Implemented get and set environment variables for posix.

src/main/java/net/rubygrapefruit/platform/internal/WrapperProcess.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2012 Adam Murdoch
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+package net.rubygrapefruit.platform.internal;
+
+import net.rubygrapefruit.platform.NativeException;
+import net.rubygrapefruit.platform.Process;
+import net.rubygrapefruit.platform.ThreadSafe;
+
+import java.io.File;
+import java.lang.reflect.Field;
+import java.util.Map;
+
+/**
+ * A {@link Process} implementation that wraps another to add thread-safety and to update the JVM's internal view of
+ * various process properties.
+ */
+@ThreadSafe
+public class WrapperProcess implements Process {
+    private final Process process;
+    private final Object workingDirectoryLock = new Object();
+    private final Object environmentLock = new Object();
+
+    public WrapperProcess(Process process) {
+        this.process = process;
+    }
+
+    @Override
+    public String toString() {
+        return process.toString();
+    }
+
+    public int getProcessId() throws NativeException {
+        return process.getProcessId();
+    }
+
+    public File getWorkingDirectory() throws NativeException {
+        synchronized (workingDirectoryLock) {
+            return process.getWorkingDirectory();
+        }
+    }
+
+    public void setWorkingDirectory(File directory) throws NativeException {
+        synchronized (workingDirectoryLock) {
+            process.setWorkingDirectory(directory);
+            System.setProperty("user.dir", directory.getAbsolutePath());
+        }
+    }
+
+    public String getEnvironmentVariable(String name) throws NativeException {
+        synchronized (environmentLock) {
+            String value = process.getEnvironmentVariable(name);
+            return value == null || value.length() == 0 ? null : value;
+        }
+    }
+
+    public void setEnvironmentVariable(String name, String value) throws NativeException {
+        synchronized (environmentLock) {
+            if (value == null || value.length() == 0) {
+                process.setEnvironmentVariable(name, null);
+                removeEnvInternal(name);
+            } else {
+                process.setEnvironmentVariable(name, value);
+                setEnvInternal(name, value);
+            }
+        }
+    }
+
+    private void removeEnvInternal(String name) {
+        getEnv().remove(name);
+    }
+
+    private void setEnvInternal(String name, String value) {
+        getEnv().put(name, value);
+    }
+
+    private Map<String, String> getEnv() {
+        try {
+            Map<String, String> theUnmodifiableEnvironment = System.getenv();
+            Class<?> cu = theUnmodifiableEnvironment.getClass();
+            Field m = cu.getDeclaredField("m");
+            m.setAccessible(true);
+            return (Map<String, String>)m.get(theUnmodifiableEnvironment);
+        } catch (Exception e) {
+            throw new NativeException("Unable to get mutable environment map.", e);
+        }
+    }
+
+}