io.sirix.page.PageReference Maven / Gradle / Ivy
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/**
* Copyright (c) 2011, University of Konstanz, Distributed Systems Group All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted
* provided that the following conditions are met: * Redistributions of source code must retain the
* above copyright notice, this list of conditions and the following disclaimer. * Redistributions
* in binary form must reproduce the above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other materials provided with the distribution.
* * Neither the name of the University of Konstanz nor the names of its contributors may be used to
* endorse or promote products derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package io.sirix.page;
import com.google.common.base.MoreObjects;
import org.checkerframework.checker.nullness.qual.Nullable;
import io.sirix.page.interfaces.Page;
import io.sirix.page.interfaces.PageFragmentKey;
import io.sirix.settings.Constants;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
/**
*
* Page reference pointing to a page. This might be on stable storage pointing to the start byte in
* a file, including the length in bytes, and the checksum of the serialized page. Or it might be an
* immediate reference to an in-memory instance of the deserialized page.
*
*/
public final class PageReference {
/** In-memory deserialized page instance. */
private volatile Page page;
/** Key in persistent storage. */
private long key = Constants.NULL_ID_LONG;
/** Log key. */
private int logKey = Constants.NULL_ID_INT;
/** The hash in bytes, generated from the referenced page-fragment. */
private byte[] hashInBytes;
private List pageFragments;
private int hash;
/**
* Default constructor setting up an uninitialized page reference.
*/
public PageReference() {
pageFragments = new ArrayList<>();
}
/**
* Copy constructor.
*
* @param reference {@link PageReference} to copy
*/
public PageReference(final PageReference reference) {
logKey = reference.logKey;
page = reference.page;
key = reference.key;
hashInBytes = reference.hashInBytes;
pageFragments = reference.pageFragments;
hash = reference.hash;
}
/**
* Set in-memory instance of deserialized page.
*
* @param page deserialized page
*/
public void setPage(final @Nullable Page page) {
this.page = page;
}
/**
* Get in-memory instance of deserialized page.
*
* @return in-memory instance of deserialized page
*/
public Page getPage() {
return page;
}
/**
* Get start byte offset in file.
*
* @return start offset in file
*/
public long getKey() {
return key;
}
/**
* Set start byte offset in file.
*
* @param key key of this reference set by the persistent storage
*/
public PageReference setKey(final long key) {
hash = 0;
this.key = key;
return this;
}
/**
* Add a page fragment key.
* @param key the page fragment key to add.
* @return this instance
*/
public PageReference addPageFragment(final PageFragmentKey key) {
pageFragments.add(key);
return this;
}
/**
* Get the page fragments keys.
* @return the page fragments keys
*/
public List getPageFragments() {
return pageFragments;
}
/**
* Set the page fragment keys.
* @param previousPageFragmentKeys the previous page fragment keys to set
* @return this instance
*/
public PageReference setPageFragments(final List previousPageFragmentKeys) {
pageFragments = previousPageFragmentKeys;
return this;
}
/**
* Get in-memory log-key.
*
* @return log key
*/
public int getLogKey() {
return logKey;
}
/**
* Set in-memory log-key.
*
* @param key key of this reference set by the transaction intent log.
* @return this instance
*/
public PageReference setLogKey(final int key) {
hash = 0;
logKey = key;
return this;
}
@Override
public String toString() {
return MoreObjects.toStringHelper(this)
.add("logKey", logKey)
.add("key", key)
.add("page", page)
.add("pageFragments", pageFragments)
.toString();
}
@Override
public int hashCode() {
if (hash == 0) {
hash = Objects.hash(logKey, key);
}
return hash;
}
@Override
public boolean equals(final @Nullable Object other) {
if (other instanceof PageReference otherPageRef) {
return otherPageRef.logKey == logKey && otherPageRef.key == key;
}
return false;
}
public void setHash(byte[] hashInBytes) {
this.hashInBytes = hashInBytes;
}
public byte[] getHash() {
return hashInBytes;
}
}