| /* Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 java.nio; |
| |
| import org.apache.harmony.luni.platform.PlatformAddress; |
| |
| /** |
| * Helper class for operations on direct ByteBuffer |
| * |
| * @see java.nio.ByteBuffer |
| */ |
| class DirectByteBuffers { |
| |
| /** |
| * Explicitly frees the memory used by the given direct byte buffer. |
| * <p> |
| * If the memory is known to already have been freed then this is a no-op. |
| * Once the memory has been freed then operations requiring access to the |
| * memory will throw an <code>IllegalStateException</code>. |
| * <p> |
| * Note this is is possible that the memory is freed by code that reaches |
| * into the address and explicitly frees it 'beneith' us -- this is bad |
| * form. |
| * |
| * @param directBuffer |
| * the direct byte buffer memory to free |
| * @throws IllegalArgumentException |
| * if the buffer is <code>null</code> or is not a |
| * <em>direct</em> byte buffer. |
| */ |
| public static void free(ByteBuffer directBuffer) { |
| if ((directBuffer == null) || (!directBuffer.isDirect())) { |
| throw new IllegalArgumentException(); |
| } |
| DirectByteBuffer buf = (DirectByteBuffer) directBuffer; |
| buf.free(); |
| } |
| |
| /** |
| * Returns the platform address of the start of this buffer instance. |
| * <em>You must not attempt to free the returned address!!</em> It may not |
| * be an address that was explicitly malloc'ed (i.e. if this buffer is the |
| * result of a split); and it may be memory shared by multiple buffers. |
| * <p> |
| * If you can guarantee that you want to free the underlying memory call the |
| * #free() method on this instance -- generally applications will rely on |
| * the garbage collector to autofree this memory. |
| * |
| * @param directBuffer |
| * the direct byte buffer |
| * @return the effective address of the start of the buffer. |
| * @throws IllegalStateException |
| * if this buffer address is known to have been freed |
| * previously. |
| */ |
| public static PlatformAddress getEffectiveAddress(ByteBuffer directBuffer) { |
| return toDirectBuffer(directBuffer).getEffectiveAddress(); |
| } |
| |
| private static DirectByteBuffer toDirectBuffer(ByteBuffer directBuffer) { |
| if ((directBuffer == null) || (!directBuffer.isDirect())) { |
| throw new IllegalArgumentException(); |
| } |
| return (DirectByteBuffer) directBuffer; |
| } |
| |
| } |