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Diffstat (limited to 'libjava/java/lang/System.java')
| -rw-r--r-- | libjava/java/lang/System.java | 1089 |
1 files changed, 0 insertions, 1089 deletions
diff --git a/libjava/java/lang/System.java b/libjava/java/lang/System.java deleted file mode 100644 index ecfad25..0000000 --- a/libjava/java/lang/System.java +++ /dev/null @@ -1,1089 +0,0 @@ -/* System.java -- useful methods to interface with the system - Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 - Free Software Foundation, Inc. - -This file is part of GNU Classpath. - -GNU Classpath is free software; you can redistribute it and/or modify -it under the terms of the GNU General Public License as published by -the Free Software Foundation; either version 2, or (at your option) -any later version. - -GNU Classpath is distributed in the hope that it will be useful, but -WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -General Public License for more details. - -You should have received a copy of the GNU General Public License -along with GNU Classpath; see the file COPYING. If not, write to the -Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA -02110-1301 USA. - -Linking this library statically or dynamically with other modules is -making a combined work based on this library. Thus, the terms and -conditions of the GNU General Public License cover the whole -combination. - -As a special exception, the copyright holders of this library give you -permission to link this library with independent modules to produce an -executable, regardless of the license terms of these independent -modules, and to copy and distribute the resulting executable under -terms of your choice, provided that you also meet, for each linked -independent module, the terms and conditions of the license of that -module. An independent module is a module which is not derived from -or based on this library. If you modify this library, you may extend -this exception to your version of the library, but you are not -obligated to do so. If you do not wish to do so, delete this -exception statement from your version. */ - - -package java.lang; - -import gnu.classpath.SystemProperties; - -import java.io.BufferedInputStream; -import java.io.BufferedOutputStream; -import java.io.FileDescriptor; -import java.io.FileInputStream; -import java.io.FileOutputStream; -import java.io.IOException; -import java.io.InputStream; -import java.io.PrintStream; -import java.nio.channels.Channel; -import java.nio.channels.spi.SelectorProvider; -import java.util.AbstractCollection; -import java.util.ArrayList; -import java.util.Collection; -import java.util.Collections; -import java.util.HashMap; -import java.util.Iterator; -import java.util.List; -import java.util.Map; -import java.util.Set; -import java.util.Properties; -import java.util.PropertyPermission; - -/** - * System represents system-wide resources; things that represent the - * general environment. As such, all methods are static. - * - * @author John Keiser - * @author Eric Blake (ebb9@email.byu.edu) - * @since 1.0 - * @status still missing 1.4 functionality - */ -public final class System -{ - // WARNING: System is a CORE class in the bootstrap cycle. See the comments - // in vm/reference/java/lang/Runtime for implications of this fact. - - /** - * The standard InputStream. This is assigned at startup and starts its - * life perfectly valid. Although it is marked final, you can change it - * using {@link #setIn(InputStream)} through some hefty VM magic. - * - * <p>This corresponds to the C stdin and C++ cin variables, which - * typically input from the keyboard, but may be used to pipe input from - * other processes or files. That should all be transparent to you, - * however. - */ - public static final InputStream in - = new BufferedInputStream(new FileInputStream(FileDescriptor.in)); - /** - * The standard output PrintStream. This is assigned at startup and - * starts its life perfectly valid. Although it is marked final, you can - * change it using {@link #setOut(PrintStream)} through some hefty VM magic. - * - * <p>This corresponds to the C stdout and C++ cout variables, which - * typically output normal messages to the screen, but may be used to pipe - * output to other processes or files. That should all be transparent to - * you, however. - */ - public static final PrintStream out - = new PrintStream(new BufferedOutputStream(new FileOutputStream(FileDescriptor.out)), true); - /** - * The standard output PrintStream. This is assigned at startup and - * starts its life perfectly valid. Although it is marked final, you can - * change it using {@link #setErr(PrintStream)} through some hefty VM magic. - * - * <p>This corresponds to the C stderr and C++ cerr variables, which - * typically output error messages to the screen, but may be used to pipe - * output to other processes or files. That should all be transparent to - * you, however. - */ - public static final PrintStream err - = new PrintStream(new BufferedOutputStream(new FileOutputStream(FileDescriptor.err)), true); - - /** - * A cached copy of the environment variable map. - */ - private static Map<String,String> environmentMap; - - /** - * This class is uninstantiable. - */ - private System() - { - } - - /** - * Set {@link #in} to a new InputStream. This uses some VM magic to change - * a "final" variable, so naturally there is a security check, - * <code>RuntimePermission("setIO")</code>. - * - * @param in the new InputStream - * @throws SecurityException if permission is denied - * @since 1.1 - */ - public static void setIn(InputStream in) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPermission(new RuntimePermission("setIO")); - setIn0(in); - } - - /** - * Set {@link #out} to a new PrintStream. This uses some VM magic to change - * a "final" variable, so naturally there is a security check, - * <code>RuntimePermission("setIO")</code>. - * - * @param out the new PrintStream - * @throws SecurityException if permission is denied - * @since 1.1 - */ - public static void setOut(PrintStream out) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPermission(new RuntimePermission("setIO")); - - setOut0(out); - } - - /** - * Set {@link #err} to a new PrintStream. This uses some VM magic to change - * a "final" variable, so naturally there is a security check, - * <code>RuntimePermission("setIO")</code>. - * - * @param err the new PrintStream - * @throws SecurityException if permission is denied - * @since 1.1 - */ - public static void setErr(PrintStream err) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPermission(new RuntimePermission("setIO")); - setErr0(err); - } - - /** - * Set the current SecurityManager. If a security manager already exists, - * then <code>RuntimePermission("setSecurityManager")</code> is checked - * first. Since this permission is denied by the default security manager, - * setting the security manager is often an irreversible action. - * - * @param sm the new SecurityManager - * @throws SecurityException if permission is denied - */ - public static synchronized void setSecurityManager(SecurityManager sm) - { - // Implementation note: the field lives in SecurityManager because of - // bootstrap initialization issues. This method is synchronized so that - // no other thread changes it to null before this thread makes the change. - if (SecurityManager.current != null) - SecurityManager.current.checkPermission - (new RuntimePermission("setSecurityManager")); - SecurityManager.current = sm; - } - - /** - * Get the current SecurityManager. If the SecurityManager has not been - * set yet, then this method returns null. - * - * @return the current SecurityManager, or null - */ - public static SecurityManager getSecurityManager() - { - return SecurityManager.current; - } - - /** - * Get the current time, measured in the number of milliseconds from the - * beginning of Jan. 1, 1970. This is gathered from the system clock, with - * any attendant incorrectness (it may be timezone dependent). - * - * @return the current time - * @see java.util.Date - */ - public static native long currentTimeMillis(); - - /** - * Get the current time, measured in nanoseconds. The result is as - * precise as possible, and is measured against a fixed epoch. - * However, unlike currentTimeMillis(), the epoch chosen is - * arbitrary and may vary by platform, etc. - * @since 1.5 - */ - public static native long nanoTime(); - - /** - * Copy one array onto another from <code>src[srcStart]</code> ... - * <code>src[srcStart+len-1]</code> to <code>dest[destStart]</code> ... - * <code>dest[destStart+len-1]</code>. First, the arguments are validated: - * neither array may be null, they must be of compatible types, and the - * start and length must fit within both arrays. Then the copying starts, - * and proceeds through increasing slots. If src and dest are the same - * array, this will appear to copy the data to a temporary location first. - * An ArrayStoreException in the middle of copying will leave earlier - * elements copied, but later elements unchanged. - * - * @param src the array to copy elements from - * @param srcStart the starting position in src - * @param dest the array to copy elements to - * @param destStart the starting position in dest - * @param len the number of elements to copy - * @throws NullPointerException if src or dest is null - * @throws ArrayStoreException if src or dest is not an array, if they are - * not compatible array types, or if an incompatible runtime type - * is stored in dest - * @throws IndexOutOfBoundsException if len is negative, or if the start or - * end copy position in either array is out of bounds - */ - public static native void arraycopy(Object src, int srcStart, - Object dest, int destStart, int len); - - /** - * Get a hash code computed by the VM for the Object. This hash code will - * be the same as Object's hashCode() method. It is usually some - * convolution of the pointer to the Object internal to the VM. It - * follows standard hash code rules, in that it will remain the same for a - * given Object for the lifetime of that Object. - * - * @param o the Object to get the hash code for - * @return the VM-dependent hash code for this Object - * @since 1.1 - */ - public static native int identityHashCode(Object o); - - /** - * Get all the system properties at once. A security check may be performed, - * <code>checkPropertiesAccess</code>. Note that a security manager may - * allow getting a single property, but not the entire group. - * - * <p>The required properties include: - * <dl> - * <dt>java.version</dt> <dd>Java version number</dd> - * <dt>java.vendor</dt> <dd>Java vendor specific string</dd> - * <dt>java.vendor.url</dt> <dd>Java vendor URL</dd> - * <dt>java.home</dt> <dd>Java installation directory</dd> - * <dt>java.vm.specification.version</dt> <dd>VM Spec version</dd> - * <dt>java.vm.specification.vendor</dt> <dd>VM Spec vendor</dd> - * <dt>java.vm.specification.name</dt> <dd>VM Spec name</dd> - * <dt>java.vm.version</dt> <dd>VM implementation version</dd> - * <dt>java.vm.vendor</dt> <dd>VM implementation vendor</dd> - * <dt>java.vm.name</dt> <dd>VM implementation name</dd> - * <dt>java.specification.version</dt> <dd>Java Runtime Environment version</dd> - * <dt>java.specification.vendor</dt> <dd>Java Runtime Environment vendor</dd> - * <dt>java.specification.name</dt> <dd>Java Runtime Environment name</dd> - * <dt>java.class.version</dt> <dd>Java class version number</dd> - * <dt>java.class.path</dt> <dd>Java classpath</dd> - * <dt>java.library.path</dt> <dd>Path for finding Java libraries</dd> - * <dt>java.io.tmpdir</dt> <dd>Default temp file path</dd> - * <dt>java.compiler</dt> <dd>Name of JIT to use</dd> - * <dt>java.ext.dirs</dt> <dd>Java extension path</dd> - * <dt>os.name</dt> <dd>Operating System Name</dd> - * <dt>os.arch</dt> <dd>Operating System Architecture</dd> - * <dt>os.version</dt> <dd>Operating System Version</dd> - * <dt>file.separator</dt> <dd>File separator ("/" on Unix)</dd> - * <dt>path.separator</dt> <dd>Path separator (":" on Unix)</dd> - * <dt>line.separator</dt> <dd>Line separator ("\n" on Unix)</dd> - * <dt>user.name</dt> <dd>User account name</dd> - * <dt>user.home</dt> <dd>User home directory</dd> - * <dt>user.dir</dt> <dd>User's current working directory</dd> - * </dl> - * - * In addition, gnu defines several other properties, where ? stands for - * each character in '0' through '9': - * <dl> - * <dt>gnu.classpath.home</dt> <dd>Path to the classpath libraries.</dd> - * <dt>gnu.classpath.version</dt> <dd>Version of the classpath libraries.</dd> - * <dt>gnu.classpath.vm.shortname</dt> <dd>Succinct version of the VM name; - * used for finding property files in file system</dd> - * <dt>gnu.classpath.home.url</dt> <dd> Base URL; used for finding - * property files in file system</dd> - * <dt>gnu.cpu.endian</dt> <dd>big or little</dd> - * <dt>gnu.java.io.encoding_scheme_alias.ISO-8859-?</dt> <dd>8859_?</dd> - * <dt>gnu.java.io.encoding_scheme_alias.iso-8859-?</dt> <dd>8859_?</dd> - * <dt>gnu.java.io.encoding_scheme_alias.iso8859_?</dt> <dd>8859_?</dd> - * <dt>gnu.java.io.encoding_scheme_alias.iso-latin-_?</dt> <dd>8859_?</dd> - * <dt>gnu.java.io.encoding_scheme_alias.latin?</dt> <dd>8859_?</dd> - * <dt>gnu.java.io.encoding_scheme_alias.UTF-8</dt> <dd>UTF8</dd> - * <dt>gnu.java.io.encoding_scheme_alias.utf-8</dt> <dd>UTF8</dd> - * <dt>gnu.java.util.zoneinfo.dir</dt> <dd>Root of zoneinfo tree</dd> - * </dl> - * - * @return the system properties, will never be null - * @throws SecurityException if permission is denied - */ - public static Properties getProperties() - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPropertiesAccess(); - return SystemProperties.getProperties(); - } - - /** - * Set all the system properties at once. A security check may be performed, - * <code>checkPropertiesAccess</code>. Note that a security manager may - * allow setting a single property, but not the entire group. An argument - * of null resets the properties to the startup default. - * - * @param properties the new set of system properties - * @throws SecurityException if permission is denied - */ - public static void setProperties(Properties properties) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPropertiesAccess(); - SystemProperties.setProperties(properties); - } - - /** - * Get a single system property by name. A security check may be performed, - * <code>checkPropertyAccess(key)</code>. - * - * @param key the name of the system property to get - * @return the property, or null if not found - * @throws SecurityException if permission is denied - * @throws NullPointerException if key is null - * @throws IllegalArgumentException if key is "" - */ - public static String getProperty(String key) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPropertyAccess(key); - else if (key.length() == 0) - throw new IllegalArgumentException("key can't be empty"); - return SystemProperties.getProperty(key); - } - - /** - * Get a single system property by name. A security check may be performed, - * <code>checkPropertyAccess(key)</code>. - * - * @param key the name of the system property to get - * @param def the default - * @return the property, or def if not found - * @throws SecurityException if permission is denied - * @throws NullPointerException if key is null - * @throws IllegalArgumentException if key is "" - */ - public static String getProperty(String key, String def) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPropertyAccess(key); - return SystemProperties.getProperty(key, def); - } - - /** - * Set a single system property by name. A security check may be performed, - * <code>checkPropertyAccess(key, "write")</code>. - * - * @param key the name of the system property to set - * @param value the new value - * @return the previous value, or null - * @throws SecurityException if permission is denied - * @throws NullPointerException if key is null - * @throws IllegalArgumentException if key is "" - * @since 1.2 - */ - public static String setProperty(String key, String value) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPermission(new PropertyPermission(key, "write")); - return SystemProperties.setProperty(key, value); - } - - /** - * Remove a single system property by name. A security check may be - * performed, <code>checkPropertyAccess(key, "write")</code>. - * - * @param key the name of the system property to remove - * @return the previous value, or null - * @throws SecurityException if permission is denied - * @throws NullPointerException if key is null - * @throws IllegalArgumentException if key is "" - * @since 1.5 - */ - public static String clearProperty(String key) - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPermission(new PropertyPermission(key, "write")); - // This handles both the null pointer exception and the illegal - // argument exception. - if (key.length() == 0) - throw new IllegalArgumentException("key can't be empty"); - return SystemProperties.remove(key); - } - - /** - * Gets the value of an environment variable. - * - * @param name the name of the environment variable - * @return the string value of the variable or null when the - * environment variable is not defined. - * @throws NullPointerException - * @throws SecurityException if permission is denied - * @since 1.5 - * @specnote This method was deprecated in some JDK releases, but - * was restored in 1.5. - */ - public static String getenv(String name) - { - if (name == null) - throw new NullPointerException(); - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPermission(new RuntimePermission("getenv." + name)); - return getenv0(name); - } - - /** - * <p> - * Returns an unmodifiable view of the system environment variables. - * If the underlying system does not support environment variables, - * an empty map is returned. - * </p> - * <p> - * The returned map is read-only and does not accept queries using - * null keys or values, or those of a type other than <code>String</code>. - * Attempts to modify the map will throw an - * <code>UnsupportedOperationException</code>, while attempts - * to pass in a null value will throw a - * <code>NullPointerException</code>. Types other than <code>String</code> - * throw a <code>ClassCastException</code>. - * </p> - * <p> - * As the returned map is generated using data from the underlying - * platform, it may not comply with the <code>equals()</code> - * and <code>hashCode()</code> contracts. It is also likely that - * the keys of this map will be case-sensitive. - * </p> - * <p> - * Use of this method may require a security check for the - * RuntimePermission "getenv.*". - * </p> - * - * @return a map of the system environment variables. - * @throws SecurityException if the checkPermission method of - * an installed security manager prevents access to - * the system environment variables. - * @since 1.5 - */ - public static Map<String, String> getenv() - { - SecurityManager sm = SecurityManager.current; // Be thread-safe. - if (sm != null) - sm.checkPermission(new RuntimePermission("getenv.*")); - if (environmentMap == null) - { - // List<String> environ = (List<String>)VMSystem.environ(); - // FIXME - List<String> environ = new ArrayList<String>(); - Map<String,String> variables = new EnvironmentMap(); - for (String pair : environ) - { - String[] parts = pair.split("="); - variables.put(parts[0], parts[1]); - } - environmentMap = Collections.unmodifiableMap(variables); - } - return environmentMap; - } - - /** - * Terminate the Virtual Machine. This just calls - * <code>Runtime.getRuntime().exit(status)</code>, and never returns. - * Obviously, a security check is in order, <code>checkExit</code>. - * - * @param status the exit status; by convention non-zero is abnormal - * @throws SecurityException if permission is denied - * @see Runtime#exit(int) - */ - public static void exit(int status) - { - Runtime.getRuntime().exit(status); - } - - /** - * Calls the garbage collector. This is only a hint, and it is up to the - * implementation what this hint suggests, but it usually causes a - * best-effort attempt to reclaim unused memory from discarded objects. - * This calls <code>Runtime.getRuntime().gc()</code>. - * - * @see Runtime#gc() - */ - public static void gc() - { - Runtime.getRuntime().gc(); - } - - /** - * Runs object finalization on pending objects. This is only a hint, and - * it is up to the implementation what this hint suggests, but it usually - * causes a best-effort attempt to run finalizers on all objects ready - * to be reclaimed. This calls - * <code>Runtime.getRuntime().runFinalization()</code>. - * - * @see Runtime#runFinalization() - */ - public static void runFinalization() - { - Runtime.getRuntime().runFinalization(); - } - - /** - * Tell the Runtime whether to run finalization before exiting the - * JVM. This is inherently unsafe in multi-threaded applications, - * since it can force initialization on objects which are still in use - * by live threads, leading to deadlock; therefore this is disabled by - * default. There may be a security check, <code>checkExit(0)</code>. This - * calls <code>Runtime.getRuntime().runFinalizersOnExit()</code>. - * - * @param finalizeOnExit whether to run finalizers on exit - * @throws SecurityException if permission is denied - * @see Runtime#runFinalizersOnExit() - * @since 1.1 - * @deprecated never rely on finalizers to do a clean, thread-safe, - * mop-up from your code - */ - public static void runFinalizersOnExit(boolean finalizeOnExit) - { - Runtime.getRuntime().runFinalizersOnExit(finalizeOnExit); - } - - /** - * Load a code file using its explicit system-dependent filename. A security - * check may be performed, <code>checkLink</code>. This just calls - * <code>Runtime.getRuntime().load(filename)</code>. - * - * <p> - * The library is loaded using the class loader associated with the - * class associated with the invoking method. - * - * @param filename the code file to load - * @throws SecurityException if permission is denied - * @throws UnsatisfiedLinkError if the file cannot be loaded - * @see Runtime#load(String) - */ - public static void load(String filename) - { - Runtime.getRuntime().load(filename); - } - - /** - * Load a library using its explicit system-dependent filename. A security - * check may be performed, <code>checkLink</code>. This just calls - * <code>Runtime.getRuntime().load(filename)</code>. - * - * <p> - * The library is loaded using the class loader associated with the - * class associated with the invoking method. - * - * @param libname the library file to load - * @throws SecurityException if permission is denied - * @throws UnsatisfiedLinkError if the file cannot be loaded - * @see Runtime#load(String) - */ - public static void loadLibrary(String libname) - { - Runtime.getRuntime().loadLibrary(libname); - } - - /** - * Convert a library name to its platform-specific variant. - * - * @param libname the library name, as used in <code>loadLibrary</code> - * @return the platform-specific mangling of the name - * @since 1.2 - */ - public static String mapLibraryName(String libname) - { - // XXX Fix this!!!! - return Runtime.nativeGetLibname("", libname); - } - - /** - * Set {@link #in} to a new InputStream. - * - * @param in the new InputStream - * @see #setIn(InputStream) - */ - private static native void setIn0(InputStream in); - - /** - * Set {@link #out} to a new PrintStream. - * - * @param out the new PrintStream - * @see #setOut(PrintStream) - */ - private static native void setOut0(PrintStream out); - - /** - * Set {@link #err} to a new PrintStream. - * - * @param err the new PrintStream - * @see #setErr(PrintStream) - */ - private static native void setErr0(PrintStream err); - - /** - * Gets the value of an environment variable. - * - * @see #getenv(String) - */ - static native String getenv0(String name); - - /** - * Returns the inherited channel of the VM. - * - * This wraps the inheritedChannel() call of the system's default - * {@link SelectorProvider}. - * - * @return the inherited channel of the VM - * - * @throws IOException If an I/O error occurs - * @throws SecurityException If an installed security manager denies access - * to RuntimePermission("inheritedChannel") - * - * @since 1.5 - */ - public static Channel inheritedChannel() - throws IOException - { - return SelectorProvider.provider().inheritedChannel(); - } - - /** - * This is a specialised <code>Collection</code>, providing - * the necessary provisions for the collections used by the - * environment variable map. Namely, it prevents - * querying anything but <code>String</code>s. - * - * @author Andrew John Hughes (gnu_andrew@member.fsf.org) - */ - private static class EnvironmentCollection - extends AbstractCollection<String> - { - - /** - * The wrapped collection. - */ - protected Collection<String> c; - - /** - * Constructs a new environment collection, which - * wraps the elements of the supplied collection. - * - * @param coll the collection to use as a base for - * this collection. - */ - public EnvironmentCollection(Collection<String> coll) - { - c = coll; - } - - /** - * Blocks queries containing a null object or an object which - * isn't of type <code>String</code>. All other queries - * are forwarded to the underlying collection. - * - * @param obj the object to look for. - * @return true if the object exists in the collection. - * @throws NullPointerException if the specified object is null. - * @throws ClassCastException if the specified object is not a String. - */ - public boolean contains(Object obj) - { - if (obj == null) - throw new - NullPointerException("This collection does not support " + - "null values."); - if (!(obj instanceof String)) - throw new - ClassCastException("This collection only supports Strings."); - return c.contains(obj); - } - - /** - * Blocks queries where the collection contains a null object or - * an object which isn't of type <code>String</code>. All other - * queries are forwarded to the underlying collection. - * - * @param coll the collection of objects to look for. - * @return true if the collection contains all elements in the collection. - * @throws NullPointerException if the collection is null. - * @throws NullPointerException if any collection entry is null. - * @throws ClassCastException if any collection entry is not a String. - */ - public boolean containsAll(Collection<?> coll) - { - for (Object o: coll) - { - if (o == null) - throw new - NullPointerException("This collection does not support " + - "null values."); - if (!(o instanceof String)) - throw new - ClassCastException("This collection only supports Strings."); - } - return c.containsAll(coll); - } - - /** - * This returns an iterator over the map elements, with the - * same provisions as for the collection and underlying map. - * - * @return an iterator over the map elements. - */ - public Iterator<String> iterator() - { - return c.iterator(); - } - - /** - * Blocks the removal of elements from the collection. - * - * @return true if the removal was sucessful. - * @throws NullPointerException if the collection is null. - * @throws NullPointerException if any collection entry is null. - * @throws ClassCastException if any collection entry is not a String. - */ - public boolean remove(Object key) - { - if (key == null) - throw new - NullPointerException("This collection does not support " + - "null values."); - if (!(key instanceof String)) - throw new - ClassCastException("This collection only supports Strings."); - return c.contains(key); - } - - /** - * Blocks the removal of all elements in the specified - * collection from the collection. - * - * @param coll the collection of elements to remove. - * @return true if the elements were removed. - * @throws NullPointerException if the collection is null. - * @throws NullPointerException if any collection entry is null. - * @throws ClassCastException if any collection entry is not a String. - */ - public boolean removeAll(Collection<?> coll) - { - for (Object o: coll) - { - if (o == null) - throw new - NullPointerException("This collection does not support " + - "null values."); - if (!(o instanceof String)) - throw new - ClassCastException("This collection only supports Strings."); - } - return c.removeAll(coll); - } - - /** - * Blocks the retention of all elements in the specified - * collection from the collection. - * - * @param c the collection of elements to retain. - * @return true if the other elements were removed. - * @throws NullPointerException if the collection is null. - * @throws NullPointerException if any collection entry is null. - * @throws ClassCastException if any collection entry is not a String. - */ - public boolean retainAll(Collection<?> coll) - { - for (Object o: coll) - { - if (o == null) - throw new - NullPointerException("This collection does not support " + - "null values."); - if (!(o instanceof String)) - throw new - ClassCastException("This collection only supports Strings."); - } - return c.containsAll(coll); - } - - /** - * This simply calls the same method on the wrapped - * collection. - * - * @return the size of the underlying collection. - */ - public int size() - { - return c.size(); - } - - } // class EnvironmentCollection<String> - - /** - * This is a specialised <code>HashMap</code>, which - * prevents the addition or querying of anything other than - * <code>String</code> objects. - * - * @author Andrew John Hughes (gnu_andrew@member.fsf.org) - */ - static class EnvironmentMap - extends HashMap<String,String> - { - - /** - * Cache the entry set. - */ - private transient Set<Map.Entry<String,String>> entries; - - /** - * Cache the key set. - */ - private transient Set<String> keys; - - /** - * Cache the value collection. - */ - private transient Collection<String> values; - - /** - * Constructs a new empty <code>EnvironmentMap</code>. - */ - EnvironmentMap() - { - super(); - } - - /** - * Constructs a new <code>EnvironmentMap</code> containing - * the contents of the specified map. - * - * @param m the map to be added to this. - * @throws NullPointerException if a key or value is null. - * @throws ClassCastException if a key or value is not a String. - */ - EnvironmentMap(Map<String,String> m) - { - super(m); - } - - /** - * Blocks queries containing a null key or one which is not - * of type <code>String</code>. All other queries - * are forwarded to the superclass. - * - * @param key the key to look for in the map. - * @return true if the key exists in the map. - * @throws NullPointerException if the specified key is null. - */ - public boolean containsKey(Object key) - { - if (key == null) - throw new - NullPointerException("This map does not support null keys."); - if (!(key instanceof String)) - throw new - ClassCastException("This map only allows queries using Strings."); - return super.containsKey(key); - } - - /** - * Blocks queries using a null or non-<code>String</code> value. - * All other queries are forwarded to the superclass. - * - * @param value the value to look for in the map. - * @return true if the value exists in the map. - * @throws NullPointerException if the specified value is null. - */ - public boolean containsValue(Object value) - { - if (value == null) - throw new - NullPointerException("This map does not support null values."); - if (!(value instanceof String)) - throw new - ClassCastException("This map only allows queries using Strings."); - return super.containsValue(value); - } - - /** - * Returns a set view of the map entries, with the same - * provisions as for the underlying map. - * - * @return a set containing the map entries. - */ - public Set<Map.Entry<String,String>> entrySet() - { - if (entries == null) - entries = super.entrySet(); - return entries; - } - - /** - * Blocks queries containing a null or non-<code>String</code> key. - * All other queries are passed on to the superclass. - * - * @param key the key to retrieve the value for. - * @return the value associated with the given key. - * @throws NullPointerException if the specified key is null. - * @throws ClassCastException if the specified key is not a String. - */ - public String get(Object key) - { - if (key == null) - throw new - NullPointerException("This map does not support null keys."); - if (!(key instanceof String)) - throw new - ClassCastException("This map only allows queries using Strings."); - return super.get(key); - } - - /** - * Returns a set view of the keys, with the same - * provisions as for the underlying map. - * - * @return a set containing the keys. - */ - public Set<String> keySet() - { - if (keys == null) - keys = new EnvironmentSet(super.keySet()); - return keys; - } - - /** - * Associates the given key to the given value. If the - * map already contains the key, its value is replaced. - * The map does not accept null keys or values, or keys - * and values not of type {@link String}. - * - * @param key the key to map. - * @param value the value to be mapped. - * @return the previous value of the key, or null if there was no mapping - * @throws NullPointerException if a key or value is null. - * @throws ClassCastException if a key or value is not a String. - */ - public String put(String key, String value) - { - if (key == null) - throw new NullPointerException("A new key is null."); - if (value == null) - throw new NullPointerException("A new value is null."); - if (!(key instanceof String)) - throw new ClassCastException("A new key is not a String."); - if (!(value instanceof String)) - throw new ClassCastException("A new value is not a String."); - return super.put(key, value); - } - - /** - * Removes a key-value pair from the map. The queried key may not - * be null or of a type other than a <code>String</code>. - * - * @param key the key of the entry to remove. - * @return the removed value. - * @throws NullPointerException if the specified key is null. - * @throws ClassCastException if the specified key is not a String. - */ - public String remove(Object key) - { - if (key == null) - throw new - NullPointerException("This map does not support null keys."); - if (!(key instanceof String)) - throw new - ClassCastException("This map only allows queries using Strings."); - return super.remove(key); - } - - /** - * Returns a collection view of the values, with the same - * provisions as for the underlying map. - * - * @return a collection containing the values. - */ - public Collection<String> values() - { - if (values == null) - values = new EnvironmentCollection(super.values()); - return values; - } - - } - - /** - * This is a specialised <code>Set</code>, providing - * the necessary provisions for the collections used by the - * environment variable map. Namely, it prevents - * modifications and the use of queries with null - * or non-<code>String</code> values. - * - * @author Andrew John Hughes (gnu_andrew@member.fsf.org) - */ - private static class EnvironmentSet - extends EnvironmentCollection - implements Set<String> - { - - /** - * Constructs a new environment set, which - * wraps the elements of the supplied set. - * - * @param set the set to use as a base for - * this set. - */ - public EnvironmentSet(Set<String> set) - { - super(set); - } - - /** - * This simply calls the same method on the wrapped - * collection. - * - * @param obj the object to compare with. - * @return true if the two objects are equal. - */ - public boolean equals(Object obj) - { - return c.equals(obj); - } - - /** - * This simply calls the same method on the wrapped - * collection. - * - * @return the hashcode of the collection. - */ - public int hashCode() - { - return c.hashCode(); - } - - } // class EnvironmentSet<String> - -} // class System |