	}
 
 	templatePath = null;
 	if ( System.getenv("DAMLENGINE_TEMPLATE_PATH") != null )
-	    templatePath = System.getenv("DAMLENGINE_TEMPLATE_PATH");
-	if ( templatePath == null )
-	    templatePath = appProps.getProperty("template_path");
+	    templatePath = Paths.get(System.getenv("DAMLENGINE_TEMPLATE_PATH"));
+	if ( templatePath == null && appProps.getProperty("template_path") != null )
+	    templatePath = Paths.get(appProps.getProperty("template_path"));
 	if ( templatePath == null ) {
-	    templatePath = basePath + "/templates";
-	    System.err.println("warning: using "+templatePath+" as template path");
+	    templatePath = basePath.resolve("templates");
+	    System.err.println("warning: using "+templatePath.toString()+" as template path");
 	}
 
 	BufferedReader buf = new BufferedReader(new InputStreamReader(System.in, "UTF-8"));
@@ -200,82 +229,77 @@ public final class DamlEngine {
 		continue;
 	    System.err.println(line);
 	    if ( (matcher=Pattern.compile("process\\s+(\\S+)(?:\\s+\\>\\s*(\\S+))?\\s*").matcher(line)).matches() ) {
-		String inf = matcher.group(1);
-		String outf = matcher.group(2);
-		InputStream in = new FileInputStream((inf.charAt(0)=='/'?"":basePath+"/")+inf);
-		OutputStream out = (outf != null)
-		    ? new FileOutputStream(outf)
-		    : System.out;
-		fullProcess(in, out);
-		if ( out != System.out )
-		    out.close();
+		final String inf = matcher.group(1);
+		final String outf = matcher.group(2);
+		final InputStream in = Files.newInputStream(basePath.resolve(inf));
+		processWithTemp(new Processor() {
+			public void process(OutputStream out) throws Exception {
+			    fullProcess(in, out);
+			}
+		    }, outf);
 	    } else if ( (matcher=Pattern.compile("process-weblog-month\\s+(\\d{4})\\-(\\d{2})(?:\\s+\\>\\s*(\\S+))?\\s*").matcher(line)).matches() ) {
-		String year = matcher.group(1);
-		String month = matcher.group(2);
-		String outf = matcher.group(3);
-		OutputStream out = (outf != null)
-		    ? new FileOutputStream(outf)
-		    : System.out;
-		WeblogSelect.fullProcess(new Context.WeblogMonthSelectionContext(year,month),
-					 out);
-		if ( out != System.out )
-		    out.close();
+		final String year = matcher.group(1);
+		final String month = matcher.group(2);
+		final String outf = matcher.group(3);
+		processWithTemp(new Processor() {
+			public void process(OutputStream out) throws Exception {
+			    WeblogSelect.fullProcess(new Context.WeblogMonthSelectionContext(year,month),
+						     out);
+			}
+		    }, outf);
 	    } else if ( (matcher=Pattern.compile("process-weblog-cat\\s+([a-z0-9\\-]+)(?:\\s+\\>\\s*(\\S+))?\\s*").matcher(line)).matches() ) {
-		String code = matcher.group(1);
-		String outf = matcher.group(2);
-		OutputStream out = (outf != null)
-		    ? new FileOutputStream(outf)
-		    : System.out;
-		WeblogSelect.fullProcess(new Context.WeblogCategorySelectionContext(code),
-					 out);
-		if ( out != System.out )
-		    out.close();
+		final String code = matcher.group(1);
+		final String outf = matcher.group(2);
+		processWithTemp(new Processor() {
+			public void process(OutputStream out) throws Exception {
+			    WeblogSelect.fullProcess(new Context.WeblogCategorySelectionContext(code),
+						     out);
+			}
+		    }, outf);
 	    } else if ( (matcher=Pattern.compile("process-weblog-recent\\s+(\\d+)(?:\\s+\\>\\s*(\\S+))?\\s*").matcher(line)).matches() ) {
-		int count = Integer.parseInt(matcher.group(1));
-		String outf = matcher.group(2);
-		OutputStream out = (outf != null)
-		    ? new FileOutputStream(outf)
-		    : System.out;
-		WeblogSelect.fullProcess(new Context.WeblogRecentSelectionContext(count),
-					 out);
+		final int count = Integer.parseInt(matcher.group(1));
+		final String outf = matcher.group(2);
+		processWithTemp(new Processor() {
+			public void process(OutputStream out) throws Exception {
+			    WeblogSelect.fullProcess(new Context.WeblogRecentSelectionContext(count),
+						     out);
+			}
+		    }, outf);
 	    } else if ( (matcher=Pattern.compile("process-weblog-single\\s+(\\d+)(?:\\s+\\>\\s*(\\S+))?\\s*").matcher(line)).matches() ) {
-		int number = Integer.parseInt(matcher.group(1));
-		String outf = matcher.group(2);
-		OutputStream out = (outf != null)
-		    ? new FileOutputStream(outf)
-		    : System.out;
-		WeblogSelect.fullProcess(new Context.WeblogSingleSelectionContext(number),
-					 out);
-		if ( out != System.out )
-		    out.close();
+		final int number = Integer.parseInt(matcher.group(1));
+		final String outf = matcher.group(2);
+		processWithTemp(new Processor() {
+			public void process(OutputStream out) throws Exception {
+			    WeblogSelect.fullProcess(new Context.WeblogSingleSelectionContext(number),
+						     out);
+			}
+		    }, outf);
 	    } else if ( (matcher=Pattern.compile("process-weblog-index(?:\\s+\\>\\s*(\\S+))?\\s*").matcher(line)).matches() ) {
-		String outf = matcher.group(1);
-		OutputStream out = (outf != null)
-		    ? new FileOutputStream(outf)
-		    : System.out;
-		WeblogIndexSelect.fullProcess(out);
-		if ( out != System.out )
-		    out.close();
+		final String outf = matcher.group(1);
+		processWithTemp(new Processor() {
+			public void process(OutputStream out) throws Exception {
+			    WeblogIndexSelect.fullProcess(out);
+			}
+		    }, outf);
 	    } else if ( (matcher=Pattern.compile("process-weblog-rss(?:\\s+\\>\\s*(\\S+))?\\s*").matcher(line)).matches() ) {
-		String outf = matcher.group(1);
-		OutputStream out = (outf != null)
-		    ? new FileOutputStream(outf)
-		    : System.out;
-		WeblogRSS.fullProcess(out);
-		if ( out != System.out )
-		    out.close();
+		final String outf = matcher.group(1);
+		processWithTemp(new Processor() {
+			public void process(OutputStream out) throws Exception {
+			    WeblogRSS.fullProcess(out);
+			}
+		    }, outf);
 	    } else if ( (matcher=Pattern.compile("populate-weblog\\s+(\\S+)\\s*").matcher(line)).matches() ) {
-		String inf = matcher.group(1);
-		InputStream in = new FileInputStream((inf.charAt(0)=='/'?"":basePath+"/")+inf);
+		final String inf = matcher.group(1);
+		final InputStream in = Files.newInputStream(basePath.resolve(inf));
 		WeblogPopulate.populate(in);
 	    } else if ( (matcher=Pattern.compile("echo\\s+(\\S+)(?:\\s+\\>\\s*(\\S+))?\\s*").matcher(line)).matches() ) {
-		String str = matcher.group(1);
-		String outf = matcher.group(2);
-		OutputStream out = (outf != null)
-		    ? new FileOutputStream(outf)
+		final String str = matcher.group(1);
+		final String outf = matcher.group(2);
+		final OutputStream out = (outf != null)
+		    ? Files.newOutputStream(Paths.get(outf))
 		    : System.out;
 		new PrintStream(out, true).println(str);
-		if ( out != System.out )
+		if ( outf != null )
 		    out.close();
 	    } else {
 		throw new IllegalArgumentException("couldn't understand command");
diff --git a/org/madore/damlengine/TodoDamlElement.java b/org/madore/damlengine/TodoDamlElement.java
index 9de2714..6949086 100644
--- a/org/madore/damlengine/TodoDamlElement.java
+++ b/org/madore/damlengine/TodoDamlElement.java
@@ -2,11 +2,11 @@ package org.madore.damlengine;
 
 import java.util.ArrayList;
 import java.util.regex.Pattern;
-import java.io.FileInputStream;
 import java.io.Reader;
 import java.io.InputStreamReader;
 import java.io.BufferedReader;
 import java.io.IOException;
+import java.nio.file.Files;
 import org.w3c.dom.*;
 
 public final class TodoDamlElement extends TodoDefaultElement {
@@ -62,7 +62,7 @@ public final class TodoDamlElement extends TodoDefaultElement {
 
 	ctx.gc.styleContent = new StringBuffer();
 	try {
-	    Reader rd = new BufferedReader(new InputStreamReader(new FileInputStream(DamlEngine.templatePath+"/included.css"), "UTF-8"));
+	    Reader rd = new BufferedReader(new InputStreamReader(Files.newInputStream(DamlEngine.templatePath.resolve("included.css")), "UTF-8"));
 	    int ch;
 	    while ((ch = rd.read()) > -1)
 		ctx.gc.styleContent.append((char)ch);
@@ -72,7 +72,7 @@ public final class TodoDamlElement extends TodoDefaultElement {
 	}
 	ctx.gc.scriptContent = new StringBuffer();
 	try {
-	    Reader rd = new BufferedReader(new InputStreamReader(new FileInputStream(DamlEngine.templatePath+"/included.js"), "UTF-8"));
+	    Reader rd = new BufferedReader(new InputStreamReader(Files.newInputStream(DamlEngine.templatePath.resolve("included.js")), "UTF-8"));
 	    int ch;
 	    while ((ch = rd.read()) > -1)
 		ctx.gc.scriptContent.append((char)ch);
diff --git a/org/madore/damlengine/WeblogIndexSelect.java b/org/madore/damlengine/WeblogIndexSelect.java
index 0361177..8f8da29 100644
--- a/org/madore/damlengine/WeblogIndexSelect.java
+++ b/org/madore/damlengine/WeblogIndexSelect.java
@@ -1,7 +1,7 @@
 package org.madore.damlengine;
 
-import java.io.FileInputStream;
 import java.io.OutputStream;
+import java.nio.file.Files;
 
 public final class WeblogIndexSelect {
 
@@ -12,7 +12,7 @@ public final class WeblogIndexSelect {
     public static void fullProcess(OutputStream out)
 	throws Exception {
 
-	DamlEngine.fullProcess(new FileInputStream(DamlEngine.templatePath+"/weblog-index-template.daml"),
+	DamlEngine.fullProcess(Files.newInputStream(DamlEngine.templatePath.resolve("weblog-index-template.daml")),
 			       out, null);
 
     }
diff --git a/org/madore/damlengine/WeblogSelect.java b/org/madore/damlengine/WeblogSelect.java
index 075cab1..a15a672 100644
--- a/org/madore/damlengine/WeblogSelect.java
+++ b/org/madore/damlengine/WeblogSelect.java
@@ -2,8 +2,8 @@ package org.madore.damlengine;
 
 import java.util.TreeSet;
 import java.util.ArrayList;
-import java.io.FileInputStream;
 import java.io.OutputStream;
+import java.nio.file.Files;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
@@ -51,7 +51,7 @@ public final class WeblogSelect {
 	    wsc.xmlData.add(content);
 	}
 
-	DamlEngine.fullProcess(new FileInputStream(DamlEngine.templatePath+"/"+templateResourceName),
+	DamlEngine.fullProcess(Files.newInputStream(DamlEngine.templatePath.resolve(templateResourceName)),
 			       out, wsc);
 
     }