org.modeshape.jcr.spi.federation.PageKey Maven / Gradle / Ivy
/*
* ModeShape (http://www.modeshape.org)
*
* 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 org.modeshape.jcr.spi.federation;
import org.modeshape.common.util.StringUtil;
/**
* The key used to uniquely identify a page of children. A page key
* is formed by joining together the id of the owning document, the offset of the page and the size of the block.
*
* @author Horia Chiorean ([email protected])
*/
public final class PageKey {
private static final String SEPARATOR = "#";
private final String parentId;
private final String offset;
private final long blockSize;
/**
* Creates a new instance from a raw string, which is expected to contain 3 parts, each representing a piece of information
*
* @param key a {@code non-null} string
* @throws IllegalArgumentException if the string is not correctly formed.
*/
public PageKey( String key ) {
String[] parts = key.split(SEPARATOR);
if (parts.length != 3) {
throw new IllegalArgumentException("Invalid block key string " + key + " . Expected parentId|offset|blockSize");
}
this.parentId = parts[0];
this.offset = parts[1];
try {
this.blockSize = Long.valueOf(parts[2]);
} catch (NumberFormatException e) {
throw new IllegalArgumentException("Block size is not a valid integer: " + parts[2]);
}
}
/**
* Creates a new page key instance passing in each individual page component
*
* @param parentId the id of the parent node; may not be {@code null}
* @param offset the offset of the page withing the total list of children; may not be {@code null}
* @param blockSize the number of children in a page.
*/
public PageKey( String parentId,
String offset,
long blockSize ) {
this.blockSize = blockSize;
this.offset = offset;
this.parentId = parentId;
}
/**
* Creates a new {@link org.modeshape.jcr.spi.federation.PageKey} instance which has the given parent ID and the same
* offset & block size as this page.
* @param parentId a {@link String} representing the ID of the new parent; may not be null.
* @return a new {@link org.modeshape.jcr.spi.federation.PageKey} instance; never null.
*/
public PageKey withParentId(String parentId) {
if (StringUtil.isBlank(parentId)) {
throw new IllegalArgumentException("Parent ID cannot be empty");
}
return new PageKey(parentId, this.offset, this.blockSize);
}
/**
* Returns the size of the block
*
* @return a long value
*/
public long getBlockSize() {
return blockSize;
}
/**
* Returns the offset of the block, which semantically represents a pointer to the start of the block.
*
* @return a {@code non-null} String
*/
public String getOffsetString() {
return offset;
}
/**
* Returns the integer representation of the offset, if the offset is convertible to an integer. Otherwise, {@code null}
* is returned.
*
* @return the int representation of the offset, or null.
*/
public Integer getOffsetInt() {
try {
return Integer.valueOf(offset);
} catch (NumberFormatException e) {
return null;
}
}
/**
* Returns the id of the document which owns the block and effectively the list of children,
*
* @return a {@code non-null} String
*/
public String getParentId() {
return parentId;
}
/**
* Checks if the given string is a valid {@link org.modeshape.jcr.spi.federation.PageKey} format.
* @param string a {@link String} instance; may be null
* @return {@code true} if the string is a valid {@link org.modeshape.jcr.spi.federation.PageKey}, {@code false} otherwise.
*/
public static boolean isValidFormat(String string) {
if (StringUtil.isBlank(string)) {
return false;
}
String[] parts = string.split(SEPARATOR);
if (parts.length != 3) {
return false;
}
try {
Integer.valueOf(parts[1]);
} catch (NumberFormatException e) {
return false;
}
try {
Long.valueOf(parts[2]);
} catch (NumberFormatException e) {
return false;
}
return true;
}
@Override
public String toString() {
final StringBuilder sb = new StringBuilder();
sb.append(parentId).append(SEPARATOR);
sb.append(offset).append(SEPARATOR);
sb.append(blockSize);
return sb.toString();
}
}
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