For CPStringBuilder to be able to construct a String without copying its character buffer, it must invoke a package-private String constructor. Currently it achieves this via reflection.
This patch separates out the reflection calls so that VMs may
provide a more efficient way of handling this.
ChangeLog:
2008-03-17 Andrew John Hughes <[EMAIL PROTECTED]>
* gnu/java/lang/CPStringBuilder.java:
Replace reflection code with calls to
VMCPStringBuilder.
* vm/reference/gnu/java/lang/VMCPStringBuilder.java:
Default implementation of constructor call
using reflection.
--
Andrew :)
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Index: gnu/java/lang/CPStringBuilder.java
===================================================================
RCS file: /sources/classpath/classpath/gnu/java/lang/CPStringBuilder.java,v
retrieving revision 1.2
diff -u -3 -p -u -r1.2 CPStringBuilder.java
--- gnu/java/lang/CPStringBuilder.java 1 Mar 2008 12:04:22 -0000 1.2
+++ gnu/java/lang/CPStringBuilder.java 17 Mar 2008 00:06:44 -0000
@@ -38,9 +38,6 @@ exception statement from your version. *
package gnu.java.lang;
-import java.lang.reflect.Constructor;
-import java.lang.reflect.InvocationTargetException;
-
import java.io.Serializable;
/**
@@ -72,30 +69,10 @@ public final class CPStringBuilder
char[] value;
/**
- * The package-private constructor for String objects without copying.
- */
- private static final Constructor<String> cons;
-
- /**
* The default capacity of a buffer.
*/
private static final int DEFAULT_CAPACITY = 16;
- static
- {
- try
- {
- cons = String.class.getDeclaredConstructor(char[].class, Integer.TYPE,
- Integer.TYPE, Boolean.TYPE);
- cons.setAccessible(true);
- }
- catch (NoSuchMethodException e)
- {
- throw (Error)
- new InternalError("Could not get no-copy String constructor").initCause(e);
- }
- }
-
/**
* Create a new CPStringBuilder with default capacity 16.
*/
@@ -1102,25 +1079,7 @@ public final class CPStringBuilder
throw new StringIndexOutOfBoundsException();
if (len == 0)
return "";
- try
- {
- return cons.newInstance(value, beginIndex, len, true);
- }
- catch (InstantiationException e)
- {
- throw (Error)
- new InternalError("Could not instantiate no-copy String constructor").initCause(e);
- }
- catch (IllegalAccessException e)
- {
- throw (Error)
- new InternalError("Could not access no-copy String constructor").initCause(e);
- }
- catch (InvocationTargetException e)
- {
- throw (Error)
- new InternalError("Error calling no-copy String constructor").initCause(e);
- }
+ return VMCPStringBuilder.toString(value, beginIndex, len);
}
/**
@@ -1133,25 +1092,7 @@ public final class CPStringBuilder
*/
public String toString()
{
- try
- {
- return cons.newInstance(value, 0, count, true);
- }
- catch (InstantiationException e)
- {
- throw (Error)
- new InternalError("Could not instantiate no-copy String constructor").initCause(e);
- }
- catch (IllegalAccessException e)
- {
- throw (Error)
- new InternalError("Could not access no-copy String constructor").initCause(e);
- }
- catch (InvocationTargetException e)
- {
- throw (Error)
- new InternalError("Error calling no-copy String constructor").initCause(e);
- }
+ return VMCPStringBuilder.toString(value, 0, count);
}
}
Index: vm/reference/gnu/java/lang/VMCPStringBuilder.java
===================================================================
RCS file: vm/reference/gnu/java/lang/VMCPStringBuilder.java
diff -N vm/reference/gnu/java/lang/VMCPStringBuilder.java
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ vm/reference/gnu/java/lang/VMCPStringBuilder.java 17 Mar 2008 00:06:58 -0000
@@ -0,0 +1,107 @@
+/* VMCPStringBuilder.java -- Growable strings without locking or copying
+ Copyright (C) 2008 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 gnu.java.lang;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+
+/**
+ * This class provides VM support for CPStringBuilder
+ * by allowing the package-private constructor
+ * of java.lang.String to be invoked. The default
+ * implementation uses reflection. VMs may replace
+ * this class with a more efficient version.
+ */
+final class VMCPStringBuilder
+{
+
+ /**
+ * The package-private constructor for String objects without copying.
+ */
+ private static final Constructor<String> cons;
+
+ static
+ {
+ try
+ {
+ cons = String.class.getDeclaredConstructor(char[].class, Integer.TYPE,
+ Integer.TYPE, Boolean.TYPE);
+ cons.setAccessible(true);
+ }
+ catch (NoSuchMethodException e)
+ {
+ throw (Error)
+ new InternalError("Could not get no-copy String constructor").initCause(e);
+ }
+ }
+
+ /**
+ * Convert this <code>StringBuilder</code> to a <code>String</code>. The
+ * String is composed of the characters currently in this StringBuilder. Note
+ * that the result is not a copy, so future modifications to this buffer
+ * do affect the String.
+ *
+ * @param value the buffered characters.
+ * @param startIndex the index at which to start taking characters from the buffer.
+ * @param count the number of characters used in the buffer.
+ * @return the characters in this StringBuilder
+ */
+ public static String toString(char[] value, int startIndex, int count)
+ {
+ try
+ {
+ return cons.newInstance(value, startIndex, count, true);
+ }
+ catch (InstantiationException e)
+ {
+ throw (Error)
+ new InternalError("Could not instantiate no-copy String constructor").initCause(e);
+ }
+ catch (IllegalAccessException e)
+ {
+ throw (Error)
+ new InternalError("Could not access no-copy String constructor").initCause(e);
+ }
+ catch (InvocationTargetException e)
+ {
+ throw (Error)
+ new InternalError("Error calling no-copy String constructor").initCause(e);
+ }
+ }
+
+}
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